Whale tail with short shaft

AJASR

Cadet
Joined
Aug 24, 2010
Messages
7
I have a 1963 evinrude 10hp short shaft on a 16ft. Starcraft fishing boat. The boat really wants a long shaft motor. The transom has been notched down but i still can't run at full throttle without getting cavitation. Will a whale tail improve this problem?
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: Whale tail with short shaft

Not likely, it may hold it off for a couple of 100 rpm but it won't be in the water if it planes.
That old style gear case can't be run too high you need to be sure it pumps water as well.
Shaft extensions for those motors used to be pretty common.
Where is the antiventplate(cavitation plate) in relation to the bottom of the boat.Measure it with a straight edge along side the keel.
 

AJASR

Cadet
Joined
Aug 24, 2010
Messages
7
Re: Whale tail with short shaft

Thanks. Where might i look for a shaft extention? Is this a project the average guy can handle or should it be done by a mechanic?
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: Whale tail with short shaft

Try twin cities used outboard parts.Not sure of the adress.Also ebay.
Its pretty straight forward a 5" extension housing, long drive shaft, shift extension and water tube extension.It has been 34 years since I did mine so I don't remember the details about the water tube if I made a longer one or added an extension.
Maybe someone who has done this recently will be along with more details.
 
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