Prop for Honda BF9.9D on Valco 14

zzz503

Recruit
Joined
Oct 21, 2019
Messages
1
1) Performance issue you are trying to correct:

I decided I want to carry a spare prop, especially taking the skiff outside in San Diego. And if I am going to get a second prop, I want to figure out if something other than the stock prop would be a better fit for my (light) boat.

Basically the 9.9 is used as a kicker for a lot of larger, heavier boats. I've got it as the main (only) motor on a small, light skiff, so I imagine I can get away with trading off some thrust. I would be interested in improving speed and/or possibly fuel economy.

Boat gets on plane no problem with the current prop.

2) Current prop manufacturer, model, aluminum or stainless as a minimum.
Stock Honda 4 blade Aluminum
3) Current prop diameter and pitch (required).
9.25" x 8"
4) Wide open throttle RPM and speed with an average load (very helpful)
No tach (tiller model engine). WOT max speed with current prop is about 16-17 mph. (Unfortunately I have no idea what the RPM is at WOT, given the lack of a tach).

5) Engine/drive make, model, year, and HP
Honda BF9.9D 2006 (9.9HP)

6) Boat make model, year, length and weight
Valco U-14 1995, 14.33 feet, hull weight 150 lbs. Max capacity 975 lbs. (and 25HP)
I weigh about 160 lbs., sometimes have another person aboard. usually not a lot of weight in gear. I usually have to make sure to carry some weight in the bow to keep the boat level (anchor, sometimes water jugs).

I would almost certainly go AL for a new prop. Looking at the Solas props. Questions are mainly 3 or 4 blades, and then what pitch?
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,782
My experience with engines of that size on small, light boats is that pitch isn't all that critical. The OEM supplied general purpose prop that comes with the engine is good for most applications. Main thing is those engines usually aren't monitored by tachometers so playing with props is just a crap shoot. BTDT
 

WesNewell

Chief Petty Officer
Joined
Jan 3, 2018
Messages
497
If the boat is truly under 200#, with 200# person and gear, you should be able to get at lest 25 mph out of it with the proper prop. My guess would be a 12p. The 8p is made for moving a much heavier load and you are probably maxing out the revs with an 8p prop now on such a light boat. The difference in speed between an 8P and 12P prop at 6000 rpm is ~11 mph. Would probably want an 11P for 2 people.
 
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