Lots of things could affect it, but a boat to Hawaii might not need a lot of gas if it has a big piece of cloth suspended from a tall upright thing. If memory serves me correctly, the conditions would allow, during much to the year, for one to sail downwind from California to Hawaii. This is not something I would attempt without lots of prior preparation. For some ideas, see: http://www.equipped.org/0698rescue.htm

I will readily admit that despite some years of sailing, a few working commercially, a number racing sailboats and some other experience, I would not want to take it on with inexperienced sailors. However, if I knew people who had a capable boat and the necessary skills, I might go long for a ride.