Saturday, 9 May 2020

Cockpit Deck | Installation

The day finally came when no more preparation was required to install the cockpit deck, and I girded up my loins for the task.

I put the port deck panel in first. Here it is, fastened down with temporary screws.



Fitting the panel went well.

It required 5 'doses' of the 2 to 1 epoxy resin mix, as measured by the measuring cups which I use. This was useful knowledge for the other panel, since I ran out of mixture part way through laying down the glue for the port panel and had to hurriedly mix a second batch.

5 doses equates to 500 ml. Quite a lot of glue. I used a proper boatbuilding 'pastry bag' to apply the thickened mixture. It is so much better to use than a freezer bag!

I crawled underneath the deck to scrape off the squeeze out and remove the blue tape. This is a horrible job. The tape and newspaper protect the boat well, but I still got resin all over myself in the process, including in my hair! My advice is to wear something you don't mind throwing away afterwards.

I cleaned up the stern compartment next, and pulled the tape. That went well.

The following day I started to remove the temporary screws from the port deck. I did not have enough screws to install the starboard deck without reclaiming some from the port panel.

I was fearful that some might resist, so I used a screwdriver rather than a drill driver so I could apply a gentle touch.

The first screw that I tried immediately snapped off cleanly at the head. Like an idiot I tried a second, which promptly did the same thing.

Hmmmm. This was annoying, to say the least.

But not to worry. I had used the heat gun to remove wires embedded in epoxy when building the hull, and out it came again. Each screw got 20 to 30 seconds at 250 degrees C and they all came out without further trouble.

Here is the screw pulling gear.




I drilled out the two broken screws and retired for the day.

Another lesson I learned when removing the tape from the port deck is that the blue tape must be applied in a single piece for each seam, and the tag to grab the tapes must be at the very end of the piece. If you use two or three pieces on one seam they stay stuck and you have to pick them off by hand, and if the tag is not at the very end of the piece it will not pull it away easily. It's tedious and very messy.

So the following day I re-taped some of the starboard panel accordingly, mixed up the required quantity of thickened resin, and installed the starboard deck. Here it is.




I cleaned up and pulled the tape in the stern compartment, and then crawled under the deck and did the same there. Quick and easy, but still more resin in my hair. But the deck joins looked great!

Twenty four hours later I removed all the temporary screws, using the heat gun. No failures.

I think the problem was that the 3.5 x 25 mm screws which I used are quite flimsy, unlike the 4.0 x 30 mm screws which I used on the forward deck which came out quite easily.

So my policy now is to always heat temporary screws before removal.

Installation of the cockpit deck is the last activity in "Chapter 2: Lower Hull Assembly" in the build manual, and installation of the forward deck is the first in "Chapter 3: Upper Hull Assembly". Which I have already done.

We are getting there!

Cockpit Deck | Hatch Openings

I next turned my attention to the cockpit deck panels themselves, and prepared them for installation.

Something I had been pondering for a long while was how to clean the glued joints and remove the tape and newspaper from the stern compartment after deck installation.

The build manual shows the decks being installed with no openings to allow this to happen. Presumably they didn't care about drips and runs in the stern on the prototype.

Clearly this was not the way ahead on my boat!

Other builders' blogs show an aperture cut roughly in the deck panel to allow access, which is what I decided to do.

However, I couldn't see the point in waiting until later in the build to make the actual hatch openings themselves. So I did it while preparing the decks for installation. I had the hatches already, so it was the obvious thing to do.

First I made patterns for the hatch opening and for the hatch itself, to be sure that the footprint was good and that there was enough room for the hatches in the aft part of the deck frame.

Here they are.



You might recall that early in the build I bemoaned the lack of measurements or alignment slots to show where the deck frame stringer between the transom and bulkhead 8 should go, exactly. I deduced it from the drawings but since I did not have the hatches at the time I couldn't check the fit.

It turns out that I have made exactly enough room for the hatches, which is a good thing because it would be a very big deal if they didn't fit!

I had previously marked out the deck frame location on the underside of the deck panels to allow the temporary screw holes to be drilled.

So now I marked out the location of the hatch openings, again on the underside of the panels. Like this, on the starboard panel.



The upturned yogurt pot has exactly the same radius as the corners of the hatch flange, so was a good way of marking them out accurately.

Next I taped out the panels with blue tape to facilitate removal of squeezed out glue and to leave clean joins, as here on the starboard panel.



Then I cut out the openings with a jig saw, as here.



I borrowed my son's cordless DeWalt jig saw to do this. It's a bit more nimble on the corners than my corded saw. Thanks Nick!

The openings were then cleaned up and carefully trimmed with the Shinto file rasp and a SpiraBand abrasive wheel to get to the correct size.



They are ideal for this task. A quick rub with a piece of sandpaper and a test fit followed for each hatch, like this.


Finally I taped out the panel around the opening itself. For some reason I forgot to take a photo of this, so you will have to imagine it for yourself!

Next we will permanently install the decks. Terrifying ...

Cockpit Deck | Prep For Installation

Lessons learned when gluing down the footwell sole and the forward deck were that careful masking with tape and newspaper is essential to:
  • Prevent epoxy dripping onto finished parts of the boat
  • Allow squeezed out epoxy to be quickly and easily removed
  • Produce neat, clean joins between panels
So I spent a lot of time taping out the interior of the cabin and the deck frame in readiness for fitting cockpit decks.

This is what it looked like when I had finished.


I paid particular attention to the stern compartment where it would be difficult to remove the tape from the frames, with limited access through the hatch openings. Like this.


As with the forward deck, the plan is to remove squeezed out epoxy as quickly as possible, and then remove the blue tape from the deck frame to leave clean joins with no runs or drips.

This blue tape is relatively expensive but is infinitely better than conventional paper masking tape. It's very strong and comes away easily without tearing.

The next step is to prepare the cockpit deck panels themselves.

Forward Deck | Installation

In readiness for gluing down the forward deck I first taped each temporary screw hole so that any epoxy that was squeezed through the holes would not glue the plywood washers to the deck.

Blue tape is good for this - nothing sticks to it. Here it is.



Then I applied a liberal amount of thickened epoxy resin and fastened the deck in place with temporary screws, each with a plywood washer to prevent damage to the deck. Like this.



The tape and newspaper inside the storage compartment protected the paintwork nicely from squeeze out. This is what it looked like.



And here is the interior after the tape was removed and the epoxy had cured.



The overhead will be painted when the boat is upside down for working on the exterior of the hull.

Looking good!

Forward Deck | Prep For Installation

In readiness for fitting the forward deck I masked off the interior of the storage compartment and taped the sheerclamps and bulkheads to protect them from squeezed out epoxy.

This is what it looked like.



I then taped out the underside of the forward deck, for the same reason.



This should allow me to scrape off the squeeze out and remove the tape at the same time, leaving clean joints.

Bow Compartment | Installing Buoyancy

With the completion of the centre board pendant hole I was ready to install the cockpit deck, but I wanted to practice this by fitting the forward deck first. Much of the interior below the forward deck is not visible, so it would not matter if things went a bit awry in this area.

So ... the first task is to install buoyancy in the bow compartment.

The recommended material for this is PIR (Polyisocyanurate) insulation board, which is rigid and waterproof.

I did consider using liquid expanding foam, as seen on one or two other blogs, but people told me it is very messy and difficult to control. So PIR it is.

I obtained a sheet of 50mm foam and set to work.

The first task is to construct a 'tunnel' between the inspection port in bulkhead 1 and the stem. This will allow a bow eye to be fitted to the stem much later in the build, after which the tunnel will be filled with pieces of foam inserted through the inspection port.

I first made a cardboard template for the sides of the tunnel. Here it is, with a very useful cordless cutter. I originally got the cutter for fibreglass cloth, but it handles most light materials with ease.


I then marked up and cut out and bevelled pieces of foam using a compass saw, which made a lot of mess with bits of foam everywhere.

Part way through this I realised that what I really needed was something with a finely serrated, long, thin, flexible blade. Like ... a kitchen knife. A visit to the kitchen revealed exactly what was required, which was promptly liberated.

Here are the tunnel side pieces, with the cutting tools.


I then made top and bottom spacers to hold the sides apart, and decided to use nylon cable ties to fix them in place. Here they are.


The long, pointed piece is the top spacer which butts up against the stem. The short piece is the bottom spacer which sits below the inspection port.

I found that a hand drill was best for making holes for the cable ties. An electric drill just makes a mess. Here is the drill.


And here is the fitted tunnel, held in position by plywood slats and tape while the cable ties were inserted and tightened to make the tunnel a rigid structure.


And this is the view inside the tunnel, looking towards the inspection port and showing the bottom spacer in place.



I then made another template for the crosswise panels to fill both sides of the compartment, starting with the largest piece at the bulkhead. This is the template with the tools used to make it. The blue object is a contour copier, useful for getting the turn of the bilge just right. It was a Christmas present from my lovely wife. Thanks Alison!


I then discovered that a jig saw cuts the panels quickly with a fine, smooth cut and very little dust. Here we are cutting out the first panels.



The angle on the side of the panel where it butts up against the hull is lifted with a bevel. Here is my antique bevel, given to me by my brother-in-law from New Zealand one Christmas. Thanks David!




See … Christmas presents can be very useful!

I worked my way towards the stem, trimming a piece off the edge of the template as required to get a good fit.

Here are two panels with the bevel marked out.



And here are the same panels with the bevel cut with the knife.



Eventually the bow compartment was filled with foam panels. Here it is.



Finally, and quite unnecessarily, I fitted a piece of 25mm foam to cover the lot up and fill the small gap below the forward deck.



That's it. Job done. I made a lot more work for myself than I needed to here, but it was good fun and I learned a lot.

Next step is fitting the forward deck!


Inspection Ports | Installation

When the inspection port gaskets were cured I undercoated and painted the edges on the outer circumference where they show in the cabin.

Then I dry fitted them all by marking out and drilling pilot holes for the fastenings, and screwing them into place.

Here is the starboard centre board case port.



I even dry fitted the drain bung ...



Finally I fitted the inspection port flanges, using white marine silicone rubber caulk. The brand I am using is Geocel, supplied by a local chandler. They say it is manufactured by Dow Corning, which comes highly recommended on many boatbuilding blogs, so I guess it's fine! It works nicely, doesn't go off too quickly, and is easily cleaned up with methylated spirits while still wet.

This is it.



Here are the centre board case flanges sealed in place.



And here is the bow compartment flange sealed in place.



Looking good!