Efficient water propulsion?

[Esme]

Apologies if this has been answered in another thread, but I couldn't find much when I tried searching for it. Is there a way to propel craft through water in KSP that doesn;t involve rockets or jets?

If not, what is the most fuel-efficient method of propulsion in water? NB: I am not concerned about speed. 1m/s is fine, provided it can be kept up for a really long time.

Reason for the question - I'd like to try a trip around Kerbin, but that'll inevitably mean a few trips across several kilometres or even tens of kilometres, of water. And I've found that electrically powered wheels provide no propulsion whatsoever in water :-(

[Slam_Jones]

Best compromise I've found (at least in 0.90) was jet-powered. High ISP, stable, can provide plenty of power. I usually chose Basic Jet Engines (now called "Wheesley" I think) due to better ISP than TurboJets.

The new drag system may be a problem, though...

[Thomas988]

Back in the day, I probably would have used one of the jet engines or the LV-N due to their fuel efficiency. Of course, these parts were really modified in 1.0 and beyond, so I'm not too sure how they'll play with water.

EDIT: Ninja'd!

[KatzOhki]

Besides rockets and jets the only way is RCS or some sort of water wheel.

Edit: Also Xenon propulsion.

Edited May 19, 2015 by KatzOhki

[problemecium]

You could build a paddle system with one of those helicopter bearings and a bunch of reaction wheels...

[DancesWithSquirrels]

Have a Kerbal jump into the water behind your ship (equipped with a probe core or other Kerbals and SAS) and push... slow, but it doesn't take any fuel, and it certainly works. just make sure to have a ladder around for them to climb aboard again.

[Murph]

You can get some comfort from using jet engines in that they are actually quite common for high end marine propulsion in the real world. Admittedly, the real world marine applications have them either driving a propeller shaft or electrical generator (for a diesel-electric system) via a reduction gearbox from the turbine shaft, not using the jet exhaust for thrust.

The RR Olympus, as used on Concorde, was used in many Royal Navy warships (both big and small), and there have been many instances of larger fast patrol boats using 1 or 2 of turbojets. The QM2 has a turbojet electrical generator for operating at full speed, for when she's doing traditional fast runs across the Atlantic, but uses traditional piston diesel generators for slow speed running, as the turbojet is so fuel hungry.

[merendel]

If you dont mind moding I know theres one or two out there that add propeller prop engines that run off electricity. Could strap one or two of those along with some solar pannles to whatever you want to travle through the water. Would let you move indefinatly during the day. I seem to recall a mod that added compressed air RCS jets (was it B9? cant remember) that could use air intakes to suck in more propellent. if you can track that down it would be another option.

Pure stock you prety much just have jets, rockets, or haveing a kerbal get out and push. I dont think a reaction wheel paddle wheel will work all that well, hasnt in the past for me. Not sure if 1.0 fixed the lader thrust glitch (kerbal climbing a ladder aimed so his head is bumping into the craft causeing phantom thrust as he climbs). If thats still in it would be faster than a swiming kerbal pushing.

[DancesWithSquirrels]

Up through 0.90 an ion engine was a good alternative - low thrust but really high Isp. Not the case any longer, though, as ion engines aren't feasible propulsion in atmosphere anymore.

[Frozen_Heart]

This could work. Unlimited ISP though limited to a couple of m/s.

[Esme]

Many thanks for your replies all. I am in v0.9, as my PC can;t quite handle all the graphics for 1.0 (hoping to get a better PC later this year). I'll bear in mind the getting a Kerbal to push option, but I'm really after something a tad more convenional, if possible :-} No, I'm not averse to using mods. I've got TAC LS , MKS, Mechjeb and Scansat installed currently.

Ion engine? Hmmn.. there's a thought! As is using a prop - wasn't sure if things like Firespitter props would actually work in water - ah, hang on - they don't have to do they, if I can fit a prop on top of my rover?! Excellent idea, so long as the props aren't too large. Thank you! I've come up with a neat little 2-man electric rover that works fine on land, and I've just trialled using RCS to propel it in water but as I can only fit on 4 spherical RCS tanks, I suspect that wouldnt get me more than a kilometre or two. If I lose the RCS that'd give me more room for batteries, enabling more night-driving.

Right, tomorrow I try to create the v3 version of the rover! :-)

Edited May 19, 2015 by Esme
typos.

[Murph]

I am in v0.9, as my PC can;t quite handle all the graphics for 1.0 (hoping to get a better PC later this year).

That seems a little odd. 1.0 isn't really much different to 0.9 for graphics. I've actually seen very little change in graphics demand from 0.21 to 1.0, maybe a little extra demand, but no major rise. Also, I can run KSP quite happily on 7–8 year old machines (which were high-isn spec back then, admittedly, but still old Core 2 with 256MB GPU), just by keeping the graphics options turned down to a sane level for each machine. I can't really discern any extra graphics demand between 0.90 and 1.0.

[Esme]

Murph, it's because my PC is a second-hand very old Dell PC which, unfortunately uses a non-standard sized graphics card. So I can't change the graphics card, and the card that's in there renders about a dozen parts in 1.0 as pure black and doesn;t show exterior views from inside the cockpit. Which is just enough to b a deal-breaker for me. When I go looking for my next second-hand PC, I'll be making darned sure it'll take standard-sized graphics cards! 8-} But it's OK - I was amazed that this old crate could run KSP in the first place, and was expecting a few problems as KSP got close to 1.0. That any problems at all only appeared with the 1.0 release on my PC is, IMO, amazing. And v0.9 is more fiun than any other game I've owned, so I'm certainly not complaining! And by the time I can get a new PC, I should have worked out how to use MKS and so be ready to start a new game with the objective of setting up a self-sustaining colony on Duna :-)