On Mon, 20 Dec 2004 22:36:22 GMT, "RichG"
wrote:

Tom, to answer your first question...my two boats are a
1. a narrow, tunnel-hull, high bowed, 16 ft. flats boat known as an El
Pescador http://www.elpescadorboats.com/
& 2. a 16 ft. Carolina Skiff STD, flat bottomed, skiff style
www.carolinaskiff.com
These two boats are as different as night and day in hull configurations.

I have a 20 foot Ranger CC and a 32 foot Contender (ok, it's say 31,
but it's really a 32). There is no practical deadrise on the Ranger
and a whole bunch on the Contender. :)

With regard to "theory on bow lift"....I'm no engineer...(a big
understatement)... but all tabs that I am familiar with... Lenco (
electric) Bennet (hydraulic) and SmartTabs (pneumatic) ....all work on the
same principle and produce similar, (though differing in degree and amount
of control), results. It is my simple impression that TABS ( any tabs)
effectively make the boat "longer" by extending the stern hull surface
outwards.

Most planing style boats have the "bow rise" built-in. Just start any
planing-hulled boat forward and the bow will rise and stay up, far too long,
until the boat gradually comes back down to "plane". I've owned over twenty
boats so far, and never had any of them that would instantly go to "plane"
without the ....Up first, level later... process. The use of trim tabs
counters this excessive bow rise and brings the boat into plane quicker. Any
planing-style hulled boat, moving on plane, is using less fuel than it would
while plowing through the waves.

I agree, but on the Ranger, I have no bow lift at all - it literally
goes from "plow" to "plane" at around 15 mph - you can't control it -
it just does it. But the bow has zero lift - just goes from one
attitude to the other with no transition. I've demonstrated this to
some people who don't believe and they just walk away shaking their
heads - it kind of contravenes conventional theory. :)

On the Contender, I pretty much use the trim tabs for lateral
stability and use the engine trim to keep the bow angle where I want
it on take off. I keep the trim tabs at neutral until we're rolling
along, the adjust as necessary for sea conditions.

~~ snippage ~~

I was a skeptic about the effectiveness of tabs, too. Now that I am a user
though, I wouldn't boat without them.

Understood - nothing like a little practical experience to help
clarify things.

It's just that I've noticed on my Contender, that the tab effect isn't
quite as advertised and in fact, if it weren't for the lateral bit, I
wouldn't even consider them.

I can see, though, how they would help your boat's situation. Now
that I think about it, I don't know how big Mike's boat is so maybe I
shouldn't have shot my mouth off. :)

Later,

Tom