Trim plates for motors

C

c-the-light

New member
I've seen some pictures on some of your C-Dorys that had metal trim plates on their motors. I believe they are made in Australia. Can anyone tell me the brand name and a dealer that carries them? I tried a Dol-fin but was not impressed.

Thanks,

Guy
 
Permatrims. Love em! We've had two, they really do a good job of getting the bow down instantaneously with the push of the trim switch.
 
Andy at SIM (Shipyard Island Marina). 1-800-213-3323. is the US importer and major seller. The web site is at:
http://www.shipyardisland.com/Permatrims.htm

I have them on the Tom Cat 255 and there is some improvement at low speed keeping the bow down, but I get a much larger quater wave, and at some speeds this is more than I want (9 to 10 knots). I have not yet tried one on the CD 25. On the Tom cat, they run a bit different than they will on the CD. The Tom Cat runs with the cavitation plate right at the surface of the water--my CD 25 runs with the cavitation plate submerged a few inches. The Tom Cat, seems to "cost" a little fuel economy and top end speed.
 
Bob, on your CD25 your cavitation plate should be even with or 1/16" below the hull bottom for optimum performance. That's where mine are NOW (brought home boat from dealer 450 miles away, found cavitation plates mounted 2 inches below bottom, made for a large water display at the transom at 30 mph during break-in runs at a lake) I relocated them next day, run perfect ever since, even in hard, full-speed turns -- except in 2-3 ft chop.
 
Thanks Steve,
I can bring the engine up 3 hole, so a lot of room to experiment. It seemd a bit low to me. Is the Cavitation plate on the surface of the water or submerged?

The TC's are on the brackets and set up 1" above the bottom for each inch aft--so they are 2" above the bottom, and seem to be perfectly set--but of course this is for cats with brackets...and different for monohulls.

The prop is a 4 Blace Honda SS 13.25 x 13. Haven't really had a chance to check the top speed or speed to plane, and fuel consumption since I just put in the new water pump, and didn't want to run it at speed until I was sure about the pump working well.

Take care.
 
Bob, the 'bottom' of my anti-ventilation plate is 1/16-1/8" below the bottom of my boat (about the thickness of the plate). You have to raise the trim/tilt till until you can sight down past the plate to the bottom of the boat.

Curiously, my boat runs most efficiently with both engines all the way down against their mechanical stops (no stop pins installed). I've tried on many occasions and sea conditions to level the engines and apply trim tabs to get the same or better speed at the same rpm, can't. Thinking permatrims someday possibly, just not sure of the extra drag they might induce even with the moment arm further back from the transom providing better leverage.
 
Thanks Steve, My past experience with a number of boats, including the CD 22 , TC and a number of various runabouts from 16 to 30 feet, is that I set the tabs full down, and motor all of the way down for comming up on a plane. When up on the plane, use the tabs to get the boat level and then bring the motor up to bring the RPM up. The boat will generally be most effecient when the prop thrust is parallel to the water surface.

I would think that trimmed all of the way down, could be a problem going down waves? Lead to bow steering?

Take care,
 
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