Whaler Central - Boston Whaler Boat Information and Photos

Posted by sabsab on 06/17/08 - 5:48 PM

Gentleman,

I have a 1993 40 hp yamaha engine on a 1975 13 ft. Boston Whaler. I am using a 10x15 aluminum yamaha prop. At 5,000 rpm (wot) my GPS indicates 29 mph carrying about 600 pounds on board.

I want to buy a stainless steel prop at Cabelas. It is 10 1/4 X 15. Can anyone give me some advice if it's a good choice. They also have 10 1/4 x 14.

Edited by Tom W Clark on 06/18/08 - 6:09 AM

Posted by CES on 06/18/08 - 5:19 AM

Sasb. I too have a 40 hp yami on my 13. I'm running a 11 1/2 x 15 (I think it's a 15 pitch) stainless on my boat. Before you buy a new prop, go to ebay or something and try to get a used one. I paid $45 for my "Flawless" SS prop. Look at my personal page to see the prop I have on my motor.....it's a Power Tech.

I'm running about 34-36 MPH with my set-up.

Posted by moose on 06/18/08 - 5:24 AM

sabsab,
I have a 1968 13' with a Nissan 40 hp.. I tried a 15" pitch and found it to be too much for the boat. Empty and trimmed out it was scary fast and unsafe at 45.1 mph. I could reach a good max rpm empty and trimmed out but with any load and trimmed for comfort I was lugging the motor. I settled for a 13" pitch SS prop and I am very satisfied with the results. I can still get good speed and rpm empty and reach the lower limits of the max rpm range when loaded with three adults and fishing gear. For skiing or other towing I would need to go down to a 12". I have the aluminum one that came with the motor.
Mike

Posted by Tom W Clark on 06/18/08 - 6:15 AM

Selection of a propeller for a boat will depend on several parameters, the WOT RPM range of the motor, the gear ratio of the motor, the anticipated top speed of the boat and he brand and model of the propeller for starters.

Different motors have different gar ratios so it is pointless to draw conclusions from one motor about the potential for another if they do not share the same gear ratio and WOT RPM range.

Propeller design is also far more complicate than just pitch and diameter. Discussing propellers in these simple terms does not always capture the performance potential of some props.

In this case we have a 1993 Yamaha 40 on a 13 footer. This boat ought to be able to do about 35 MPH.

What is the manufacturer's recommended WOT range for this motor?

What is the gear ratio of this motor?

What brand and model of stainless steel propeller from Cabela's is being considered (they sell quite a few)?

Edited by Tom W Clark on 06/18/08 - 6:15 AM

Posted by sabsab on 07/20/08 - 8:59 PM

Thank you guys for your responds. Yamaha recommends 4500-5500 for my 1993 C40. Its a 2cylinder 2stroke with a 2.0 gear ratio. Cabela`s has a ss prop they call Cabelas high performance yamaha prop. item:IJ-011960. they have a 10 1/4x13, 10 1/4x14, 10 1/4x15. They state that this prop is for 40,50,55 and C65hp 2&3 cylinders with small gearcases.I am running a 10x15 aluminm now and it is pushing 29 mph on my gps and 5,000 rpms on my tach. I need a back up prop, so I would like to buy a SS prop and maybe pick up the rpm to 5500 and mph to maybe the 35.

Posted by Binkie on 07/21/08 - 2:27 PM

My daughter runs a 10 1/4 x 14 on her `75 13 footer, with an `03 2 stroke Merc 40hp. and it really runs well. as about max. rpm. I think 15" is to much pitch, especially with 600 lbs of weight. I think you are lugging your engine.

rich

Posted by CES on 07/21/08 - 8:50 PM

Binkie wrote:
My daughter runs a 10 1/4 x 14 on her `75 13 footer, with an `03 2 stroke Merc 40hp. and it really runs well. as about max. rpm. I think 15" is to much pitch, especially with 600 lbs of weight. I think you are lugging your engine.

rich

I'm running a 15 pitch with my setup and it runs like a bat out of.....well, you know. It runs well!