ways to sink in eve's oceans

[king of nowhere]

I recently discovered, visiting laythe, that there are some science measurements you can't take from the surface of the ocean, but you can take from the ocean floor. So, in order to collect everything, i need to reach the ocean floor.

As far as I know, the densest parts are ore tanks, so those should sink me. So I experimented a quick sinking platform, made of one ore tank, the 2 science instruments i want to sink, a crew seat, a docking port, small reaction wheels and a single battery. the idea is that the contraption should be dropped by a mothership, and after touching bottom and taking measures, it should dump its ore content to resurface, and dock with the mothership again. this works fairly well on kerbin and laythe.

eve has denser oceans. I tried that, and i found out I needed 30 tons of ore to try and make the apparatus sink. at 0.1 m/s, no more. and if i speed up time, it stops moving. can't  be worked. I also tried clipping, but clipped parts don't sink any better; apparently the extra volume still counts.

any suggestion on how to make stuff sink on eve? possibly without adding too much mass? (ore tanks are not a problem because i can send them empty and mine the ore on the spot. unless i need many tons of tanks, that is)

[Spricigo]

3 hours ago, king of nowhere said:

but clipped parts don't sink any better; apparently the extra volume still counts.

Use service bays to toggle extra volume open/close.

[Vanamonde]

I haven't tried this myself but two possibilities come to mind. You could give the diving craft propulsion and use wing parts to try to drive it down like an inverted airplane. Or perhaps make a craft which stays on the surface but extends the testing parts down on an arm. 

[Spricigo]

4 hours ago, Vanamonde said:

You could give the diving craft propulsion and use wing parts to try to drive it down like an inverted airplane.

No wings are necessary for this particular application. It just need to have downward propulsion  strong enough to overcome the buoyancy.

In any case, both ideas are viable, if maybe less practical for deep waters explodium

 

[Klapaucius]

10 hours ago, Spricigo said:

No wings are necessary for this particular application. It just need to have downward propulsion  strong enough to overcome the buoyancy.

In any case, both ideas are viable, if maybe less practical for deep waters explodium

 

You don't need wings per se, but having canards or some form of diving plane helps.  However, you can make flying subs as well (or submerging planes, depending on how you look at it)--I've got a few submersible planes in my inventory. The problem with Eve is that the oceans, like the atmosphere, have no oxygen, so you are stuck using rockets which are really inefficient.  I have not tried stock props underwater, so that might be a better solution.

[king of nowhere]

3 hours ago, Klapaucius said:

 I have not tried stock props underwater, so that might be a better solution.

i have heard they don't work

i have a lot of experience with propellers, but seeing how difficult it is to submerge anything, i never made dedicated experiments.

still, i would prefer to use weight. more convenient.

[OHara]

The propeller blades from the Breaking Ground add-on don't give any lift from water, but the normal aerodynamic surfaces work just fine.   Electric propellers, driven by rotors if you have that add-on or otherwise just reaction wheels, are useful for Eve.

The trick of clipping ore tanks inside a closed cargo bay or fairing is very effective, as the simple rules of KSP discount fluid forces, including buoyancy, on things inside closed bays.  

[king of nowhere]

just tried the bay, it works fine, and i can do it with less than 1 ton. thanks to all