Question about Fuel Line?
 

How many feet of fuel line would I need to go from my main tank under the floor to my fuel water seperator in the back right side top hatch in a 1987 V 20 Fisherman?

REAL easy trick I've used for building wiring harnesses and routing hoses... route a test run of rope through and measure it, then and add a couple feet for slack.

Personally I'm a little on the lazy side and can never have too much fuel hose around so for this one, instead of measuring, I'd get 20 feet and just use whatever I needed.

Approximately 12 feet. I redid my V20 Step this past month. I probably could have gotten away with about 8 feet of it but I re routed it so it was out of the way of my battery wires etc.