Knotmeter Paddlewheel

Jun 23, 2010
6
Hunter 31 foot Sausalito
Had a diver clean my 31' Hunter (1984) last week. My Knotmeter has not been working. He told me the paddlewheel is shot. He thought it would be an easy fix, if I can find a paddlewheel to replace the busted one. Anybody have experience with this issue??
 
Jul 27, 2013
298
Hunter 37.5 1065 Rock Hall, MD
It could be the paddlewheel or the recieving unit. Is it a stowe product?

Ben
 
Jul 27, 2013
298
Hunter 37.5 1065 Rock Hall, MD
The paddlewheel shoud be easily removable, and there should be a cap that screws onto the through hulll so you can take the paddlewheel out when not in use. This way, you can clean out the paddle wheel frequently without diving for it.

If it is stowe, i had the display refurbished, and got new paddle wheel parts. They were really great about it.

Ben
 
Jul 27, 2013
298
Hunter 37.5 1065 Rock Hall, MD
Can you see the paddlewheel transducer when you pull up the floor boards?
 
Jun 23, 2010
6
Hunter 31 foot Sausalito
I need to go down to the boat and poke around. The diver told me the location is port side just forward of the keel. I know there is a cap on a through hull of some kind close to that location, which is just outside the head. I don't recall any cables running to it though.
 
Jul 7, 2010
30
Hunter 31 Deale
I have the exact same boat, the knotmeter that was installed in mine was a Datamarine S-100KL knotmeter.

A replacement sending unit with paddlewheel was $130.00 I don't know if they sell the paddlewheel itself separately.

Contact:
DMI Marine Inc. 18 Commerce Park Road Pocasset, MA 02559 Tel-508-564-7491 fax-508-564-7497 dmi@dmimarine.com www.dmimarine.com
 
Jul 27, 2013
298
Hunter 37.5 1065 Rock Hall, MD
The OP boat is a 1984. Dmi was established in 2001. Guess it was aftermarket installation 7 years later?
 
Jul 27, 2013
298
Hunter 37.5 1065 Rock Hall, MD
John, I forgot to mention that despite getting the knot meter all fixed up, I use speed over ground from my iPad running isailor. I don't even fuss with putting the paddle wheel in, but I have it available if I want to detect current, etc.

Ben
 

braol

.
Apr 16, 2014
348
Hunter 27 Rebel 16 Great Lakes Naval Base, IL
John, I forgot to mention that despite getting the knot meter all fixed up, I use speed over ground from my iPad running isailor. I don't even fuss with putting the paddle wheel in, but I have it available if I want to detect current, etc.

Ben
Speed over the ground is great when you are headed for a destination but I find speed through the water becomes informative when trying to maximize performance. Those pesky paddlewheels are one of the first things i look at at haulout (also one of the things most easily broke by a lift...).
 
Jul 27, 2013
298
Hunter 37.5 1065 Rock Hall, MD
Speed over the ground is great when you are headed for a destination but I find speed through the water becomes informative when trying to maximize performance. Those pesky paddlewheels are one of the first things i look at at haulout (also one of the things most easily broke by a lift...).
You know, that is a great point about sail performance feedback. Doesn't matter that the paddle wheel is off from SOG, but you get much faster feedback in terms of either a gain in speed or a loss of speed when trimming sails looking at the paddle wheel knot meter. Good point.

Ben
 
Jun 23, 2010
6
Hunter 31 foot Sausalito
What does "shot" mean? Broken paddlewheel blades? Who is your diver?

Boat Bottom Cleaning Service, Christopher Steinberg

He said the paddle wheel had broken off, but that it looked like it would be fairly easy to replace the paddle wheel if I could find a replacement part. I need to go down to the boat and see if I can determine who the manufacturer was.
 

Scott

.
Sep 24, 1997
242
Hunter 31_83-87 Middle River, Md
As Bob said, call DMI. Datamarine was the OEM on my '86'. They went out of business for a short period of time and resurfaced as DMI. I think over the years I have purchased 2 or 3 paddle wheel kits for about $23 each. Usually the axle wears causing vibration/malfunction.
 
Jun 1, 2009
1,822
Hunter 49 toronto
Reccomendation

As Bob said, call DMI. Datamarine was the OEM on my '86'. They went out of business for a short period of time and resurfaced as DMI. I think over the years I have purchased 2 or 3 paddle wheel kits for about $23 each. Usually the axle wears causing vibration/malfunction.
Not sure when you're hauling out next.
When you are, install a current unit.
You can buy a used Raymarine km on ebay for 100 bucks or so.
Just a better use of your dough
 
Dec 19, 2006
5,818
Hunter 36 Punta Gorda
Look

Look top the transducer for the name and if Airmar should be able the pull
it out and put in plug but if Airmar.
Nick
 
May 28, 2009
764
Hunter 376 Pensacola, FL
The speed transducer is probably from Airmar. You can buy a rebuild kit from them that will include a new paddle wheel and axle.

http://www.airmartechnology.com/index.php

Or check with your local marine supplier.

The transducer should be removable, and you should unscrew it and remove it and insert the blanking plug when you're not using the boat. That will keep the wheel clean. If you're in salt water, I've found that setting the transducer in a cup of vinegar does a good job of removing marine growth if I forget to remove it and barnacles start forming.