A good all-around prop for a '00 Launch

[Launchman2000]

Just got my boat out last weekend and it seemed a little sluggish to me. I had bought it a couple months ago and had it at the shop for an engine service and a few small issues. I have the 310 hp Indmar engine. I have an OJ 13 x 12 3-blade, pretty sure it is left hand looking at the shape of the prop. It matches the OJ website list for Supra boats, I assume it was the original stock prop. From my past boating experience, I know smaller pitch props give you better hole shot and more power. Is it possible this prop is just too small for this size boat? Is a 4 blade prop better for all around use? I have about 2 inches of clearance now between the prop, hull, rudder and trailer. So I assume there is room to get a little bigger prop.

This is going to be mostly a family boat doing everything from tubing, skiing, wakeboarding, etc.

This is my first inboard boat to own so I still have a lot to learn. Thanks for any suggestions.

[jasonwm]

There are a number of props that would work very well for you, so ultimately it will depend on which aspect of the performance you want to optimize.

There are two main measurements we use to determine how a propeller will perform:

Diameter: All else being equal, a larger diameter prop will result in blades that have a larger surface area, which means the prop will transmit power to the water better. That will make for better acceleration, but the additional mass of the prop will limit the top speed of the boat.

Similarly, a 4 blade prop will generally have more surface area than a 3 blade, which makes them better for applications where acceleration is important.

Pitch: All else being equal, a prop will lower pitch will have better acceleration, but lower top speed, than a prop with a higher pitch.

It's the balance of these two characteristics that makes selecting the correct prop difficult, and that's why it's important to work with someone that has a lot of experience.

Because your Launch is at the lower end of the weight spectrum, I would suggest sticking with a 3 blade so that you have good blend between acceleration and top speed. If the prop that's on your boat is indeed a 13" (diameter) x 12" (pitch), then it doesn't sound like that's the stock prop. A 13x13 would have come on your boat from the factory in 2000.

I would look at either an ACME 525 or an OJ 310, both of which are 13" x 11.5" props, so you'll get an upgrade in terms of acceleration at slow speeds, but you won't give up a lot of top end.

If you have any other questions let me know.

[Launchman2000]

Thanks for the help, very informative.

[jasonwm]

No problem, let me know if you want to demo either or both of the props.