Transom Drain Tube Replacement

[ATPNW]

I have three transom drain tubes that look pretty corroded and probably need replacing. Two are drains from the motor/splash well of my Venture. And the third is lower, draining from the bilge area between the two gas tanks. I believe all the tubes are currently brass. I have two questions on this:

1. For the bilge drain tube, should that be switched over to a Garboard style drain?

2. Is brass still the preferred metal to use on the motor/splash well drains as those are above water?

I know whichever way I go to oversize all the holes and then fill with epoxy before proceeding.

Thanks

Alex

 

[Reelin2]

Personally, I wouldn’t have anything but garboard style under the waterline. The brass style are fine for the splash well.[/img]

 

[ssobol]

On my 22 I installed a new bilge drain that is lower down than the original. It allows for complete draining of the bilge, not the ~1" standing water that was left by the original (my winter has subfreezing temps).

I installed a bronze garboard style fitting. I drilled the hole, epoxied the core, and then installed a thin wall plastic tube with 5200 as a lining. The original drain plug was left in place but is no longer used.

 

[ATPNW]

On my 22 I installed a new bilge drain that is lower down than the original. It allows for complete draining of the bilge, not the ~1" standing water that was left by the original (my winter has subfreezing temps).

I installed a bronze garboard style fitting. I drilled the hole, epoxied the core, and then installed a thin wall plastic tube with 5200 as a lining. The original drain plug was left in place but is no longer used.

Do you recall what plastic you used? I read somewhere that schedule 40 pvc can be used, but I see it has a temperature rating down to 32 degrees (my concern is that it gets colder than that here in WA). Also, when screwing the garboard in did you use bronze screws to keep the metals the same?

 

[ATPNW]

Personally, I wouldn’t have anything but garboard style under the waterline. The brass style are fine for the splash well.[/img]

After looking through your album I think I recognize your work from the C-Dory Facebook group. You are doing excellent work, I can only hope mine turns out that well. It’s always a little nerve racking working with holes below the water line.

 

[Flashyfish]

I changed over to the garboard style drain on my C Dory. I used the Perko bronze garboard drain and 3m 5200 sealer along with silicon bronze screws.
Like any dissimilar metals submerged in seawater, the closer the metals match, the less galvanic corrosion
Strong, dependable and watertight.
On the splash well next to the outboard, I used the standard brass drain tubes. My transom is a solid seacast structure, so I did not have to do the prep work to protect the interior wood.

 

[ssobol]

On my 22 I installed a new bilge drain that is lower down than the original. It allows for complete draining of the bilge, not the ~1" standing water that was left by the original (my winter has subfreezing temps).

I installed a bronze garboard style fitting. I drilled the hole, epoxied the core, and then installed a thin wall plastic tube with 5200 as a lining. The original drain plug was left in place but is no longer used.

Do you recall what plastic you used? I read somewhere that schedule 40 pvc can be used, but I see it has a temperature rating down to 32 degrees (my concern is that it gets colder than that here in WA). Also, when screwing the garboard in did you use bronze screws to keep the metals the same?

It was a long thin plastic container that contained bubble liquid I got from a $ store. The diameter was just right so I cut off a section of the container.

Something like this:https://www.fivebelow.com/products/fubbles-giant-bubble-wand-14-5in

I looked at PVC pipe, but the wall thickness was too much.

Yes, I used bronze screws, but my boat is mostly used in fresh water and lives on a trailer so the materials are not as crucial as maybe for others.

 

[srbaum]

If any C-Brat ever needs to install a brass drain plug tube in their boat, feel free to reach out, as I have the installation mandrel that draws both inside and outside of the tube, in properly. I can mail the tool out and you can just return it, when you finish the task. I will also provide detail directions, so that the new tube is cut to the correct length and sealed correctly.

 

[Marco Flamingo]

I replaced mine when I was looking for places that might have had water intrusion. The brass lining and caulking had held, but it was a good time to increase the size and placement. The original holes didn't drain very fast or get the splash well very dry and I wanted to lower the hole 1/8th inch.

I used thin walled PVC pipe. I drilled out to fit the O.D. of the pipe and then worked on the end of the pipe to get it to fit the splash well. The outside edge I just let "run wild." I then gooped everything up with epoxy and cabosil and slid it into place. Once cured, I masked the exterior with tape and used a flush cut saw. It only took a little sanding to clean up the edges. I surprised myself by not even scratching the gel coat. Pictures in my photo album under Modifications - Splash Well Drain Holes.

I think the 32 degree low temp recommendation for PVC pipe is for when full of water. It splits open easier than PEX, copper, etc. My boat has been below freezing many times without issue.

 

[Reelin2]

Personally, I wouldn’t have anything but garboard style under the waterline. The brass style are fine for the splash well.[/img]

After looking through your album I think I recognize your work from the C-Dory Facebook group. You are doing excellent work, I can only hope mine turns out that well. It’s always a little nerve racking working with holes below the water line.

Yep, I jump around both groups. I oversized, bedded 1” PVC in thickened epoxy. Installed new garboard bedded in 4200. Easy project. I added a few photos to my album.