Is this a cored hull bottom?

[Terestron]

I am replacing a Thru-Hull Transducer in my 1987 Chris Craft. I removed the original existing one pretty easy. The silicone seemed pretty flexible so I do not think it was 5200.

I need to drill out a 2" hole for the new transducer but I want to make sure if this a cored bottom hull or not so I can install properly. I know the sides of the boat are cored hull material. To me it looks like several layers of fiberglass.

Thanks for looking!

[Tortuga's Lie]

Can't really tell, the pic on the right looks cored while the one on the left looks solid glass.........Chris Craft sailboat or power?

[Terestron]

It is a power boat. the left is from inside and the right outside. Hole is very near the keel. When I run my finger along the side it is very solid edge.

[flee27]

If it is cored they should have removed the coring around the hole and filled it with thickened fiberglass or epoxy. Go ahead and open the hole up to what you need and you should be able to tell then. If it is cored you will need to remove some of the coring and fill with appropriate resin to seal the new opening.

[lk240]

If you poke around with a sharp object can you get small bits of wood?

[MJH]

Originally Posted by Terestron

I am replacing a Thru-Hull Transducer in my 1987 Chris Craft. I removed the original existing one pretty easy. The silicone seemed pretty flexible so I do not think it was 5200.

I need to drill out a 2" hole for the new transducer but I want to make sure if this a cored bottom hull or not so I can install properly. I know the sides of the boat are cored hull material. To me it looks like several layers of fiberglass.

Thanks for looking!

Contact Chris Craft with the make, model, and year.

~ ~ _/) ~ ~ MJH

[Flatswing]

“I need to drill out a 2" hole for the new transducer but I want to make sure if this a cored bottom hull or not so I can install properly. I know the sides of the boat are cored hull material. To me it looks like several layers of fiberglass.![/QUOTE]

Once you drill the new hole it should be clear, just have some epoxy & your favorite thickening agent available, in case it is cored. Procedure will be the same other than removing some core and sealing with epoxy (plus allowing epoxy to cure) before installation. I assume you know not to use silicone for your new installation. Aggressive use of scotchbrite pad or equivalent plus several acetone wipes to remove any remaining old silicone (if that what was actually used) inner & outer surfaces would be optimal.

[Terestron]

Originally Posted by Flatswing

“I need to drill out a 2" hole for the new transducer but I want to make sure if this a cored bottom hull or not so I can install properly. I know the sides of the boat are cored hull material. To me it looks like several layers of fiberglass.!

Once you drill the new hole it should be clear, just have some epoxy & your favorite thickening agent available, in case it is cored. Procedure will be the same other than removing some core and sealing with epoxy (plus allowing epoxy to cure) before installation. I assume you know not to use silicone for your new installation. Aggressive use of scotchbrite pad or equivalent plus several acetone wipes to remove any remaining old silicone (if that what was actually used) inner & outer surfaces would be optimal.[/QUOTE]

I plan on using 4200 sealant. Ill drill out the 2" hole and then I will see for sure if it is cored. The previous installer certainly did not use any epoxy. I assume they used something similar to 4200.

[Scaramanga F25]

I mount all transducers inside. No hole if no core.