When to use AP .vs HE?

[nattydread]

Originally Posted by deamyont

There are explosives in AP rounds aswell, its not just a ball of steel inside...

The AP rounds on our vessels also contain HE? I know some types of AP rounds have HE, but i didnt know the AP rounds used in game had them. Is there some where we can confirm this. If so, The AP would be best for internals and HE for hull. I assume the AP has a delayed fuse to allow it to penetrate with a small hole, and cause explosive damage in side...still not neccesarily the best round for causing flooding.