Transom, Is 18" too high for 9.8 nissan short shaft?

[bzajdek]

my transom is currently at 17" and my 2008 nissan 9.8 four stroke has a dolfin hydrofoil but at all trim positions and speeds the foil is below the water and doesnt plane well on my 12' whaler. I have shimmed up one inch and it seems better, but should I glass in the shim or use it a couple more times to make sure it doesn't cavitate. Worried 18" may be too high! Has anyone heard of going that high?

 

[VeroWing]

Re: Transom, Is 18" too high for 9.8 nissan short shaft?

Rule of thumb optimum condition is when cavitation plate (flat part above propeller) is aligned with hull bottom where outboard is mounted. Some people will tell you that a little higher than that is even better. I wouldn't glass anything in until I operated boat in conditions it will be used in (loaded weight, similar speeds, etc..) Just my opinion, Mike.

 

[henrye718]

Re: Transom, Is 18" too high for 9.8 nissan short shaft?

Here is a good guide..

http://www.marinepartsman.com/installing-an-outboard-on-your-boat.html