Parallax wrote:
Cruising sailboats and powerboats have very different ideas on fuel
use and the needs of the sailboat are rarely addressed. For example,
most powerboaters are very concerned about the overall cost of the
fuel they use primarily because they use a LOT of fuel.

That depends very much on the powerboat. Most "cruising" powerboats are
relatively economical. For example, in the 2 years we've owned & cruised
(several thousand miles) our 36' power boat, we've spent far less on
fuel than we did on a slip to keep it in. Or insurance.

OTOH if you want a POWER boat, twin engines & big wakes and all that,
then yeah, fuel is going to cost a lot. I hear guys with big
sportsfisherman talk about burning 30 gph, or ~ $500 day. Ouch!


Most sailboats have a smaller engine for their displacement than a
powerboat because their primary power is supplied by free wind.

I dunno, for the cost of a new genoa or cruising spinnaker for a boat of
similar size to ours, I could buy 5,000+ miles worth of fuel.


However, fuel use (hp/liter or hp/ounce) and overall power sometimes
are important for a sailboat. A long distance cruiser can only carry
a small amount of fuel and if he has a long period of no or contrary
wind, he might want to be able to motor for a long time with little
regard for the cost of the small amount of fuel.

Yep. That's why a *sailboat* should have good light air and upwind
performance. Most people don't have the patience, or the time; that's
ignoring a large group that don't have the skills or the inclination.
And most people want to bring along all the comforts of home on a boat
barely big enough to hold them, which also degrades sailing performance.


... So, are fuel additives available
that would effectively increase the hp/ounce of fuel burned even if
they greatly increase the overall fuel cost? Would octane boosters
help (or cetane boosters)?

There are a lot of fuel additives, but they typically cost more and
don't improve fuel performance enough for your purpose.


... Is it possible to temporarily increase the power
outpuit of a small engine by some means, perhaps a blower, a turbo or
even using NOS?
... This might give the sailboat the ability to better
motor off a lee shore in strong winds

Usually the problem with motoring off a lee shore is
1- prop out of the water
2- engine sucks air into cooling system.
3- crap in fuel gets stirred up & clogs filters.

So increased power isn't going to help a thing.

Maybe if you're interested in increased range & efficiency you should
try one of those electric drives with battery bank and solar panels? Or
if you just want to go fast, get a speedboat.

Fresh Breezes- Doug King