Allied Greenwich 24: Sanding Prep & Filling Cockpit Holes

February 23, 2019

I got a relatively early start this morning on the Allied 24, and had intentions of continuing work on closing in holes within the cockpit as well as fairing recent repairs I had made to the core in a multitude of places across her decks. Since I wanted to begin closing the holes in the vertical surfaces of the cockpit seating, I knew I needed to sand the backside of those surfaces in order to add a backing layer of 1708 biaxial and this required sanding. At one point, I think I had nearly all of my sanding tools in the cockpit with me, and the scope of the sanding soon spread into removing the old topcoat paint on the cockpit sole as well as the vertical surfaces of the bridge deck and seating. On the recent cockpit sole core repair area, I sanded the areas that were proud of the surrounding surface, leaving a coat of fairing compound to finish the fairing work. This coat of fairing compound would have to wait for another day however.

I then moved into the cockpit lockers to sand the interior of the hull and other adjacent surfaces. I noticed the tabbing was pulling away from the bulkhead that separated the locker from the interior of the boat.

I grabbed an oscillating tool, cut through the tabbing at the transition of the hull and bulkhead, and then gently pulled the worthless fiberglass from the locker opening. This will be added to the list of repairs to be made in the coming weeks. I finished up sanding within the lockers.

I quickly hit the targeted repair areas (those openings shown in the picture below) with the DA random orbital sander, and just before calling the decks good for the day, I sanded the recently cored areas on the aft deck - either side of the lazarette.

I moved down to the ground to begin to prepare for the glassing-in of the outboard opening (aperture) in the overhang. I applied the typical 12:1 ratio of taper-to-thickness rule, and marked the area to grind the taper within. Since the glass here was laid up 1/4" in thickness, I applied a 3" bevel around the opening, grinding a taper ever-deeper as I moved toward the existing opening.

I also prepared the interior surface of the overhang to accept additional structural support, and accomplished this by sanding down to "fresh" fiberglass. The owner has selected a Torqeedo Cruise 4.0 pod drive, an electric-powered outboard, to serve as the auxiliary engine - essentially, to move on and off the dock/mooring ball. The engine will be a fixed-mount installation, and will require adequate support and structure as I close-in this area. For now this would be the extent of the work, with more to come.

The taper is complete on the outboard side...

...and the interior surfaces are prepped for additional work.

While I was on the ground, I figured that I would proceed forward and grind a similar 12:1 taper in the areas of the old head discharge through hull. Some time ago, I removed the original bronze through hull, which had been sealed from the interior with a pipe fitting. The previous owner had a porta-potty in use for the head. A small port-potty would certainly serve the owner well, but definitely had to be a new purchase!

I also ground a 12:1 taper around the old through hull water inlet - also for the head.

I cleaned things up inside the cockpit and within the cockpit lockers by vacuuming thoroughly and then wiping the surfaces, those which were to accept new fiberglass, with a solvent. I then used a large sheet of plastic sheeting to take patterns for the new biaxial cloth. I traced the areas to be glassed-in, labeled them, and then cut them out back in the shop.

Using pieces from my biaxial scrap pile - cuttings that were left from larger installations - I prepared the layers for the work back up on the Allied 24. There would be a layer of 1708 applied to the backside of the existing hole, along with a sheet of peel ply for that "backing plate". I also prepared a layer, and in some cases two layers, for the outside, which would also have a sheet of peel ply applied.

Firstly, I wet out the backside surfaces with neat epoxy - epoxy resin without any fillers added to thicken it. While the straight, or neat, resin was tacking up, I made my way back to the shop to wet out the first two backing plates. I placed the first two on the interior surface of the holes to be filled, ensured the peel ply was thoroughly wet out, and then headed back to the shop to repeat for the other holes.

The process went smoothly, and I was able to get the 5 backing plates on in short order.

A view of the backside of the area to be repaired.

I then headed back to the shop to mix a pot of thickened epoxy - again, I thickened the epoxy resin with 406 colloidal silica and 407 low-density filler - returned to the boat and applied this thickened epoxy to the remaining cavity at each hole location. The thickened epoxy was applied to the exposed surface of the backing plate and brought up fair, or level, with the prepared surface of the existing fiberglass.

With the holes ready to receive new biaxial fiberglass, I returned to the shop to wet out the various pieces. Some holes required a couple layers of glass, and this was due a more sever taper that I had ground into the surrounding surface. All holes will get a coat or two of fairing compound to complete the fairing process. I applied the new cloth, and finished the work with a layer of peel ply.

I moved on to the last of the day's tasks: getting a coat of fairing compound on the aft deck core repair areas. I wiped the surfaces down with a solvent, headed back to the shop to mix a pot of thickened epoxy, and with a firm squeegee roughly 12" in length applied the epoxy. I worked the thickened mixture into the remaining voids, and generally leveled the starboard work area so that it was fair to the surrounding deck surfaces.