On 23 Nov 2004 15:31:50 -0800, (Big Daddy) wrote:

Wow. Thanks for all the great comments. Let me clarify a few
things...
I don't even need to use the trim tabs to get on plane, even with full
tank and many people. I guess the duoprop twin outdrives do the
trick.
I will check into the flowmeters, but I think the reason I don't buy
them is that I'd like to get good at finding what you have all called
"the sweet spot" by watching the gps speed vs rpm while making
adjustments. All I can think of is all the gas I can buy for the 2 or
3 hundred dollars for flow meters for my twins! (I hope that isn't a
dumb answer).

Yes and no. It would seem a wasteful purchase and I should know - I
had to be convinced that it would help with my Contender. I have to
admit that I was wrong. The fuel flow meters help because they can
show you if, all things being equal, you might have a problem. And
you can pretty much keep track of how much fuel you are using at any
one time. The ones I have keep track of total fuel usage also.

What I really should have asked is; Would I get better fuel mileage
by running on plane at a slower speed with larger trim tabs versus
running at a faster minimum planing speed with the tabs I have now.
I think you have all answered my question. Leave it alone. The tabs
are Bennet and installed new on the boat. The boat runs great the way
it is. I really like the advice to watch rpm and speed while changing
things.

Ah - it if works, it works. My motto. :)

Thanks a lot.

Hey, one more quick one. Has anyone else noticed in some of the
magazine boat reviews where they show the rpm, boat angle, and mpg
that in some tests, the best mpg that they measure is when the boat
angle is at it's steepest, like 5 degrees? That seems odd to me.
That, I would think is the very worst angle for good gas mileage and
yet they show it as the best.

Once again, depends on the type of hull. I would bet that those boats
at that angle don't have a great deal of deal rise.

Later,

Tom

On 23 Nov 2004 15:31:50 -0800, (Big Daddy) wrote:
Hey, one more quick one. Has anyone else noticed in some of the
magazine boat reviews where they show the rpm, boat angle, and mpg
that in some tests, the best mpg that they measure is when the boat
angle is at it's steepest, like 5 degrees? That seems odd to me.
That, I would think is the very worst angle for good gas mileage and
yet they show it as the best.

============================

Depends on the boat and how it is loaded. 5 degrees is not all that
much but it is probably enough to get the forward third of the boat
out of the water and thus reducing hull friction. If you increase the
angle too much the stern squats and digs in, creating a different kind
of drag.

I would also expect that a certain amount of bow rise helps the boat
climb onto the surface of the water just as a small angle of attack
helps an airplane climb through the air. In each case the downward
flow deflection creates an upward lifting force.

On Tue, 23 Nov 2004 22:10:12 -0500, Wayne.B
wrote:

On 23 Nov 2004 15:31:50 -0800, (Big Daddy) wrote:
Hey, one more quick one. Has anyone else noticed in some of the
magazine boat reviews where they show the rpm, boat angle, and mpg
that in some tests, the best mpg that they measure is when the boat
angle is at it's steepest, like 5 degrees? That seems odd to me.
That, I would think is the very worst angle for good gas mileage and
yet they show it as the best.

============================

Depends on the boat and how it is loaded. 5 degrees is not all that
much but it is probably enough to get the forward third of the boat
out of the water and thus reducing hull friction. If you increase the
angle too much the stern squats and digs in, creating a different kind
of drag.

I would also expect that a certain amount of bow rise helps the boat
climb onto the surface of the water just as a small angle of attack
helps an airplane climb through the air. In each case the downward
flow deflection creates an upward lifting force.

My Ranger has zero bow lift. There is a slight tilt when power is
applied, but for the bow to actually "lift" is damn near impossible -
I know, I've tried raising and lowering the motor, different tilt
angles. As power is applied, the boat just lifts itself out of the
water sans bow lift.

I've never been able to figure that out. Most bay boats in my
experience have similar bow lift to bass boats - this one doesn't.

Later,

Tom

On Wed, 24 Nov 2004 11:29:02 GMT, Short Wave Sportfishing
wrote:
My Ranger has zero bow lift. There is a slight tilt when power is
applied, but for the bow to actually "lift" is damn near impossible -
I know, I've tried raising and lowering the motor, different tilt
angles. As power is applied, the boat just lifts itself out of the
water sans bow lift.

I've never been able to figure that out. Most bay boats in my
experience have similar bow lift to bass boats - this one doesn't.

============================

I think it's all in the hull shape.