I will be adding a manual bilge pump, mounted to the starboard seat longitudinal. Above, you can see the intake strainer which is in the sump area between bulkhead 7 and 8 (on the left), and the output is a through hull into the upper aft end of the centerboard trunk.
So, as far as I can tell, I have done all the prep work on the parts so its time to glue them in. I started with the aft 3 bulkheads. I had braces hanging down from the ceiling joists to hold them upright at the correct angle (didn't get a picture of these). I then placed the port, and then the starboard longitudinal. Then, the centerboard trunk logs were glued and screwed in place. Last, bulkhead 4 (the front one in the picture) was glued and screwed in place - I put a vertical cleat between the port longitudinal and bulkhead 4 (you can see the screws in the picture). The clamps and spreader sticks help to hold some pressure on while the epoxy cures.
The inner trunk is being held against the bottom with spacer blocks and wedges, and the spreader stick is putting pressure on the joint with bulkhead 5 on the other side of the trunk (longitudinal).
I didn't glue in the outer center board trunk side yet, because I wanted to have easier access to installing the centerboard uphaul tube in the front of the trunk. Here, I set the centerboard in place so I could mark the location for the tube.
Kind of neat to see the board from this perspective, as we won't be able to later.
Kind of neat to see the board from this perspective, as we won't be able to later.
The uphaul tube location was marked on the inside of the trunk, but given limited space, I drilled the hole from forward. I use this borrowed portable drill fixture to get a plumb hole.
I installed 1/2" copper tubing for the uphaul. I decided to use a method proposed by Peter E on the SCA SCAMP forum (here). The tubing was flared using a standard flaring tool - but it leaves the flare at about a 45 degree angle (to mate with flared plumbing fittings), so I flattened it with a ball-peen hammer. Then, I inserted the tubing in the hole - flare to the inside of the trunk - and measured about 3/16" overhang in front of bulkhead 4. I used a copper pipe cutter to cut to length.
After priming the hole with straight epoxy, the straight end of the tubing was heated with a plumbing torch and doused in water, then cleaned, slathered with epoxy, and inserted in the hole in the trunk log. Using a metal plumb bob (has a nice conical shape), I started a flare and then switched to the ball-peen hammer for the finish. It was quite easy to create the flare with this method - Thanks Peter!
After priming the hole with straight epoxy, the straight end of the tubing was heated with a plumbing torch and doused in water, then cleaned, slathered with epoxy, and inserted in the hole in the trunk log. Using a metal plumb bob (has a nice conical shape), I started a flare and then switched to the ball-peen hammer for the finish. It was quite easy to create the flare with this method - Thanks Peter!
Having finished inner-trunk work, the outer trunk side was screwed and glued in place (using those same blocks and wedges inside the slot to hold pressure to the hull bottom). Then, the outer part of bulkhead 5 was glued in place, along with the cleat to the hull bottom.
The doublers on each side of the centerboard trunk are the last pieces to be added. Scotch tape strips are used over the epoxy-filled screw holes to keep the glue in place, and provide a smooth surface which needs minimal cleanup.
Now that all of the pieces are glued in place, it is time to apply fillets. This was my first time making epoxy fillets, so I started at the aft end of the boat, on bulkhead 7 to bottom joints. After a while, I started getting the hang of it. It took a few hours and several batches mixed, but in all, went well I think.
I learned a couple things doing the fillets: one is that I am not convinced that the blue tape was worth the effort. It took a a fair amount of extra time to apply, and then to remove, and I still had to do some cleanup inside the tape on many fillets. I think I will try a few fillets without the aid of tape next time. The second thing is that it would save a lot of time and effort if you can apply the fillets soon after the parts are glued together - the squeeze out from the glue-up becomes part of the fillet, and no prep (sanding, etc) is needed before adding the fillets. This, of course, requires some planning so that you have time to do all of this in one go.
I learned a couple things doing the fillets: one is that I am not convinced that the blue tape was worth the effort. It took a a fair amount of extra time to apply, and then to remove, and I still had to do some cleanup inside the tape on many fillets. I think I will try a few fillets without the aid of tape next time. The second thing is that it would save a lot of time and effort if you can apply the fillets soon after the parts are glued together - the squeeze out from the glue-up becomes part of the fillet, and no prep (sanding, etc) is needed before adding the fillets. This, of course, requires some planning so that you have time to do all of this in one go.
Next, I set myself to the task of drilling the hole in the centerboard trunk for the pivot pin. This requires a fair amount of precision for the pin to be able to easily pass through the bronze bushings in both side of the trunk, and for the pin to be perpendicular to the trunk so that the centerboard will be centered in the trunk along its length.
I started by drilling the 3/4" hole with a forstner bit on the outside of the trunk using the portable drill jig screwed to a pieces of plywood clamped to the trunk side.
I then inserted a bushing in this hole, and a 31/64" drill bit in the bushing, and drilled through to the other side of the trunk. I then clamped the plywood fixture to the other side of the trunk using the 31/64" bit to position it, then switched to the 3/4" forstner bit.
The result was that the hole on the inner side of the trunk was a little less than 1mm low for proper alignment with the outer hole. Using a round file, I enlarged the hole a bit to allow the inner bushing to be aligned with the outer bushing.
I installed the centerboard in the trunk several times during this process to check alignment of bushings. When I was happy with bushing locations, I had to insert a sliver of HDP (high density polypropylene) that I had laying around (no, I didnt cut up one of my wifes kitchen cutting boards), under the inner bushing to hold it in alignment.
After a prime of neat epoxy, and ample scoring of bushing surfaces, I glued the bushings in place with thickened epoxy. I started by slathering thickened epoxy on the hole and the bushing, inserted into the hole and put packing tape on the trunk inside side to limit squeeze out on that side. Added the HDP sliver to the inner bushing. Let this setup for 15 min or so, cleaning up squeeze out, then removed the tape and inserted the SS pin (coated with wax to keep from gluing it in) so that the bushings would be in proper alignment while epoxy cured. I checked every 1/2 hour or so, and rotated the pin to make sure it wasn't getting stuck. After about 4.5 hours, I removed the HDP sliver and filled the hole with thickened epoxy using a syringe.
I started by drilling the 3/4" hole with a forstner bit on the outside of the trunk using the portable drill jig screwed to a pieces of plywood clamped to the trunk side.
I then inserted a bushing in this hole, and a 31/64" drill bit in the bushing, and drilled through to the other side of the trunk. I then clamped the plywood fixture to the other side of the trunk using the 31/64" bit to position it, then switched to the 3/4" forstner bit.
The result was that the hole on the inner side of the trunk was a little less than 1mm low for proper alignment with the outer hole. Using a round file, I enlarged the hole a bit to allow the inner bushing to be aligned with the outer bushing.
I installed the centerboard in the trunk several times during this process to check alignment of bushings. When I was happy with bushing locations, I had to insert a sliver of HDP (high density polypropylene) that I had laying around (no, I didnt cut up one of my wifes kitchen cutting boards), under the inner bushing to hold it in alignment.
After a prime of neat epoxy, and ample scoring of bushing surfaces, I glued the bushings in place with thickened epoxy. I started by slathering thickened epoxy on the hole and the bushing, inserted into the hole and put packing tape on the trunk inside side to limit squeeze out on that side. Added the HDP sliver to the inner bushing. Let this setup for 15 min or so, cleaning up squeeze out, then removed the tape and inserted the SS pin (coated with wax to keep from gluing it in) so that the bushings would be in proper alignment while epoxy cured. I checked every 1/2 hour or so, and rotated the pin to make sure it wasn't getting stuck. After about 4.5 hours, I removed the HDP sliver and filled the hole with thickened epoxy using a syringe.
This is the inner bushing, the one that needed the HDP shim. The hole in the wood is not as big as this shows, as I rounded over the edges of the hole before glue up to provide more of an annular ring of epoxy to forestall water intrusion.
Lastly, I glued in the centerboard bushings. The flanges on these sit proud of the board about 1/2 their thickness, so I added a mini-fillet to also help keep water from wood.
The centerboard installed in the trunk on the left, and on the right you can see looking down on the pivot pin, the gap between the bushings with a single 1/16" nylon washer between them. This shows the gap between the board and the trunk, as the board is mostly shoved to the other side at this point.