Transom height and cavitation plate relationship

[ultra353]

I just picked up a boat that has the short transom -16", the motor i got with it is a shortshaft measuring from the cav plate to the transom bracket is 18". The previous owner has the transom on the boat built up with a piece of wood that raises the motor up about an 1"-1 1/2" and the cavitation plate is just level with the bottom. I don`t know why, any insight? Should i take the wood off the transom and put the motor on , will the 1" or 2 lower make that much of a difference on drag or performance. Thanks.

 

[rockyrude]

Re: Transom height and cavitation plate relationship

For the best all around performance, the cavitation plate SHOULD be even with the keel to as much as an inch above the keel.

 

[NSBCraig]

Re: Transom height and cavitation plate relationship

Most boats like 1" up if you have a notched transom. bracket or jack plate then go up from there.

 

[ultra353]

Re: Transom height and cavitation plate relationship

Ok thanks for the replies. I`ll leave it alone for now( everythings frozen over anyways!) and test it in the spring.

 

[NSBCraig]

Re: Transom height and cavitation plate relationship

Frozen! Burrrrrr!

 

[lncoop]

Re: Transom height and cavitation plate relationship

Not to be a smart*****, but while lots of people refer to it as the cavitation plate it's actually the anti-ventilation plate. Just a useless bit of knowledge for ya.

 

[Captain Caveman]

Re: Transom height and cavitation plate relationship

Don't mess with the system in place unless you think that the performance is suffering. I had the same issue with incompatible transom and motor issues. Initially I used a 1x1 block but found that the motor fasteners were too close to the top of the transom. I then welded a bracket together and that raised my motor to the perfect height.

1x1 wood block:


welded motor lift

 

[ultra353]

Re: Transom height and cavitation plate relationship

LoL, Incoop i like that. I can always use more info! I`ll leave it alone until spring and take it out for a try. Its a 1985 Starcraft 14ft sf with a 1969 johnson 20hp. Capt. Caveman thats about the same height that my motor is raised up on the transom - about 1". Thanks for the replies. HA! you warm weather guys!!

 

[NSBCraig]

Re: Transom height and cavitation plate relationship

Been wearing shorts for two weeks here!

 

[lncoop]

Re: Transom height and cavitation plate relationship

Been wearing shorts for two weeks here!

Ain't fair, is it? I'll be changing my tune around mid July though. The natural state will be in full swelter by then.