Sonic Speed transducer repair/replacement - how?

Colin - ex SV Island Pearl

We have moved Gary's comment into a new topic so we can track this thread in future.

On #332 our B&G Sonic speed has recently started playing up with readings either too high or too low randomly. We assume that this would also impact our log distance readings too. We think this problem started after we last slipped the boat because, if you position the front boat lift strap exactly in line with the recommended lift points/large stainless/rigging boat lift hook position, then unfortunately that has the boatyard lift machine strap wrapped over the forward sonic transducer!! Unfortunately we only realised this too late when lowering the hull on the hard. Whilst we could see no damage, we now have unreliable boat speed readings.

Like Gary on #335, this is the only current problem with out boat and we would like to get it resolved as we found this sonic speed and log extremely accurate on the Atlantic and Pacific crossings, and therefore do not want to go to the paddle wheel option if at all possible.

Has anyone replaced these with new B&G sonic equipment or managed to fix a similar problem with the sonic speed/log equipment? 

Colin & Lauren Streeter

Island Pearl II, SM#332

Newport, QLD, Australia 


From: amelyachtowners@yahoogroups. com [mailto:amelyachtowners@ yahoogroups.comOn Behalf Of amelliahona
Sent: Saturday, April 11, 2015 7:19 PM
To: amelyachtowners@yahoogroups. com
Subject: [Amel Yacht Owners] Re: Bill- water tank vent



Hi all:


The hose in photo number 4 (labeled tank vent), is NOT a tank vent. It is a hose that exits at the inboard edge of the the aft locker under the table in the saloon.  


If you look closely in the picture, and you can check this on your own boat, you can make out that there is an electrical cable inside the hose.  I asked Olivier about this hose when we took deliver y of the boat and he indicated that the hose was there to protect the cable inside, and that cable is the sonic speed indicator sensor/transmitter that is imbedded in the leading edge of the stub keel (i.e. the lower aft transducer of the two sonic speed transducers). At the forward end of the hose the cable exits and traversed starboard to route to the sonic speed computer that is strapped under the shelf in the forward lower cupboard beside the starboard side saloon seat.


Olivier, if you see this, can you shed some light on how it might be possible (or not possible) to replace the sonic speed sensors (both in the stub-keel and the forward hull).  It seems many of us have had failure of the transducers.  Are the sensors in some sort of conduit that allow them to be pulled and replaced?  


All the best, 


Gary Silver

s/v Liahona  

lying Sapphire Bay Marina, St. Thomas,  USVI

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