cavitation plate height?

tuna troller

Cadet
Joined
Jul 27, 2008
Messages
27
how low should the cavitation plate be below the transom? and on the 1980 50hp evinrude witch is the cavitation plate?
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,226
Re: cavitation plate height?

It is the flat plate above the propeller. It normally runs even with the bottom of the boat, or slightly below. Experimentation is the rule. Run it as high as you can without excessive cavitation/ventilation. You will know when that happens. Having said all that, many go-faster boats run motors considerably higher than that. But those people also put up with an awful lot of ventilation for a go-fast trade-off.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: cavitation plate height?

as said it is an experiment. from even with keel to 1 1/2 inches above. it depends on the boat and motor combination, trim and tilt all have to work together to get the optimum set up.
 

wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: cavitation plate height?

At WOT, the plate should NOT be covered with water. If it is, come up a hole and check again. Also, after adjusting, try some fast tight turns. If it doesn't cavitate, it's OK. If it does, back off one hole. It's always found empirically.

BTW, most hull manufacturer boats have motors rigged too deep (never get a caviation complaint). The downside is a slower boat and worse, one that uses considerably more fuel. My boat almost always runs offshore for 1.5 to 2.5 hours each way. My fuel use dropped 20% by getting the "x" dimension right.
 

Sparkadelic

Cadet
Joined
Jun 30, 2004
Messages
18
Re: cavitation plate height?

Thanks for the easy to understand replies. This will/has helped me too.
 
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