Marine Sealant Question

mrmamiller

Petty Officer 2nd Class
Joined
Mar 7, 2011
Messages
167
We are replacing a transducer on a fiberglass boat and there is a 5/8" diameter hole where the existing broken transducer cable went through. The hole is close to the waterline, being under a swim platform. We are replacing with the same model transducer and will use the same hole. I know there are a lot of varied opinions on which sealants to use, but it seems that most say use Life Seal or 3M 4200 for this sort of job. I'm wondering about using Life Seal on a hole of this diameter, never having tried it before. We want something that can be removed without a lot of trouble, as the marina forklift will probably break the transducer off again. Thanks for your help.
 

jigngrub

Fleet Admiral
Joined
Mar 19, 2011
Messages
8,155
I get the heebie-jeebies just thinking about a hole that big filled with sealant in a transom... anywhere in a transom.

Can you not run the wire exposed on the outside with screws and wire clamps holding it?
 

mrmamiller

Petty Officer 2nd Class
Joined
Mar 7, 2011
Messages
167
No Title

Difficult to re-route wiring without ruining the boat appearance (and it isn't my boat). Boat is a 22' Sea Ray Sundeck, and the swim platform is part of the boat. The previous owner had the transducer installed the way it is and the hole sealant (whatever it is) works fine. The existing sealant to be removed is white and somewhat flexible. We're not sure what it is but it is tough, flexible and is sealing well. We're hoping that we can find a product similar for this repair. The only pic I have of the hole is attached, didn't have any others.
 

mrmamiller

Petty Officer 2nd Class
Joined
Mar 7, 2011
Messages
167
Difficult to re-route wiring without ruining the boat appearance (and it isn't my boat). Boat is a 22' Sea Ray Sundeck, and the swim platform is part of the boat. The previous owner had the transducer installed the way it is and the hole sealant (whatever it is) works fine. The existing sealant to be removed is white and somewhat flexible. We're not sure what it is but it is tough, flexible and is sealing well. We're hoping that we can find a product similar for this repair. Tried to upload pic but got a message saying I didn't have permission, must be something with the new forum format.
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
16,313
Life seal Silicon works well for the application. 4200 would work but it's not as flexible and or as easy to work with.
 
Joined
Mar 1, 2005
Messages
958
I've used Marine Sealant many times to plug holes like that. Just make sure that you use enough to fully fill the hole. It holds watertight but can be easily removed. It truly is the duct tape of boating. I keep a tube in my boat tool box for emergencies.
 

Thalasso

Commander
Joined
Jan 18, 2011
Messages
2,879
If you want to do it right you need to drill the hole larger then whats needed and epoxy the whole hole. Then re drill it to the size you need it to be. Then use 4200 for the sealant. The reason for this is it protects the wood in the transom from water intrusion.
 

Triangleboater

Petty Officer 1st Class
Joined
Mar 5, 2013
Messages
207
+1 to the above. Mix some epoxy with some filler (cabosil) to a thickened state and fill that sucker and start over.
 
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