Hey there! I just ran into another horror show while re bedding all the stuff going thru the hull on my hunter 34, The speed sending unit with the paddle wheel was just resting in the hull with some 4200 gooped around it! After we removed it we found that it does not appear that it is the original because the diameter of the tube it is resting in does not seem to be the proper diameter and one of the wings on the paddle wheel is broken off! When we checked it by rotating the wheel we get a reading on the gauge. Any ideas here where I can get the correct mushroom to for the unit!
Hunter 34 speed sending unit puzzle!
- Thread starter hunter healer
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Insufficient info. What type, manufacturer, model speed log is it? The boat model is not an indicator of what instruments you may have.
ST30?
Your unit looks very much like the Raymarine ST30 speed transducer that I have on my 2000 H340. Mine went bad last year. Raymarine no longer supports theST30 instruments but I found that an Airmar replacement transducer, Raymarine #E26031 – for ST30/ST60 will fit the old thru hull fitting and drive the ST30 display. I found a new transducer with a complete thru hull fitting and plug on the Internet for about $60 (Just Google Raymaine #E26031). The new transducer also has the ability to measure water temperature but that function is not supported by my ST30 display. If the display also fails, Raymarine says that their ST40 display will work with the old or new transducer. Raymarine also suggested that I could contact GEM Electronics Co., the maker of Airmar transducers at 803-693-0777 to get their recommendation on replacing the transducer.
It was impossible for me to route the wires from the new transducer to my cockpit display without destroying most of the boat's interior. I spliced the new wires together with the old wires and the speedo works just fine
Your unit looks very much like the Raymarine ST30 speed transducer that I have on my 2000 H340. Mine went bad last year. Raymarine no longer supports theST30 instruments but I found that an Airmar replacement transducer, Raymarine #E26031 – for ST30/ST60 will fit the old thru hull fitting and drive the ST30 display. I found a new transducer with a complete thru hull fitting and plug on the Internet for about $60 (Just Google Raymaine #E26031). The new transducer also has the ability to measure water temperature but that function is not supported by my ST30 display. If the display also fails, Raymarine says that their ST40 display will work with the old or new transducer. Raymarine also suggested that I could contact GEM Electronics Co., the maker of Airmar transducers at 803-693-0777 to get their recommendation on replacing the transducer.
It was impossible for me to route the wires from the new transducer to my cockpit display without destroying most of the boat's interior. I spliced the new wires together with the old wires and the speedo works just fine
Re: ST30?
Thank you I will take a closer look to see what type of head is being used. I found the orig bronze transducer in the boat I may be able to take the paddle wheel off of that one! The o rings around the transducer where would I find them? Its a little strange that there is not a notch in the mushroom for the transducer to lock into maybe with new o rings it will fit snug!
Thank you I will take a closer look to see what type of head is being used. I found the orig bronze transducer in the boat I may be able to take the paddle wheel off of that one! The o rings around the transducer where would I find them? Its a little strange that there is not a notch in the mushroom for the transducer to lock into maybe with new o rings it will fit snug!
I hope that you are able to get a replacement paddle wheel so that you can have an accurate speed indication.
Your post indicates that only 4200 was holding the sending unit. The retaining ring was not threaded onto the fitting?
McMaster-Carr carries O-rings and many other useful items. I had a good experience getting stuff from them.
Your post indicates that only 4200 was holding the sending unit. The retaining ring was not threaded onto the fitting?
McMaster-Carr carries O-rings and many other useful items. I had a good experience getting stuff from them.
Still cannot find a supplier for the paddle wheel! I have the original bronze unit but the paddle wheel is a little different ! I'm going to try to exchange it I have nothing to loos
My suggestion is to eliminate the speed sensor at your next haul out. That paddle wheel just slows you down and provides a place for underwater growth. You already get your speed over the ground through GPS.
Sorry, Can't let this pass
You claim a paddle wheel slows down the boat?
You can flick a paddle wheel with your little finger.
This is about 6 orders of magnitude less than what it takes to drive the hull through the water.
Look at it another way. Jump off the boat. Now, with all your might try and push the boat. Then with your small finger, tap your wrist.
I respectfully hope this makes sense.
My friend,,,
You claim a paddle wheel slows down the boat?
You can flick a paddle wheel with your little finger.
This is about 6 orders of magnitude less than what it takes to drive the hull through the water.
Look at it another way. Jump off the boat. Now, with all your might try and push the boat. Then with your small finger, tap your wrist.
I respectfully hope this makes sense.
That paddle wheel is in continuous operation. Lets just say it reduces speed by 1/100 of a mile per hour. 1/100th of a mile is 53 ft. For a typical 5 mile race that is 265 ft. - AND you can have that 265 ft with no investment or applying any skill! I have been in a lot of races that were decided by less than 265 ft. Now, I do not know if the 1/100 of a mile per hour is at all accurate, but any speed increase adds up over time.
I like your logic
Let me put this even more in perspective.
(I used to service instruments so I know this real well)
If you take a raymarine paddle wheel and blow on it, it will read between 6-12 knots, depending how hard you blow.
So, put your hand in front of your mouth.
Blow real hard. That's the drag at 12 knots.
The water resistance is so small, it's immeasurable.
So, while I appreciate that you don't throw out any racing advantage, the paddle wheel won't do anything.
In comparison, the effects of a prop are huge. If you don't have a feathering prop, it's like towing a bucket behind your boat.
Not to mention marine growth.
Btw, just to put some numbers on things, the older knotmeters used analog dials. The full scale reading was typically 12 knots.
On the simple units (signet, etc.) the paddle wheel directly powered the needle through a diode & capacitor to take out surges.
The meter was full scale 100 micro amps.
(Micro Amps are a millionth of an amp)
The smallest red led needs 10 milliamperes just to get visible light.
A milliampere is a thousandth of an Amp.
An incadescent tiny flashlight bulb takes about 1/10 th of an amp, and it barely gets warm.
If you're a Newton fan, the old ruie is energy can't be created or destryed; just transferred.
So, now think about how much energy 100 millionths of an amp really takes out of a multi- ton yacht going at 5 knots.
Not much.
Ok,,, I'm done.
But the math is wrong
Let me put this even more in perspective.
(I used to service instruments so I know this real well)
If you take a raymarine paddle wheel and blow on it, it will read between 6-12 knots, depending how hard you blow.
So, put your hand in front of your mouth.
Blow real hard. That's the drag at 12 knots.
The water resistance is so small, it's immeasurable.
So, while I appreciate that you don't throw out any racing advantage, the paddle wheel won't do anything.
In comparison, the effects of a prop are huge. If you don't have a feathering prop, it's like towing a bucket behind your boat.
Not to mention marine growth.
Btw, just to put some numbers on things, the older knotmeters used analog dials. The full scale reading was typically 12 knots.
On the simple units (signet, etc.) the paddle wheel directly powered the needle through a diode & capacitor to take out surges.
The meter was full scale 100 micro amps.
(Micro Amps are a millionth of an amp)
The smallest red led needs 10 milliamperes just to get visible light.
A milliampere is a thousandth of an Amp.
An incadescent tiny flashlight bulb takes about 1/10 th of an amp, and it barely gets warm.
If you're a Newton fan, the old ruie is energy can't be created or destryed; just transferred.
So, now think about how much energy 100 millionths of an amp really takes out of a multi- ton yacht going at 5 knots.
Not much.
Ok,,, I'm done.