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Author Topic:   Report on new prop - 13 Sport w/ 40 Merc

marbisi posted 08-14-2006 09:14 AM ET (US)
I was quite disappointed with my hole-shot, which made it somewhat of a challenge to pull kids on a tube or get the boat on plane with a full load. I also had trouble keeping speed in turns, so the kids were giving me a hard time about the "boring" ride....
Whaler told me that the factory set-up on the Mercury 40HP two-stroke came with a 10 3/8 x 14 prop, which proved to be a good prop for cruising, but was far too sluggish for watersports. So, based on the Mercury prop selector tool, I bought a new Mercury 10 3/8 x 13 prop. The prop on the boat turned out to be a 10 7/8 x 14, so I went down in both pitch and diameter.
All I can say is that the new prop has resurrected my 13 Sport! I'm not interested in top end speed, and the boat now really comes out of the hole, and maintains speed in turns with a little throttle. My son was the first one on the tube with the new prop, and I put him in a slingshot that nearly had him even with the boat! With the other prop, I could barely get the kids out of the wake.
I haven't been able to conduct any testing, but the old prop limited max engine RPM to 5,200-5,300, slightly below the engines rating of 5,500. It looks like the new prop will get the max RPM's to 5,500, or perhaps slightly higher. I do wonder if a better compromise would have been the 10 7/8 x 13, but I'm thrilled with the performance of this new prop.
From a speed perspective, I'm guessing I probably lost 3-4 MPH on the top end, but again, cruising at 20MPH is more than sufficient for our usage, so we gained everything and lost nothing.
For those that said the 13P was the right prop for this particular boat/engine combination, you were right on the money!!!!!
Thanks!
Operaman posted 08-14-2006 01:36 PM ET (US)
Gotta tell ya, success for me also this past weekend. There is a nice thread about speed in a 13 Whaler and it gets into prop size pretty good. Mine is an 87 SS with an 87 Evinrude 40. I went from a 11.75x17 to a 12.5x13 and like you, I am speeding in the fun zone. I now get what people are talking about when the say a 13 Whaler is so much fun. I could be turning a little highr rpm's, but it is definately in the acceptable range. I am in the middle trim pin hole (can go two more higher) and getting 5100-5200 with a max of 5500. Planes off with a load, even in the back. Took my neighbor for the first ride with the new prop. He says, wait a minute, I will lean foward so we can plane off. I stated he should stay right where he was. Well, he couldn't stop going on about how he never saw a 13 foot get up on plane like that. Glad it worked for you also.

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Author	Topic: Report on new prop - 13 Sport w/ 40 Merc
marbisi	posted 08-14-2006 09:14 AM ET (US) I was quite disappointed with my hole-shot, which made it somewhat of a challenge to pull kids on a tube or get the boat on plane with a full load. I also had trouble keeping speed in turns, so the kids were giving me a hard time about the "boring" ride.... Whaler told me that the factory set-up on the Mercury 40HP two-stroke came with a 10 3/8 x 14 prop, which proved to be a good prop for cruising, but was far too sluggish for watersports. So, based on the Mercury prop selector tool, I bought a new Mercury 10 3/8 x 13 prop. The prop on the boat turned out to be a 10 7/8 x 14, so I went down in both pitch and diameter. All I can say is that the new prop has resurrected my 13 Sport! I'm not interested in top end speed, and the boat now really comes out of the hole, and maintains speed in turns with a little throttle. My son was the first one on the tube with the new prop, and I put him in a slingshot that nearly had him even with the boat! With the other prop, I could barely get the kids out of the wake. I haven't been able to conduct any testing, but the old prop limited max engine RPM to 5,200-5,300, slightly below the engines rating of 5,500. It looks like the new prop will get the max RPM's to 5,500, or perhaps slightly higher. I do wonder if a better compromise would have been the 10 7/8 x 13, but I'm thrilled with the performance of this new prop. From a speed perspective, I'm guessing I probably lost 3-4 MPH on the top end, but again, cruising at 20MPH is more than sufficient for our usage, so we gained everything and lost nothing. For those that said the 13P was the right prop for this particular boat/engine combination, you were right on the money!!!!! Thanks!
Operaman	posted 08-14-2006 01:36 PM ET (US) Gotta tell ya, success for me also this past weekend. There is a nice thread about speed in a 13 Whaler and it gets into prop size pretty good. Mine is an 87 SS with an 87 Evinrude 40. I went from a 11.75x17 to a 12.5x13 and like you, I am speeding in the fun zone. I now get what people are talking about when the say a 13 Whaler is so much fun. I could be turning a little highr rpm's, but it is definately in the acceptable range. I am in the middle trim pin hole (can go two more higher) and getting 5100-5200 with a max of 5500. Planes off with a load, even in the back. Took my neighbor for the first ride with the new prop. He says, wait a minute, I will lean foward so we can plane off. I stated he should stay right where he was. Well, he couldn't stop going on about how he never saw a 13 foot get up on plane like that. Glad it worked for you also.