who has added a hull drain

[timb]

I'm thinking of adding a hull drain on my marine trader. I guess at the aft end of the keel . I was thinking about coming up an inch or so from the bottom . does that sound right? I guess i should hit concreate . drilling holes below the water line scares me . i guess i should use a 1/2 npt drain like on a small power boat maybe the type with three mounting holes and some 5200?

 

[O C Diver]

I put a drain hole in my Bruno and Stillman charter boat 15 years ago. It sits on blocks all winter and didn't want water collecting in the hollow keel and then freezing.

Mine is in the bottom of the keel at the stern. Took a stainless 3/8" plate 3" x 3", tapped 1/4" pipe thread in the center and drilled 1/4" holes in the corners. Through bolted it to the bottom of the keel. In OCD retrospect, I should have counter sunk the 1/4" holes and used flat head screws and used a socket head flush plug, but I've never had a problem. I use a brass pipe plug to seal the drain. As a point of reference a 1/4" pipe plug hole is close to 1/2" and drains very quickly.

Ted

 

[FF]

IF access is easy a screen in the keel for the winter can keep bugs from coming aboard in the spring .

 

[OldDan1943]

I use a brass pipe plug to seal the drain. As a point of reference a 1/4" pipe plug hole is close to 1/2" and drains very quickly.

Ted

Not brass!! Use bronze!!!

 

[O C Diver]

Not brass!! Use bronze!!!

It's an annual replacement item. The plug is the remnants of an anode.

Ted

 

[mike66]

Guess I'll put mine at that lower hole. 1986 Albin40. Now, hull leak, stern tube, ???? The saga continues.

"I shot six holes in my freezer, I think I've got cabin fever"

 

[Comodave]

That’s some impressive drainage going there.

 

[mike66]

Lotsa beer

 

[mike66]

Pretty clear, didn't smell. Guessing relatively new water.

 

[Comodave]

We had a Trojan with a hollow keel that was full of water. It smelled worse than a holding tank. I cut the top off so I could clean it and drain the water regularly.

 

[CaptTom]

I added a drain hole (using a common stainless garboard drain fitting) to my keel. I somehow managed to hit the exact right spot, with the hole coming in just a hair below the inside surface.

I did a lot of measuring from a nearby thru-hull, but as a final confirmation I put a bright light inside and checked the location from the outside after dark. The line of light/shadow wasn't 100% clear but it seemed to confirm my measurements.

 

[timb]

tom my keel is enclosed I can't use a light . how far off the bottom did you go?

mike you probably could go a little lower.

 

[mike66]

Probably, but I think this should be good enough. I'll be removing bottom paint near the prop and shoe looking for cracks. There are some just below the prop. I'll glass them over. My big question is whether the tube is leaking. I'll get the shaft out of there and pressure test it in the spring. Other option is not do that, just fix cracks and install a bilge pump into the keel and check out the rate of ingress when we launch. If there is a hole in the tube I'll find it, maybe temp patch with resue tape.

 

[Comodave]

I added a drain hole (using a common stainless garboard drain fitting) to my keel. I somehow managed to hit the exact right spot, with the hole coming in just a hair below the inside surface.

I did a lot of measuring from a nearby thru-hull, but as a final confirmation I put a bright light inside and checked the location from the outside after dark. The line of light/shadow wasn't 100% clear but it seemed to confirm my measurements.

If you have access inside the easiest way to measure for the hole outside is to get 2 rare earth magnets. Tape one inside where you want the hole. Then go outside and the second magnet will find the inside magnet and stick to the hull. Then mark the spot, remove the magnets and drill. 100% sure where the hole goes, no guessing.

 

[Shrew]

Not brass!! Use bronze!!!

A Brass pipe plug is usually hollow on the inside. A Bronze garboard plug is solid on the inside. Even though they share a thread and size, I would never use a brass pipe plug from a plumbing supply as a garboard plug.

 

[Shrew]

I'm thinking of adding a hull drain on my marine trader. I guess at the aft end of the keel . I was thinking about coming up an inch or so from the bottom . does that sound right? I guess i should hit concreate . drilling holes below the water line scares me . i guess i should use a 1/2 npt drain like on a small power boat maybe the type with three mounting holes and some 5200?

I would drill out from the inside. Locate the lowest spot on the transom where the starboard and port hulls meet and drill out from there. Drilling in from the outside forces you to guess where the hole will land on the inside.

Too low and you're into the keel. To high, and the lip will prevent complete drainage.

 

[timb]

I would drill out from the inside.

Too low and you're into the keel. To high, and the lip will prevent complete drainage.

I can't get to the inside . it's filled and glassed over.

 

[OldDan1943]

A question......
Has anyone consider the water in the keel as additional ballast?
I know the water tanks of the N46 were inside the keel and I considered additional ballast.
When a storm or hurricane were coming, I filled the water tanks (5 tanks)

 

[CaptTom]

tom my keel is enclosed I can't use a light . how far off the bottom did you go?

I measured down from a thru-hull, not sure exactly how high up. Plus I imagine it's different for every hull.

If you have access inside the easiest way to measure for the hole outside is to get 2 rare earth magnets.

Now THAT sounds like the best idea yet!

 

[Comodave]

I measured down from a thru-hull, not sure exactly how high up. Plus I imagine it's different for every hull.



Now THAT sounds like the best idea yet!

I use the magnets all the time for drilling holes in the hull, through bulkheads and the like. I used them to locate the handrail stanchion bases which were covered on the inside with headliner material. I took one on the deck and a friend went inside. We found the base and then put blue tape on the headliner. Then I ran the magnet around the base while he followed it on the inside with the second magnet. He drew on the blue tape so I could see the exact position of the stanchion base. Then I was able to cut the headliner precisely where I needed to in order to get to the nuts on the base. Worked perfectly.

 

[jleonard]

I went on the bottom of mine. Then used an allen head bronze plug so nothing would protrude.

 

[Brooksie]

A "must have" when putting your boat away especially in freezing weather but also where rain could fill your boat while on the hard.
I have done it to two boats. On one I used a regular bronze 1-1/4" thruhull w/ a bronze cap inside where I could reach it. On my narrow keeled downeast boat, I used a regular garboard drain, 1" that has a flush plug outside that you remove with a 1/2" square wrench that came with it.
In both cases. I started with an oversized holesaw & chisel, making a shallow 1/8" recess to accept the OD of the fitting, then using a smaller holesaw to accept the fitting stem. This way it will not catch on something and be knocked out of the boat. 5200 and bronze fasteners finish the job.

 

[Njlarry]

Magnets are a brilliant idea!
My current boat had a garboard drain plug. Neither the AO marina operator or the dumb as @##% po thought to ever remove the garboard drain plug so I got a 30 year old boat with a 1 year old engine thanks to the insurance claim after a frozen broken cockpit scupper. Even with shrink wrap I never forget to remove the plug every fall on the hard.
Garboard drain plugs are such CHEAP insurance I don't know why they aren't required by either marinas or ins companies.