Prop Question

[JPritch]

The full throttle operating range on my boat is 5000-6000 rpm (Yamaha F60), max power 60hp@5500rpm.

My current prop is 11x15 aluminum. I can get up to 5000rpm but no higher. I would really like to get into the upper end of that operating range and improve my hole shot which is terrible, especially if I have a passenger on board.

My prop has been banged up through the years, all 3 blades have some gouging on the edges, and one blade has a slight bend in it. Is that type of wear and tear enough to keep me from getting 5500+, meaning I could just get the same replacement prop. Or would I still need a smaller pitch prop to overcome that hump?

I never got to fully test the capabilities of that prop when it was new b/c my motor had fuel issues from basically day 1, which I've since fixed. The motor would never get above 4500rpm but now gets 5000 just after revamping my fuel system. Now I'm just looking to squeeze out the rest of its potential.

I appreciate the help.

 

[steelespike]

Re: Prop Question

Really need more info.Need rpm and speed,dry weight of boat or model and year. al or fiberglass?

 

[JPritch]

Re: Prop Question

I've never measured top speed or speed at certain rpm's, my boat isn't equipped to do so.

The boat weight is 975 lbs (2006 Cape Craft 16cc), fiberglass.
http://www.capecraftfishingboats.com/boat_details.php?model=16cc

I also run off a portable 12gal fuel tank placed in the back of the boat). I'm also 275#. I keep all my gear stored in the front to offset some of this weight. When another adult is aboard, I usually can't get on plane unless that person goes and sits up front.

I hope this helps.

 

[sublauxation]

Re: Prop Question

Easiest thing would be to get the current prop fixed then try it out. It should around $40, and if you don't get the performance you need at least you'll have a spare.

 

[steelespike]

Re: Prop Question

OK Your 15" pitch is only 2 props down from highest pitch.And your pushing a chunk of weight.
Rule of thumb is "about" 200 rpm change for each inch of pitch. You need to makeup "about" 1,000. If you go to a 13" pitch it should put you at "about" 5,800. This should help your problems.You can also check your motor height.The antivent plate(just above the prop) should be visable at speed.Usually ends up about an inch higher than the bottom of the boat.In the extreme you could gain a couple of mph.If you borrow/buy a gps you could check your speed.

 

[JPritch]

Re: Prop Question

Thanks for the replies guys. I have a 11x15, and I see where I can get either a 10 3/8 x 13 or an 11 1/8 x 13 as the two closest options made by Yamaha. Either one better for me?

Also like the idea of getting the old prob refurbished and keeping it as a spare!

 

[steelespike]

Re: Prop Question

Usually diameter is not a consideration but I like to stick close to the original diameter
so the 11 1/8 seems a good bet to me.I also believe the larger prop will resist venting better.
Being 3/4" smaller the smaller prop may rev easier.But likely difference will be little.

 

[JPritch]

Re: Prop Question

I am about to purchase the prop....do I need to buy any of the other hardware I see listed for it......thrust washer, spacer, washer, prop nut? I assume I'll need a cotter pin and a prop wrench.

Sorry for the simplicity of my questions, props are an entirely new thing to me.

 

[Home Cookin']

Re: Prop Question

you should be able to reuse your washers spacers and prop nut, but sinc eyou are keeping your old one for a spare, think about gettnig a spare prop nut too--lose that and you are out of business no matter how many spares you have.
likewise buy extra cotter pins. I have float tested them and they fail.
I have never used a prop wrench and think it must be like a metric crescent wrench or a sky hook.