Raymarine ST60 Log

[Scorcher IV]

I have been having difficulty getting the log to read something like the actual through the water boat speed, so having read the manual decided to switch over to SOG as that was available from Seattle, great that works and shows the SOG speed as per the GPS. the problem is the log reading no longer increases and remains the same. Have I turned something off or do I have a fault on the system. If anyone else has had a similar problem I would appreciate knowing how you fixed it before I start buying things.

[Krill]

You can calibrate the log speed but you need to know your speed through water to calibrate it correctly, i.e no tide (which is difficult in UK waters) so i live with a semi accurate log

manual is here;

http://www.km-yachtcharter.de/fileadmin/content/Content/Km-yachtcharter/pdf/Handbuch/Raymarine_st60_tridata.pdf

if i recall correctly its something like pressing both depth and speed together to a few seconds, then speed, then there is a CAL factor or something like that if it cant get info from seatalk, and you basically have to fudge about with that until your SOG on the display matches whats on the GPS (slack tide conditions)

problem is if your doing 2 knots, and 5 knots the room for error moves about, i.e. my log is accurate at 5 knots but at ~2 knots its a little pessimistic and only displays 1.5knots or so.

then as soon as you get a little bit of dirt in it you need to re-calibrate it all over again! yay!

[Salty]

You can calibrate the log speed. . .
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then as soon as you get a little bit of dirt in it you need to re-calibrate it all over again! yay!

Or you take the log speed transducer inboard, fit the blanking cap to the top of the through hull fitting while you clean the transducer, then remove the blanking cap and refit the transducer once you are satisfied with your cleaning efforts. This is all very easily done, even while the boat is afloat. The amount of water that enters through the through hull fitting is minimal and is minimised by a rubber flap which reduces the flow rate of the water, and with the cap in place your hull is watertight. Just make sure that the arrow on the top of the transducer points forward when the transducer is refitted into place. Then mop up the small (normally less than a bucket full) amount of water and you’re ready to go.

[Scorcher IV]

Thanks for the comments, I have tried calibrating the log after cleaning it. The log still registered a lot less than the actual boat speed even allowing for tide, so I decided to use the SOG via sea talk as detailed in the manual, this now displays fine but the actual log reading no longer changes and remains on the same distance travelled no matter how far I have travelled.

[Ziffius]

Have you checked under the boat to see if there are any bushes growing on the hull in front of the log that might disturb the water flow past the log? That is what happened to mine this year, once I had cleaned the hull in front the log started working again properly.

[Krill]

Thanks for the comments, I have tried calibrating the log after cleaning it. The log still registered a lot less than the actual boat speed even allowing for tide, so I decided to use the SOG via sea talk as detailed in the manual, this now displays fine but the actual log reading no longer changes and remains on the same distance travelled no matter how far I have travelled.

you can increase the calibration factor until it does match, but as salty mentions make sure you start with a clean paddle wheel on the log!

but if it is displaying speed the trip log should be increasing, try using it without the seatalk SOG and see if it increases then (of course the paddle wheel speed needs to work)