Water in the Keel and/or Rudder – Fitting a garboard plug

The hulls of Aloha 27 (8.2) and 28 (8.5) models were moulded in 2 halves and then bolted together fully encapsulating the keel ballast. This is both a significant blessing and a minor curse – there are no keel bolts to worry about and the boats can hit the ground fairly hard without serious damage but occasionally they can suffer from water entering a foam filled void area in the keel. Either water from the bilge makes its way down into the keel or small splits appear along the join and allow water into the keel. On boats sailed in freshwater and removed onto land in freezing winter conditions the water expands as it freezes and creates or makes the split worse, and could damage the glass laminations if it is not detected and corrected in a timely manner.

One solution is to drain and then fill the “voids” (see the article Filling the Voids), but Perry Basden has provided details of his solution which he has applied to his Aloha 34 and which involves installing a “garboard plug” to allow any water to be drained.

I installed a garboard plug on my Aloha 34 for under a hundred dollars.  I believe this is pretty cheap insurance considering the cost of repairs necessary should the hull or rudder split.  The information and photos show how I solved the problem.

Photo 1 – Keel Weeping

The vessel obviously had water intrusion problems in the keel area.  This fact was noted during a pre purchase survey of the vessel.  The photo is of the starboard side of the keel where one can clearly see several small holes with water stains near the bottom of the keel.  The area had been painted over, as seen by the different colour of paint.  It might also be noted that the small pin holes were found only on the starboard side of the keel and none on the port side.

Photo 2 – Keel Drainage Holes

I drilled a hole in each of the areas where water appeared to be leaking from the keel.  I was surprised at how much water was in the hull.  I’d guess that there were several quarts of water that gushed from the 1/4″ holes.  Once the holes were drilled and the water allowed to drain I did a little exploratory work to try and get a handle on the extent of water intrusion.

Photo 3 – Keel Foam Core

I used a coat hanger and managed to dig a little foam out of the hole. Closer examination revealed that there was only about 2 inches of foam between the lead ballast and the bottom of the keel.  The bottom of the keel was almost three inches of solid fiberglass.  This exploratory work also helped me to determine the exact position of the garboard plug.

I purchased a Perko garboard plug from the local marine chandlery.  The plug is basically a cast bronze flange with a tapped and threaded hole in the center that will accept a brass plug.  The flange also has 4 mounting holes to allow the flange to be attached to the hull with the stainless screws provided.

Photo 4 – Ground out Recess

After the location of the plug was determined, I drilled an inch and a half hole to accommodate the spigot of the garboard plug using a hole saw attached to an electric drill.  The hole was positioned just slightly below the solid glass bottom of the keel to ensure that all the water would drain from the keel.  I also removed as much of the foam core as possible so that any water in the hull could drain into this pocket.

Photo 5 – Dry Fit Plug

Once the hole for the spigot was drilled, I inserted the garboard plug and scribed its outer circumference on the hull. This area of the hull was ground out so that the complete plug would fit flush against the hull.  Grinding was done with a four-inch disk grinder for most of the area, with the final touches done with a Dremel tool.  While doing the grinding work, I used the plug often to check the fit.  This also ensured that the plug was fair to the hull.

Photo 6 – Waxed Plug

I wanted a good seal between the hull and the plug when it was installed to try and prevent water from entering the hull through the plug installation.  I decided to use epoxy and mold it to the shape of the plug.  This was done by using the garboard plug as the mold.  I waxed the plug using the handiest item I had available, a liberal coating of boat wax, to prevent the epoxy from sticking to the plug.

Photo 7 – Epoxy Check

I used WEST System epoxy mixed to a very stiff consistency as it had to cling to the vertical surfaces of the keel.  I also added micro balloon fillers so that I would be able to sand off any excess epoxy.  Once the epoxy was trowelled into place, I inserted the plug into its final position and held it in place with a brace until the epoxy set.  The plug was then removed and any gaps or voids in the epoxy were filled.  I also removed any excess epoxy that may have gotten into the hull recess and prevented water from draining from the hull.

Photo 8 – Plug Installed

I cleaned the garboard plug with thinners and then applied a liberal coating of marine sealant to the plug as well as the predrilled screw holes in the hull.  The plug was then installed using the four stainless screws.  Excess sealer was cleaned and the threaded plug installed.  I used Teflon tape on the threaded plug to make removal of the plug easier.

Photo 9 – Finished Plug

The whole project required two days of work.  Installation was not difficult and could be completed by anyone with some mechanical skills and a few power tools.  The hardest part for me was drilling the inch and a half hole for the garboard plug spigot.  For some reason, I’m always leery of drilling a big hole in the bottom of a boat.

When the boat was hauled out for winter storage in the fall of 2003 the threaded plug was removed.  There was about a quart of water that came out and the keel continued to seep water for several weeks.  Installation of the garboard plug will prevent any future damage to the keel.

Written by Liam Fitzgerald