Whaler Central - Boston Whaler Boat Information and Photos

Posted by e_digg on 05/12/14 - 7:04 AM

I have a 1966 13' with a 1988 Yamaha 2 stroke 25hp short shaft. Current prop is 3 blade aluminum and has stamped "9 7/8 X 11 1/4 F". Do you know what the F stands for? The issue is that our family is getting older and bigger. We took the boat out for a spin and just like the end of the summer, we don't get up on plane. There also has not been enough power to go tubing with 1 other person on board. The current prop is probably original and it is not at all perfect. There are some divots and small bends. What do you suggest for pitch? This is the kids' boat so I don't really care about top end speed.

Thanks
Ed

Posted by kamie on 05/12/14 - 5:15 PM

Did the prop used to work? It's possible that you just need a new one of the same size. Do you have a tach on the boat so you know what RPM's your actually getting too?

Posted by e_digg on 05/12/14 - 7:47 PM

Hey Kamie! There is no tach but I can tell it's not getting to higher rpm with a full load. I think a different prop should do the trick but I am not sure how far to go down in pitch. Also the SS props have the lip but I don't want to sink too much into this.

Posted by e_digg on 05/19/14 - 5:53 AM

Bump.

Or

How about answering this question: If the current pitch is 11 1/4, and I want to have quicker take off's then do I go a higher or lower number in pitch? How much higher or lower?

Thanks
Ed

Posted by e_digg on 05/19/14 - 7:34 AM

MarkTemplar wrote:
Get a 1:13 pitch prop. Plenty of websales. I use Iboats.com. You'll be fine.

Increasing the pitch will be for faster top end speeds, not faster hole shot, correct? Or am I backwards?

Edited by e_digg on 05/19/14 - 7:48 AM

Posted by Joe Kriz on 05/19/14 - 9:59 AM

Ed,

Less pitch will give you a faster hole shot but only in the same brand of propellor.
If you switch brands of props, you will need to start all over again or rely on others with your same setup.

You may not reach full RPM with a full load. That is why using a tach to setup a prop using the recommended WOT is the way it is done.
Light load, WOT specifications, etc., then the motor runs within the manufacturers recommendations at all the other speeds.
http://www.whalercentral.com/articles...cle_id=108

Posted by tothemax on 05/19/14 - 10:13 AM

I had a Honda 9hp on a RIB inflatable that worked fine and then one day it wouldn't get on a plane. Engine ran fine and the prop didn't look damaged but on close inspection there were a couple of knicks and a very small dent from hitting a piece of wood or grounding. Talked to my dealer and he said with smaller outboards a knicked prop can make or break performance and suggested I clean up the prop with a file as a test. Worked like charm... we eventually replaced the prop.

Edited by tothemax on 05/19/14 - 10:15 AM

Posted by MarkTemplar on 05/21/14 - 11:02 AM

Correct me if I'm mistaken, but by *hole shot* you're talking about how quickly boat planes from DIW? If so, I've noticed 13' Whaler planes rather quickly. Indeed, much quicker than maybe a deep V hull featuring same power plant and same length. What's OP trying to accomplish? A ski boat?

If OP is attempting to have a 13' Whaler w/25 hp motor lug a full load while attempting to pull a skier, I think there's to be frustration even when the motor's working within its power band no matter what prop pitch.

JMO.