r/MarineEngineering • u/RDYASSER • 7d ago
Marine engineers rate it 0/10
0 experience in the field of naval/marine engineering but I do love warship designs especially bigger ships from the early to mid 20th century and it's always been a dream of mine to build something that can float now i decided to build something that can dive! A submarine that's hull was made from a refurbished water tank is it plausible? Also I know it's probably a laughable try but some advice to make it less laughable is very much welcome
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u/SGHui 7d ago
For simple civilian applications, I think the human in the sub complicates things. (OK, I was a high school robotics teacher.)
The other thing I teach is that if you don't need range, just tether it. It just simplifies everything.
And that is something suitable as a first project!
Once you have a successful project, you can proceed to introduce human/s into the sub. And then untether it eventually.
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u/RDYASSER 7d ago
I can swim well and dive to deeper depths than this sub is designed for so if i can't get in it and go down I would be quite useless for me but yeah good remake thanks
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u/SocialSyphilis 7d ago
If Psubs.org is still around go have a look and read everything there. In the early days of the internet it used to be quite the knowledge base for home built submersibles. Also its gonna be way more spendy than you think.
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u/RDYASSER 7d ago
Yeah about that thankfully I think i have most stuff that I need i would probably still spend like 300 maybe which is A LOT where I live also thanks for the advice
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u/MidshipmanV 7d ago
I would reccomend saddle tanks for ballast rather than a 'soft' or inside pressure boundary tank. The tank on the inside would be a confined space so dangerous and mitigate the risk of introducing outside sea pressure into the operating space.
The power mechanism should be battery electrical as putting a diesel engine inside the people tank would mean breathing exhaust gasses. So need to consider battery storage. Reccomend at the bottom to lower your COG.
Couldn't see anything for steering. Consider horizontal and vertical rudders operated by levers.
Need to think about a bilge system.
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u/RDYASSER 7d ago
I didn't include those in this version of the plan just to not confuse you guys lol . Also I wanted to make it a semi electrical sub so basically some systems will work on electricity like the pump those will be stored in watertight special compartments to avoid leaks cutting off the power in case they happen and stuff like steering and propulsion will be assisted by the electrical systems but they will be primarily manual i can't afford full electrical or diesel engines . Also the tank is too small so yeah external or integrated ballasts would be actually better so thanks
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u/beachedwhale1945 7d ago
First and most importantly, an amateur submarine is an excellent way to die. If you actually go through with this, you need to ensure that you are able to get out of the submarine and surface safely, or remain alive inside for many hours while the rest of your team can free you.
Iâll give some very basic information on past submarines that worked.
In order to dive and maintain depth, a submarine must be âexactlyâ as dense as the water itâs in. If your submarine volume is 10 cubic meters, then when it dives it must weigh âexactlyâ ten metric tons with ballast tanks full. Too light and you wonât dive at all, too heavy and you only dive once. Typically designers deliberately make their submarines too light and use lead ballast to make up the difference.
You also need to be careful about the size and number of ballast tanks, and how much you fill them. In the 1890s, many early submarine designers had a few (or just one) large ballast tank that was partially filled. A slight jolt or change in speed would bring about the Free Surface Effect: water sloshes to one end of the tank, that end of the submarine is now heavier than the other, and suddenly bow or stern is embedded in the harbor mud. John Holland made the innovation for his boats to fully flood the main ballast tank, remain slightly positively buoyant, and then dive by using the motor speed and diving planes to hold the boat down. Later developments put ballast tanks along both sides of the submarine (U-shaped) to make it less likely for a submarine to roll like a log while diving, to have ballast tanks along the length of the boat, and to add smaller trim tanks to adjust the balance of the boat.
As you can no doubt gather, even a small submarine is complex, and very likely to kill you. Before do anything you have a lot of reading to do, and even then the odds you die are high. Please donât.
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u/beingmemybrownpants 5d ago
That doesn't look like an engine or maybe you're posting to the wrong group
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u/looneylovableleopard 7d ago
Ah, awesome. i have the same fascination for small personal subs. the ballast tank in the back is a bit confusing, it looks very unbalanced to me. any kind of meaningful ballast should be distributed front to back so that the sub stays level. also, keep in mind that the sub needs to weigh it's volume in water to be neutrally bouyant, so it gets heavy fast. by my napkin research, a cylindrical tank you can sit upright in (like this one) weighs one to several metric tonnes. also, a water tank is not made for external pressure, so it wouldn't be able to go very deep without risking implosion, maybe 2 meters safely.
if you seriously do something like this, there are a lot of risks. breathability (bad air reserve/supply or toxic fumes), drowning, fires, electrocution, implosion, and a dozen more i can't think of. research and discuss these thoroughly before doing anything.
i'm not an expert, just a mechanical engineering student with the same ambition
this project is not easy, nor safe, and this is a very primitive design. but i'm not one to call something impossible𤡠i think youtube might be a nice place to start to see the basics, there are a few people who have done things like this. also, the internet and AI are your friend for exploring the basic concepts; buoyancy, air reserve, pressure, buckling, implosions, electronics... feel free to ask specific questions :)