Sorry for the slow reply!
Cargo ships won't load from an Offshore rig. They appear to function normally (as in following orders to 'stations', etc.) but the oil won't pump from the rig into the ship. As soon as I disable Hovercraft they load again and stop if I reenable. If you are using it without problems then it might be another mod interacting with both... all I did to test it was disable hovercraft and the cargo ships worked again. The inserter-based ships (i.e. the Cargo Ship as opposed to the Tank Ship) seem to be working fine no matter what, it was just the Tanker that was having the problem and only on loading from rigs (unloading is fine).
I did manage to get everything working together but I needed to remove a whole lot of swimming code and related animations (which also means no cool wake behind the hovercraft).
While I'm here, can confirm Ships Extended was not related, that seems to be another conflict altogether, sorry about that! I'll test some more to see if something else is messing with all 3 of these mods... I assumed not because nothing else modifies water (or at least, nothing is supposed to).
