No thom, it's not that type of system, thats what I thought it was.
This is just a fine tuning system to balance the boat.
After he gets out of the yard I'll snap a few pictures.

Joe

Joe wrote:
No thom, it's not that type of system, thats what I thought it was.
This is just a fine tuning system to balance the boat.
After he gets out of the yard I'll snap a few pictures.


Ever seen an articulated rudder? Similar except that it's
controlled by a linkage to the rudder post that makes it
turn the same way as the rudder only a little bit further.
More efficient steering.

Using a trim tab just to offset the force on the rudder
blade from normal sailing doesn't make sense to me. It just
adds drag. It would be better to adjust the sails so as not
to have so much helm, or to add balance area to the rudder
blade forward of the pivot point (rudder post).

Fresh Breezes- Doug King

"DSK" wrote in message
. ..
Joe wrote:
No thom, it's not that type of system, thats what I thought it was.
This is just a fine tuning system to balance the boat.
After he gets out of the yard I'll snap a few pictures.


Ever seen an articulated rudder? Similar except that it's controlled by a
linkage to the rudder post that makes it turn the same way as the rudder
only a little bit further. More efficient steering.

Using a trim tab just to offset the force on the rudder blade from normal
sailing doesn't make sense to me. It just adds drag. It would be better to
adjust the sails so as not to have so much helm, or to add balance area to
the rudder blade forward of the pivot point (rudder post).

Fresh Breezes- Doug King


The Flettner "trim tab" improves stall characteristics of the rudder.

Bob Crantz wrote:



The Flettner "trim tab" improves stall characteristics of the rudder.

That may be true, but if you have to push the rudder to one side to
"balance" the boat, (doesn't drag increase with angle of attack?), then
you're going to increase drag. Better to trim the boat properly with
the sails and not have to shove bucket loads of water around.

Cheers
Marty
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"Martin Baxter" wrote in message
...
Bob Crantz wrote:



The Flettner "trim tab" improves stall characteristics of the rudder.

That may be true, but if you have to push the rudder to one side to
"balance" the boat, (doesn't drag increase with angle of attack?), then
you're going to increase drag.

It's the L/D ratio. If L increases faster than D the rudder is more
effective.



Better to trim the boat properly with
the sails and not have to shove bucket loads of water around.

This is only true if the boat sails in a straight line down its centerline.



Cheers
Marty
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That may be true, but if you have to push the rudder to one side to
"balance" the boat, (doesn't drag increase with angle of attack?), then
you're going to increase drag.


Bob Crantz wrote:
It's the L/D ratio. If L increases faster than D the rudder is more
effective.


Not so. If the L/D ratio increases, then it is possible to
have less rudder drag with the same turning force (or to
generate more force with the same drag) but it not the same
thing as reducing drag overall, which can be done wuite
easily by minimizing the turning force needed.

Some designs have the underwater foils set up so that the
lift of the rudder is a significant factor going to
windward... Hobie 16s are a good example of this. Then, the
L/D ratio should be optimized because the lift is getting
you somewhere. In all other cases, the "lift" from the
rudder isn't helping anything other than to prevent the boat
from going where you don't want it to.

Fresh Breezes- Doug King

Well I asked him if it would be better to balace the sails better, he
said yes and no. Sometimes on some points you just end up with a
weather helm, and all you have to do is dial it out with the trim tab.

Joe

it should work w/water...trim tabs work
great on planes.....