Looking for prop recommend for CL340 w/ console - Honda BF20D

[geekoman]

I am looking for a recommended propeller for our dinghy. I know the engineered approach is to test with various pitch props to achieve WOT, but, I suspect there are cruisers that have done this process and have an acceptable solution.

Our dinghy is a CL340 with console and is powered with a Honda BF20D outboard. The prop that came with the dinghy is 10 x 9.5, 4 blade Honda prop - the standard for the BF20D.

I was looking for better performance when moving 4 - 6 adults, watching how other dinghys performed seemed to move to plane with even 6 people on board. High speed is not necessary, just getting to plane with up to 6 (usually 2, sometimes 4) people and snorkeling gear.

I purchased a spare prop, and was only able to get a 3 blade, same pitch and diameter. I put it on yesterday and noticed significant speed increase. But, now I want to make sure this is the right/best thing to do.

I will be buying and installing a dolfin once we get back in to the States.

Anybody have a CL340 w console and 20HP outboard that can recommend a prop size they really are happy with having installed?

[a64pilot]

Buy a tachometer, otherwise you pretty much have to buy a bunch of props.

The fewer blades generally make for higher speeds as there is less drag, more blades are usually for more “bite” at lower speeds, high thrust props for example will have more blades.
However four blades props are generally thought to give the stern more lift, or hold the bow down, same thing.

Those wings on an outboard are a patch at best, they correct for an incorrect setup. They work by generating lift, which raises the stern, lowers the bow, but if an engine is trimmed correctly and the boats CG is correct, they are not needed and are only excess drag.
Ever wonder why no engine is supplied from the factory with them installed?

If your dinghy is a center console and you cannot move your weight forward, that is when you need to go with a Dolefin or similar, but fixing the proposing etc with the engine height and trim being correct and the boats CG being correct is the best way.

I bought this tach for my motor and used it to ensure my prop was correct, but it’s also an hour meter and I can schedule services based on operating hours, I also put on on my Honda generator.
You would think these high dollar, electronic controlled engines would have an hour meter that the user can access. The engine ECU tracks hours, but only the dealer can access it.


Planing your big dinghy with 4 to 6 people and gear with only 20 HP is going to be tough, you will likely need a prop that with only one person that you will hit the rev limiter.