The longest trek I've done is about 10 total miles there and back on lake erie in 10-15 mph winds out of the NW. The coast line goes SE from harbor to harbor for most of the lake, including this ride.
I started heading SE from Mentor Lagoons to Fairport harbor with a 21 foot sea ray and a capable support crew next to me in view of the coast. On the way there was choppy ass 2-3 footers. The kind of stuff that makes you have to try hard. Thank fully i was going with the wind and waves so I had my fun using the swells as momentum the whole time. So we get to fairport harbor and stop to eat. I check gas and i'm just above a half tank. I start to sweat it a bit because I figured I'd be fine originally, misjudging the size of the chop before I went out in to open water. I go outside the harbor walls to check open water conditions (about a half hour later) and its 5 foot swells!
At this point I knew I wouldnt make it back on fumes assuming conditions didint change or got better. I had to buy gas off a local so I could make it back.
The way back was one of the best rides of my life. It was me and a support boat with 5-7foot swells. I rode the beach line and sand bars (boats with depth finders rule). I was able to slash and jump the entire way home with a full tank of gas (thanks to the help of a fellow rider I didin't even know very well) When I got back to the original harbor I was DEAD spent AND at a 1/4 tank of gas.
Had I gone alone I'd have ran out. Riding in high frequency high amplitude swells like the great lakes can suck gas going through the power band constantly as you ride up and down the waves just to keep control, let alone with any style. So fuel is a HUGE issue.
I recommend doing the trip with a support boat if anything with capable crew members on hand who can set you up a line OR TWO in seconds and get to safety.
