Propeller question

[richardh10]

Possibly a bit of a dim question, but how do you tell when your prop needs replacing rather than just polishing. I had a few problems with cavitation last year and I think it is down to the prop.

Assuming that it does need replacing(I'm working on the assumption that the most expensive option will be the one I have to take!), where is the best place to get one?

Cheers

 

[rbmatthews]

I am not sure why the prop would cause cavitation unless there is obvious damage - i.e. bits missing or bent - or growth on it. If it is an outboard you are talking about, check that the anti-ventilation plate is level with or about an inch below the bottom of the transom.

Rob.

 

[richardh10]

I am not sure why the prop would cause cavitation unless there is obvious damage - i.e. bits missing or bent - or growth on it. If it is an outboard you are talking about, check that the anti-ventilation plate is level with or about an inch below the bottom of the transom.

Rob.

There was some growth on it, but there are also some chips out of the blade. Maybe the combination of both these things? If not, I'm a bit stumped as to what did cause it.

And it's an inboard

 

[rbmatthews]

Try each one in turn. It shouldn't take much to remove the growth and see if that makes any difference.

R.

 

[richardh10]

Slight problem in that the boat is out of the water at the mo and I wanted to try and get,it sorted before I go back in. I suppose filing the chipped edges back is not a good idea? Clean it, file the edges and see what happens?

I don't use the engine that often, but its useful to have it working on the occasions when I do! Unlike the time when I was in forward gear being held completely stationary in the river about 2ft from my mooring!

 

[oldsaltoz]

Getting the chips professionally repaired and the prop re balanced will cost a tiny fraction of replacement cost.

Good luck and fair winds.

 

[Tranona]

As you know your prop runs in a very small aperture behind a long keel and cavitation is not unknown. Suggest you get the prop refurbished and checked that it is an appropriate size for your application. Props don't wear out so don't need replacing if the metal is still sound, and of course they are the right size. You can get an idea of what the correct size should be by feeding your boat's data into the Propcalc programme on www.castlemarine.co.uk