(There's not much of a visual on this one -- unless I take a picture of the water next to my boat, with no diesel slick showing!)
A friend suggested this one: a high loop in the hose can be used to eliminate fuel spillage and seawater contamination through the fuel tank vent.
My SJ28ís fuel vent was routed directly to a through-hull vent just below the starboard toe rail. By lengthening the hose, and looping the extra way up inside the aft cabin corner and back down to the through-hull, I avoid spillage from over-filling my tank, and prevent water entry (and/or diesel drainage) at extreme heel.
Way cool, and I didnít have to relocate the vent opening, as Iíd been planning.