Jimmy,
Years ago I was one of those dummies. We were desperate to get to the canyons and always wanted to have extra fuel to be 'safe.' I did it about five times and learned that going to the NJ canyons on a 24' boat with marginal fuel capacity was just not worth the effort. We would run out till we burned about 25 gallons, dump the five containers in the tank, troll all afternoon, anchor or drift overnight, troll all morning and run home. Never actually needed the extra fuel, but came very close once when the seas were a little nasty.

I now have a larger boat with ample fuel capacity. Looking back, buying a 25 gallon plastic deck tank for about $100 would have been a much smarter move. No mess, no gasoline smell on your hands (and bait, lures, etc) and much safer.

I don't always agree with Jawz, but he is absolutely correct with his statements above. Another idea to consider is to go on an open boat trip with one of the charter captains on this site. Many captains go offshore regularly and have room for one more or even a couple of guys.