Sorry - missed that !
IF all else fails you could use the console to step the quests forward to completion (best not to jump straight to the end without entering each step along the way) for the unexpected voyage it goes through stages 10 , 20 , 30, 40, 50, 60 then splits depending on if you kill selene or capture her -- for capture uses 70, 75, 78 - for kill skips those and goes to 80 (do not enter 80 if you use steps 70-78) -- then both continue to 90, 95 (this is the one that resets the outer door for use so do not skip it !) then finally 100
Entering all of those should complete the quest properly and get you back to where the quest is complete and the bloated float is back in port and accessible !
EDIT : Sorry forgot the quest is named MS31 - so you would use setstage MS31 10 etc. in the console --- also the quest has a script added that kicks people out and lets them back as you go through and complete the quest so just jumping to 100 without the other stages could leave problems.