In my opinion.... The short reply to your specific question is "Idle
Speed". We all know that WOT is not economical because of prop slip, etc.
The "sweet spot" is the point where the boat is planing at a moderate speed
(as compared to WOT) the boat is trimmed out well with minimum yaw and has
no list. Then you have reached the point where you can run an enjoyable
speed, throw a nominal wake and not dump gas through the engine(s)
excessively. Inboards, outboards, I/O's, water jet, the same rule applies
to all of them.

Almost no prop slip occurs at idle speed, you are pushing a minimal amount
of water out of the way of the bow and not wasting energy on throwing a
plowing wake. Most of us don't buy power boats to idle the though.

Don Dando




"RB" wrote in message
...
I've had several boats with big single and twin o/bs in the past. I
remember most as having a "sweet spot", which was just down from wide open
throttle (WOT). Many of you are probably familiar with a sweet spot.
Cars
and trucks have been known to have them. Seems like going to WOT can eke
out a little more speed, but things are straining, coming back down a
little
seems to let everything harmonize and get in the groove, and run more
smoothly.

The question I have is: assuming a boat with o/b has a sweet spot, is my
fuel consumption more efficient at the sweet spot than wide open? Sounds
like it would be -- a little bit---as you come back on the throttle to get
to the sweet spot. Or, is it that there's no real reason to run at the
sweet spot, other than it "feels right", and good?

Just curious