Looking for better performance

[Numlaar]

Hi all,

I have a 1985 Riviera bowrider, with a 1976 Johnson 75hp Stinger.

My current prop is a 14x17p.

The boat weighs around 700lbs (boat, motor, fuel, batteries, etc.)

I top out at 32mph, (speedo, I dont have a GPS), and thats at 5500rpm.

I am looking for a prop recommendation to get a little more speed out of the boat, without losing bottom end. For a boat this light, with this much HP, it seems a trite slow.

I can get a 14x19p for cost from work (west marine), so wondering if this would be the one I should use, or something else?

 

[steelespike]

Re: Looking for better performance

Your 17" prop is right on as the "standard" prop and your boat sounds typical for the application.I do think your weight is optimistically light. typically a 15 ft fiberglass boat runs about 700lbs dry.I'm pretty sure with motor gear and gas your over 1,000.
then add people.Your at an ideal rpm for todays doctored fuels.
I think you may be able to work with your setup.The antivent plate(just above the prop) should be visable on plane.If not raise it until it is. In the extreme this could
result in 2 to 3 mph and additional rpm.Does the bow raise some when you trim out,or does it lay down flat like its glued to the water?Weight placement and elimination will help.Bottom clean and smooth.