J22 Ives Knoll - Main Bulkhead Replacement project
Our club J22 fleet is aging and two boats required new main bulkheads. This page documents the replacement on the main bulkhead in J22 #6 Ives Knoll due to rot at the port side chainplate. There are also some other minor repairs documented here.
Ready for last glass work on a beautiful day
Bulkhead weakened at chainplate on port side
The first step was to create a template of the existing bulkhead. This was done using cardboard on the previous boat (J22 #5) and we had created pressboard templates for port and stbd halves of the bulkhead. These pieces were test fitted and some minor modifications made. Once we were happy the chainplates and all other hardware caps and fiddles were removed from the existing template and a proper test fitting was completed.
Templates aligned on the Coosa board to cut new bulkhead core.
Pink coloured pencil was the best contrast
New core pieces cut.
Test fitting the new core pieces
The templates were oriented on the coosa core material in a manner to produce the least wastage. Then they were traced in pink coloured pencil and cut using a jigsaw. Back in the boat they were placed against the existing bulkhead to ensure a proper fit. A minor modification and we were happy with the fit and ready to proceed with the demolition stage.
Old bulkhead mostly removed
Old bulkhead removed. Now cleaning up leftover edges
The last bits of the old bulkhead chiselled out. Ready for grinding
Grinding complete. A lot of mess!
Gelcoat removed for tabbing and the mess mostly cleaned up. Ready for new bulkhead.
With the templating process ccompleted it was time to remove the old bulkhead. Despite being rotted at port chainplate the rest of the bulkhead and the tabbing was very strong and difficult to remove. Tools of choice were Reciprocating saw, angle grinder with cutting disc, cordless drill, BFH (Big F...ing Hammer), prying tools, wood chisels.
Initially a 3/8 inch bit on cordless drill was used to make a hole for the saw. Then we cut around the edges of the bulkhead and applied liberal doses of bashing with the BFH and even some prying to get rid of the bulkhead. The process required frequent changing of blades in the reciprocating saw but eventually the old bulkhead was removed in three pieces. There was still some tabbing and some of the plywood from the old bulkhead attached at the hull. The cutting disc on the grinder took care of the tabbing material and a wood chisel and a lot of patience removed the wood residue.
With the bulkhead removed it was time to prep the surfaces. The interior of the J22 is gelcoat. This must be ground away for 5 inches on each side of the bulkhead to allow the new tabbing material to bond to the hull. The angle grinder once again used with a sanding disc. The process was not difficult but very messy. It is even worse due to the cramped and low ventilation conditions inside a J22. Following this process 30 minutes with a shop vac was required to cleanup the large amound of dust and gelcoat residue.
New bulkhead core joined with strip of Biax cloth
New bulkhead assembled and ready for installation
To say the interior of a J22 is cramped is an understatement. For Ives Knoll we decided to assemble the bulkhead outside of the boat where the working conditions are much more pleasant. Leaving approx four inches uncoated at the edges for the initial tabbing material both front and back sides of the bulkhead were covered with biaxial cloth. Following this process the exposed edges of the new bulkhead were covered with 6 oz cloth. These are the edges that will be exposed once the installation is complete so the 6 oz cloth makes for a more finished look. We are now ready to install the bulkhead in the boat.
New bulkhead in place and ready for tabbing
First layer tabbing applied. View from forward
With the bulkhead now assembled it is time to move back inside the boat. A bit more grinding and some minor persuasion with a rubber mallet and the new bulkhead was in place. It was a very snug fit which is great. With the bulkhead in place the next step was to apply the first layer of tabbing to the forward side of the bulkhead. For this we used 6 inch wide tabbing tape which is basically biaxial cloth that comes on a roll. The aft side will have any gaps around the edges filled with Polyfair and then will also have a layer of 6 inch tabbing. This will be followed by a layer of 8 inch tabbing (biaxial cloth) and then a full covering of forward and aft faces of bulkhead extending 5 inches out on to hull as the final tabbing.
Initial layer tabbing complete fore and aft
Polyfair applied around compression post step. Some cleanup required
One interesting side project involved a small gap between the mast compression post step and the new bulkhead. When cleaning up the area around the old bulkhead some edges of the forward tabbing were left in place as a guide to location of new bulkhead. With the new bulkhead tight against these edges there was a 1/4 inch gap between the step and the new bulkhead. One option was to tighten the bolts once bulkhead was complete, however it was decided that this would cause a bend in the bulkhead. Instead we opted to tighten two of the bolts to the point where the fit was tight but the bulkhead not bent prior to tabbing. Then the small gap between the compression step and bulkhead was filled with resin soaked fibreglass mat. With this done Polyfair was used to seal the edges of the gap. As seen in the above photo there will be a sanding required to clean this up after it cures. Cloth will then cover the polyfair up to the edge of the compression step.
2nd layer of Tabbing cloth applied. Ready for final layer cloth
Final layer of cloth fitted and ready for resin
Final layer of cloth complete
Ran out of gelcoat!
Now that the bulkhead was tabbed in place it was time to apply a second wider layer of tabbing. The first layer was 6 inch wide and the second 8 inch wide to provide an overlap. 24 hours later we were ready for the final full layer of glass. This was a full covering of the bulkhead and extended its tabbing 5 inches on to the hull. After sanding the bulkhead was still tacky so held the new cloth in place while a genourous amount of resin was applied. Following this was a 24 hour wait for curing, a final light sanding and then gelcoat was brushed on rather than paint. Unfortunately there was only enough to coat the forward face of the bulkhead and a small bit around the chainplates port and starboard. Project on hold pending the arrival of more gelcoat.
Four bolt holes drilled for mast compression post step and 2 limber holes
Port chainplate re-installed
Stbd chainplate re-bedded. Needs screws for cap
While waiting for more gelcoat to arrive some final steps of the bulkhead replacement task were undertaken. Most of this involved drilling holes. First the chainplates had to be reinstalled. The temporary caulking was removed at the deck and then using a cordless drill the bulkhead slots were re-shaped thru the fibreglass tabbing. Then the chainplates were put in place, bolt holes drilled and bolted in place. Once that was complete on deck the chainplates and covers were bedded using 3M 4200 adhesive sealant. Thankfully we had enough gelcoat the previous day to apply a coat where the chainplated would sit on the bulkheads and where the chainplates would come thru the tabbing on underside of deck. A final task was to prepare for rebolting the mast compression post step to the bulkhead and to drill limber holes for drainage. Once the final coat of gelcoat is applied the step will be bolted in place.
Port bulkhead with slight bump out for chainplate
Bulkhead installation complete. Just requires hardware bolted in place
Bulkhead complete with chainplates and mast compression step bolted in place. Some cleanup required
The gelcoat supply had been replenished and we were ready to complete the bulkhead. However we did notice an odd thing. This J22 had a bulkhead that was thicker than the previous one and we were using the same stock for bulkhead core. This resulted in a finished biulkhead whose aft side was approx 1/8 inch forward of the chainplate holes in the deck. Due to this there was a gap between chainplate and bulkhead where bulkhead meets deck. The chainplates were removed, the painted on gelcoat was sanded off and a patch four layers thick of biaxial cloth was built at chainplate locations port and stbd. In the picture above you can just see this bumpout that removes the gap. With this complete the aft side of the bulkhead was brushed with gelcoat and the bulkhead installation is now complete. The chainplate needed to once again be installed and bedded and the mast compression step bolted to the new bulkhead.
Gunwhale Repair
Aft section was in the worst state
Forward the damage was less severe
There had been some damage to the port gunwhale in four separate places. Two places were simply cracked gelcoat while the other two were through to the layup material. The section that was aft actually was cracked completely through with the fairing material beneath crumbling while the forward section was surface only. The two small sections with cracked gelcoat need only to be ground faired and new gelcoat applied.
Aft section with damaged material ground out. Nasty
Forward section cleaned up and 3 layers 6oz cloth in place
Aft section with 5 layers cloth
The two main areas were ground to remove the damaged material. The one aft had crumbly fairing material inside a hole. This was dug out and replaced with polyfair and then five layers of 6oz cloth were applied. We could not get biaxial cloth to lay flat over this bend so 6 oz cloth was used. The forward area had 3 layers of cloth applied and looks ready for sanding and fairing. The aft section needs to be built up with bit more cloth before it is faired. The other two minor sections require fairing material only. This will be faired using coloidal silica mixed with polyester resin for added adhesion, strength and for its white colour.
First fairing coat applied. It is not white
Port Aft Gunwhale area faired and sanded
Port Fwd gunwhale area faired and sanded
One more layer of cloth forward and another aft was applied. Next West 406 coloidal silica was mixed with the polyester resin as a thickener. The intent was that it would be white but instead the colour of the resin won out and the result was an aqua colour. The thickened resin was applied to the four repair areas to fill any hollows and then sanded. A second very thin layer of fairing compound was then applied almost as a skim coat. Once this is sanded the areas will be coated with white gelcoat and sanded with 220 then 400 and 600 grit. Following that rubbing compound. It is our hope that this will blend in with the hull more or less.
Fairing coats complete. Gelcoat brushed on
Closeup shot of repaired area. Close but not exact colour match
Another shot this time from aft. All four repaired areas are visible in this picture
Miscellaneous smaller repairs
With the major problems addressed we now had to turn to some smaller tasks that needed to be done prior to using the boat. These included rebedding stbd jib track, relpacing stbd cam cleat and drilling and refilling the many holes on deck, in cockpit and on sea hood where hardware had at one time been installed. Once this is complete the bottom will be cleaned and painted and then the boat will be ready for the water.
Sea hood holes drilled and ready for fill
Sea hood holes filled with thickened resin
All the holes filled and ready for sanding
The deck, cockpit and sea hood of this boat had a larger number of holes from previously installed hardware. Most of the holes had been sealed with resin but were not flush with the deck while those on the sea hood and cockpit seats had been filled with silicon and had some water intrusion. Our plan was to drill all holes slightly larger, fill with thickened resin and then sand flush. Any water in the core and associated rot would be addressed at a later date. The good news is that all of the holes in the deck were filled with resin and water tight leaving only the sea hood and some areas of the cockpit with possible wet core. In the above pictures you can see holes on the poop deck, cockpit seats forward of the traveller and less visible near the toerail and on bow. This boat at one time had stanchions, pulpit, pushpit and lifelines. When added to the sea hood that makes for a lot of possible places for water intrusion.
Starbord jib cleat needed to be replaced
New jib cleat in place
J boats usually have a cam cleat on a bulkhead or coaming beneath the winches for sheets and halyards. The J22 is no exception. The starboard jib cleat was broken and missing parts so was replaced with a shiney new cam cleat.
Fasteners for starbord jibtrack. 2nd bolt from front broken. The aft ones we had removed for bolt sizing
Jib track holes drilled larger and wet core dug out
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Holes filled with thickened epoxy and sandy flush
Holes redrilled for installation of track
The starbord jib track had one bolt broken and showed obvious signs of leakage. The track was removed, holes drilled larger, wet core dug out around edge of hole using an allen key. Once this was completed the holes were filled with thickened epoxy, sanded flush with deck, redrilled for fasteners and the track rebedded. Water can no longer get into core around these bolt holes
Ives Knoll washed, waxed, bottom painted and ready to go back in service