Join Date: Nov 2009
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Re: Outboard Engines Limit
Given the issues with OBs on sailboats that have already been mentioned, the OP would be well advised to have towing insurance (like TowBoat Us, SeaTow, or part of boat policy).
While the newer 4 strokes are more fuel efficient, until the parameters of the new (to the purchaser) OB are understood, it would be prudent to figure on 1 gal of gas per hour for a 9.9 at full throttle and then allow at least a 100% margin for safety. So, assuming 5 mph speed in flat water (no wind or tide) and 75% throttle, the whole trip would take 18 hrs (straight shotóno detours) and consume 13.5 gal of gas. With a 100%margin, the OP should have at least five 6 gal containers of gas available (along with OB oil if a 2 stroke). If the weather turns nasty or there is a foul tide, the amount of fuel would be greater.
In any case, the OP would be well served to have bail out options planned ahead of the trip.