Propeller pitch question

[kitestir]

I have a 17' Sea Nymph Aluminum(deep v) Fish N Ski with a 1983 Mercury 90 hp I-6. The current prop is a 19p 48-77346.( As marked on the side). The previous owner cut the blades down to get a better hole shot for skiing. The diameter is now approximately 12.5 inches. My problem now is that the propeller needs to be replaced and I am not sure what to put on it for a prop. There is no tach so I cannot tell what the RPM's are. With the current setup and 2 people in the boat she gets to 39 MPH which seems a bit slow to me with this setup. The boat is relatively light with little extra gear. I am looking at getting a tiny tach but that really won't help me pick the initial prop. How should I go about finding a new prop??? I was thinking of another stock 19p as that is what was with the motor originally.

Sorry for the rambling and thanks for any suggestions.

 

[Dhadley]

Re: Propeller pitch question

Sounds like the old owner didn't have a lot of good advice sent his way, what a shame. Just from what you've described a decent 17 or 19 would seem to be a good starting point. It stands to reason if he messed with the prop design the whole thing might be off target as you found out. Obviously a tach is a must.

 

[hwsiii]

Re: Propeller pitch question

I am showing a current all up weight of about 2,200 with 3 people in the boat loaded regularly. You should be running a mercury 13 x 19" prop as you have on there now. And it should be getting into your upper RPM range at WOT and you should be doing about 36 MPH.

H