Coamings

I got the coamings done yesterday.

After breaking several pieces of 6mm ply in an attempt to bend the sharp curve at the front, I finally decided to follow John's directions and make the piece from 2 layers of 3mm ply. I was hoping to make this piece from the same 6mm ply I used throughout the boat so I could varnish the coamings, but no luck so I will paint them instead.

I trimmed the forward coaming a bit to allow better access to the storage locker.

And trimmed the aft coaming a bit to clear the tiller.

I also got the rubrails finished.

Next up: Deck paint

On Decks

This weekend I got the decks glued and screwed in place. Earlier I had cut them oversized and temporarily installed them so that all the screw holes could be pre-drilled, then removed them so I could work on the seat tops.  Despite all that prep work I still managed to install the decks slightly out of alignment.  If you look closely at the deck right at the stem you can see that the seam is mislocated slightly to starboard. Oh well, that's the way it goes sometimes.  Fortunately the deck still overhung all around and the seam will disappear when finished so the misalignment won't  matter.

I enjoyed making the aft deck. After a bit of head scratching I decided to laminate and install a beam, seen here in this earlier photo. This beam was made by laminating three layers of 1/4" mahogany, clamped directly on top of the transom. After it cured it was trimmed and glued in place between the cockpit stringers. The beam's natural springback seems to have made the curvature turn out just right.

After making a template from doorskin, I used it to trace and cut out the aft deck plywood piece and then installed it.  There was quite a bit of force involved in bending the plywood to this much curvature, so a temporary post was used to prevent the beam from deforming.

Doublers were then installed at the forward end of the cockpit for attachment of the coaming in this area.

I used my trim router with a flush trimming bit to trim the deck flush to the hull and cockpit stringers all around. Longtime readers may remember The Gain Machine.  It came in handy once again to trim the deck flush and at the proper angle to the sheerstrake and transom.

And finally, I began working on the rubrails.  A coworker donated some rough cut vertical grain Amish white oak to the project.  Lovely stuff to work with, although it's got a greenish cast that I don't really care for.  No problem as I was planning on painting them anyway.

Now it's time to finish up the rubrails and then tackle the coamings.

Mahogany Decked Seats Part 2

After all the mahogany decking was laid the next task was to apply caulking to the seams. There are two ways this can be done.

The traditional way is to apply caulking to the seams, wait for it to cure, and then sand the entire deck smooth. This method sounds easy but there were some uncertainties. I have never done a laid deck before. I was concerned about caulk getting deep into the grain of the wood and then requiring excessive sanding to get it all out. This is a concern because the hull and the bulkheads limit access to sanders. I also didn't know how easy or difficult the caulking would be to sand.

The other way is to mask the deck, caulk the seams, smooth the caulk, remove the tape, and do a final finish sanding. Although there are more steps involved, I felt more comfortable with this method.

Masking

After giving the decking a thorough sanding I applied masking tape to the entire deck and everything else that I didn't want black goop on. I bought two large rolls of masking tape just in case I needed more than one roll. I nearly ran out.

Trimming

After the tape was applied, I used a single edged razor blade to trim the tape away from all the seams.

Trimming done

Apply and spread caulking


Next I pumped Sikaflex into the seams. I needed 13 tubes of caulk. It really pays to have a good caulking gun for a job of this magnitude. I had to replace my cheap gun half way through. My hand is still sore a week later.

Pulling tape

When the tape is pulled is important. I used the LOT (Long Open Time) formula of Sikaflex which takes about 5-7 days to cure. Before I caulked the boat, I made a test piece to see how the caulk behaved after each day of curing. I determined that the best time to remove the tape is 24 hours after application of the caulk. If you try to pull the tape before then, the caulk will make a mess by leaving residue on the paint. If you wait beyond 24 hours the tape will be more difficult to remove. The caulk will be be too firm and the tape will tear rather than cutting the caulk.

Sanding

My test also revealed that sanding must wait until the Sikaflex has cured for at least 4 days. Before then it is too soft. Attempting to sand it will tear out chunks of caulk from the seams.

Lumps

Lumps like this were easily sanded off after the caulk had cured for 4 days.

Finish Sanding

Sanding was not difficult and went very well. If it wasn't for the access issues with the bulkheads and hull, I think method one would have been a better way to go.

 

Done sanding and ready for oil

Applying Teak Oil

I have to apply 5-6 more coats of oil, but after only one coat I couldn't be more pleased with the results!