[LW] [LW11] ST50 SPEED Odd readings

[Marc Feeling]

Two years ago we bought a 10meter ailing yacht with old raymarine equipment. One of them is the ST50 SPEED. It always functions, however the readings don't make sense. Sometimes it looks like it gives the right speed, but sometimes it gives a speed that is more than twice the speed we sail. The paddle wheel (if that is the right English word) runs freelly. The temperature also has very odd readings. What to do?
Best, Mark

[Louise - Raymarine - Moderator]

Dear Marc Feeling,

Thank you for your post.

This sounds like the thermistor is failing in the transducer. What are the temperature readings versus the actual sea temperature? Is the temperature displayed always higher than expected?

If this is the case you will need to replace the transducer, do you know the model of your transducer? There would have been a white label on the cable showing the part number. Take a look to see if this is there and revert back with the part number.

Many Thanks
Louise

[Louise - Raymarine - Moderator]

Dear Marc Feeling,

Thank you for your post.

This sounds like the thermistor is failing in the transducer. What are the temperature readings versus the actual sea temperature? Is the temperature displayed always higher than expected?

If this is the case you will need to replace the transducer, do you know the model of your transducer? There would have been a white label on the cable showing the part number. Take a look to see if this is there and revert back with the part number.

Many Thanks
Louise

[Marc Feeling]

Dear Louise,

Thank you for your quick reply. Sorry for my late reaction, I expected a email to let me know I had a reply.

Next week I will go to the boat and look at the part number.
However the temperature is not the main problem. The speed is the main problem. Both, temperature and speed have very odd readings. Sometimes the speed (knots) makes sense, however sometimes we go (on the sails) twice as fast as the wind speed, while the wind speed stays the same. The water temperature changes in 3 minutes from 25 celsius to 0 in five minutes, while the water is around 16 celsius.
As mentioned above, next week I will look for the number you asked me.
Where can I find the white label on the cable, near the transducer or near the instrument? I doubt if it is still there.

Thanks for your help.
From now on I will check for messages regularly.

Best,

Mark

[Louise - Raymarine - Moderator]

Dear Marc Feeling,

Thank you for your post.

Your transducer has become faulty and needs replacing. Without knowing what transducer you have I cannot suggest the replacement.

I suggest contacting your local Raymarine dealer who can advise on the suitable upgrade for your vessel, you can find one via our website here.

Many Thanks
Louise

[Marc Feeling]

Dear Louise,

Thanks for your quick reply.
On the cable near the transducer I found the following number:
NT 0854/31-203-4-13

Can you tell me what to replace it with?

Best regards,

Mark

[Louise - Raymarine - Moderator]

I have sent you a private message.

Many Thanks
Louise