I'm posting this for a new CD owner who is not on line. He has a serious water leak around the transducer for the depthsounder (i.e., water covers the cabin sole overnight) He wants to know if there is anything holding the external pad to the hull outside of the transducer shaft itself. Might there be buried screws in the pad in addition to the threaded shaft and nut? The interior backing plate has a one eighth inch crack in it also. Were these bedded in something like Life Caulk or something more serious such as 5200? Anybody have experience with these transducers?
TacCambria@thegrid.net
CD 30 depthsounder transducer question
Moderator: Jim Walsh
-
Jerry
Re: CD 30 depthsounder transducer question
I believe the depth sounders and transducers were part of dealer prep rather than factory installed, thus installation techniques (and transducer type) may be different from boat to boat. On my '84 CD30 (hull # 321) I have teak blocks inside and outside the hull formed to the hull shape. The blocks are installed with some type of bedding compound or Life Caulk, but definitely not 5200 since I was able to remove and reinstall them without trouble. On my boat, there are no screws holding the blocks to the hull. The sandwiched unit of blocks, hull and transducer is held together by the shaft and nut of the transducer. Hope this helps.Tom wrote: I'm posting this for a new CD owner who is not on line. He has a serious water leak around the transducer for the depthsounder (i.e., water covers the cabin sole overnight) He wants to know if there is anything holding the external pad to the hull outside of the transducer shaft itself. Might there be buried screws in the pad in addition to the threaded shaft and nut? The interior backing plate has a one eighth inch crack in it also. Were these bedded in something like Life Caulk or something more serious such as 5200? Anybody have experience with these transducers?
-
Ed Haley
Re: CD 30 depthsounder transducer question
If this is a removeable transducer, then the external housing is probably seated with a bedding material of some sort. I have not seen the housing afixed with screws. This external housing is more substantial than the removeable transducer. If your friend has this much of a leak, then he should be able to tell by inspection if the leak is from the external housing or from the holding nut of the transducer itself.
There is a circular neoprene seal that is seated within a groove in the inboard end of the fixed external housing where the mounting nut of the removeable transducer is to be attached and hand-tightened only. In addition, there is a 1 inch notch in the external housing near the outboard end where a key on the removeable transducer is inserted as it's mounted to keep it from turning as the mounting nut is tightened. If the 1/8 inch crack is near the mounting nut, the nut may have been overtightened. Or it was tightened when the seal was missing.
eghaley@dreamscape.com
There is a circular neoprene seal that is seated within a groove in the inboard end of the fixed external housing where the mounting nut of the removeable transducer is to be attached and hand-tightened only. In addition, there is a 1 inch notch in the external housing near the outboard end where a key on the removeable transducer is inserted as it's mounted to keep it from turning as the mounting nut is tightened. If the 1/8 inch crack is near the mounting nut, the nut may have been overtightened. Or it was tightened when the seal was missing.
eghaley@dreamscape.com
-
Dana
Re: CD 30 depthsounder transducer question
My suggestion is....no matter what....it is time to pull the boat for the repair. Something is very, very wrong and I doubt it can be fixed in the water...Here's why.
That 1-1/2 to 2" diameter continuous tread should be an integral part(one solid piece extension) of a round depth sounder flange on the outside surface of the boat. It can only be pulled out from the outside. In many installations this thin transducer flange rests right up against the hull surface. One of the questions is......is the continuous thread material made of bronze or plastic. If plastic, the flange to treaded stem may be cracked. This can be caused by overtightening of the large retension nut. Can not remove without hauling......There is also a danger of the flange letting go completely.
A backing block (made of marine ply or wood) is generally used on the inside and under the tightening nut to enlarge and spread the tightening force of the nut over a larger inside surface of the hull.
Now, sometimes folks will use an additional wood block on the outside of the hull to spread the tightening load on the transducer flange on the outside surface of the hull. This is especially true with a boat which has a thin hull. But, in my opinion, this can be more leak prone. These outside wood pads are not generally screwed into or thru the hull, just sandwiched between the transducer flange and the outside hull surface. The transducers flange center continuous threaded post just passes thru the center of the wood. I generally do not like this type of installation....it is more prone to leaks because you are trying to seal two surfaces on the outside of the hull instead of one.....and the surfaces are made of wood.
Anyway....it's time to pull that boat. The threaded flange can only be removed from the outside......and something is really wrong which can not be repaired in the water.
darenius@aol.com
That 1-1/2 to 2" diameter continuous tread should be an integral part(one solid piece extension) of a round depth sounder flange on the outside surface of the boat. It can only be pulled out from the outside. In many installations this thin transducer flange rests right up against the hull surface. One of the questions is......is the continuous thread material made of bronze or plastic. If plastic, the flange to treaded stem may be cracked. This can be caused by overtightening of the large retension nut. Can not remove without hauling......There is also a danger of the flange letting go completely.
A backing block (made of marine ply or wood) is generally used on the inside and under the tightening nut to enlarge and spread the tightening force of the nut over a larger inside surface of the hull.
Now, sometimes folks will use an additional wood block on the outside of the hull to spread the tightening load on the transducer flange on the outside surface of the hull. This is especially true with a boat which has a thin hull. But, in my opinion, this can be more leak prone. These outside wood pads are not generally screwed into or thru the hull, just sandwiched between the transducer flange and the outside hull surface. The transducers flange center continuous threaded post just passes thru the center of the wood. I generally do not like this type of installation....it is more prone to leaks because you are trying to seal two surfaces on the outside of the hull instead of one.....and the surfaces are made of wood.
Anyway....it's time to pull that boat. The threaded flange can only be removed from the outside......and something is really wrong which can not be repaired in the water.
darenius@aol.com
-
Tom
Re: CD 30 depthsounder transducer question
Thanks to everyone. She was hauled this afternoon and everything rebedded and a new back up plate fabricated and installed.Tom wrote: I'm posting this for a new CD owner who is not on line. He has a serious water leak around the transducer for the depthsounder (i.e., water covers the cabin sole overnight) He wants to know if there is anything holding the external pad to the hull outside of the transducer shaft itself. Might there be buried screws in the pad in addition to the threaded shaft and nut? The interior backing plate has a one eighth inch crack in it also. Were these bedded in something like Life Caulk or something more serious such as 5200? Anybody have experience with these transducers?