Aloha 32 – The full “Mortar in the bilge” story!

We purchased an Aloha 32 late in the fall of 2001 and during the process of cleaning her up to get ready for launch the following spring we made an unpleasant discovery.  Our purchase survey suggested replacing the aft most keel bolt nut and adding a substantial backing plate.  When I got to cleaning things up and preparing for the job I discovered that Ouyang Boatworks had filled the aft most compartment of the bilge with cement based mortar.  In the mortar was bedded an oak 2 x 4 x 8″ long through which the aft most keel bolt projected.  Most of the mortar and all the oak were then glassed in leaving an arrangement that probably looked proper when new but in the long run didn’t seem to drain very well. It seems this arrangement was chosen because the aft most keel bolt is in too narrow a portion of the bilge to allow a nut (or even a washer) to be run down to the bilge floor.  The builder chose instead to use mortar to build the bilge floor up to a workable level.

The photos below outline the repair steps undertaken. Since these were completed, I’ve been corresponding with a few Aloha 32 owners and it seems there are a number of keel configurations on the water.  One of the people I corresponded with doesn’t know his arrangement because his bilge covers don’t go back as far as mine.  Another had a carbon steel 2″x4″ hollow structural steel piece wedged in the turn of the bilge.  It rusted away so he replaced it with solid steel.  Yet another owner has the keel bolt far enough forward that it can sit on the bilge floor as do the rest.  So there are a number of arrangements.  If you have mine, I hope this write up helps you when it comes time to clean things up.

When we started this “backing plate” project, we found half the glass over the oak had delaminated from the hull. This photo shows the arrangement reconstructed after having initially been disassembled for inspection.  In the photo it is evident that I had already started scratching away the mortar.

The oak board uncovered. When the delaminated glass was pulled off, the oak was messy but still basically sound.  The mortar under the oak was decomposing into sand; quite a mess.  Nevertheless, the oak was still bearing the load transferring it directly to the turn of the bilge.  Some prodding revealed that the mortar was breaking down to a sandstone form (easy to crumble) wherever it was against fiberglass.

The mortar with the very beginning of the excavations in progress. I used a 3/4 “ hammer drill to make swiss cheese of the mortar and then dug it all out.

The bilge cleaned out.  It is interesting to note that the lower half of the bulkhead that contained the mortar was rotted out and the mortar at its base was decomposing into sand and contaminating the rest of the bilge.

The next step was to glass in a new bulkhead well aft in the excavated compartment.  Into this new, smaller compartment was poured about a litre in 4 lifts of epoxy resin filled with chopped glass.  Over the fill were laid about 8 layers of roving and cloth as bedding for the recommended stainless plate.  Everything was arranged, with the help of poured resin, to ensure a clean drainage path from the aft end to the newly opened bilge.

The final arrangement with the new bulkhead in place and the space filled with epoxy and chopped glass. In the end, the plate was icing on the cake because all the other keel bolt nuts bear directly on the fiberglass through a washer.  In this case there is the stainless plate and two washers.  Notice the floor has been re-sanded in this one and has the first coat of varnish.  Another 2 coats, and light sanding has made it look pretty good.

Written by Zsolt Kecskemeti