Prop Diameter
WalleyeHunter
Posted 7/15/2007 9:36 PM (#58582)
Subject: Prop Diameter


Member

Posts: 238

What difference does prop diameter make? I was just wondering what a bigger prop would do on my boat...and how big I would dare to go? Hoe much of a gap do they require on the cavitation plate?

Any help?
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WalleyeHunter
Posted 7/15/2007 9:42 PM (#58583 - in reply to #58582)
Subject: RE: Prop Diameter


Member

Posts: 238

Also what does a 4th blade help achieve? New to the prop game and still looking?

Thanks!
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sworrall
Posted 7/15/2007 9:45 PM (#58584 - in reply to #58583)
Subject: RE: Prop Diameter




Location: Rhinelander
What brand motor/horsepower/ current prop are you running?
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KHedquist
Posted 7/16/2007 5:42 AM (#58586 - in reply to #58582)
Subject: RE: Prop Diameter



Member

Posts: 1991

Have you been to Mercs web site, they have some good info on props in there tech page.

A larger dia prop will more than likely decrease your rpm ballpark 200 rpm +- 100, as will adding 4 th blade if you stay with the same pitch, also blade surface area will decrease or increase rpm based on the prop, a 21` Tempest will be harder to turn than a Laser 21
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WalleyeHunter
Posted 7/16/2007 12:29 PM (#58611 - in reply to #58582)
Subject: RE: Prop Diameter


Member

Posts: 238

Sworral Im running a 115 Yamaha 4 stk. with a 13.25X19 right now in the second hole from the top as far as mounting goes...I was just really curious as to what affects diameter and extra blades have?
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KHedquist
Posted 7/16/2007 1:00 PM (#58612 - in reply to #58611)
Subject: RE: Prop Diameter



Member

Posts: 1991

I tried a 4 blade TRO4, I was not impressed, this prop was more for a Bass boat type hull, very little speed increase and a quite a decrease in rpm, what are you running now for a prop and some current performance data.

One thing I found with my Mr Pike with a F115,(the boat was rated for 135) is that if are not running the max hp, a change in prop pitch, blade design, number of blades, diameter is not as forgiving.

If you are looking at that 18p 4blade, that would make a good all around prop, dont expect a big increase of speed, but better hook up and bow lift.

Back when I got my Lund, I tried 6 differnt props on the same day each one was different, same pitch, but different styles, Laser 2, Vengaence, Trophy, and a Stilleto all where differnt speed, rpms, and bow lift
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budsbud66_w
Posted 7/18/2007 4:40 PM (#58703 - in reply to #58582)
Subject: RE: Prop Diameter


I always thought diameter is efficency.. You want the largest diameter prop you can fit safely. 4 blade and 5 blade props increase the surface area and work very will in producing a better hole shot, They also give your boat alot of control. Which is the reason you see bass heads running hi-5's those boats have more then enough power and control becomes more of an issue.

Once you understand these minor things.. there are another 100 things that are a factor in choosing a prop, including rake, pitch and cup. Different props can cause more lift from your hull or can produce more total lift.

What ever you choose. I recommend trying a few before you buy. And stainless is the only way to go for performance..

However if your planning on fishing inland lakes, flowages and rivers. pick up a cheap aluminum prop off ebay. for 40$ you can have a prop that will work fine and you wont be mad when you damage it.

The prop game can be very very addicting. have fun!
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