building a submarine

[king of nowhere]

they say we know the moon better than the bottom of the oceans.

so, i decided i wanted to explore the oceans. and once i have the vehicle ready, i want to explore laythe and eve oceans too.

this requires a submarine, of course. and i would like it as close to neutrally buoyant as possible, so i don't have to compensate for it rising or sinking all the time.

well, here comes the first problem. i can't make anything that sink. i experimented on kerbin oceans trying to use the densest pieces i could see. mostly i tried using RTGs, they contain uranium and they are shielded with lead, this should sink, right? wrong. well, one of them does sink, all right, but even strapping 20 rtg to a single hecs2 probe with a cupola on top, the thing floated with the cupola completely out of the water! so, clearly not enough. in other news, i have used half a million in nuclear piles as ballast. that should count as an achievement of some sort.

So, problem 1) i need something that i can use as ballast.

then i need propulsion. and here we come at problem 2) i can't make a propeller that works. i already asked about it previously, but i didn't got any useful answer, so i'm asking again. neither for boats, nor for helicopters. i tried everything i could conceive, but no way of turning the helixes seem to generate any amount of upward force. and this is very frustrating; optimizing a ship design to overcome its limitations is entertaining, but attaching a rotor with some aerodinamic surfaces to a command module and having the thing not work, with no idea why it does not work since in reality it would work and the pieces you are using are made specifically for that purpose...that's horrible. like "uninstall the game, give it a schating recension, and never, ever buy anything from the same producers ever again" kind of horrible, if i wasn't already hooked on the rocketry part. but then, i've already done rockets to go in all the places without atmosphere, so turning to boats and helicopters to explore what's left is the logical choice.

i've also seen youtube videos o'f people making boats and submarines, and i can't see how their propellers are done any different than mine, except those propellers work.

 

so, i'm hoping someone can help me figure out how to make a boat that sinks, or a propeller that works, or at least a helicopter.

[bewing]

A) Ore tanks full of ore are extremely negatively buoyant. That's what everyone uses as ballast for submarines.

B) Kerbals are smarter than us, and their jet engines work underwater. Propellers? Bah. Try wheesleys.

[king of nowhere]

jet engines use fuel. the rover would come with a maximum range. even if i strapped a convert-o-tron on it, it would increase weight greatly, and would require long pauses for refueling. and i'd still be screwed if i run out of fuel on a biome with no ores.

on the other hand, a propelled with a few rtg will go continuously. but even if jet engines run with no fuel, i'd still would like to make propellers

this is not a game with a winning strategy to pursue, for the simple reason there is not a winning strategy. you are the second person answering to my questions about submarines, and the second person telling me not to do them. why? there's plenty of people doing unoptimized things. there's people making huge rockets with little to no purpose. there's people making ssto, and nobody goes telling them "it would be cheaper to put some boosters and recover them". so, why are people trying to tell me to not make submarines?

furthermore, i also need to figure out propellers for helicopters. am i supposed to not do helicopters either?

i appreciate advice on how to realize my projects. i even appreciate being told that something is unfeasible in the stock game, it saves me the wasted effort. but i do not appreciate being told that i should do something else.

[HansAcker]

Bug #23271 Propellers don't work in water - https://bugs.kerbalspaceprogram.com/issues/23271

There are helicopter examples in the stock vehicles but I'm not sure if they already use the new controls. Check out their action group axis settings.

 

Edited August 4, 2020 by HansAcker

[Zhetaan]

2 hours ago, king of nowhere said:

even if i strapped a convert-o-tron on it, it would increase weight greatly

Wouldn't that address your ballast problem?

Actually, with respect to both your propeller and your range problems, you might be able to get better results by trying something more like a bathyscaphe than a submarine.  I say this from a purely theoretical position, of course, so you'll need to do the testing, but you could design a vessel that is neutrally buoyant at something less than full tanks of ore.  You can take wheels, Wheesleys, and some amount of wing to keep off the seafloor (probably trivial because you can tailor it so that buoyancy cancels most of your weight), explore the ocean bottoms, and when you start running low on fuel, begin converting ore.  As you gain positive buoyancy, you also gain fuel and can use that to make your way to somewhere that you can mine to recover ballast and dive again.

Also, I believe that fuel floats but I do not know whether the tanks float higher without fuel--i.e., I don't know whether the empty space is properly accounted, so I don't know what effect burning the fuel would have on your buoyancy.

It's not a working propeller but it might be a place to start.

[bewing]

3 hours ago, king of nowhere said:

and the second person telling me not to do them. why?

I'm not telling you not to do them. I have a very nice submarine that I use. KSP submarines simply are either very slow or they have very limited range. And they are difficult to launch. But they are fun.

I have made suggestions to the devs to put anomalies under the sea for players to find. I have also suggested that survey contracts be created that require submarines to complete.

I have never made a helicopter. But I know they are fairly easy to do. I don't know why you are having a problem with that.

[RizzoTheRat]

I also keep thinking I should have a play with subs at some point so watching this with interest.

Presumably in a jet engine sub, as you use fuel it gets more buoyant?  I'm sure I've seen people say landing gear has different buoyancy deployed and stowed, are there any parts than can be used to control buoyancy like that?  I guess drain valves can be used to increase buoyancy, but I'd like to be able to decrease it as well.

[s_gamer101]

I recommend to put full ore tanks in a cargobay or service bay. When you close the doors, they don‘t produce lift any more but are still heavy and your submarine should start to sink. When you open the cargobay, it should start returning to the surface. And you don‘t have to drop the ore every time, what makes your submarine reusable.

But according to my experience, command  pods, elevons and other stuff are often causing submarines to float (even when they shouldn‘t float). Maybe you could attach command pods and crew cabines also inside the cargobay and move them out with offset tools. The game will „think“ that they are in the cargobay and don‘t generate lift. But I‘ve never tried this to be honest.

Edited August 5, 2020 by s_gamer101
Spelling

[s_gamer101]

@hazard-ish made a cool stock submarine:

https://m.youtube.com/watch?v=F7bmwJoAujU

He mentioned that the radial ore tanks are the densest ones.

[bewing]

3 hours ago, RizzoTheRat said:

Presumably in a jet engine sub, as you use fuel it gets more buoyant?  I'm sure I've seen people say landing gear has different buoyancy deployed and stowed, are there any parts than can be used to control buoyancy like that?  I guess drain valves can be used to increase buoyancy, but I'd like to be able to decrease it as well.

Generally, my experience says to make subs slightly positively buoyant. Yes, using fuel makes them even a bit more positive. I have never found a good reason to deliberately modulate the buoyancy. The ore tanks are generally so massive compared to the onboard fuel that fuel usage does not change buoyancy by a significant percentage. A positively buoyant sub means they will always come back to the surface, which means they are always reusable. (Provided you do not come back to the surface too violently, which will always destroy parts of your sub.)

You build a sub just like a plane, except that the medium is much denser -- so you don't need much (or anything) in the way of wings, and small control surfaces are plenty adequate. So long as your control surfaces remain below the surface of the water you can use them to dive or climb.

 

[XLjedi]

Positive buoyancy sub deployed via seaplane (Mk3 Cargo).  So a viable option for interplanetary delivery.

 

All my craft are on KerbalX

https://kerbalx.com/XLjedi/UV-14-Barracuda

[king of nowhere]

On 8/5/2020 at 4:50 PM, s_gamer101 said:

@hazard-ish made a cool stock submarine:

https://m.youtube.com/watch?v=F7bmwJoAujU

He mentioned that the radial ore tanks are the densest ones.

i was hoping to see how he made the propeller work, but he was using a jet engine for propulsion.

on the other hand, i see i am not the only one who uses a cupola module to drive in first person view

[Lewie]

Use the mod sink ‘em all. It’s super easy to use, try it out!

[jimmymcgoochie]

Try doing the opposite of what real subs did- use an electric propeller while on the surface (the props must be fully in the air so put them on the top of your sub) and then use a jet engine to propel yourself underwater. Solar panels, RTGs and the jet’s alternator will recharge the batteries while submerged and ore tanks are great for ballast as you can fill the, up by mining and drain them using an ISRU, a fuel drain valve or by just dumping the entire contents if you want to surface RIGHT NOW. If you’re worried about range, just build a really really big sub with a huge reserve of fuel or bring some drills and an ISRU along to make more as you go.