The Knotmeter on my 2003 Hunter 356 works for about a day after I launch. I'm told the paddles get fouled but why so quick and is there a solution?
Knotmeter
- Thread starter Deltabravo
- Start date
Mine does that too. I think some are more prone than others, mines an old Datamarine. I'm in fresh water, I coat the paddles with anti foul, but it doesn't stick well to the plastic and out doesn't take long for the mussels to clog it up. Don't know if there is a solution. Can you pull the core out of of yours and replace with a dummy plug? That process is a pain and lets a lot of water in the boat but you could leave the dummy in when you're not sailing.
axle
The axle and paddlewheel wear out and the paddlewheel "oscillates" on the axle instead of running smooth. Think of a worn front wheel bearing on your vehicle. I've replaced the the axle and paddlewheel about 4 times over a 25 yr period. Cost for the kit is about $25 from DMI.
The axle and paddlewheel wear out and the paddlewheel "oscillates" on the axle instead of running smooth. Think of a worn front wheel bearing on your vehicle. I've replaced the the axle and paddlewheel about 4 times over a 25 yr period. Cost for the kit is about $25 from DMI.
I can pull the plug but the knotmeter stops so quickly after launch I know it is not seaweed. Could a buildup of bottom paint cause the problem? The paddles spin freely when she goes into the water. When I had her surveyed, he said they never work in Hunters hence I only use my GPS but would like to know what the tides are doing to me.
Re: axle
Thanks Scott. Is this the part that would fit a Hunter:
P-6, 6 paddle replacement Paddlewheel Kits - $30.00
P-4, 4 paddle replacement Paddlewheel Kits - $35.00
Thanks Scott. Is this the part that would fit a Hunter:
P-6, 6 paddle replacement Paddlewheel Kits - $30.00
P-4, 4 paddle replacement Paddlewheel Kits - $35.00
Most important info here is the make of the knotmeter sensor (paddlewheel).
Mine did the same thing in our waters and it's due to a fine filament like growth on the paddles. I usually clean mine before leaving on a long cruise and it keeps working as long as the boat keeps moving every other day. When we get back, it seizes after a few more days and that's it until it's cleaned again.
I found it's not worth the effort and just use the GPS.
I wouldn't bother ordering a replacement kit until you know the make of the sensor.
Speedo
Last year the Raymarine speedo on my 2000 H340 would not function. I cleaned and replaced the wires on the back of the display unit but that did not help. I was able to scroll through all of the functions on the display head but still got no speed data. I pulled the transducer (almost no water comes in) and spun the paddle wheel but could get no reading. I ordered a new # RAYE26031 ST30 ST60 transducer from Boatersland and spliced it into the current wires from the thru hull. The new transduce fits the old thru hull but does not click into the detent for finding the correct forward direction. Raymarine suggested that I contact GEM ElectronicsCo., the maker of Airmar transducers at 803-693-0777 to get their recommendation on replacing the transducer.
Their method to Test the Speed Sensor:
• Verify that the transducer’s paddle wheel is free of marine growth and rotates freely on its shaft
• Power down the instrument
• Disconnect the GREEN and SHIELD transducer leads from the instrument display or instrument pod.
• Connect a multimeter to the GREEN and SHIELD transducer leads and configure the multimeter to measure continuity or resistance.
• Slowly rotate the transducer paddle wheel by hand. Note that as the paddlewheel is rotated, the multimeter should alternate between an open circuit and a closed circuit with each quarter turn. As such one complete revolution of the paddle wheel should open and close the circuit four times.
Should the multimeter respond as indicated above, then the speed sensor element of the transducer would be deemed functional. If not, then the transducer has failed and should be replaced.
The paddle wheel should have magnetic arms/cups and can be checked with an iron tool.
Also, water may enter the transducer and damage the electronics. Raymarine says to let it dry out for 24+ hrs and recheck for function as above. “O” rings must be intact.
Last year the Raymarine speedo on my 2000 H340 would not function. I cleaned and replaced the wires on the back of the display unit but that did not help. I was able to scroll through all of the functions on the display head but still got no speed data. I pulled the transducer (almost no water comes in) and spun the paddle wheel but could get no reading. I ordered a new # RAYE26031 ST30 ST60 transducer from Boatersland and spliced it into the current wires from the thru hull. The new transduce fits the old thru hull but does not click into the detent for finding the correct forward direction. Raymarine suggested that I contact GEM ElectronicsCo., the maker of Airmar transducers at 803-693-0777 to get their recommendation on replacing the transducer.
Their method to Test the Speed Sensor:
• Verify that the transducer’s paddle wheel is free of marine growth and rotates freely on its shaft
• Power down the instrument
• Disconnect the GREEN and SHIELD transducer leads from the instrument display or instrument pod.
• Connect a multimeter to the GREEN and SHIELD transducer leads and configure the multimeter to measure continuity or resistance.
• Slowly rotate the transducer paddle wheel by hand. Note that as the paddlewheel is rotated, the multimeter should alternate between an open circuit and a closed circuit with each quarter turn. As such one complete revolution of the paddle wheel should open and close the circuit four times.
Should the multimeter respond as indicated above, then the speed sensor element of the transducer would be deemed functional. If not, then the transducer has failed and should be replaced.
The paddle wheel should have magnetic arms/cups and can be checked with an iron tool.
Also, water may enter the transducer and damage the electronics. Raymarine says to let it dry out for 24+ hrs and recheck for function as above. “O” rings must be intact.
I agree with Ralph. Old school knot meters are unreliable and deceiving because of current, etc. Is there any reason why you wouldn't just use a GPS?
My knot meter still functions but I rarely look at it and when I do it's normally just to get a sense as to how much current I'm working with
My knot meter still functions but I rarely look at it and when I do it's normally just to get a sense as to how much current I'm working with
Fair enough. Guess I'm just not sophisticated enough to worry about it. I find the knot meter often registers a reading that doesn't make sense based on the tide, etc. Like you say, it's probably due to a back eddy or something but I rarely put it to any significant use. If the one my boat was broken I would have a lot of other priorities before spending money to fix it.That IS the whole purpose..
I pretty much clean my paddlewheel every time I go out. Just part of the prep in the cabin - turn on instruments, pull up floorboard, spin off collar, pull out transducer, stuff in plug, spin paddlewheel, clean alongside wheel with a tiewrap I leave in the space, brush it off with a stiff brush, pull the plug, rinse the wheel in the geyser, stuff it back in, put the board back in place. Go sailing.
Very few times have I sailed without the knotmeter. I use it to help tweak the sails or the heading. Current runs from nothing to 2.5 knots so gps only helps tell where the current is stronger etc or gives me an arrival time.
If I didn't have the flapper in the hole or the plug, I'd be tempted to buy a different transducer. Previous boat didn't have it so suffered through big geyser of water when I pulled the transducer to clean.
The one issue I have is beneteau installers did not leave any slack in wires so you can't pull the transducer up to a comfortable position for cleaning.
Very few times have I sailed without the knotmeter. I use it to help tweak the sails or the heading. Current runs from nothing to 2.5 knots so gps only helps tell where the current is stronger etc or gives me an arrival time.
If I didn't have the flapper in the hole or the plug, I'd be tempted to buy a different transducer. Previous boat didn't have it so suffered through big geyser of water when I pulled the transducer to clean.
The one issue I have is beneteau installers did not leave any slack in wires so you can't pull the transducer up to a comfortable position for cleaning.