Submerged submarines are damaged by surface fire.

[ghost]

This is caused by the addition of "Water" to the SS & MSUB underwater TargetTypes.
I think simply removing "Water" from the SS & MSUB Underwater TargetTypes should fix this.
SS & MSUB:
->Targetable@UNDERWATER:
-->TargetTypes: Water, Underwater, Repair

[playtest-20170902 & bleed]

[Smittytron]

I was under the impression that force-firing water to fish for suspected submarines was a correct and legitimate tactic.

[ghost]

It was never a tactic in the past, it was unintentionally introduced into the playtest when refactoring CreateEffectWarheads. #13543

[pchote]

All these regressions wrt water effects are starting to feel a bit silly now. @reaperrr would this be better solved by introducing a new set of target types for RA?

[reaperrr]

I think simply removing "Water" from the SS & MSUB Underwater TargetTypes should fix this.

I doubt it's that easy, iirc I added it because otherwise water splashes would not display on cells occupied by submerged subs, indirectly revealing their position. At the very least I know I added it for a reason.
Edit: I remember now. On previous releases, since subs don't have the Water target type, if you have for example a cruiser selected and move the cursor over water, the 'crossed through' cursor will be shown on cells occupied by subs even if they're submerged, because the Underwater (and Repair) target types are invalid for the cruiser weapon.
So the idea was to fix that exploit which allowed you to spot submerged subs.
Reverting that might be the easiest quick fix, though, we'll just be back to how it was in previous releases already.

@reaperrr would this be better solved by introducing a new set of target types for RA?

Technically yes, the main cause of this whole mess is that Ground and Water are shared between actors and terrain, so getting the behavior right in every combination is currently a brain twister from hell.

However, I'm not convinced we can get that right in one try without causing another, new set of regressions, because many trait and weapon properties default to Ground, Water for target types.
I'd like to first make one last attempt at fixing this with as few changes as possible, and then revamp the RA target types from scratch for Next+1 to bring back some sanity into the setup.

[pchote]

Ok, that sounds fair. I suppose that here we can get away with adding a new Submarine target type that is invalid for damage but valid for effects. Edit: Given your edit, this won't work. IIRC the current state of the code requires at least one valid damage warhead for something to be targetable.

I think reverting that fix to behave the same as the last release would be acceptable.

[pchote]

A hacky workaround would be to use the cloaked condition to activate a different armor type that recieves 1% damage from Water damage types.

[reaperrr]

Actually I just tested with Water removed from target types and didn't spot any issues with the cursor.
Not 100% sure if that was really the problem.
I think it's safer to revert it and risk reopening a minor issue than introducing such a hack. I'll file a PR.