Forgot to add:

Ducttape as above, Spare rope(s) in case you shred one (or it gets shredded by a rescue boat if you tip it in)
Grease proof paper (for simple gel fixes - makes a nice smooth surface that may not need any sanding if in a hurry)
Drill (cordles with 2 batteries at least)
Drills
Gas powered Hair dryer (it's not warm in the UK, sometimes <img src="http://www.catsailor.com/forums/images/graemlins/smirk.gif" alt="" />)
Spare blocks if you have them