OCC Forums » Systems and Maintenance » Electronics » Speed Transducers

RE: Speed Transducers

dcaukill — Mon, 01 Jul 2019 11:55:36 GMT

I had an Airmar ultrasonic log the whole of our circumnavigation. The advantage of ultrasound is that it doesn't need to be raised and cleaned all the time - is maintenance free. You often learn that the paddle wheel needs cleaning when you most need to know your speed - particularly if you have been stationary for a week or so. The disadvantage of ultrasound is that it is very sensitive - it measures the speed of the boat as it hunts on its anchor - even a light cross current. 0.1-0.2 knots. If you spend a week at anchor you can easily find the boat has measured a 50-100 mile passage. Switching the depth sounder instrument display off may stop the system logging the distance - or not - depending on how it is set up.

Eventually, I gave up and fitted an Airmar paddle wheel. However, 4 years on and I am thinking of returning to the ultrasound because i am fed up with cleaning the crud off!

Speed Transducers

simoncurrin — Mon, 01 Jul 2019 11:54:56 GMT

We have a tradition paddlewheel speed transducer which has become increasingly unreliable in recent years- it is 13 years old. For much of the time now it registers ‘0’. I am looking to replacing it with an ultrasound sensor such as the one made by Airmar. Does anyone have any experience of these? Simon

RE: Speed Transducers

Dick — Mon, 24 Jun 2019 18:09:20 GMT

+x[quote]

[b]Simon Currin - 6/24/2019[/b]
We have a tradition paddlewheel speed transducer which has become increasingly unreliable in recent years- it is 13 years old. For much of the time now it registers ‘0’.I am looking to replacing it with an ultrasound sensor such as the one made by Airmar. Does anyone have any experience of these?Simon
[/quote]

Hi Simon,
I am no expert, but I believe that Airmar is the go-to brand in this area. I have used Airmar transducers and paddlewheels for decades and been quite happy. They crap out occasionally, but rarely. I also think that many of the "packages" from the big name instrument makers use (or re-brand) Airmar gear in their packages.
Let us know if that fits with your researches.
My best, Dick Stevenson, s/v Alchemy