Knot meter repair

[Gary]

Can you pull out the thru hull paddle wheel while the boat is in the water and how would you do it?

 

[Warren Milberg]

Most Knot meter

... paddle wheels can be removed with the boat in the water. A lot depends on what kind you have and if you have a dummy plug to put into the through-hull (quickly!) when you pull the paddle wheel out. My Datamarine unit has a detent pin holding the paddle wheel in place. When you pull the pin and pull the unit up out of the through-hull, you basically have a 2 inch hole in the bottom of your boat = lots of of water coming in. Getting the dummy plug in place quickly is an artform.... Once you get the knack of this, most people can pull the impeller and only get a pint of water or so in the boat.

 

[Les Blackwell]

Do it with the boat moving at full speed

I learned a trick from someone many years ago when I installed my first knot meter. If you need to pull the paddle wheel, do it while the boat is under power going a hull speed. The water is going by so fast that very little comes into the boat. You should get very little water coming through the fitting.

 

[Roy Mosteller]

Not Hard To Do

The thought of having a hole in the bottom is a major worry but with practice I have learned to pull the impeller with about 1 to 2 pints of water being admitted. Make sure you have the proper size plug ready in one hand when you pull the impeller with the other. Work under several bath towels and they will keep the water from going everywhere and soak up much of it.

 

[Doug_Meyer]

Not a problem

My knot meter paddlewheel occasionally gets jammed up with those blasted Zebra Mussel babies. My transducer threads into the through-hull from inside and is provided with a cap to go over the opening when the paddle wheel is pulled. I just lay a towel downsteam in the bilge and quickly pull the wheel and cap the through hull. Very little water comes in.

 

[Jack W]

For what it's worth...

I friend of mine has an older boat and has lost the plug that came with it.He uses one of those emergency wooden plugs that you get from the marine store.He wraps a plastic bag around it which acts as a seal. It helps in removing as well. He also put a screw eye into the end with a line attached in case he has to muscle it back out.Seems to work for him.