continued on the Thread entitled "SmartTabs"

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..

"Short Wave Sportfishing" wrote in message
...
On Mon, 20 Dec 2004 20:42:10 GMT, "RichG"
wrote:

I haven't been following this thread, but you can add SmartTabs for below
$200.00 ..maybe even below $150.00 depending on size ( buy the "scratch
and
dent" specials directly from the manufacturer, Nauticus ).

I have them on two smaller boats. They DO keep you on plane longer and at
lower speeds and they DO get you up on plane faster. I surely didn't buy
them for cost (fuel) savings but rather to get up and out from the
shallows.
The over-all effects of Trim Tabs ( any brand of trim tabs ) is so very
positive that I think every boatowner/manufacturer ought to consider
adding
them. --
RichG manager, Carolina Skiff Owners Group on MSN
http://groups.msn.com/CarolinaSkiffOwners

I'm curious as to what kind of boat you have to make that claim.

On my Ranger, trim tabs would be useless because of the transom
design. On my Contender, I guarantee you that the trim tabs have
nothing to do with getting on or off plane faster or longer. Lateral
stability at speed yes - planing, no.

Trim tabs aren't the end all for planing problems which is why I asked
what kind of boat you have. They work for some, but not all.

I have a suspicion that Mike's might not be one of those.

Later,

Tom

Depending on the cup, etc of a prop, it can induce lift in the transom area.
So a prop can help in getting up on and maintaining plane.

"NOYB" wrote in message
nk.net...

"Gene Kearns" wrote in message
...
On Sat, 18 Dec 2004 11:01:15 -0500, MikeG
wrote:


The planning speed thing was what was bothering me also. It's the main
reason I got to thinking about re propping.

The present prop is in pretty sad shape. I'm hoping that even without
changing anything a new prop of the same spec's will show an improvement
in that area.


The direction of this thread seems to have made a left turn and gotten
me a bit lost....

The *prop,* per se, has *nothing* to do with the speed at which a boat
planes. While, you may well pick up some efficiency and/or top end
with a new prop, it won't change the planing speed at all.

the prop has nothing to do with the speed at which the boat planes, but it
does affect the ability of the boat to maintain that speed before falling
off plane. For instance, his boat may actually plane at 17 mph...but his
current prop can't maintain the boat on plane at 17 mph, and it quickly
falls off plane. It sounds to me like 20 mph is simply the minimum speed
at
which he's able to *maintain* plane...and he's calling that his minimum
planing speed. Changing props won't change the speed at which the boat
planes, but it very well may change the boat's ability to maintain a lower
planing speed. I'd say try the 4-blade. If he drops the pitch, the
engine
will overrev...unless he also increases diameter to compensate. Of
course,
he could also have a prop shop add cupping to the blades, but then it
becomes even less of a science and more of trial and error.

While true that props can be built to have tail/stern lift and/or bow lift.
This does not come into play at lower rpms that your talking about to
maintain plane. Higher rpms are required to have any effect. So prop lift
will have no effect.

As stated before - planing speed of a hull is planing speed. No prop is
going to change that. A whale tail will which in effect changes the hull
design by adding a hook to push the bow down. A more efficient prop will
allow you to achieve the theoritical plane speed but it will not change it.


--
Tony
my boats and cars at http://t.thomas.home.mchsi.com
"Calif Bill" wrote in message
ink.net...
Depending on the cup, etc of a prop, it can induce lift in the transom
area.
So a prop can help in getting up on and maintaining plane.

"NOYB" wrote in message
nk.net...

"Gene Kearns" wrote in message
...
On Sat, 18 Dec 2004 11:01:15 -0500, MikeG
wrote:


The planning speed thing was what was bothering me also. It's the main
reason I got to thinking about re propping.

The present prop is in pretty sad shape. I'm hoping that even without
changing anything a new prop of the same spec's will show an
improvement
in that area.


The direction of this thread seems to have made a left turn and gotten
me a bit lost....

The *prop,* per se, has *nothing* to do with the speed at which a boat
planes. While, you may well pick up some efficiency and/or top end
with a new prop, it won't change the planing speed at all.

the prop has nothing to do with the speed at which the boat planes, but
it
does affect the ability of the boat to maintain that speed before falling
off plane. For instance, his boat may actually plane at 17 mph...but his
current prop can't maintain the boat on plane at 17 mph, and it quickly
falls off plane. It sounds to me like 20 mph is simply the minimum speed
at
which he's able to *maintain* plane...and he's calling that his minimum
planing speed. Changing props won't change the speed at which the boat
planes, but it very well may change the boat's ability to maintain a
lower
planing speed. I'd say try the 4-blade. If he drops the pitch, the
engine
will overrev...unless he also increases diameter to compensate. Of
course,
he could also have a prop shop add cupping to the blades, but then it
becomes even less of a science and more of trial and error.

"tony thomas" wrote in message
news:FFKxd.535630$wV.355519@attbi_s54...
While true that props can be built to have tail/stern lift and/or bow
lift. This does not come into play at lower rpms that your talking about
to maintain plane. Higher rpms are required to have any effect. So prop
lift will have no effect.

As stated before - planing speed of a hull is planing speed. No prop is
going to change that.

Like I said, I think that many boaters misspeak when they're discussing
planing speed. When they say "my boat planes at 20mph", they mean that that
is the minimum speed they need to run in order to *stay* on plane. However,
it's quite possible that his boat planes at 17 mph, but won't maintain that
speed...and thus he interprets that to mean that 20 mph is his minimum
planing speed.

A lower pitched prop may allow such a boat to *maintain* a lower constant
planing speed.