What size shaft on grady 24?

[Bigfishin82]

I was just wondering what size shaft can I run on my 1986 24ft grady white offshore pro? I have a 250 yamaha i want to put on it and it has a 30 inch shaft. Will that be ok or does it have to be a 25 inch shaft? Thanks in advance guys.

 

[Tuna Man]

I had a 1988 24' Offshore with a cutout transom, 25" shaft.
I had a 19992 24' Explorer with bracket, 25" shaft.

My guess is that your boat is also requires a 25" shaft. You can go to the Grady site and look it up, I think they listed the shaft length in the catalog.

 

[Bigfishin82]

Ok well will a 30 inch shaft be ok? Can I use it still without any problems?

 

[Tuna Man]

Do you have a transom mount or a Grady Drive?

 

[Tuna Man]

I have never tried using a 30" shaft on a transom designed for a 25", so take what I write with a grain of salt.

I think your cavitation plate will be so low in the water while on plane that the engine will perform poorly. I'd be willing to bet that with the 30" shaft, the lower unit will have way too much drag.

If you decide to try it, mount the engine at the highest mounting holes.

 

[Bigfishin82]

I have a open transom in the back. I just want to make sure i avoid any problems if I can before they happen. So with the words of wisdom from you great people I should get a 25 inch shaft or will i be ok with the 30 at the highest holes mounted?

 

[Tuna Man]

I would try to get a 25" shaft or convert yours over to 25". Not an easy job to do and not cheap either. I'm sure others will chime in when they get some time.

 

[cobrapowersys]

I an going to repower my 1995 268 Islander. I spoke to Grady, and they said you can use a single motor with a 30" shaft, or twins with 25" shafts. The reason being the "V" in the hull. You wont be able to reuse that 30" shaft if your are going with twins. Also be sure not to overpower the nameplate rating. Mine is 400HP max. I currently have a 2001 250HP Yamaha OX66 saltwater with a 30" shafft. I will have to sell that motor and buy two new/used 25" shaft 200HP max. You are most likely in the same "boat".