Re: How big is your boats tank
My 21' Marlin bowrider with 260 HP Mercruiser (350 Chev) has two 20 Gal tanks... Actually think they're a couple more than 20 each. In any event, running around the river I might burn 10-15 gals max per outing, or 30 max per weekend if out both days. If I do a bunch of watersports it'll burn a fair amount but since gas was pricey last summer I did a lot of anchoring off an island, or trailer boat to water, drive boat to waterfront eatery. Those days 3-4 gals burned maybe.
And to think, I filled both tanks to the brim at the end of last summer thinking I was real smart, buying it while it was cheap!