On Mon, 20 Dec 2004 10:42:42 -0500, MikeG
wrote:

~~ snippage ~~

Lower planning speed - This is the tricky one for me so let me know
where I am going wrong. My boat has a planing hull as opposed to a
displacement hull. It is designed to work most efficiently up on a plane
rather then pushing the water out of the way al la displacement hull.
The
boat falls off the plane and starts pushing water below 20 MPH/4700 RPM.
A lower planing speed may mean it takes longer to get to a fishing spot
but if that means one or two more trips a month in the gas budget I can
live with it. So, and this is where I can see I may be looking at things
wrong, a lower planing speed means lower RPM s with the boat still
operating efficiently, planning rather then displacing, and lower RPM's
mean better mileage.

I think you are way over estimating the difference 3 mph will make on
fuel consumption. Even after several long runs, I doubt if you are
going to save a significant amount of fuel savings such that you will
be able to make additional trips to the fishing grounds. What's the
difference between 17 and 20 in terms of RPM - a 5/600 at the most?
Not enough to justify tinkering with planing speeds.

My Ranger is 20 foot, has a FICHT (which I admit is probably more
efficient than EFI or a carbureted engine), but still, the difference
between 1800 and 2300 is pretty insignificant. I don't have the
figures right at hand, but as I remember, the difference was in the
very low tenths in terms of GPH.

Now having said that, I normally run at 30 mph which is right under 4k
- there I can see savings over the max speed of 42/43 mph at 5500.
But again, the difference is in tenths - closer to a full GPH, but
still tenths.

I'll look for the data when I return from fishing this afternoon and
give you some examples.

Whale tail or similar - A budgetable item I have been playing with the
idea of. The things I've read on these additions have all been
advertisements giving glowing reports on them. However, life being what
it is, you can't pay Peter with out stealing from Paul. What is the down
side to be considered?

For my money, these things suck.

The main reason is that they work even when you don't want them to
work. And you lose the ability to close trim the motor at speed.

On my Princecraft with the Johnson 25, yeah - they make a difference
in a lightly loaded boat by keeping the bow down.

For your application, it wouldn't be something that I would consider.

Later,

Tom