# Prop/motor guards?



## Duece22 (Mar 30, 2004)

First of I have a 16 foot flat bottom with a 25hp short shaft motor that I use for river fishing. I have been looking at getting a prop/motor guard and was wondering if anyone had any input on them. The two I have been looking at have been "The Rockhopper Motor Guard" and the other is "Mac's River Runner" If anyoe has any input on them or any other guards it would be much apreciated. 
Thanks
Ric


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## frenchriver1 (Jul 5, 2005)

Dont know about any commercial rock guards, but have seen two homemade ideas that you might try, a pitchfork head welded to the front of the skeg, the curve toward the motor, so as to protect the prop, and a circle of steel that you form by bolting into your cavitation plate. Have to get the right kind of steel and width to protect the prop, but you screw one end down on the cavitation plate, and then force the steel into a circle that surrounds the prop, and then bolt the other end to the other side of the cavitation plate. Simple but effective.


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## sdanville (Jan 16, 2006)

I was wondering if anyone has testedd the effiiciency of with and without a prop guard.
I have a little 14' Sstarcraft with a 5 HP Honda with a prop guard. I cannot afford to lose any power. I often wonder if the guard slows it.


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## BVG (Nov 18, 2004)

I have a Mac's River Runner on my Duck Boat. 16 foot Sea Nymph with a Mercury 40 Hp. 
I hunt Saginaw Bay and would rebuild a couple of props every year, and buy a replcement every second year or so.

I have not replaced or rebuilt a single prop since I installed the Mac's River Runner.

I have hit rocks and logs on plane and plowed through gravel at slow speed.
The worst damage I have had is a couple of nicks where gravel got between the prop and the guard.

I see no difference in performance.


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## frenchriver1 (Jul 5, 2005)

sdanville said:


> I was wondering if anyone has testedd the effiiciency of with and without a prop guard... I often wonder if the guard slows it.


My son the genius would offer that if the guard forms a tight circle around the prop, it may follow the same laws of physics of a similar set-up with a propeller, and a ducted fan propeller is more effective than a non-ducted propeller... Has to do with the flow within the circle of the duct.

My guess is that any loss of power is proportional to the square inches of the guard exposed to the water flow, the bigger the area the higher the drag and resultant loss of "power"... Any guard would cause some additional drag, no way around it...

Also, the guard disrupts the clean smooth flow of water to the prop, so again a loss of "power." It is a question of whether the loss of power is worth the occasional need for the guard, depending on the waters you plow through...


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## Hotwired (Jan 24, 2001)

Duece22,
Check out this article.
If you want the guard to prevent wire in the prop, make your own.
If you want it to protect in shallow water, buy a Mac's.
I have a Mac's on my 6hp kicker and I love it with very little loss in power.

http://www.dwfonline.com/propellor_guard_-_$75_or_$5.htm


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