Raymarine Instraments

[Tally Ho]

My 1996 H280 came with the following instruments installed by the PO:
ST 4000 Autopilot
ST 30 Depth
ST 50 Plus Wind & Close Hauled/VMG
ST 50 Plus Tridata and Repeater
ST 50 GPS & Nav Data display
ST 50 GPS Beacon Receiver

I have 2 nagging issues to resolve in the spring:
1) The wind anemometer at the top of the mast does not seem to work correctly....in light wind it stops, seems OK in stronger wind. I am hoping that getting up on the mast and cleaning / lubricating the anemometer solves the problem.

But is it possible to buy replacement parts for this unit? Would seem that the arm and cups would be typical replacement items.

2) My speed log is also not working correctly. I am able to calibrate it, at one speed, but it is off at higher or lower speeds. I had hoped it was just fouled, but it was pretty clean when I inspected it at haul-out. I did clean it, but won't know until commissioning in the spring if it works more accurately. And since it is not registering correctly, the distance travelled and average speed readings are wrong. I will check the connections to the display unit once I uncover it in the spring, but not sure what else to check.

Since I have a GPS on the Seatalk network, and I am sailing on Lake Michigan and don't have to worry about currents, can the Seatalk system be instructed to use the GPS SOG instead of the knot log to calculate distance travelled, average speed, max speed, etc?

Any help / advice is appreciated.

Greg

 

[Steve Dion]

I think you may want to go to the Raymarine site. They have a Q & A section where you can key in your question and they have many solutions.

If that does not work, you can try giving them a call. I have no idea what type of support they have since the buyout.

 

[Jackdaw]

The st50 wind has a rebuild kit. You can find them everywhere, including eBay.

The st50 knot log uses an airmar transducer. They also had rebuilt kits. See their website.

 

[Bill Roosa]

knot logs are problimatical as far as making them accurate. If you have a bad instlation that is off center, behind some obstruction etc it will never read correctly no matter how you calibrate it. Even if your instlation is "to factory specs and recommendations" it will not read correctly at all speeds. this can be fixed by messing with the calibration but you need an accurate way to determin the actual speed through the water (not SOG except in no wind and current conditions).
I would recommend finding a spot that has little to no current and very light winds and motor the boat at your "most common sailing speed" Note the GPS SOG and calibrate the knot log to match it. Change the boat speed and note how wrong the knot meter is. Write this down. ie @2 knots displayed = 2.1 knots actual
exactly like a dievation chart on your compass. Post it near the knot log.
As far as the actual distance traveled I believe you can set the AP to display the GPS version while the knot log will display it's version when you press the right buttons on the log display. The only way I know of to get the log to read distance correctly is to note the time you start and boat speed and then record the boat speed and time every time the boat changes it speed by some significant amount. Then use D=R*T to sum up the individual distances to a total. It will never account for current though so this is more of a backup if you have GPS. I do use even our uncalibrated (I gave up two years ago and just note the changes) knot log to help trim sails though. it responds more consistantly to changes than the GPS. so if I see the speed go up I know what ever I'm doing is having a beneficial effect (assuming I'm still going tward my destination)

 

[Jackdaw]

To answer your last question, that would be possible in theory, but the firmware of the devices do not allow it.

What bill suggests about water flow IS possible... But barring that condition the sender/gauge should be able to read accurate speeds over the very narrow range of speeds a sailboat sees.