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Depth sounder problem


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Hi All

I am going through one of those phases where nothing seems to work, and we uncover more issues as we go :( . I knew we had speed log and depth sounder issues from our trip out at new year, so I have decided to try to get them resolved. The log transducer I have removed from the through hull fitting and put the plug in (VERY scary taking it out of the hole and watching the water come in unti lI could get the plug screwed in :o , but seemd to work as planned). The paddle wheel is covered in ant-foul so I reckon that's not helping. I've purchased a new paddle wheel, so hopefully that one will be sorted.

The depth sounder issue is a bit more involved, and starting to look expensive. It's readings are somewhat erratic, and sometimes it decides to flash, which the manuals tell me is a lost signal.

The sounder is an Autohelm SeaTalk, and is probably about 15 years old installed on the boat from new. I have had the display unit rigged up to a test transducer in a workshop at Cliff Marine Services, which was suspended in a tube of water about 4 ft long, and the reading was correct and steady.

Next, the test transducer from the workshop was taken to the boat and suspended in the water over the side. The display ranged from 6 feet to 33 feet deep (in 6 feet of water) without the transducer being moved. We did wonder if this was due to a rapid temperature change from the workshop to the water in the marina?

The problem seems to be no signal from the transducer installed in the boat, but I am also not sure if the display unit is giving the right reading even when there is a signal provided.

Anyone had similar problems? I am hoping to borrow another display unit from CMS on Wednesday to take to the boat to see if that points to the my transducer being cream crackered. If it does, then its a £200 lift to fit a £60 transducer.

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Hi Mark, The depth sounder is a very impotant piece of kit, especialy when it comes to navigation and anchoring, from memory you do not have radar so if you end up in fog you are either going to put absolute faith in your chart plotter or you are going to check where you are on the contour lines, or even follow them home.

That said, we had the same problem with the same piece of kit on White Lady but as soon as she was given a blast in salt it would work fine for a few months on the river. After a few months on the river it would start to play up again but the salt treatment worked every time.

Ian

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A bit of river slime or a small amount of growth will often give a false reading, it is very rare (but not unheard of) for the head to be the cause of varying depth readings. That is a scary moment when you remove the paddle :o later ones have a flap that stems the flow a bit untill you can pop the plug in. Raymarine actually stipulate that the paddlewheel be withdrawn and the plug left in when you leave the boat for more than a couple of weeks, I never go to quite that length though.

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No that's a different sender Trevor. Mine isn't retractable (it's the ST50/ST60 fixed one).

That said, we had the same problem with the same piece of kit on White Lady but as soon as she was given a blast in salt it would work fine for a few months on the river. After a few months on the river it would start to play up again but the salt treatment worked every time.

Ian

That's interesting Ian. After our little Breydon blast, it did seem to start working for a while. I wonder if the crap that grows on it somehow blocks the signals? I have just emailed Goodchilds to see how much they would charge for a lift out and a couple of weeks on the hard. I am pretty sure the sender will need changing, and at the same time I could check out the trim tabs and the oils in the legs for peace of mind. A lift and hardstanding at Brundall Bay would cost me over £400 which I can't afford at the moment :cry:

That is a scary moment when you remove the paddle later ones have a flap that stems the flow a bit untill you can pop the plug in. Raymarine actually stipulate that the paddlewheel be withdrawn and the plug left in when you leave the boat for more than a couple of weeks, I never go to quite that length though.

You're not wrong David. Mine is the sort with the flap, but I didn't know if it was going to work. Now I've done it once, I'm fine as I know what to expect, but that first time was a clenched buttock and sweaty kneecap moment :naughty:

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Hi Mark,

We have the auto helm system you mentioned and ours isn't a through hull except for the paddle wheel which works when it feels like it :naughty:

GPS is used for speed and all we have for depth is the auto helm device which senses through the hull without a skin fitting. It's almost like a heavy piece of metal that just sits in place using it's own weight and if accidentally knocked over (when working on the tanks etc) readings go all over the place. The previous owner tried to glue it down using silicone.

It took me a good while to work it all out and I wonder if you have the same setup. Raymarine now have the auto helm stuff as part of their portfolio and they told me that most kit is backwards compatible. The latest skin fittings have auto closers and they told me the sensors will still work with older helm gear. Far less scary than a shed load of water pouring in when you open them up and then try and find the bung!

Give them a call (their number is on the net) They went out of their way to be helpful when I rang them a few years back :clap

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HiIt took me a good while to work it all out and I wonder if you have the same setup.

Hi Jim

Both the depth and speed are definately fixed through the hull. I wish it was as simple as a chunk of metal masticed down. Sounds very sensible to me :lol:

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A lift and hardstanding at Brundall Bay would cost me over £400 which I can't afford at the moment

Think you will find that Goodchilds are about the same, the lift is about £150 each way, then there is a preasure wash chocking and time ashore.

Jonathan is out at goodchilds at the moment so should be more up to date.

If the drives have not been serviced in the last 12 months then I would say get it out now, changing the oil will tell you if there is any water getting into the legs, something that if left unattended will without doubt spell a very quick end to a £4000 leg. Sounds drastic but White Lady had water in her oil due to a leaking seal, the legs were 3 years old with 50 hrs on them. Fortunately it was caught early and amounted to no more than a couple of weeks in the menders and a £300 bill.

Ian

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If the drives have not been serviced in the last 12 months then I would say get it out now, changing the oil will tell you if there is any water getting into the legs,

The legs were apparently serviced in July last year, but to my mind, there is no substitute for checking these things out yourself. I'd at least be able to aquaint myself with the soggy side of the boat and have a look at the condition of the anodes. I know a couple of my props have got chips in them too, so they could be attended to at the same time.

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Have a good poke around the boots too Mark, if serviced last summer I imagine they will be fine but they are a vital service item and need changing at the specified intervals or if damaged, cracking or perishing even slightly. Whip the props off and check behind them for fishing line as that stuff is a bugger for damaging the final drive shaft seal and there's plenty of the stuff floating about the broads.

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I think I've finally identified the depth sounder display unit is the problem. I hooked up another display (albeit a later model Raymarine one) and it worked fine, so the transducer is okay. I'm still going to lift the boat to check out hte legs and trim tabs etc, but it seems my sounder problems are quite simple to fix, but isn't it always the way that it's the most expensive part that needs replacing, not the cheapest :roll:

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  • 4 weeks later...

The depth sounder I won on ebay was faulty :cry . Even though it was sold as seen with no warranty, the seller has kindly agreed to exchange it for a tri-data display so fingers crossed on that.

HOWEVER.... down a tthe boat on Sunday, I noticed purely by chance that at some point the depth transduce appears to bave been trodden on, and where the wire exits the unit, there is some damage, which makes me think some of the issues I have had are simply down to a broken wire :roll:

Next problem is to try to shoe-horn myself under the engines to get to the bloddy thing to see is a repair is viable ..... What I need is a 2ft tall munchkin who's good at soldering :grin:

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Guest chriscraft

oh well i suppose i,d better own up,i purchased a new/ex display clipper depth sounder kit off ebay ,for 130 quid,my intention was to glue the new transducer next to the though hull one already fitted and pull the new cable though to the dash with the old one,soooo i got hold of the old cable and low and behold ,the DASH end appeared instantly ....it wasn,t wired up!! :oops::oops::oops::bow .So bit of swearing and the like later i wired in the new head unit and plugged the fixed transducer up to it ,it worked great!.Then it was the bastard of a job to get the cable from under the cabin floor though the bedroom and up to the helm arghhhh.so at least now it all works thank god!Some one had wired the depth head unit in the dash to an old navico plotter!!

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  • 2 weeks later...

Aaaargh! This depth sounder problem WILL get sorted :mad: .

I tried to solve the issue by crawling half under one of the engines to get to the broken wire, only to find the wire was not broken, only the outer insulation damaged. I decided to cut the wire anyway and reconnect temporarily with a junction block, but this still didn't work. I did notice, however, a lot of corrosion on the shield wire, so my best guess is that water has penetrated down the damaged insulation and into the transducer itself.

To stop going around in circles, I have booked a 2 day stint in the slings in a couple of weeks, and am going to fit a new transducer AND and new display unit. At least that was I know it's going to be fixed :roll:

The hard bit now is going to be getting the old transducer out of the hull after 15 years. Methinks my trusty angle grinder will see some action...... :o

Out of interest, what type of sealant would you guys recommend for this sort of below waterline application?

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There are many types of Sikaflex, use the right one and you shouldn't have any real issue with removal should it ever be needed, have a look at their site, the number of sealant products is legion. They make adhesive sealents as well as pure sealents and those can be a bit difficult but by no means impossible to remove. I would use Sikaflex 291 GP sealant if available at the time but would happily use, and have used the 295 adhesive sealent too.

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