Paddle wheel speed transducer is driving me nuts

[Jd1]

Is there anything available that is reasonably accurate for speed through water (let's say +/- 0.1 knot) that doesn't mind a bit of marine slime and is compartible with a Raymarine Tridata ST60+ display ?

[Wotname]

No (AFAIK).

[Wotname]

There are high end doppler units but you will need a need display

[44'cruisingcat]

It doesn't seem to take much to stop the Airmar speed transducer Raymarine use.


I have an Echopilot FLS with speed, and that paddlewheel keeps going pretty much all the time. It's a simpler, much broader paddlewheel.


Don't know if it would be compatible with seatalk though.


There are versions of Echopilot FLS's that transmit NMEA sentences, but that would be a very expensive way of doing it.

[motion30]

Why bother. Gps is the answer

[Wotname]

GPS doesnt solve the the OP's problem. He wants STW not SOG.

[Snowpetrel]

Originally Posted by motion30

Why bother. Gps is the answer

+1, yachts are complex enough without adding more troublesome underwater parts.. I can normally get a good enough feel for boatspeed by eye, and current from the shape of the waves.

Sent from my HTC_0PCV2 using Cruisers Sailing Forum mobile app

[roverhi]

Have sailed many thousands of miles, some passages 20 days or longer, with paddle wheel transducers for the knot meter/log without any problems. Take the paddle wheel out when you aren't sailing. Only takes a minute and no fouling build up. Yeah, it's been a pain to clean the bugger if I forget to pull it and it sits in the water for awhile. Reinforces the need to pull the thing.

[Jd1]

Originally Posted by 44'cruisingcat

It doesn't seem to take much to stop the Airmar speed transducer Raymarine use.


I have an Echopilot FLS with speed, and that paddlewheel keeps going pretty much all the time. It's a simpler, much broader paddlewheel.


Don't know if it would be compatible with seatalk though.

Thanks ! I was no aware that the Airmar teansducer is known for easy stopping. I kinda lumped them all into one and declared paddlewheels as a group to be crap.
I will look into an Echopilot FLS.

For those people suggesting that STW is not required, please note that I did not ask if STW is required or not (rest of rant deleted after re-reading).

[Jd1]

How accurate is an ultrasonic transducer at low boat speed? How tolerant is it of slime buildup ?

[kas_1611]

Originally Posted by roverhi

Have sailed many thousands of miles, some passages 20 days or longer, with paddle wheel transducers for the knot meter/log without any problems. Take the paddle wheel out when you aren't sailing. Only takes a minute and no fouling build up. Yeah, it's been a pain to clean the bugger if I forget to pull it and it sits in the water for awhile. Reinforces the need to pull the thing.

I agree, take the wheel out when you leave the boat for any length of time and you save a heap of hassle. We get a lot of calcareous tubules building up here so we clean our transducer/wheel in vinegar before we put it back in at the start of a trip. Haven't had a problem with the log wheel since.

In the warmer months it's even a good excuse for a swim as it doesn't take much to dive under and quickly clean the paddles of any gunk

[Jhhastie]

I believe the maker of my log meter is Eagle Claw. It is a manual knotmeter for trolling up to 5 knots. It is also referred to as a taffrail log.

[PPLepew]

If your speed over water is not known, your true and apparent wind speed will always be the same on the ST60 Wind dial.

[Robin3]

I have always found that a light coating og ablative antifouling paint works, otherwise take it out when not in use and get praciced at whipping it out for a quck clean and replace under way. I leave an old toothbrush in the bilge ready for the clean. Best to slow down for the removal to keep water inrush to a minimum before the blanking plug goes in

BTW we now have all new Garmin instruments and they too have an Airmar paddlewheel.

[jlrubin83]

I've been through 2 of them, they get crud in them and fail. I got a reconditioned Garmin unit for $200, now I have moving map and ground speed and it works!