Tuesday 25 August 2020

Cabin Roof, Dorade Box Cleats & Forward Deck Sheerclamp | Fairing

I left the cabin roof and Dorade box cleats to well and truly cure before I started to fair them to receive the cabin roof itself.

I was not sure that this would be a straightforward exercise.

If all the bulkheads were at the correct height and all the cleats were correctly installed to leave sufficient stock projecting above the bulkheads to allow for fairing, all should be well.

However, it was difficult to know just by eyeballing the boat if this was going to be the case.

There was also quite a lot of stock to remove. I thought about purchasing a power plane, but in the end decided it would be a wasteful investment when I have perfectly good hand planes to do the job.

In the end the ideal tool set for the entire fairing exercise turned out to be the good 'ole jack plane, the block plane, and a rasp and a good paring chisel. Here they are.

I started on the port side, and worked on the sheerclamp and the carlin first to get my eye in. 

That went well, so I moved on to the cabin roof cleats on bulkhead 2 and the rear cabin wall, using a piece of straight edged stock to check the bevel.

That went well too, so I moved on to the Dorade box cleats and finished off the port side.

It turned out that the jack plane is ideal for roughing out the bevels, and the block plane and rasp and chisels are great for finishing.

Here is the port side of the boat, with a frontal view of the Dorade box and all cleats faired.

And here is the starboard Dorade box, with all cleats faired.

The trick at the sheerclamp is to shave it down to its upper edge and no more, and to shave down the bevel until you have a continuous smooth edge with the topside panel. It actually works out really well. You have to be patient, that's all.

Here is a starboard view of all cleats faired.

When fairing the carlins to support the top of the cabin roof I clamped a thin strip of edging across the boat to check the fit. Like this.

This works well.

This just left the sheerclamp between the Dorade boxes and the stem to be sorted out.

I hadn't been entirely sure how this would work out, and had left any finishing of the sheerclamp in the forward deck space until now.

It was now obvious that the only thing to do was to continue the bevel along the sheerclamp to the upper breast hook, with it becoming steadily shallower until it was flat.

Here is the side view of the faired sheerclamp on the port side of the forward deck.

She's looking pretty good!

Saturday 22 August 2020

Cabin Roof & Dorade Box Cleats | Installation

I next made cleats to go inside the Dorade boxes to support the cabin roof.

Both cleats require bevels to achieve a good fit, and this turned out to be a time consuming exercise.

I wanted to be sure that the cabin roof would be properly and soundly secured to the tops of the Dorade boxes, so I didn't mind the extra effort required to achieve this.

Here are the cleats test fitted in the port box.

When I had made the Dorade box cleats I test fitted them and all the cabin roof cleats once more. Here they are.

I adjusted the fit of each cleat until they all lined up nicely and then marked in the line where each would be glued in place, leaving sufficient stock projecting above the bulkheads to be planed away to achieve a tight fit for the cabin roof.

Finally, I glued them all in place, as here.

I left them to cure and wondered how difficult it was going to be to fair them all.

Dorade Boxes | Trimming Top Edges

When I fitted the Dorade boxes it was obvious that the sides were slightly oversize and would need to be trimmed.

I laid the long level across the bulkheads to see where the cabin roof would meet the Dorade box sides, like this.

I marked in the line where roof and box sides meet, as here in the port box.

Lastly I removed the excess material with a sharp Japanese saw and cleaned up the edges, ready to install cleats where the roof will land.

Seatback Lockers | Painting The Interior

I would soon be fitting the seatbacks, sealing in the buoyancy compartments forever.

Before doing so, however, I decided to paint inside the lockers while I had easy access.

This is the first undercoat on the seatbacks.

And here are the port and starboard lockers.

I am using Teamac single pack marine paint, made here in the UK. It seems like very nice paint. The undercoat builds well and provides a good flat surface for the gloss, yet to be applied.

Looking good!

Dorade Boxes | Sanding Fillets

Inevitably the time came when I had to create a nice finish on the Dorade box fillets before I could do anything else.

My standard practice now is to dress the fillets with a carbide burr in my corded Bosch drill to achieve a reasonable first finish. A carbide burr in the cordless Bosch is good for dressing fillets where they meet in the corners. Here they are, with the port box dressed.

After dressing the fillets are sanded by hand using profiled sanding rubbers made of cardboard until a good P80 grit finish is achieved. 

These are the fillets on the outside of the starboard box, after hand sanding.

Finally I applied fairing compound made from phenolic glass micro balloons and epoxy resin to achieve a smooth unblemished surface. Here are the starboard box outside fillets, after fairing.

And here are the faired fillets inside the box.

I was pleased to complete this activity!

Boom Gallows Poles

My hardware pack contained a length of stainless steel tubing to make the poles for the boom gallows.

I now needed to test fit the poles in the seatbacks to make sure that the holes were big enough for a snug but easy fit. The tubing is 25mm in diameter, so will not fit directly into the seatback holes as drilled at 25mm.

The tubing looked very shiny and very hard, and I had been wondering for some time how to cut it.

I didn't think an ordinary hacksaw blade would be up to the task, but advice available on tool vendors' sites was that a bimetal blade would do the job.

I didn't have a bimetal blade, so obtained one and tried it. No problem at all! I cut the tubing in half and cleaned up the ends with a file.

Here is a support pole, test fitted in the port seatback.

It was necessary to round out the holes to achieve a good fit. A rasp was used on the hole in the upper seatback, and a small Spiraband abrasive wheel in the corded drill with a right angle drive did the trick in the lower support blocks.

Here are both poles test fitted in the boat.

We're getting there!

Seatback Buoyancy | Installation

The next job was to fill the interior of each seatback with foam to provide buoyancy.

As in the bow compartment, the preferred material is PIR (Polyisocyanurate) insulation board, obtained from a builders' supplier.

I had purchased two full sheets of 25mm board for the seatbacks, thinking it would be more than enough. In practice I used all of both sheets.

As in the bow compartment I used a finely serrated kitchen knife to cut and trim the pieces of foam.

Here is the starboard seatback, stuffed with foam.

This is the view from above.

I find it reassuring to know that there is an entire 2.4 x 1.2m sheet of buoyancy in each side of the boat!

Cabin Roof Cleats | Rounding Over

I wanted to round over the visible edges of the cabin roof cleats, and set up the router table with a bearing guided 3/4" cutter, like this.

It is not possible to use the fence on the router because the cleats are curved, hence the use of a bearing guided cutter.

I ran the cleats against the bearing to get a nice rounded edge. Here is one of the cleats test fitted.

Looking good!

Dorade Boxes | Inspection Port Gaskets (Revisited)

This is the second time I have reviewed the inspection port requirements for the Dorade boxes.

The drawings say to install 4" inspection ports in bulkhead 2, to provide access to the boxes. So I duly purchased a pair, and set them aside. As mentioned in a previous post.

Now, as I started to build the Dorade boxes I thought about their final fitting out.

I retrieved the ventilator cowls from the hull hardware pack to check them out, and re-discovered that they have a hefty screw-in flange inside the Dorade box to seal them off securely and completely from the outside when not in use.

This flange does not fit through the 4" inspection port. That would mean it would be imprisoned permanently inside the box when unscrewed, rattling and banging about while sailing or on the trailer.

That's no good.

The only practical alternative is to switch to a 5" inspection port, with sufficient room to remove the cowl sealing flange completely when sailing.

So I duly purchased two more inspection ports.

Now I had to make a new pair of gaskets as well.

First I scribed out the hole using a compass on some scrap ply.

Then I cut out the hole with a Japanese keyhole saw, which made short work of the task.

I cleaned up the inside edge of the gasket with a Spiraband abrasive wheel ...

 ... resulting in a perfect drop fit.

Then I cut out the gasket with a jig saw ...

 ... and cleaned it up with a rasp.

Lastly, here is the pair of new 5" gaskets, ready to fit when required.

Monday 3 August 2020

Dorade Boxes | Cleats & Blocking

In readiness for completing the Dorade boxes I got the pieces for internal installation prepared. These are the cleats for fastening down the cabin roof over the boxes, and the blocking for the mooring cleats.

At this stage I simply gave them a clear coat of resin and rounded them over with a 1/4" bit on the router table when cured.

Here they are.

One day someone will look inside the Dorade boxes, and I don't want them to think that the builder did not pay attention to detail!

Cabin Roof Cleats | Test Fit

My timber pack provided more than enough Douglas Fir boards to make the cabin roof cleats. I managed to make all five cleats from just two boards, so I have spare stock for other parts.

I made the cleats 1 1/4" deep, allowing for enough to be planed off when levelling for the installation of the cabin roof.

I will apply a 3/8" round over before fitting, but for now here are the two cleats either side of the companionway on the rear cabin wall.

And here are the three cleats between carlins on the forward face of the cabin, on bulkhead 2.

Looking good!

Cabin Roof Cleats | Making Patterns

While the Dorade box fillets were hardening to their terrible granite, sharkskin finish I switched to the easier task of making patterns for the cleats which support the cabin roof.

The build manual calls it a deck, but I won't be spending much time standing or sitting on it!

The patterns are easy to make. I clamped the sole remaining piece of scrap packing ply to bulkhead 2 and scribed in the curve, as here.

Here is the resulting pattern for the forward cabin wall, marked out. The upper, outside curve is being trimmed with the block plane.

And here is the lower, inside curve of the pattern being cleaned up with a rasp after cutting out.

Lastly, here are the three required patterns ready for use.

A quick and easy task, for a change!

Dorade Boxes | Fillets

When their tack welds were secure I pulled the wire stitches from the Dorade boxes and set about applying fillets, inside and outside the boxes.

This went quite well, using a 'pastry bag' to dispense the wood flour fillet mixture evenly.

Here is the starboard box with its external fillets.

And here are the internal fillets, on the inside of the box.

As usual and despite my best efforts, the fillets cured like roughly poured concrete. At least I know I have the right tools and techniques to reduce them to smoothly contoured joins ...

Dorade Boxes | Tack Welds

Satisfied that the Dorade boxes were wired in correctly I went ahead and fixed them permanently with tack welds.

Here is the port box with tack welds.

And just to be sure that the sides are aligned correctly, here is the pattern taken from the drawing on the inside of the box.

Looking good!

The next step with these Dorade boxes is the application and finishing of fillets, which as any reader knows is my least preferred activity of all time.

Locker Flanges | Rounding Over

When the flanges for the locker openings in the seatbacks were fully cured I rounded them over on the inside edge with a 1/4" bit in the router.

Here is the starboard seatback on the bench, held up from the bench with pieces of ply to give clearance for the router bit. More pieces of ply of the same thickness as the flanges are laid on top of the seatback to provide a wide surface for the router to slide across.

It took a while to set up but the task was completed in minutes.

Boom Gallows Tube Support Blocks | Installation

When the support blocks for the boom gallows tubes were well and truly cured I cleaned them up and glued them in place, secured by a temporary screw through the hull side to make sure they were in exactly the right position.

This is the port block glued in.

It looks a bit messy at the moment but it will tidy up nicely later.

Dorade Boxes | Test Fit & Wiring In

While waiting for the boom gallows tube support blocks to cure I started on the Dorade box test installation.

I started by doing what the build manual says, which is to mark a vertical line for the side of each box outboard of the cabin roof carlin. Here we are doing this on the starboard side, using a level to make sure it is plumb.

Then I loosely wired in the Dorade box side pieces, to get a feel of how they fit.

Here is the port box.

I had lifted the angle of the fit between the box sides from the drawings, to be sure to get the right fit. I made a cardboard pattern to test the fit, as here on the port side.

You can see that we have a perfect fit here. However, you can also see that the forward face of the box is only very slightly slanted forwards towards the bow. In the drawings the slant is much greater, which raises a question. Which is correct - the fit of the box side pieces as supplied, or the drawing?

This is a real conundrum. How come I have got the correct angle of join as specified in the drawing, but have a significantly different angle of slant of the forward face of the box towards the bow?

It can only be because the parts as supplied are different to those set out in the drawings. I can't be more specific than that, but to have the same angle of join between the two sides of each box and to have the forward face slant at a greater angle towards the bow would require the side face to be fixed to bulkhead 2 further outboard than specified in the manual.

This in turn, following the instruction to locate the side face just outboard of the cabin roof carlin, would require the companionway to be wider.

It just didn't make sense. For the first time I was convinced that the drawings are significantly wrong, and asked for comments on the PocketShip forum.

I didn't get much feedback, to be honest. I looked at a number of other builders' blogs and their Dorade boxes looked just like mine - almost square on to the bow, with a very slight slant forwards.

So I decided that the boxes were just fine the way I had them, like this.

You can see here that the forward faces of the port and starboard boxes are almost square with bulkhead 2, with a barely perceptible slant towards the bow.

Satisfied that I had come up with the right configuration I wired the box sides rigidly in place for permanent installation, as in this pic of the starboard box.

And finally, here is the pattern inside the starboard box showing the correct angle of join.

PocketShip certainly has her fair share of eccentricities!