B&G Sonic Speed sensors replacement


MICHELE LUCCIOLA
 

Hello and good evening from Rome
This summer I experienced  on  my SM2000 some troubles with the reading of the B&G speedometer.
I saw the documents in the files section, but there is not indication about how to replace them.
 I have to replace the sensors (that I have found in Ebay) but I'm not sure that this is an easy work ....especially to remove the old ones. Does anyone did this job before? I'm very scared about the sensor on the keel....I have seen that the sensors are two little plastic tubes but I don't know how they are fixed to the boat because there is no o'rings on the tube so I assumed that the tube is fixed with resin to the hull and to the keel....
If possible I prefer to replace the sonic speed sensors and don't do a new hole to instal a new sensor; for that reason I will be happy to receive comments from you
Thanks in advance
Michele


Jason Rutledge
 

Michele,  I did this last year with Gary Silver.  It wasn't hard.  The sensors in the boat and keel, were just pushed in.  We carefully drilled a small hole into each broken sensors (this was the hard part) and then put a screw in the sensor.  There is a hard piece of something inside the sensor, that took some patience to drill through,  We made sure the cables were loose and pulled on the screws and the sensors came right out.  I believe Bill Rouse has a write up on it....
--
Jason Rutledge
SV Liahona
SM 335


Marco Mancini
 

Dear Michele we did last year because our probe failed and I have tried with success  to replace the older one instead to put a new probe for several  reasons  . We  replaced ( my sailor man didi)  both the sensors  because we had to buy for about 300 US $ .  The cables run into a dedicated pipelines ( you may  easily see upper part of the one relative to the probe that look forward ) just in the compartment below the table dinette where you will see the cable inside a transparent pipe.  
 You can exract the probe and cable from the housing in the keel using a witness cable  and insert the new one pulling the witness cable from inside. You need to seel the probe in the keel with neoprene .  Check that the reading geometry of the front and rear probe is the same. 
I hope this may help 
sincerely 

Marco Mancini

Il giorno 09 set 2021, alle ore 20:09, MICHELE LUCCIOLA <michelelucciol@...> ha scritto:

Hello and good evening from Rome
This summer I experienced  on  my SM2000 some troubles with the reading of the B&G speedometer.
I saw the documents in the files section, but there is not indication about how to replace them.
 I have to replace the sensors (that I have found in Ebay) but I'm not sure that this is an easy work ....especially to remove the old ones. Does anyone did this job before? I'm very scared about the sensor on the keel....I have seen that the sensors are two little plastic tubes but I don't know how they are fixed to the boat because there is no o'rings on the tube so I assumed that the tube is fixed with resin to the hull and to the keel....
If possible I prefer to replace the sonic speed sensors and don't do a new hole to instal a new sensor; for that reason I will be happy to receive comments from you
Thanks in advance
Michele


Gary Silver
 
Edited

Hi Michele: 

I will echo what Jason Rutledge posted and perhaps amplify the procedure.  I provided about a dozen photos to Bill and perhaps he will post them if he hasn't done so already..  Jason and I did this job together.  It is a two person job.  

The sensors and cables run in smooth plastic chases (pipes) from their position below the waterline to a position above the waterline so no sealing is necessary.  Our sensors (SM Hull # 335) were not sealed in any way, however, they are a loose interference fit in their recesses/counter-bores.  I have been told by Bill that some were sealed with 3M 5200 or other type sealant.  The plastic wire chase for the forward sensor comes up just in front of the forward seat of the saloon table.  The wire exits the chase at this point, makes a "U" turn and re-enters a chase that goes to starboard, enters a fiberglass chase that end in the cabinet where the sonic speed computer is located (next to, and forward of the starboard side fore-aft saloon seat).    The rear sensor, that is on the leading edge of the stub keel has a chase that appears in the aft, under-table, athwart-ship locker beneath the saloon table.  It is encased in a semi-clear hose that takes it further above waterline and enters the same fiberglass chase that takes the cable to the computer.    It is easiest to remove this hose at the fixed chase in the under-table locker so you are only working with 2-3 feet (1 meter) of cable.  

Start by identifying the routing of both cables.   Next, remove (gently pull on) the 1/2 in (1.5cm) long rubber covering of the transducers at the hull forward and aft transducer positions.  You will find underlying those rubber transducer covers a ceramic like plastic face of the actual sonic transducer.  The  rubber acts  as a protectant "sonic coupling".   Use a drill to gently and patiently drill a small hole in the face of the transducer to a depth of about 1/2 inch.  Into that hole thread an appropriately sized sheet metal screw (coarse thread) such  that it has good grip on the coupling but doesn't fracture it or expand it creating excess drag.  Next, while a person inside the boat pushes on the transducer cable (close to the chase so as to exert pressure on the cable without kinking it), gently and patiently pull on the previously inserted screw in the transducer to extract it from its counterbore (recess).   In our case these slid out with minimal traction.  There was no evidence of marine growth or other "cementing" adhesives.  The blunt end of the chase tube is positioned such that it provides a shoulder for the counter-bore that exactly positions the transducer so that it CANNOT be seated too deeply into the recess.  Exact distance between the transducers is important and has been expertly calculated by Amel.  

You use the old cable as a messenger line to pull the new wire into place.  In our case I cut off the old transducer, stripped a small section of cable cover and I soldered the wires of the old and new together.  It takes minimal traction to pull the new wire into place.   I lubricated the new transducer and counter-bore with silicone grease and it slid into place easily.   I WOULD NOT SEAL THIS TRANSDUCER WITH ANY KIND OF SEALANT AS IT ISN'T NECESSARY AND WILL ONLY MAKE THIS TASK MORE DIFFICULT IF IT NEEDS TO BE REPEATED IN THE FUTURE.  AGAIN, the chases ends above waterline and there is no need to seal the transducers.  Thread the respective cables thru their respective hose and/or chase to the computer making sure you somehow label them as fore and aft (as this will be required for proper connection).  Use the old cables as messenger lines  Cut the cables long enough to have a proper service loop (copy what Amel did).  Strip the insulation and extract the wires from the shielding.  Attach at the computer in the same manner as previously.  See the information in the files section for setting the dial in the computer for illumination of the calibrating red LED.  Calibration is also done on the B & G Multi-function display at the nav station (instructions in the installation manual for that unit as provided by Amel).    If you have any questions don't hesitate to email me at garysilver at mac dot com.  

This was a relatively easy job that I had dreaded (unnecessarily it turns out) for years.  You need someone to push/feed and someone to feed/pull at the same time, hence the two person job.   There is a bunch of information in the photos section and the files section on the Sonic Speed.  I did trim the rubber coupler fair with the face of their hull and keel faces (at a more marked angle for the keel coupler) by gently slicing with a razor blade.  Try to make a smooth cut.   Also read this:  https://amelyachtowners.groups.io/g/main/files/B%20&%20G%20Sonic%20Speed%20Information/SonicSpeedTroubleshooting.pdf

All the best, 
Gary S. Silver, M.D.,  Farmington, UTAH,  USA
former owner of s/v Liahona (from new to age 20 years)    Amel SM 2000 # 335   now owned by Jason Rutledge


 

You can find the photos Gary mentioned at https://amelyachtowners.groups.io/g/main/album?id=268273



CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar

On Sun, Sep 19, 2021 at 11:00 AM Gary Silver via groups.io <garysilver=mac.com@groups.io> wrote:

[Edited Message Follows]

Hi Michele: 

I will echo what Jason Rutledge posted and perhaps amplify the procedure.  I provided about a dozen photos to Bill and perhaps he will post them if he hasn't done so already..  Jason and I did this job together.  It is a two person job.  

The sensors and cables run in smooth plastic chases (pipes) from their position below the waterline to a position above the waterline so no sealing is necessary.  Our sensors (SM Hull # 335) were not sealed in any way, however, they are a loose interference fit in their recesses/counter-bores.  I have been told by Bill that some were sealed with 3M 5200 or other type sealant.  The plastic wire chase for the forward sensor comes up just in front of the forward seat of the saloon table.  The wire exits the chase at this point, makes a "U" turn and re-enters a chase that goes to starboard, enters a fiberglass chase that end in the cabinet where the sonic speed computer is located (next to, and forward of the starboard side fore-aft saloon seat).    The rear sensor, that is on the leading edge of the stub keel has a chase that appears in the aft, under-table, athwart-ship locker beneath the saloon table.  It is encased in a semi-clear hose that takes it further above waterline and enters the same fiberglass chase that takes the cable to the computer.    It is easiest to remove this hose at the fixed chase in the under-table locker so you are only working with 2-3 feet (1 meter) of cable.  

Start by identifying the routing of both cables.   Next, remove (gently pull on) the 1/2 in (1.5cm) long rubber covering of the transducers at the hull forward and aft transducer positions.  You will find underlying those rubber transducer covers a ceramic like plastic face of the actual sonic transducer.  The  rubber acts  as a protectant "sonic coupling".   Use a drill to gently and patiently drill a small hole in the face of the transducer to a depth of about 1/2 inch.  Into that hole thread an appropriately sized sheet metal screw (coarse thread) such  that it has good grip on the coupling but doesn't fracture it or expand it creating excess drag.  Next, while a person inside the boat pushes on the transducer cable (close to the chase so as to exert pressure on the cable without kinking it), gently and patiently pull on the previously inserted screw in the transducer to extract it from its counterbore (recess).   In our case these slid out with minimal traction.  There was no evidence of marine growth or other "cementing" adhesives.  The blunt end of the chase tube is positioned such that it provides a shoulder for the counter-bore that exactly positions the transducer so that it CANNOT be seated too deeply into the recess.  Exact distance between the transducers is important and has been expertly calculated by Amel.  

You use the old cable as a messenger line to pull the new wire into place.  In our case I cut off the old transducer, stripped a small section of cable cover and I soldered the wires of the old and new together.  It takes minimal traction to pull the new wire into place.   I lubricated the new transducer and counter-bore with silicone grease and it slid into place easily.   I WOULD NOT SEAL THIS TRANSDUCER WITH ANY KIND OF SEALANT AS IT ISN'T NECESSARY AND WILL ONLY MAKE THIS TASK MORE DIFFICULT IF IT NEEDS TO BE REPEATED IN THE FUTURE.  AGAIN, the chases ends above waterline and there is no need to seal the transducers.  Thread the respective cables thru their respective hose and/or chase to the computer making sure you somehow label them as fore and aft (as this will be required for proper connection).  Use the old cables as messenger lines  Cut the cables long enough to have a proper service loop (copy what Amel did).  Strip the insulation and extract the wires from the shielding.  Attach at the computer in the same manner as previously.  See the information in the files section for setting the dial in the computer for illumination of the calibrating red LED.  Calibration is also done on the B & G Multi-function display at the nav station (instructions in the installation manual for that unit as provided by Amel).    If you have any questions don't hesitate to email me at garysilver at mac dot com.  

This was a relatively easy job that I had dreaded (unnecessarily it turns out) for years.  You need someone to push/feed and someone to feed/pull at the same time, hence the two person job.   There is a bunch of information in the photos section and the files section on the Sonic Speed.  I did trim the rubber coupler fair with the face of their hull and keel faces (at a more marked angle for the keel coupler) by gently slicing with a razor blade.  Try to make a smooth cut.   Also read this:  https://amelyachtowners.groups.io/g/main/files/B%20&%20G%20Sonic%20Speed%20Information/SonicSpeedTroubleshooting.pdf

All the best, 
Gary S. Silver, M.D.,  Farmington, UTAH,  USA
former owner of s/v Liahona (from new to age 20 years)    Amel SM 2000 # 335   now owned by Jason Rutledge


David Crisp
 

Gary, excellent description and encouraging, thanks.  I too have been feeling nervous about tackling this job but your description is great and the above waterline cable exit is reassuring (I'd expect nothing else of Amel!). 

I have an A54 (#58 2007) and so far have been unable to find the route the cables take from the transducers to the computer.  In my case the B&G sonic computer is located in the locker under the forward athwartships saloon table seat. See attached photo.  This is the only place I can see the transducer cables, I hope it is possible to pull the cables around the various corners through to here.  Does anyone know the route these cables take and if there is any other point to access/feed them on an A54?
It appears the transducer cables have been bundled up rather than cut.  Is this significant?  Does cable length matter because of signal processing/timing? 

I will be hauling out in a couple of weeks and will I'll tackle this job then, will share anything I learn.

Best,
David Crisp
SV Wilna Grace
Amel 54 #58


antonio scipioni
 

Hi Michele, 
If you live in Rome you can try to powerline by paolo ceccarelli that’s BeG dealer.
Br
Antonio
Vagabundo SN108
Tuscany 

Inviato da iPhone

Il giorno 19 set 2021, alle ore 12:52, Marco Mancini <marcomancini61@...> ha scritto:


Dear Michele we did last year because our probe failed and I have tried with success  to replace the older one instead to put a new probe for several  reasons  . We  replaced ( my sailor man didi)  both the sensors  because we had to buy for about 300 US $ .  The cables run into a dedicated pipelines ( you may  easily see upper part of the one relative to the probe that look forward ) just in the compartment below the table dinette where you will see the cable inside a transparent pipe.  
 You can exract the probe and cable from the housing in the keel using a witness cable  and insert the new one pulling the witness cable from inside. You need to seel the probe in the keel with neoprene .  Check that the reading geometry of the front and rear probe is the same. 
I hope this may help 
sincerely 

Marco Mancini

Il giorno 09 set 2021, alle ore 20:09, MICHELE LUCCIOLA <michelelucciol@...> ha scritto:

Hello and good evening from Rome
This summer I experienced  on  my SM2000 some troubles with the reading of the B&G speedometer.
I saw the documents in the files section, but there is not indication about how to replace them.
 I have to replace the sensors (that I have found in Ebay) but I'm not sure that this is an easy work ....especially to remove the old ones. Does anyone did this job before? I'm very scared about the sensor on the keel....I have seen that the sensors are two little plastic tubes but I don't know how they are fixed to the boat because there is no o'rings on the tube so I assumed that the tube is fixed with resin to the hull and to the keel....
If possible I prefer to replace the sonic speed sensors and don't do a new hole to instal a new sensor; for that reason I will be happy to receive comments from you
Thanks in advance
Michele


MICHELE LUCCIOLA
 

Thank you very much Gary for your explanation; I was going  crazy to find the second pipe below the table....
I have found on ebay a spare sensors and i will do the job this winter when the boat will be houled.
For the moment I wish to thank you for your assistance. If you need something from Italy I'm at your disposal
Big Hug
Michele