ThruHull Exit Clamshell

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GB42SandraK

Member
Joined
Feb 26, 2019
Messages
7
Location
USA
My 42 has a missing clam shell on the hull where the forward sink thru hull exits. I've searched all the company's that make thru hulls. The outside diameter is 4". Anyone know where I can find one?
 
Groco strainers

Maybe one in this flyer will work.
 

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I put a 4” S/S clamshell over a dryer vent on a previous boat so I know that they are available. But I have no idea where I got that one.
 
Seafit clamshell # 13528-S is 5-3/4" wide x 6-3/4" long x 2-1/4" high so maybe another option. It's 304 stainless.
 

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Personally, I would not obstruct an above waterline discharge, especially for a sink. Just make sure your hose is in good condition and is double clamped. Even if you get into some quartering waves or wind the only thing which will happen is that your sink may not drain very well until the conditions change.

pete
 
On some boats with thru hulls forward on the bow curve, with short hose runs and near the waterline, clamshells are necessary to keep water from entering the boat during plunging or wave slapping.
 
Seafit clamshell # 13528-S is 5-3/4" wide x 6-3/4" long x 2-1/4" high so maybe another option. It's 304 stainless.

I was watching this thread hoping for something like this! I pulled two aft deck speakers and wanted to vent and cover the holes. Thank you :flowers:
 
AKDoug,

Another option (since unlike the OP you don't have a through hull to work around), would be something like a Vetus Typhoon or Scirocco. I'm sure they are quite a bit more expensive, but they "do more" than the clamshell.

This is a screenshot from the 2016 catalog:
 

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The speakers were mounted flush against the sides in the cockpit, and finding round vented covers for 5" holes (plus screws) seems to be impossible. Keeping them close to the side unimpeded moving around in the cockpit is the goal, the engine and Webasto heater draw air from that space so easy air draw is also a goal.

Thank you for the suggestion though :)
 
Many variations available, but I bought two originals direct from GB factory a year or so ago.
 
Sink drain clamshells

Many variations available, but I bought two originals direct from GB factory a year or so ago.

Any chance you could share the contact info and maybe even the GB part number for these clamshells?
Thanks!
 
I had one missing on my GB49 in the bow area. I removed the second one and molded a new part using glass cloth and epoxy. With a little sanding and paint it look nice. The old and new parts were rebonded to the hull with 3M 4200. I took less than 2 hours to make.
 

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