youen
Well-Known Member
Can you swap a Raymarine paddle wheel speed sensor for an ultrasonic sensor in a Seatalk system st 60?
raymarine paddle wheel
- Thread starter youen
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nigelmercier
RIP
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- Live in Kent, boat in Canary Islands
I believe the Airmar number is CS4500. I considered this option, but way too expensive. I've finally started work on my YAPP-like box to simulate the paddle wheel from the GPS signal.
john_morris_uk
Well-Known Member
I'm confused as to why you would devise such a system. The paddle wheel log (despite its problems with occasional bits of weed etc) gives speed through the water and the GPS already give us Speed Over Ground so why would you bother to design a YAPP like box? (On our boat the Raymarine log display will even give the SOG so such electronic trickery wouldn't be just to avoid a redundant display.) More importantly to me I actually like to know how fast we are moving through the water. We compare Log Speed and SOG frequently because it tells you what the tide is doing and boat speed by log aids sail trim. (GPS derived readings can often react too slowly to alterations in speed). There are obvious nav advantages to having a functioning proper log.
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macd
Well-Known Member
Me, too. If there's a logic, I'd love to hear it.
Otter
Well-Known Member
I'm guessing that it's because certain Raymarine kit requires a speed input but will only accept it from the STTW sensor, not GPS SOG. I think that includes the wind sensor.
I'm a recent convert to speed through the water data, it helps with much more than I thought it would. Surprised how slowly the paddle furred up.
I'm a recent convert to speed through the water data, it helps with much more than I thought it would. Surprised how slowly the paddle furred up.
RichardS
N/A
I don't have a paddle wheel and I can't seem to get my Raymarine kit to display log information i.e. distance travelled, from the GPS signal.
Is there a way of doing this? Could be I am doing something wrong!
Richard
john_morris_uk
Well-Known Member
Because it isn't designed to do such a thing. If the GPS fails, most people would say that the key issue for navigation is how far you've travelled through the water and that's why you need a paddle wheel or one of those very expensive doppler units that works without a paddle wheel...
RichardS
N/A
I understand from some online research that I did a couple of years ago that it is possible to obtain log information from GPS but it needs another electronic box. Maybe this box is the one Nigel is intending to make himself?
Richard
johnalison
Well-Known Member
I think that we should always rejoice at every sinner who repents. You're right.
Lucky Duck
Well-Known Member
The current range of plotters keep a log of distance travelled as recorded by the GPS, unfortunately mine appears to have got a little confused during a software update and it telling me I have travelled some 5,000 miles this season
Otter
Well-Known Member
The current range of plotters keep a log of distance travelled as recorded by the GPS, unfortunately mine appears to have got a little confused during a software update and it telling me I have travelled some 5,000 miles this season
You'd be amazed at how many on the forum claim to do that in a typical weekend. Perhaps they have a similar software problem
nigelmercier
RIP
- Joined
- 20 Jun 2007
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- Live in Kent, boat in Canary Islands
Several reasons for my project.
My paddle wheel log is not accurate enough to be any use, errors of 25% are not uncommon.
My cruising ground is tidal, but the tidal streams are minor compared with the general flow.
I want speed data on the SeaTalk bus, so the True Wind function will work.
If I really need to know my speed through the water, I time a passing object from bow to stern (or chuck over a bit of bread). Converting 2kn = 1m/s is only 2% error, plus a small timing error of course.
From my point of view, the only downside is loss of water temperature reading if the paddle wheel is not installed. I'm considering what I could use this display for, perhaps engine coolant.
My paddle wheel log is not accurate enough to be any use, errors of 25% are not uncommon.
My cruising ground is tidal, but the tidal streams are minor compared with the general flow.
I want speed data on the SeaTalk bus, so the True Wind function will work.
If I really need to know my speed through the water, I time a passing object from bow to stern (or chuck over a bit of bread). Converting 2kn = 1m/s is only 2% error, plus a small timing error of course.
From my point of view, the only downside is loss of water temperature reading if the paddle wheel is not installed. I'm considering what I could use this display for, perhaps engine coolant.
rogerthebodger
Well-Known Member
I am also looking at this type of box. My reason is that I would like SOG on my little mobo and a I have a mumber of SIMRAD water speed display that I could use with a GPS model/mouse to give boat speed.
I do have 2 paddle wheels on my sail boat with a change over switch. This I would not change as in my sailing is in an area with a fastesh current and it helps to determine the speed of current for most efficient sailing SOG
I do have 2 paddle wheels on my sail boat with a change over switch. This I would not change as in my sailing is in an area with a fastesh current and it helps to determine the speed of current for most efficient sailing SOG
youen
Well-Known Member
Do you need to buy an interface box to link the Airmar ultrasonic sensor to the Seatalk or you can plug the sensor directly the same way as the paddle wheel?And at end is the Ultrasonic efficient and reliable?Thanks
FWB
N/A
I have had an ultrasonic speed sensor fitted to the boat for over ten years now. It's a Raymarine one, presumably now Airmar. It was fitted when I commissioned the boat from new so I'm not sure of the wiring arrangement but details from Airmar are here..
http://www.airmartechnology.com/uploads/installguide/17-263-01.pdf
As to its reliability, it works faultlessly on my long keeler. I think there may be issues with modern fairly flat bottomed designs where the transducer may not be constantly in smooth flow.
