3 vs 4 bladed prop

[Dale L]

I am going to buy a spare SS prop. I would like to know if I can improve low to mid range performance because I do mostly towing of skiers/tubers. I would like opinions on whether a 4 bladed SS prop would help - or stick with the 3 bladed prop I currently have.
This is the data on the boat & prop:
Prop: Turning Point Express, 14-1/4" dia X 17" pitch, SS, 3 blade
Boat: 2006, 386 Stratus (fiberglass) with 150 hp, 4 stroke Yamaha OB
Weight: approx. 2,000# empty, gas tank capacity = 32 gal
Weight as loaded for trials: 3,250#
Wind: 10-15 mph with light chop (Minnesota lake)
@ WOT: 42.6 mph @ 5,625 rpm (speed by gps & avg of into and with wind)
Time to plane: 5.2 seconds

 

[craze1cars]

Re: 3 vs 4 bladed prop

The closer you can get that motor to its 6,000 rpm max (I believe that figure is accurate??? can you confirm) the better it will pull skiiers.

Since you already have a very good 3 blade prop for cruising, etc, and you want another stainless, I'd recommend trying a 15 pitch in a 4 blade Stainless. I find it pretty hard to beat a Solas HR Titan for value/performance/price...

 

[Texasmark]

Re: 3 vs 4 bladed prop

4 Blades have more surface area and thus more water interface which translates to more engine thrust to speed for a given set of conditions. Usually preferred for a high load condition as you mention you have. 3's can do it, but 4's can do it better....but 4's usually cost you in top end as you have more losses....but it seems top end is not what you are looking for. Last, to recommend a 4 of whatever mfgr and style over your current 3 is pure lunacy.....too many unknowns.

Your numbers mean nothing to me as I would have to be there and experience your situation and have variable resources to experiment with to get you the best solution.

I would suggest that you go to a reputable prop shop where you can try props till you get what is best suited for you. You will have to return the prop undamaged (in saleable condition as new) and expect to compensate the dealer for his time and trouble.

I would write the cost off as the best money you ever spent for when finished, you will have a boat with which you are satisfied over the years and the money you spent is gone forever. If you low ball it you probably will be out the money and out the enjoyment and if you are out the enjoyment, why are you boating in the first place.....food for thought....good luck.

HTH,

Mark

 

[Dale L]

Re: 3 vs 4 bladed prop

Thanks for the input. I am leaning towards reducing the pitch to 15" or 16". As to the variety of props available, it seems endless!! I will see if I can get a local marine dealer to let me try one out and return it if I don't like it. The literature I see on the motor says 6,000 rpm is the top end so I want to get a little closer to that.
Dale