Whats up, /diy/ I'm in process of building a small, one

>>1167466
Maybe you could try a soft metal seal? They use a copper ring that deforms when you clamp a hatch's harder metal shut on it for some purposes, but it typically requires replacing the copper after each run.

The pressure's going to be on the outside of the sub, so as long as the gasket is rigid enough not to squeeze everywhere, you'll be fine. If you have a pressure chamber of some sort you could run some scale tests. Better yet, if you could control the submarine remotely, even if it's by a cable out the top, your life wouldn't be in any danger, and the sub would probably be fine even in the event of a sudden leak. I say you should be trying to find some sort of marine-grade sealant, maybe even a thick, solid O-ring.

So is it electric or pedal powered? How do you control the buoyancy? And how do you seal the control surface shafts?

I did hear that the Irish used screen doors

>>1167484
Its electric, i have 2 115 ah marine batteries. I'm going to use a minn kota trolling motor as my screw. I'll also have a rudder and elevator. Both of which will be controlled by brushless motors mounted outside the hull. I have 4 10 gallon propane tanks mounted outside the hull to act as ballast tanks. A valve on the inside of the sub will allow water into them. Another propane tank will contain pressurized air to displace the water in the ballast tanks. A small compressor inside the sub will pump up the reserve air tank while on the surface.

>>1167466
You the same guy who posted his thread a few years back?

>>1167466
I would use a hatching mechanism with a nice big o-ring

>>1167494
Maybe, if you're talking about the dive helmet, i asked for advice. But i've moved on to the sub, which has just started to take place. I'll post pics this weekend. I'm at university

>>1167496
I just dont know where to find a 2' diameter o-ring

>>1167484
Aluminum would also work. That is what home pressure canners use for 1000s of cycles. It requires machining of course.

>>1167484
>>1167500
My issue with metal seals is that i'm not sure how i could make one large enough. But also that they would need to be annealed/ replaced after each use

>>1167466

you're gonna die

>>1167466
O-ring def. the best idea, as >>1167484 noted, pressure is working for you, deeper you are, more it seals. Also reusable, one-use gasket is retarded & error-prone - dunno what you using as hatch, but,if possible, have a locking mechanism, cut a groove for the O-ring mount, and keep clean af. That all works, then how well the rest of Das Boot sealed together comes into play, but, first things first.
>>1167498 >dunno where O-ring that big
me neither, but, saf, someone must.
>>1167502
This as well.

>>1167497
Looking forward to the pics
I remember enjoying the dive helmet thread

>>1167510
If all that is needed is a 2 feet o-ring then any rubber v-belt for a car engine will work.

>>1167516
There were a lot of diy dive threads then

>>1167498
The are specialised shops for sealing even in my small nondescript country. Tours probably also. And you can make a o-ring from material from rolls. You glue it so that the long strip magically becomes a ring!

I remember the helmet. Was thinking about it the other day. Good to know that it worked.
With a helmet the bailout it to take it off and swim up. Also small fuckups is okay as the pressure is equal to the ambient in the helmet. Leaks just leak air out.

With your sub water will leak in. I'd consider bailouting to be a top priority. But you might consider different. This project sounds like it's on a completely different scale than the helmet as there are pressure differences and confines spaces that can be water filled in a SHTF-situation. But good luck on this, I think I'll vote for a eventual disaster but its not my ass on the line so whatever.

>>1167466
You are a complete madman and I love you for it. I can confirm that rubber O-rings are the way to go for Scuba diving stuff, but that is much smaller scale. You could try a sort of V-shape, where the pressure will come from the top which will push in something rubber or similar. Remember to use lube to make the seal even better. There are specials lubes for pressure sealing with rubber O- rings. Much smaller diameter, but that stuff works great for keeping in 300 bar of pressure in an air cylinder. How deep do you want to go with it? Any ideas for air supply/CO2 scrubber/oxygen supply?

And if you have pics of the helmet in action that would be awesome!

>>1167466
Don't know if you've seen them, but Cody'sLab has a few videos with his massive vacuum chamber/pressure vessel. If you look for big pressure-vessel O-rings you should get what you're looking for. You might even be able to use the pressure-vessel door as your hatch. Just check that they're rated for the right pressure.

>>1167466
I would say a large precision ground metal surface with a rubber O-ring (giant rubber O-ring).

>>1167608
I dont plan on going deeper than 30'. At that depth, i'll only have to deal with around 15 psi. As for air, i'll just breath the air in the sub. I've calculated that i have an hour and a halfs worth of air before co2 levels become to high. However, i dont plan on staying under for more than 45 minutes at a time. Maybe eventually i'll make a small scrubber and invest in a co2 monitor

>>1167524
Yes, bailing out the top is the plan. I'll definitely get some pictures for you guys this weekend.

>>1167519
Thats a really good idea

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>>1167519
/thread

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>>1167466
Cannot find picks. Drove a water truck some. Had like 10 "bolts" on the truck it is slited and a T shaped bolt swivels up and you use a giant wing nut and just cinch it down in 10 spots. We had a gasked on one and rights stuff on the other. Neither ever leaked. Sorry for sgit explanation. Will try and find better pics. Good luck not dying.

>>1167497
DO IT OP!!!!

>>1167497
That dive helmat work good? Does it fog up?

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>>1167498
DIY? Maybe?? Never tried but seems easy enough. Especially if you ground a small grove in the sub for this to set in.

http://www.theoringstore.com/index.php?main_page=index&cPath=117&zenid=cc15602d9d8946b7ffb9e1043e4ea5b7

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>>1167502
(You)

>>1167689
It does work really well. A garden hose connects to the top and feeds air from 2 12v compressors running off a marine battery.

It does fog up a little. However, the water line is righ below your chin, so its easy to suck up some water and spit it on the glass to defog

>>1167519
Seems like its not quite squishy enough. If u are in US i can send you some used 2-5 ply conveyor belting. I would bet money a custom or home made O-ring would be cheaper tho. The shit is fucking heavy and shipping would kill.

That being said though i maybe could organize a free delivery to a truck stop near an interstate within the month?

>>1167691
I didnt know anyone made that. I think this is what i'll go with. I found some that is .75" diameter.

>>1167695
Thanks, anon. I'll probably just go with the o ring cord. You a trucker? My grandpa owns a trucking company in WV

>>1167524
Ohhhh shit. Maybe electric actuator? Can lift 200 pounds. Should be plenty. Push button hatch with emergency manual pin or something?

For sure want a reserve emergencu dive tank in there with u OP

>>1167608
We should post on /biz. If you can get through the sea of unending shitcoiner proxies there are some guys in dive school

>>1167610
Mayne weld a large pressure cooker to the top? I have an aluminum one i can probably fit my head it.

Giant vaccumn chamber. Relevant to my interests.

>>1167610
Top fucking kek anon. I have been hunting for a propane tank to do large epoxy resin runs. I hear a heat gun works well but they say vaccumn chamber is master race. And if i am making burlwood epoxy resin gun stock blanks at $200 each just for epoxy and wtf ever i pay my autistic bro to go hunt burls i want master race 100 gallon or more vacumn chamber.

And OP, the fucking swivel bokts in pic and vud related were wtf i was trying to say. For the lid tho just weld on oversized nuts or drill the threads out so they dont catch.

Obviously u gotta do it from the inside somehow or we can get hold of some navy fags and see how the real submarines do it with the big wheel and screw.

>>1167632
Shit anon. If u only going 30 feet deploy a small floatie with an air fikter to keeo shit out of it. Run a small vent fan to circulate good air from time to time or suck on the hose if you screen both sides.

>>1167466
https://www.youtube.com/watch?v=GYiSXHZvZFc
op this is your head, inside that thing,with plexy cuting though your face

>>1167708
Without the hose being pressurized by a compressor, it would quickly collapse. Even at shallow depth

>>1167716
How silly. Dive helmets are pressurized via an air hose and compressor on the surface. Therefore, the helmet feels no pressure.

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>>1167692
You know OP, if it becomes more trouble than it is worth you could strap scuba gear to your dive helm and make a gay looking scooter. Then nothing but your head needs water proofed.

As insanely fucking stupid as pic related looks the functionality seems legit. Maybe u could buy or build a mini bike chopper frame or something so some poor scuba diver doesnt look up and see a massive faggot on a yellow scooter buzzing around.

Glad to see someone around here actually finishes oprojects around here at any rate.

I am building lithium packs soon. Will build u packs at cost if u like but i cant promise it wont burn your house down so...

>>1167694
Kek. Nice. I hear u need ro be carefuk with compressors as some produce carbon dioxide. But i'm sure you are fine. I hear they make an anti fog spray coating but i don't know anything about it. Also, after a bit that garden hose might taste like shit. Highly recomend expensive ass "flexzilla" 5/8 garden hose.

But, sounds like u get along just fine.

Is this hobby related or u trying to dredge for gold or something?

>>1167697
Yeah i didnt eaither. My dads an uneducated genious. I swear to fuck he could put a man on mars with a $300 budget and a welder.

Let me know how it works out. If i csn buy/build a vacumn pump for my VW motor or 10hp electric motor i am building a vacumn chamber out of a reinforced 200 gallon orooane tank. Gonna need a giant manhole that is air tight.

>>1167698
Mah, i used to drive reefer for Central Refrigerated out of Utah. Got an online friend who made a trucker fb page and it sort of exploded. Long Hauling Bandits. Like 8,000 of us get on there and shitpost and trade shipping shit.

I will be in Tulsa Oklahoma soon. In theory i could throw that belting in the weeds behind the flying J and then somone could snag it on the way by and get it to a truck stop near you. Kind of a clusterfuck of a deal but hey, free shipping is free shipping.

>>1167734
Mostly just a hobby. I can see lake erie out my kitchen window. She becons for undersea adventures

>>1167739
That's hilarious. You should check out sv seeker while you're in tulsa. Thats always been a dream of mine

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>>1167716
People autisrically screach and make pallet shit. DIY bitches.

OP wanna buikd a fucking submarine. Autistic screaching...


Sigh.

Good luck OP.

Bonus points for water proof led fog lights.

https://youtu.be/JsoE4F2Pb20

>>1167718
Hrmmm. Use a hydraulic hose then?

>>1167741
Fucking badass. I work at a rock quarry in Kansas. Clearest water around me. Can see less than 1 foot...

Honestly been looking into pool filters and shit. I wanna filter it and make a 20 foot crystal clear dive pit but it isnt mine and i cant manage to filter millions of gallons of watter effeciently.

>>1167742
Mfw. Watching the vid of him casting props promted me to buikd a trailer mounted foundry.

MFW i have been trying to get my hands on a junk pontoon boat to mount a 4.6 liter v8 crown vic on top of...

Buikding dreams from litteral junk is my life anon. Hell, i drove to work today in a 43 year old limo i drove out of the junk yard.

For sure will cruise by this boat.

>>1167750
You seem like my kind of guy. Everything i have ever build has been from junk. Partly cause i'm poor, but functional things made from trash makes it that much cooler

Get yourself some caterpillar valve cover gasket. It's a rope seal sold by the foot or meter so you can shape it any way you want, it'll hold in hot oil, and it's easy to replace. Just contact pretty much any heavy duty truck dealership and ask for it. If you have a cat dealer in your area even better.

>>1167752
Yup. Grew up in a trailer park. Dad is pretty handy and we were poor but always had a house full of food since mom babysat. Gas was cheap and we always had dirtbikes and gocarts and shit. We wantes a swingset. Old chains and blown structual tubung. Wanted a mary go round like the park has. 2 days latter dad has 4 boat seays bolted to a car rim and the front hub from a junk car cemented in the ground. Wanted monkey bars. Blown tubing and pumo tubes.

We had shit just like the rich kids for fucking free or a 6 pack. Lol.

Guess i kinda ran with it. I make more money that i ever have and still have a yard full of lawnmowers and shit.

Gonna male it real easy to invest and get rich. Over half my paycheck goes into forcing aporeciation of shitty rental houses.

I will be the crazy old drunk millionaire in town building dune buggies and shit out of crashed corvettes.

>>1167742
>>1167750
I was about to say this, man I wish I could visit them too. Boy does it suck to live on the other side of the world. Great thread btw.

>>1167702
Lol /biz/ is so retarded. I would love to see someone start a submarine / underwater coffin business

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>>1167725
>massive faggot on a yellow scooter buzzing around

I lost my shit

>>1167466
what are you using for the Hull? an oversized propane tank?

>>1167993
The hull is an old boiler. 2' diameter and 5' long. The conning tower that ones head will stick up through is made of an old air compressor tank. Also 2' diameter

>>1168000
>2' diameter
How's the underwater coffin coming along?

Also not sure if it matters as long as your centre of buoyancy is above your centre of mass, but will you get the motor torquing your sub if you don't have two contro-rotating screws?

>>1168138
I guess we'll have to find out. If so, I'll probably add some kind of ailerons to controll roll

>>1167741
Do you live in Derby or something? Or are you canadian? I live in Hamburg OP

>>1167489
Actually it was the Italians. You could tell because whenever you closed one it would go "Wop!"

>>1168287
I live in ohio. I have no knowledge of your leaf towns

>>1167694
Are you sure the air coming out of the compressors is safe to breathe?

>>1168413
I have an oil/ water trap installed

>>1167986
>>1168313
It is yellow so the rescue divers can find your body easier.

>>1168288
Actually it was the polish

>>1168313
>barrel rolls
You know it's gravity that keeps the air in the helmet, right? It's like doing a barrel roll in a spitfire where the centripetal force from the tight turn keeps your fuel flowing, except you're doing 2 miles an hour underwater in some faggot sea-scoot.

>>1168430
Yellow it is then!

>>1168660
That's why hold breath is.

>>1168423

oil traps meant for no fucking up your paint job, aren't anything close to oil traps meant for breathing air.

fwiw.

>>1168713
Sucky sucky me cocky. There definitely is. Its an oil trap specifically made for filtering breathing air. Large paint booths use them to breath air while spraying inside a paint booth. I got them for free cause i know a guy who works for sherwin williams

>>1168315
How do you leafs pronounce Derby? I'm in Derby UK and we say Darby

i'm doing the same actually, I only need the propeller now...7 year project

>>1168768
post pics or stfu

>>1168773
Same goes for OP...

>>1168773
>>1168780
I'm on my way home from university right now. Should i post pics here or start an "under the sea" general thread?

>>1168797
Meh, if op doesnt care this thread is already near the top so id post here

>>1168768
Dude. Like $10 at walmart for troller motor parts in the boat section.

>>1168800
I am OP. I'll post here i suppose. I just bought a bunch of angle grinder blades for this weekends work

>>1168766
US.

Durby

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OP here, gonna post a few photos. This first one is the hull. Its mounted on an axle and has a hitch for ease of transportation. The propane tanks you see will be ballast tanks. The hole in the top is for the "conning tower" that your torso/ head will stick up through.

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>>1168836
A second angle.
Ps. How can i keep my pictures from rotating when i upload them?

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>>1168838
Finally, this is what i will be using for the conning tower. The top will be cut off and used as a hatch

>>1168836
>>1168838
>>1168839
honestly, this could work.

i've seen similar set ups for amateur submarines.

>>1168840
Fuck yeah it'll work, you really think i would cabbage patch this shit? I'm not a hack

>>1168841
do you have access to a machine shop? the seal on this bitch is going to have to be pretty tightly toleranced. 30' is actually quite a bit of pressure.

>>1168842
I do not have acess to a machine shop. I'm sure i can get it mated properly with just my grinder. I ordered some o ring material that is 3/4 inch thick, so that should help.

>>1168846
>I'm sure i can get it mated properly with just my grinder.

ehhh, if you set up a really tight jig maybe. what you are talking about doing is like trying to resurface an engine head with a grinder.

remember, even though you are only planning on going 30' you should design for a pressure of 60'.

you could probably be a bit sloppy if you made a fuck huge flange for your hatch/conning tower connection.

what kind of mechanism are you planning on using for the latch?

>>1168848
I was planning on installing a flange. I dont see how 1/4 inch +/- will matter when the compressable, rubber o ring will be nearly an inch thick. I'm making my own hinch mechanism

>>1168852
>>1168852
>I dont see how 1/4 inch +/- will matter when the compressable, rubber o ring will be nearly an inch thick.

water finds a way. your o-ring mate isn't going to be absolutely perfect and your flange should be doing most of the "sealing". the o-ring is just there as a bit extra. i'd try for at least +/- 1/16 in your flange mate.

is your hatch design going to include a mechanical assist? you are going to need it in case you need to evacuate under water.

>>1168860
I'd like it to, but i have yet to come up with a mechanism

>>1168865
>I'd like it to
it's not a like, its a need. unless you are the fuckin' hulk, you aren't going to be able to open that hatch underwater (unless your vessel is already completely flooded) without a mechanical assist.

i guess a way around this is to have a scuttle valve that intentionally floods the vessel and a small scuba tank on hand in case of emergencies.

>>1168868
Lets settle down a bit. I understand the implications of not having mechanical assist. I was also thinking about having a valve in the top as it is already threaded for one.

>>1168873
>Lets settle down a bit.
don't you tell me to settle down faggot.

enjoy your aqua coffin

What you guys don't realize about OP's venture is that he's talking about doing this on lake Erie. Sure it's a Great Lake and all, but it's about like a kiddie pool for depth. If OP goes down (like the faggot he is) while playing seaman (heh heh, faggot), all he'll have to do to not drown is stand up.

>>1168886
Enjoy your tendies

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Cutting the hatch off

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Got the hatch off. I might get rained out for the day

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>>1168852
Here is how the o-ring is supposed to seal. It needs a groove and those can be tricky.

>>1168860
An evac method would be to attach airbags to the outside of the craft. Got a car yard nearby?

>>1168933
I was planning on making a groove with a router

>>1168945
That is a pretty good idea. Do you know if they can survive under water? And also, dont they deflate fairly quickly?

>>1168956
>>1168956
you'd be better off attaching a pressurized air tank to your ballast and blowing the water out the way real subs do.

>>1168933
>Here is how the o-ring is supposed to seal
Fucking doubt it, groove should be slightly wider but shorter than the oring so its compressed to increase the contract area on the sealing face.

>>1168958
Thats what i'm planning on doing. I'm talking about in case of a failure. I'm already going to install drop ballasts.

>>1168971
Be careful amd get pressure regulator. Consider light weight composite fire and rescue shit. I got 4 rescue air tabks free because they were out dated and the fire chief is a bro. He nor.ally tosses shit like thst and i funnel a case of water or 10 bucks to the slush fund for shit like this normally.

>>1168945
Co2 self inflating rafts?

>>1168896
The "deep spot" in a local lake is 15 feet. I lost a $100 trying to swim accross it. Got tired half way back and went to tred water and catch my breath. Fucking stood uo and walked back....

>>1168840
I watched a documentery on cuban coke smuglers building subs feom fibergkass amd trash to cart shit up river. Its fucking hilarious

>>1168838
U cant because 4chan is cucked and fucking stupid. It just happens sometimes. You coukd pre rotate it if it happens a lot but i get like 1 in 10 so then 90% woukd be fucked

>>1167466
anyone else ever wonder how many /diy/ers died while doing?

>>1167718
Use a vacuum hose

>>1169169
>vacuum hose
Those things can't hold anywhere close to an atm of pressure, and every 10m underwater is another atmosphere of pressure.

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Currently drilling holes in the bottom of the ballast tanks to let water in... if anybody still cares.

Anybody got any name suggestions? I cant wait to take this bitch to the homemade vessel inspection to get it registered.

>>1169449
The LPG Lungfish? The lake is only 64m deep at max, so if you can seal against at least 6.4atm of pressure you'll be golden, and it's not too much of a task provided your O-ring is good enough. You said you'd purchased some O-ring material? I'm a little concerned whether the seam between each side (glued I hope) will be able to hold nearly as much pressure as the rest of the ring. I was sure you'd be able to buy 24" diameter complete O-rings, but good luck all the same.

I'm guessing you'll have two holes leading into the ballast tanks, one for compressed air in and one for water in/out. The compressed air will need to be at a higher pressure than the water around you, so >15psi for 10m, or >95psi for the full 64m. Since a propane tank can hold >300psi, you should be fine. If the control valves are all manual valves in front of you then even if you run out of battery power you'll be able to surface.

It would be cool if you had explosive bolts to decouple the ballast tanks.

>>1169183
then steel pipe

>>1169497
The tops of the ballast tanks are threaded. Blackpipe will connect them all and then run into the hull. The bottom of the tanks are open to the water and turning a valve inside the hull will allow air to bubble out the top while water fills from the bottom.

>>1169516
I'd personally have the tanks all seperate, so if your weight is a little too far forward or to one side you can make the correction. How is the valve at the top of the ballast tanks controlled, through electricity? You going to put windows on it?

>>1169449
The Massive Yellow Faggot ofc
All in favor say aye

>>1169524
It will have at least one window. Small, 1" thick plexiglass. As for the valve, it will be a ball valve inside the sub. The pipes will run inside the hull of the sub after they conjoin. Then back outside the sub

>>1167466
How deep you do plan on going exactly?

>>1169005
Kek!

>>1169671
Erie is shallow, but he could still get in trouble. Average depth is 62', max is 210', according to Google. I'm guessing visibility is probably shit, too. If he goes all the way to Canada he could have some 'splainin' to do as well.

>>1169678
Welp. Good luck OP. Stay safe

>>1169678
Doesn't the Canada-US border cut halfway across the lake? Will OP be arrested by a coastguard/sea border patrol ship with sonar?

>>1169721
It does kind of cut the lake in half. I'm thinking it's 30 miles or so at the narrowest, so he'd have to go at least 15 miles to get to Canada. That's a long way at the speeds he'd be traveling. Especially since he'll die anyway.

>>1169727
Assuming he's at the far end. OP might be one of these >>1169008 contraband runners after all. Don't get caught smuggling microagressions into Canada!

>>1167492
Lead acid batteries? Do not do. Stupid to put those in a sealed chamber which you will be occupying.

>>1169766
I'd rather be in a sealed container with a couple of trusty lead acids than a Li-Ion. Assuming OP has SLA batteries and not unsealed ones. You worried about acid vapours?

>>1169773
Acid leakage and hydrogen vapors are a possibility. Lead acids and li-ions are not the only options either. I would rather use NiCad or AGM batteries than marine lead acids, sealed lead acid being another possibility.

>>1169782
SLA is almost certainly the cheapest way to go, and I think all marine batteries are sealed anyway. Vapour pressure of H2SO4 is measured in single ppm and it boils at >°C so you shouldn't have much to worry about there, but I'm not sure what kind of effect hydrogen gas buildup would have on the submarine or its occupant. I'd just seal the batteries in their own container with some monitoring circuitry on in there to check battery voltage, current, temperature, and pressure relative to the cabin.

It would be good to have 2 pressure dials, one for external pressure relative to internal, and one for internal pressure relative to 1atm. Though maybe having a dial that measures external pressure relative to 1atm would also be useful, though it does provide redundant data.

OP should keep a little solar panel to drive the compressor/trolling motor when surfaced, not sure of the wattage requirements of either, could get expensive and a waste of space.

>>1169809
>but I'm not sure what kind of effect hydrogen gas buildup would have on the submarine or its occupant.
Hmm, I wonder what hydrogen gas in an enclosed space with operating electric motors which may or may not all be brushless could do.

>>1169602
Aye!

>>1169809
Also a personal locator beacon so when OP doesn't return from his maiden voyage his family doesn't have to wait long for his remains.

>>1169834
The motor is external, it's a standard trolling motor. Not sure what else in the way of electronics OP will have in the cabin, but if he seals the battery box and replaces the air in it with CO2 or N2 he should be fine.

>>1170116
If your submarine did suddenly let 64m of water pressure into your submarine, would you be able to survive by putting on scuba gear? Chances are OP's sub is going to be compressed somewhat by the water pressure and be somewhere in between the 1atm on the surface and the 7.4atm at the bottom anyway, it would be interesting to see how much it compresses and run the calculations on how deep you could go before the internal pressure reaches maximum human survivability.

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>>1168836

Are you adding an Emergency Surface/Blow system? It would be highly advisable.

https://en.wikipedia.org/wiki/Emergency_main_ballast_tank_blow

>>1170276
Not OP but how would that be done differently to the standard ballast tank "aeration"?

>>1170262
>If your submarine did suddenly let 64m of water pressure into your submarine, would you be able to survive by putting on scuba gear?
No. And it is incredibly unlikely that OP's sub would not be crushed well before that, I highly doubt it could take more than 3atm of pressure.

>>1167466
Passes OP 20 feet under the surface an giant yellow Fagmobile doing barrel rolls laughing my drunk as off.

>>1169449
HAHAHA! fucking do it. And if they say no call them cucks. They will never find u

>>1169721
Autism induced international incident.

Op please paint Pepe on it holding up a piece sign for when u cause a CNN seizure

>>1170262
He had best have a phone in there for livestream his death or arrest by based Canadians.

>>1170300
You have a backup system with its own completely independent systems and, ideally its own ballast tanks in case the normal ones are damaged.

Additionally, a system whereby enough ballast to make the boat positively buoyant even without the ballast tanks that can be released manually would be a very good idea. Taking a step further, for any serious dives, having the release on a failsafe whereby power failure drops the ballast (i.e. a hopper of steel ball bearings with an electromagnet around the aperture, holding them back) would greatly enhance safety.

>>1170432
Forgot to add: you should definitely trial several full pressure emergency blows and check the entire system for ice, frosting formation in the HP air system from gaseous expansion is what killed the Thresher.

>CTRL+F lego
>No result
How has nobody noticed OP's helmet looks like a lego figure head?

>>1170509
Oh i did. Funny as shit when people paint grill tanks

>>1170433
Shit. Yeah op u gonna need an air dryer. They sell 12v in line ones.

>>1170276
Yes, i plan on adding several emergency back up. Including drop ballasts.

>>1170433
>>1170521
OP here, this is good stuff to consider. Thanks.

>>1170570
Might consider diy. I think they are kinda high. Check out the lowrider forums for the guus with air bag setups.

>>1170570
Oh hey, might consider piping in an old radiator or a few heater cores and pumps. Under water might be okay but i rode in the trunk of a car for instant sweat lodge.

Fuckit just stay 10 foot under it should be fine.

>>1170643
Cover the bottom your submarine with peltier devices just in case you happen to be in direct sunlight on the surface for too long. Maybe consider painting the top of the sub white to reflect sunlight and not absorb it, but it won't be camouflaged enough for smuggling pepes at that point.

>>1170930
kek that's a dumb suggestion
Peltier devices are very inefficient, his battery capacity won't be sufficient to power a peltier powered air conditioner

>>1171800
Peltier powered ac. TOPKEK.

that being said i saw a guy online bolt a bunch to his wood stove and power a 12 volt fog light. Supper fucking inneficeint

>>1170930
Also op. Bring a cardboard box and wrap up a bunch of powdered sugar and pictures of pepe. So if u gmdo get caught in canada u are our hero for causing an international incident smuggling pepes.

I will be you sidekick and be charged with inciting a riot wesring a pepe mask.

>>1172250
I'll smuggle pepes and untaxed maple syrup

>>1168836
you my hero op. I had the same goal this year w no budget. at least I'm getting my degree. I'm starting my own sub this summer. will post.

>>1172374
Smuggle corn syrup in maple syrup bottles, they'll love that.

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>>1167466

Sup fellow aqua bro. I would try to talk you into a dry ambient sub but it sounds like you have your heart set on 1atm.

If you really don't mind the extra difficulty and expense, go for it, but there is a lot you will need to learn about life support. The life support system for a dry ambient sub is just a slowly leaking bank of scuba cylinders, the excess bubbles out carrying CO2 with it.

The life support for a "real" 1atm sub is essentially a rebreather. Rebreathers are very complicated. Here is an example of a dry ambient sub and an explanation of what makes them cheaper and simpler to build: http://www.submarineboat.com/dry_ambient.htm

>>1172554
>>1172551
I'm sorry, deleting posts on 4chan never made sense.

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>>1172611

It was just this pic. Similarly named but not the one I intended. People have been building their own diving gear for a long time, it's a sweet hobby.

This just goes to show that unlike space, the underwater world is within reach of regular people. Not just anybody, it does take ingenuity, but not billions of dollars.

I fully expect undersea homesteading to become a thing in my lifetime

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You cut an LP tank...?

Are you aware that cylinders are not good at remaining uncrushed under pressure that is coming from the exterior?

>>1173974

Why are submarine hulls cylindrical?

>>1173974
While it is true that the cylinder is a naturally stable form for holding in high pressure, all sections designed to hold in pressure are astable in that way. Circular sections are still the most effective forms to keep pressure out of a vessel, and are some of the least unstable. And it would hardly be a hassle to weld in a couple of cross-braces or supporting rings if the walls happen to be too thin. Besides, no more than 7atm pressure max, and that's if OP's sub loses all buoyancy in the middle of the lake. The walls do look a bit thin for any deep lake diving, so I would recommend a healthy bit of bracing.

Does anybody know how difficult it would be to blow the form of an ambient pressure submarine out of glass? Because that would be the shit!

>>1167492
>trolling motor as my screw
This

>>1172884
>I fully expect undersea homesteading to become a thing in my lifetime
Put down the kush buddy

>>1173979
I don't see why you think similar shape means good at the same thing.

A rifle barrel and a piece of conduit are the same shape too.

>>1174194
THIS THREAD. SO MUCH WIN.

>>1173980
Use that thick ass lexan like on the aquarium show Tanked

>>1172554
Watterproof phone inawater shitpoosting when!

>>1172540
Top fuckung kek i love it when greentext is made real

>>1172374
Top fugging kek anon.

>>1167466
Cut the ring from a old agricultural tire tube,one 18.4x38 should give you 2 flat rubber seals you can rivit and silicone onto you door or sub.

>>1174517
Tire tubes are neither buna-n nor silicone, and the pressure that standard tube rubber is meant to hold is barely enough for OP's plans in a best case scenario. I wouldn't trust tubes at 5m, let alone at 64.

RIP in peace OP

sick iron coffin though

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Sub-Anon here. Currently cleaning the rust out of the inside. I got all the fittings and pipe I need for the ballast tank. Once the rust is cleaned out and the pipes are welded, the insode will get some paint. Also, i found a little chair for it.

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>>1174786
Its pretty comfy desu, senpai

Have you considered taking video step-by-step of your build? If your sub works you might be able to pay for your time in pageviews. just sayin

>>1174786
Walmart sells a cheap shitty sand blaster. Just fyi

>>1174798
THIS.

SUBANON IS OUR GUY

>>1174819
>>1174798
I did a little bit, then i stopped cause i didnt think anybody would care. I will if you guys want me to

>>1174817
I was using acid. It works pretty well

>>1167466

F

>>1174833
if you pull this off and post some vids you will forever be a meme on /diy/. you can join bunker bro in the halls of maker valhalla.

even if you don't pull it off and die, it will still be great to read about you on the news.

>>1172554
Have you done any more psychedelics underwater?

>>1170570
For an emergency ascent device you could rig up a couple of modified airbags to inflate at the push of a button

>>1173955
>Let all the gas out
>take the valve off
>fill with water to displace any propane
>cut

>>1170276
>>1170433
>Emergency blow
OP might want to consider a chunk of jettisonable ballast for emergency use instead (or in addition). I'm sure it'd be simpler and more reliable.

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>>1174194

An Italian diving club built 4 undersea habitats in 2007 for 1.4 million in total. Three of them were two person living/sleeping spaces, the fourth was a shared common area with amenities like hot water for cooking and hydrating food.

https://www.youtube.com/watch?v=EE0vVje7vMY

1.4 mil for a 6 man setup may seem like a lot, but the ISS houses 6 people typically and cost 150 billion, with a b. That's over 100,000 times the cost.

>>1174873

I am more into caves lately:

https://steemit.com/psychedelics/@alexbeyman/psychedelics-tripping-in-an-underground-cave-system-aka-psychogeonautics

>>1174954
Anon, what the actual fuck?

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>>1174990

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>>1174954

Im afraid to type that into my browser.

>>1174222

Water is an extremely good radiation shield. That includes cell phone transmissions. The signal would vanish after just a few feet, maybe one depending on distance to the nearest tower.

The only kind of radio that goes any useful length in water is ELF, or "extreme low frequency". The long, stretched out and low profile sine wave does not strike water molecules as easily but it is also too low bandwidth for anything except morse code or SMS.

>>1175144
A human is a 1/2 foot of water, I never notice a worse signal when standing in a crowd. Water is a good frequency absorber, but that's talking 10s of metres at least. While I know ELF is used exclusively for underwater and underground communications, I can't seem to find a low frequency guide to water RF absorption. All the diagrams only go down to cm waves at the smallest, showing the IR, visible, and UV spectra and nothing else. It would be nice to see a more complete picture of this.

I wonder how easy it is to get total internal reflection with radio waves? Judging by pic related, the index of refraction peaks in the range of 10 in the 10m range, so damn your cellphone signal would not get out of any water at any more than 5° to the normal (vertical), assuming the index of air doesn't change similarly.

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>>1175169
Pic actually related.

How do you plan to reinflate the ballast tanks? A quality compressor will add weight (but your making this out of steel so it's probably negligible) and require quite a bit of power. I would stick a handcrank on it just incase of electrical failure.

>>1175233
A pressurized tank that is pressurized by a small compressor while on the surface

>>1175169
>I never notice a worse signal when standing in a crowd.
There are base stations all around you, particularly in places where large crowds are common. The signal strength indicator on your phone also covers a huge range, which makes the extra attenuation more difficult to notice.

>I wonder how easy it is to get total internal reflection with radio waves?
Optics-like (quasi-optics) approaches are pretty common at millimeter waves.

>It would be nice to see a more complete picture of this.
You would probably have better luck with searching (complex) dielectric constant vs. frequency graphs.

>>1167466
Wouldn't the helmet be able to take more pressure if the "viewholes" were round instead of square? I thought pressure would build up more around the corners. Kinda the reason why airplanes don't have square windows.

dude you're fucking talanted

>>1170300

You use a different air tank that is designated for the purpose, with higher pressure air.

>>1175903
You are right, but that helmet is only supposed to match the outside pressure. The window doesn't need to handle pressure, only be water tight

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>/underwatercoffingeneral/

Don't leave any mysteries. Add a slab with a name and birthdate, leave a empty part to fill in later.

>>1177692
Bumping underwater coffin thread. I got faith in you OP. But there is no bad way this can go for your fans here. Coffin or pepe smuggling machine u win.

>>1179123
You mean WE win, unless OP's goal is to become a meme whether he dies or not. If that is your goal however, godspeed.

God speed op, im new to /diy but I support your becoming a meme, I wish you luck or at the very least a sudden and near spontaneous death underwater in your coffin

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>>1168836
>>1167466

... daily reminder that pressure vessels are meant to keep pressure IN and not out.
That compressor tank and propane tank are meant to keep pressure inside the tank.

When you go down underwater they will crumple and crush you inside of it.

>>1180031
See >>1173980

>>1180031
You are wrong, a pressure vessel can withstand pressure going either way. Also your example is of a non pressure tank under a vacuum

>>1167466
OP please visit a channel on youtube called SVseeker.
The guy has build at least two subs and is now in process of making chinese junkboat in his back yard.
He has ton of useful info.

>>1180088
See >>1167742

>>1180083
Nowhere near the same amount, though.

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>>1180031
If everyone listened to shit like you we would never have interesting things to see on the news.

https://www.youtube.com/watch?v=bSIICuJvsIk

These guys builded one out of bathtubes, but vid lingo is in Yuro

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Plumbing for the ballast tanks are going in this weekend. I didnt realize how much of a cunt threading shit HD pipe could be.

>>1180392
>that rust
Better paint that shit when you're done. Are the wheels staying attached, or are they just a carriage? I think it might be fun to drive along the surface of the lake, assuming it isn't a muddy shithole down there.

>>1180392
Als have you done any rudimentary buoyancy calculations to see if your craft will float when all the tanks are full of air and sink when all the tanks are full of water? By the looks of things it will float in both cases, which is fine because it just means you need extra ballast on the outside, which gives you the freedom to make it detachable in the case of an emergency. If you dump the dimensions and weights of the rig and the stuff to go in it I could run the numbers for you.

Just running some ballpark figures, (assuming your compartment volume is 1m^3, total ballast tank volume is 0.1m^3) it looks like your submarine will weigh 100kg extra when the ballast tanks are full as opposed to empty. Since the total volume of your submarine was estimated to be 1.1m^3, you'd be displacing 1100kg of water, and thus would need 1050kg of submarine weight so you'll float when the tanks are full of air and sink when the tanks are full of water, which is pretty nuts. I'd advise going for bigger ballast tanks to make this mess;y 100kg difference bigger, but that also means a bigger compressed air cylinder in with you. The mass of air, ambient pressure or otherwise, makes barely 70kg of difference over the depth of the lake so it probably isn't worth putting too much thought into. If my numbers are off please tell me.

>>1180392
>>1180465
speaking of rust, did you attempt to inspect the interior of those gas bottles? How are they? I guess they don't get moisture like a compressor tank so maybe not so bad...

>>1180486
I have done the calculations. I have 40 gallons of ballast tanks, giving me about 320 lbs of buyancy. I know the volume of the sub hull. I plan on weighing the whole thing at the local feed mill that has a drive on scale. Once i do that, i'll know how much weight i'll need to add based on the buyancy calculated from the volume of the hull. Exclude the volume of the ballast tanks. I plan on adding weight in the form of railroad track and lead to the bottom of the hull. Based on my calculations, i'll probably need anywhere from 500-700 lbs of extra ballast weight. I wont know untill its all together and put on the scale.

>>1180486
>>1180840
Btw, the volume of the hull will be roughly 22.5 cubic feet, minus the volume of a human.

>>1180465
>>1180493
The wheels will stay attached. I plan on trailering this bitch around down the road with my truck. It has a hitch atgached to the front that will also stay attached. The bottom of erie is sand. You can walk on it. I've done so in my dive helmet.

All the rust is surface rust. The inside of the tanks are clean.

>>1167497

how did you affix the glass/what type of screen is that?

>>1180845
The material is plexiglass. It was bent with a heatgun. It is affixed using just bolts and nuts, with a sealant of clear silicon.

>>1180847

did you use any technique to ensure airtightness? how was it held when processed like that?

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>>1180848
I just heald it in my hand, you dont have to get it very hot to bend it. It is airtight. But that isnt much of a concern in a pressurized diving apparatus regardless. If there is a leak, air just bubbles out of it. It wont fill with water. There an upclose pic of the seal

>>1167466
Scuba diver and Engineer here. I thought about dong this several years ago, had a general design worked out but never went through with it. Ok, couple of things here to keep in mind:
1) You said something about 15 psi at 30 feet... It's double that. You're under 14.7 psi on the surface, and an _additional_ 14.7 psi every 32 feet of depth in freshwater so you're pretty close to 30 psi.
2) Putting the coning tower on top like that has one major problem; if failure occurs it will press the tower straight down into the cabin. In my design I had the same overall shape, however I ran the tower/cylinder all the way down to the floor for structural strength, and cut a "U" shape out fore and aft for cabin access.
3) As for a seal on the top hatch, consider a flange design with 2 flat surfaces. Any hard flat rubber strip will seal fine, as the pressure actually helps seal as you dive. If you check out other DIY subs, they typically just use a few small c-clamps to hold it down, once you're more than a few feet down you don't even need them any more.
4) Probably the biggest problem...weight! Floating is easy, the hardest thing to deal with in DIY subs is the (relatively) massive amount of weight need to dive. Taking a SWAG at it, your sub may well end up being in the 4-6000 lb range... not something that you easily tow behind your Ford Ranger. That's why you don't typically see external ballast tanks on subs, it makes them too heavy.
Edit: Just saw where you said the internal volume is only 22.5 ft^3...seems awfully low. At 3' diameter by 6' long you're at 42.4 ft^3...

Good luck OP. Don't die.

>>1180888
You fail to take i to account that while the psi at the surface is 14.7 psi, there is no pressure difference. Thats why we feel no pressure. At the surface, the outside of the sub and inside of the sub have the same pressure. Therefore the pressure felt is zero. So at 30', the inside of the sub is at 15 psi (the pressure at the surface) and outside the sub is 30. So you subtract the two to get a net pressure of 15 psi pushing inwards.

>>1180912
I didn't fail to take it into account, I chose not to express it that way. You're absolutely correct in the pressure _difference_ being 15ish psi, it's just not how I'm used to referring to it. It's a minor technicality that likely makes little difference in reality, I just wanted to make sure that he was aware of the difference.

>>1180915
Right, so the technical fact is irrelevant. A vessel made to wistand 16 psi will survive at a depth of 30'. If you take a psi guage to 30' underwater, it will read 15 psi. Everything is zeroed to atmospheric pressure.

I know someone who forges aluminum

>>1180840
Sounds about right. I'd advise using the extra weight for structural reasons as opposed to dead weight, especially with the conning tower like engineer-anon suggested, but make sure the centre of mass remains below the centre of buoyancy at all times. Don't want to go upside-down, do you?

>>1180888
Pretty sure it's less than 3' wide, looked more like 2'4" to me. That gives about 26 ft^3, or about 3/4 m^3. Plus the conning tower and you'll probably be looking at 35 ft^3 or 1m^3.

You also need to take into account that the air inside the ballast tanks is at ambient pressure, not 15psi. This means as you go deeper the volume of air in your tanks will decrease, making you descend faster. I don't think it's easy if even possible to acquire a stable equilibrium depth without some sort of feedback. Over the depths you're talking about it doesn't matter very much, but it's still something to take into account.

>>1180850
So is it like a lexan material or are you using regular plexiglass. I would personally be more inclined to trust lexan with my life over plexiglass.

>>1181278
Its just plexiglass, the original dive helmets were made of just leather. Since you're at pressure, the helmet feels no pressure.

>>1180888
Fucking bump for love of thos board and the people here.
Mostly nohomo

>>1167610
A second nod for Cody'slab.
Everyone here should be aware of him.

>>1181395
He the dude with the giant vacumn chamber?

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Op here, pressure testing the ballast system before it all gets tied together. No leaks, gonna hold it at 100psi for a few hours to make sure it doesnt drop at all.

>>1173979
Subs aren't completely cylindrical, but their shape makes it harder for enemies to find them.
They require huge internal superstructures to withstand pressure however.

>>1175169
They use swimming pools to store radioactive waste, water is an excellent radiation insulator.
Every 7cm of water reduces the detectable level of gamma radiation from a source in half.

Phone signals probably aren't as strongly dampened by water but a few meters will probably block it.
The reason why your phone works in a crowd is because the signals go above your head, not horizontally through the crowd.

>>1182010
Those are the holes in the bottom of the tanks? How quickly does water drain through them when you pump air in? Also 100psi isn't enough for anything deeper than 7m, you should be able go up to 10 times that if you want to get buoyancy from the bottom of the lake, or 300psi if you want to get buoyancy from 20m down. Of course your tanks don't need to be able to support that kind of pressure difference, as the relative pressure between their inside and outside will always be 0, but you need your source tank to hold quite a lot of air at higher pressure than the surrounding water.

Technically you could use some sort of collapsible external source tank that takes pressure from the outside and use a small pump to send that air into the tanks, but it would take up a lot of room at the surface since it would pretty much be a massive weather balloon. A better way to do this would be to get a small weather balloon and put it within your source tank (not sure how you'd do that) and put many small holes in the source tank connected to the outside.

>>1182016
This is mostly wrong. Submarines typically take a tubular shape because drag underwater is a big problem. Lower frontal area = less drag. Slower civilian submarines take a more spherical shape because it's stronger and they don't go as fast. A tubular shape still gets many of the strength benefits that a sphere does, there's a reason they build sausage-subs instead of teardrop-subs. I agree that OP would definitely need some internal reinforcements if he descends any decent depth, but he isn't going more than 20m under. No more than 70m at the max. And I imagine a good deal of safe testing is possible such as:
>not being in the sub
>having semi-connected braces that noticeably take up load when the external pressure is too great
>instant floatation
>scuba gear and patience
>a big pressure chamber full of water and the submarine
>actual engineering calculations
>meme magic

Good luck!

>>1182200
I'm wondering where exactly these numbers are coming from. Apparently you must have some
>actual engineering calculations
That elude the common folk. Even at 10m, a 100 psi storage tank would be more than pressurized to blow the ballast. The ballast tanks will only be at 15 psi. See, what actually matters is not only psi in the tank, but the size of the tank. At 10m, if one could theoretically have a storage tank of 500 gallons pressurized to 15.5 psi, it would be plenty to blow the ballast. Have you forgot the gas laws? P1V1=P2V2. You seem like an insufferable little cunt that seems to feel entitled by his bachelors degree. Your little pee pee probably gets rock hard everytime you use a calculator; for it makes you superior. You're assuming OP is an idiot. I bet you dont even drive 5 over the speed limit you boot licking little faggot!
>Actual Engineering
>Pulling random integers from his tight little asshole

>>1182236
Shit, I think I had an extra factor of 10 in there. I'm from a British colony, so I'm always converting to and from metric when I talk to people on /diy/, who happen to be mostly Americans. Maybe instead of flags we could just have unit systems next to our posts.

Alright:
10m_water = 1bar = 1atm = 15psi
64m_water = 6.4bar = 6.4atm = 96psi

You are absolutely correct, my bad. I don't actually have my bachelors yet, and I'm not up to speed on thermodynamics because I haven't studied it in more than a semester. My degree is in physics because I couldn't get into engineering at my country's best uni.

The perforated balloon-tank™ would actually work well for this application. Say you've compressed your balloon-tank up to 60psi. While you're above 40m depth you've still got higher relative pressure in the tank than the outside, so that pressure alone is enough to force air out of the tank and into the ballasts. But once you get below 40m of water, instead of creating a negative relative pressure trying to suck water from the ballasts back into the storage tank, the balloon contracts and stays at ambient pressure, so you barely need any force in what could easily be a hand-pump to inflate the ballasts. Of course your storage tank would need to be similar in size to your ballasts, which probably isn't normal for a low-depth sub. You could even pump the ballasts back again instead of letting that air go to waste. Wait that's doing no work at all, isn't it? Same mass of air taking up the same volume regardless.

So OP, what pressure will your storage tank be at? 300psi is liquid propane storage-tier, and is probably a safe bet. But since P1V1 ≈ P2V2, if you plan on going 10m down you'll be able to fill up your ballast tanks with about 10x the volume of your storage tank. Since you've got 4 ballast tanks, I hope your storage tank is at least the size of one of your ballasts, otherwise you won't get many cycles. Preferably >2x bigger.

>>1182241
OP here, i'm debating on using a mini compressor to pressurize the the storage tank to about 100 psi. I dont plan on going deeper than 10m. I'm also tossing around the idea of using propane for the ballast tank. It is stored at well over 100 psi and is in a liquid form. Therefore, that pressure would be consistent all day as long as there is still liquid in the tank.

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>>1182241
To continue, if you do plan on going the full 64m down without having to dump weight to get up again, a 300psi tank would need to have more than 1/3 the volume of the ballasts, which is pretty big, and that's only one cycle. Of course you're not going to be pumping quite the whole ballast system full to ascend, it should require less than that.

Now pic related is important. Depth "d" is the maximum depth you can go before your ballast tanks even when full of air do not have enough buoyancy to get you going upwards. Since when you go deeper the air in your ballast tanks increases in pressure, it becomes more dense, until the net density of your submarine is greater than water. It's not like you won't have detachable weights, but it's still a bad idea to get to this point. If your ballast tanks are too small then the two lines "full" and "empty" will be too close together and limit the maximum depth. You can translate them up and down by changing (increasing) the weight of your sea craft, but you can only move them further apart by increasing tank volume. By the looks of things you should be fine. I'm currently working on the maths to figure out how big of a ballast tank you need, but it might take a bit.

Theoretically the maximum depth you can go with ambient-pressure air like this is 8.3km below the surface, which is 5/6 of the way down the Mariana Trench.

>>1182243
Propane might be a good idea by ease of use, but it is twice as dense as air.

>>1182264
Oops, the full density should stay constant.

>>1182264
Thats good to know, how exactly would i go about calculating that depth for my particular size sub?

>>1182264
I imagine my hull would crush long before i reached that depth. I have about 36 gallons worth of ballast tanks.

>>1182392
Before you go on your final voyage you should do a test run. Put the contraption on a rope and lower it to a pressure of (approximate estimated max depth)*X where X is your safety factor.

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BAMP

>>1182403
Definitely going to do safety tests. Just working out how exactly i'm going to go about it. Flooding and pumping the ballasts wont be an issue from outside the sub. The issue is the location. Preferably, i would test it in a large pond on my property. However, getting it in and out of the water may be an issue. The bank is soft and steep. I'm woried it may sink in. I know i could pull it out with my equipment, but it may destroy the grass/ bank. The other option is lake erie. But the water rarely is suitible for such a small vessel. I may build some kind of 2x6 ramps.

>>1182511
Yeah. Skid it on ramps or pay ~250 for a load of 2 or 3 inch base rock or 2inch clean and make u a boat ramp.

>>1182527
The thing is going to weigh a a lot. I think i'm going to use peices of rr track for ballast.

>>1182371
>>1182392
I tried to derive an equation for the minimum size of ballast for a submarine to be able to go down to 64m and back up again (10m should be a piece of cake regardless), but it told me I needed less ballast when going deeper than when going shallower, and I could get away with no ballast to go down to 8323m, the point at which air becomes as dense as water. I obviously need to rework this equation.

If anybody else wants a go (SI units):
density of air = 0.12*depth + 1.2
density of water = 1000

And from there you've got to figure out whether the water inside the ballast tank counts as mass or surroundings. I don't really get it. It's like when Cody's Lab measured the mass of polystyrene packing peanuts to be different in a vacuum than in the atmosphere; that kind of practical air pressure dynamics goes over my head.

I hope you've got some way to tow the submarine.

>>1182640
Ballast tanks count as surroundings. Ballast tanks dont sink you. They only float you.

>>1182649
That's good to know.

>>1182640
Its mounted on an axle with wheels btw

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>>1167501
0.060 Indium wire

>>1182709
>Indium
Wow that's only $200 worth of metal that you may well have to replace, great idea.

>>1182741
Well it works very well and in a sub if things don't work well you drown.

>>1182989
Better than an O-ring or two?

>>1183075
Yes, unless the o-ring is very expensive.

>>1180031
came here to post this

File: IMG_6576.jpg (2MB, 3264x2448px) Image search: [Google]

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Welding up the ballast system. Once this is done, work on the conning tower can commence

>>1184334
And here I was wondering if the thread would die, thanks for keeping us updated. Is the air storage tank going to be mounted externally?

>>1180031
Fun fact: Space launch vehicle fuel tanks are proportionally thinner than soda cans.

>>1184334
Looking more and more professional. I'm getting more confident that your gonna survive.

>>1180031
yeah man, every fucking time I drain my compressor i gotta get a new tank cos it shits itself.

Also, they never let me swap my empty gas bottles, they always say they're too crumpled.

>>1184448
That's pressure from inside, not from outside.
>>1184486
When you drain your LPG tanks you drain them down to 1 atm, the same as outside, not to a relative negative pressure, so there's no net force on the outside of the tank. Not that it means a pressure tank can't handle an internal vacuum.

An oil tanker will definitely crumple under a hundred kPa like that, but a pressure-rated LPG tank will not. OP stated that the hull is made from a boiler, and the tower from an air compressor, both of which should be rated for multiple atmospheres of internal pressure. With only one additional atmosphere of pressure at 10m submersion, I'm pretty sure OP will be fine, especially with all the metal pipes crossing through the hull. But I'd make sure to put a good bead of weld on either side of the tower connection, and around the concave base.

>>1184334
Maybe some redundancy on the ballasts. Now they are connected. If one catastrophically fails then all will fail. If you hit the bottom hard for example. That might bend the pipe and the fittings could leak.

Hey I just realised that since you only want to go down 10m, you could just test the thing by pulling a vacuum on it. 30ft under water is about 14psi of differential pressure, the same as atmospheric pressure without any pressure pushing back from inside. A 5% (5kPa) vacuum should be close enough to test it, but I'd go down to 1% (1kPa) if possible. If it doesn't implode, dent, or leak significantly after a day under vacuum, you should be good to go.

>>1184334
When do you reckon you'll start the conning tower?

>>1184660
But then you can't test for the safety factor. Whatever that might be.

>>1184849
It's a lot better than nothing, and easier than an unmanned wet test.

Out of curiosity rather than having to flood those propane tanks all the way have you considered hanging some solid ballast under the sub that you could in an emergency release allowing your sub to be positively bouyant?

>>1184996
(Not op) That was something they were considering but it seems like this will be a pretty shallow water sub (10m <)

>>1184996
>>1185010
He'll need a lot of solid ballast anyways, because a sub needs to weigh its volume in water to descend. There's no real reason not to install emergency detachable ballast aside from reliability. I'm thinking the way to go is some sort of cable system, but you'd have to rig up a few pulleys about the craft.

After thinking about airbags for a bit, I realised that the pressure needed to inflate them at 20m+ down would be enough to burst the bags near the surface, if they didn't leak for whatever reason.

I just hope OP has some way of measuring his depth. I guess a hydraulic pressure gauge will do? How do you measure internal pressure?

Stop with the airbag suggestions.
Airbags have huge holes in them. They inflate in 30-40 milliseconds, and deflate in 60-70 milliseconds.

>>1184426
Op here, most likely due to the size constraints of the hull.

>>1184480
Thanks

>>1184639
My back up in case of a failure in the ballast tanks consist of drop ballast weights.

>>1184660
Thats my current plan, stan. Now, where to get a cheap vacuum pump. Anyone know if a converted refrigerator compressor will work?

>>1184838
Probably later this week. Over the next few days i'll finish up the final work on the ballast system. Coping that shit should prove fun.

>>1185664
http://www.instructables.com/id/Making-A-Fridge-Compressor-Into-A-Vacuum-Pump/

>>1185670
NOICE

>>1185656
Is the inside go the hull really that packed? The more volume your sub has on the outside the more solid ballast you'll need.

>>1185661
Have you found a way of detaching the solid ballast yet? I thought maybe you could have them tied by cables to metal pegs inserted snugly in metal pipes which are hooked up via valve to the storage tank. This way you'd blow out the pipes in an emergency and the ballast would drop. It's hardly an ideal solution though because it would be hard to make sure all the pegs would blow out at once, so I'll keep thinking on that.

Ideally you'd have them automatically detach if you sink too deep, which with enough pressure gauge stuff would be possible, but how to use compressed air to release a thousand pounds of steel is the biggest hurdle here. Electricity might be easier, running a couple of electromagnets on either side of the rail(s) with springs to pull them away once the power is cut, but you'd be wasting quite a bit of power constantly. At least it would detach automatically if you run out of juice. Any mechanical connection through the hull wouldn't work (easily), so you're pretty much limited to wires or air pipes. Pic related is my two best ideas, where hitting lower air pressure than the outside triggers the left one, and hitting low battery triggers the other. Of course it would be somewhat easy to trigger them manually.

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>>1185797
Actually pic related.

>>1174954
Helly yeah, I go caving all the time. Not sure if I'm ready to be tripping in one just yet though

>>1185819
Where about do you go caving? Do you do it with personal friends or as part of a caving organisation? I've been on a few of the more technical tours and have been looking for a more independent experience, but caving's not terribly big where I live apart from the odd tourist attraction.

>>1180083
Not really. A pressure vessel that's internally-pressurized is under tension and thus stable, while one containing a vacuum is under compression and may buckle if inadequately braced.

You wouldn't expect a rope that can hold 500 pounds in tension to be able to push 500 pounds of compression, would you?

>>1182709
Aren't indium o rings only useful for cryogenic purposes due to its cold welding properties?

>>1185851
I'm with a club in NSW, Australia. Where I am, being in a club isn't too necessary because are lot of caves are publicly accessible but borrowing gear and being able to access caves on private land is a bonus + like minded people.

>>1167524
Remember to breathe out as you ascend or your lungs will inflate with the pressure drop and you'll tear your insides

>>1185853
Ever pulled a vacuum on a propane tank? people do it all the time for redneck vacuum chambers. Just look at ElectroBoom's tesla coil in a (partial) vacuum under a GLASS dome. Pressure is additive not multiplicative, so partial vacuum of a less than a psi of absolute pressure is easily close enough.

>>1185885
They got limestone or marble there? I'm across the river in New Zealand and can either go to the tourist caves in central/north of the North Island, or somewhere way down south where the pros go, and I'm too wrapped up in student expenses to go down there at the moment, and my uni doesn't even have a caving club. I wish I lived near caves.

>>1185959
Redneck propane tank vaccumb chamber big enough for a car.

....soon.

I have motors. I need a vacume pump that could quickly pull vaccumn on a 1 car garage sixed tank.

Any ideas?

>>1185664
>>1185670
>>1185694
A windowshaker AC compressor is better. A little bigger. I have two that I use as vacuum pumps for automotive AC repair and other stuff.

>>1185959
A propane tank is designed to handle a duty load of about 10 atmospheres of internal pressure and is required to have a burst rating of around 70 atmospheres. Withstanding a single atmosphere of external pressure is VERY modest by comparison. I guarantee you it will crush under anything close to it's rated internal pressure, let alone it's burst pressure.

>>1186140
I'd trust one to handle a couple of atmospheres of internal pressure, but sure their external pressure capacity is definitely less than their internal pressure capacity.

>>1186035
How the hell are you going to seal it? Also I'm interested because I want a space car. AC compressors >>1186090 sound ok, and looking online + ballpark values gives me around 2-6 hours to pump down a garage, but that's assuming your compressor is continuously geared down for lower and lower pressures to be at maximum efficiency. Either way, I can't see it being more than 3* my estimations. The 6 hours is for a compressor ~2.8kW one, and the 2 hours is for a ~12kW one.

File: ring-stiffened shell buckling.jpg (159KB, 750x509px) Image search: [Google]

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>>1186185
>>1186140
I suppose it's worth mentioning that a bit of bracing/stiffening with rings and possibly stringers could make a tremendous difference in the buckling, crush depth and all-around safety of the pressure hull. These stiffeners don't need to take on the compressive load directly, all they need to do is brace the shell walls from buckling. Big submarines sort of have this innately due to the extensive internal bulkheads and compartments, but with a pressure hull this small, it'd probably be easier to put the stiffeners on the exterior (or between the pressure hull and light hull, if applicable).

I didn't look into it too deeply but "shell buckling" seems to turn up a lot of relevant information on google.

>>1185797
>>1185798
Op here. I plan on casting the drop ballast weights out of lead. To release them, i'll cut a hole in the botom of the sub and weld a nut over the hole. A bolt will seal the hole (with a lot of thread tape). The bottom of the bolt will stick out the bottom of the sub and have arms welded to it. Spining that bolt will spin the arms and release the weights. I can post a drawing later.

Here an interesting question for everyone: How can I run electrical wires from through the hall and seal the hole? JB weld? JB+Silicon?

>>1167734
Scuba diver here, Rub spit on the inside of your mask/helmet to prevent fog. Yes, I'm serious, it works better than the anti-fog spray.

>>1185959
The caves I go to are all limestone

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>>1186301
Can agree. If OP has enough pipes going through the sub it might work somewhat like this, but I'd wager that uneven bracings are worse than no bracings.

>>1186334
Ah, that's a great idea. I'm not sure if threading tape or thick grease is the way to go with the bolt, you might want to cut a specially low-clearance thread. Maybe welding a small cylinder to the floor of the sub for the non-threaded part of the bolt to stick into with a few O-rings around it could probably help if it doesn't seal properly, something like pic related.

Now when it comes to wires, I don't think silicone will seal any better than the JB-Weld itself. I guess just put the wires through the smallest hole possible. Ideally you'd use some kind of pressure-proof plug so you can unplug the motor/lights or whatever else you have, and I don't think it would be hard to make something like that, as long as you use the water pressure to help seal it. A couple of little metal hemispheres with an O-ring in between should do it, probably with some internal pegs for alignment, which should probably be the terminal itself. Something like pic related.

Are you grounding the hull? I'm not sure the protocol when it comes to boats, let alone submarines, but surely nothing bad would happen if you used the hull for the negative terminal.

>>1168836
>>1168838
>>1168839
that corrosion doesnt look very uniform op. be careful of stress corrosion cracking especially if your going into a lake that they dump shit into/lots of boats. u gonna put a coating on it?

>>1186459
Pretty sure it's going to be hella camouflaged so he can smuggle corn syrup in maple syrup bottles into Canada.

>>1186451
I dont plan on grounding the hull

OP, you should keep that helmet on you in case your hull starts to leak. How many minutes of air can that thing hold anyways?

>>1167466
Can we call you Scuba Steve?

>be me
>be fishing ona boat
>see what apears to be a large propane tank break the surfice
>OP pops the top and quietly tosses me a bottle of maple syrup. >says it is the best
>come morning male pancakes while trying to tell of what happened
>get friends and family to finally believe me.
>the children are laughing, havibg a good time
>bist out the worlds greatest maple syrup from bottom lake dwelling stranger
>its corn syrup

>>1188744
I need this.

to the top?

>>1189999
unrelated but nice quads dude
also god speed op, be sure to keep us updated, im rooting for you senpai

>>1190319
I'm sure he'll make us a new thread in a week or two.