Knotmeter Problem

[Rich]

I have an Autohelm ST50 knotmeter. For some reason it has started reading about half of the actual boat speed. I have cleaned the transducer, checked all of the cabling and tried to calibrate it three different times now with the same result. Has anyone ever had this problem? I'm thinking it's probably a computer problem which means the unit will have to be sent to Raytheon for repair. Is anyone aware of any other possible cause before I go to the trouble of removing and shipping?

 

[Ed]

knotmeter

I had a similar problem with a Signet unit. They sent me a procedure for resetting it. Maybe you could call the service dept to see there may be a similar procedure that you can do yourself.

 

[Mark Roskin]

Transducer problem

I have an ST50 tri-data and had to replace the transducer to solve a similar problem.

 

[Rich]

Contacted the Factory

Thanks for the feedback. I talked to the factory. They told me to try replacing the paddlewheel. If that doesn't work they told me I'll have to remove the head and send it to them for service.

 

[Guest]

Paddlewheel replacement

During a haulout last year, the straps brushed the paddle wheel on my boat and bent the axle which caused the paddlewheel to bind and register improper speed. I replaced the axle this spring and everything works fine. Did you notice this after a haulout?

 

[Rich]

Just happened one day

I didn't have a problem after my last haulout, last September. Just one day I went sailing and knew it wasn't reading right. Figured out how much it was off by comparing it to the speed registered on my GPS. I also sail with several other boats that could tell me what they were registering. The paddle wheel doesn't even look worn but I'll give the replacement a shot. My gut reaction is that it's an electronics problem and something needs to be replaced. I'm sure I'm going to be sending it back to the factory for service. Maybe that's just my computer experience talking. If only I could just re-boot it and run scan disk....