Garboard drain plug

Nov 4, 2025
1
Catalina 36 MKII tall rig South Haven
This is my first post. I hope to get first hand knowledge from other owners of boats like mine. I apologize in advance for rookie posting mistakes. I'll learn.
I have a 1996 Catalina 36 mkii tall rig wing keel with a keel stepped Zspar furling mainsail. I am slipped in Southwest Michigan. I keep my boat in a cradle, shrink wrapped, on the hard during winter. Every year I get almost 25 gallons of rain water down the mast into my bilge. This creates the obvious moisture problems (ice, condensate, mold). Question: Has anyone installed a garboard drain in their bilge? What type? Where did yo locate it? Has it been a success? I am thinking of installing one with hopes it will allow rain water to drain out of my bilge and not accumulate over the winter. I have seen different types a) a t-handle brass plug which installs inside the bilge and b) a 1/2 in brass square threaded plug which installs on the outside of the hull. That one attaches the flange to the hull with 3 screws. I suspect the core needs to be sealed with an epoxy after drilling a hole through the hull to the bilge. I guess a proper sandwich type thruhull with inside and outside flanges aren't used here. I'm guessing the tricky part is finding the best location to get the most water out. thinking would have to be the lowest place in the bilge yet exit above the keel. I am thinking the bilge compartment in the salon, lowest point, (thats where my bilge pump is) or the section just forward
 
May 1, 2011
5,208
Pearson 37 Lusby MD
Not a Catalina, but . . .

1/2 in brass square threaded plug which installs on the outside of the hull.
Mine's installed on the outside of the hull. You're looking for a bronze fitting.
thinking would have to be the lowest place in the bilge yet exit above the keel. I am thinking the bilge compartment in the salon, lowest point, (thats where my bilge pump is) or the section just forward
Mine's as far aft as possible in the bilge and exits above the keel.

Welcome to the forum! :beer:
 
Jan 11, 2014
13,311
Sabre 362 113 Fair Haven, NY
Only use Bronze, brass below the water line will fail in any application.

Use the type where the plug screws in from the out side. Water pressure will work with you on this.

Don't use the type with a T handle. It can anything floating, line, seaweed, trash. Use the flush plugs with a ⅜" square hole. A ⅜" ratchet fits and allows you to tighten and remove the plug easily.
 
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Jan 1, 2006
7,733
Slickcraft 26 Sailfish
I'm not a Catalina owner but I think the hull is not cored. It would still be important to seal the laminate to prevent water ingress into it.
 
Apr 18, 2012
46
Catalina 400 MKI 67 LaSalle,Mi
We have one on our C400. The previous owner installed it a couple of inches from the bottom of the bilge. I remove the bilge pump from its mount so it doesn't freeze in the remaining water. Seems to work as it is supposed to as long as I remember to put it back in before launch.
 
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