Cutting cable ST 60 Depth transducer

F

fontmell

Well-Known Member
Joined
5 Nov 2004
Messages
206
Visit site
Hi help please
I need to replace the transducer holding plastic top nut-The one you undo to get the transducer out to clean) which I stupidly chewed up (if I cant find suitable replacement plastic nut will mean replacing whole thing!!)
My question is I need to cut the cable to do this as cannot thread new one through conduits etc. Can i just rejoin the cable using standard connector or will there be a problem


many thanks
 
fontmell said:
Hi help please
I need to replace the transducer holding plastic top nut-The one you undo to get the transducer out to clean) which I stupidly chewed up (if I cant find suitable replacement plastic nut will mean replacing whole thing!!)
My question is I need to cut the cable to do this as cannot thread new one through conduits etc. Can i just rejoin the cable using standard connector or will there be a problem

I think there will be a problem.It specifically tells you not to shorten the cable in the instructions for the old seafarer & when I did that it (only finding out later) it ceased to function.
Click to expand...
 
The answer might be brand-specific but given that most transducers are actually made by Airmar, maybe not. If I had to cut and join a cable I would, but then would make sure to recalibrate the sounder afterwards.

But why do you need to remove a depth transducer to clean it? Just buff it up when the boat is next out of the water, or give it scrub when snorkelling if you're into rubber. I've never found that fouling makes much difference to the reading.
 
fontmell said:
Hi many thanks i meant the log not the depth
Click to expand...

Well I binned that at the same time I replaced my echo sounder.Why does anybody need a log now that we have gps & it is not susceptible to current & sea drift or just a bit of sea weed clogging the damn thing up?You can get a good hand held unit like an etrex for about 30 quid off ebay.
 
Last edited:
I have cut and rejoined such cables successfully, despite the manufacturers warnings. Some claim that the cable length is tuned, but I can't see that even with the depth transducer unless you're significantly changing the length. I don't see how the wire was fitted originally in any conduit unless the plug were threaded through so it should be possible to pull it back out whilst you fit the new nut (surely that will go over the plug?). If you must cut, then it would be best if you can do it such that the repair will not lie in bilge water and the repair can be sealed in heat shrink tube with glue inside.

Rob.
 
Nicholas123 said:
Well I binned that at the same time I replaced my echo sounder.Why does anybody need a log now that we have gps & it is not susceptible to current & sea drift or just a bit of sea weed clogging the damn thing up?You can get a good hand held unit like an etrex for about 30 quid off ebay.
Click to expand...

Extremely useful to compare SOG with STW.
 
Very many thanks all, I will split it
Just in response,
1) I like to know what speed through the water and navigate traditionally as well as back up by GPS - I had dead battery in the middle of Biscay once, no GPS but found Cornwall on dead reckoning - thats why I want a mechanical log
2) The conduits are full of cables and 90*bends - Sods law says If I get it out I will not pull a new one thru easily - Why do boat builders use min dia they can get away with!!!
Thanks again
 
Nicholas123 said:
Well I binned that at the same time I replaced my echo sounder.Why does anybody need a log now that we have gps & it is not susceptible to current & sea drift or just a bit of sea weed clogging the damn thing up?You can get a good hand held unit like an etrex for about 30 quid off ebay.
Click to expand...

Agree with the GPS idea. My NASA log had been waterlogged when I bought the boat. I used an E-Trex that did the same job as the Log would do.
 
Nicholas123 said:
Why does anybody need a log now that we have gps & it is not susceptible to current & sea drift
Click to expand...

Because boat speed and speed-over-ground are not the same thing.

Plus, even if you don't care how fast you're sailing (as opposed to how fast the tide is moving you), ST60 kit won't work out true wind without a log reading.

Pete
 
I have previously been advised by Raymarine that it is OK to cut and re-terminate the ST60 log cable BUT NOT to reduce the length significantly.
(I suspect, but have not checked, that the depth transducer cable is more senistive and should not be cut without checking with Raymarine).
As said by others, the water speed is very useful and I'd always keep it as part of any integrated system (eg my chartplotter shows a vector for tide direction and strength).
Cheers,
Andrew
 
fontmell said:
Hi many thanks i meant the log not the depth
Click to expand...

Still usually a proprietary unit. All the fitting instructions I've come across specifically rule out cutting and rejoining the cable, so I'd suspect it's likely to be unsuccessful.

I suspect the only safe option is to replace the whole transducer and cable.

If such an archaic model that it involved unscrewing to remove, instead of a quick-release pin and flap-valve to limit water ingress, the transducer; thank the Gods for your good luck and hurry to MES to replace the whole instrument.
 
Nicholas123 said:
Well I binned that at the same time I replaced my echo sounder.Why does anybody need a log now that we have gps & it is not susceptible to current & sea drift or just a bit of sea weed clogging the damn thing up?You can get a good hand held unit like an etrex for about 30 quid off ebay.
Click to expand...

I suspect that familiarity with cars and not boats has misled.

The speed function of a log is pretty irrelevant in the scheme of things, but the log (which you know as the odometer, no doubt) and gives you distance run is most important, if you want to indulge in the passe skill of dead-reckoning. Some need it to check their sail-trim, there are plenty of other signals (if you use tell-tales) and yet others use the comparison between the speed through water and the SoG to work out currents and tidal-flows. However this latter is possibly too arcane for most weekend sailors who, after all, are now as competent navigators as James Cook, thanks to GPS and Galileo.
 
prv said:
Because boat speed and speed-over-ground are not the same thing.

Plus, even if you don't care how fast you're sailing (as opposed to how fast the tide is moving you), ST60 kit won't work out true wind without a log reading.

Pete
Click to expand...

I'm generally aware of the tides & currents.If an ST60 is one of those wind things most people have at the top of their masts that's another thing I somehow miraculously have managed to do without.
 
Last edited:
nigelmercier said:
Yes and no. The cable is just a standard multicore, but I'd be careful how you joined it. Make sure it can't get wet, so do it as high as possible. I would solder it and cover each join with adhesive heat-shrink.
Click to expand...

Agee with Nigel, after all you have nothing to loose. You will probably find there is a foil shield under the plastic coating so aim to cut away from the sender unit and give yourself enough space to make good again. Garmin have a similar warning for their sounder transducers but with no option I just cut it and made good with some tiny heat shrink joiners a friend in the aircraft world gave me, wrapped the foil back and then slid another piece of heat shrink over the top of the lot.

Just a thought, when I fitted my ST60s I didn't have a problem of a moulded plug on the end, doesn't the cable come with bare wires on the opposite end?

Pete
 
Last edited:
ianfr said:
My main use of a log is for sail trimming, as it updates faster than GPS so a small adjustment of trim shows quickly.

Ian
Click to expand...
I'll leave esoteric comparisons to others who find them useful. However I can't imagine that an e-trex could react less quickly than anything else. It shows yawing at anchor in decimals of a knot.
When checking my car speedo it reacts as quickly as I change the throttle.
 
You must log in or register to reply here.

Share this page

Top