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 gallows boom 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 is 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!

Boom Gallows Tube Support Blocks | Drilling Holes

When the laminated tube support blocks were fully cured I cleaned them up and gave some serious thought to how I could drill holes for the 25mm stainless steel tubing.

Somehow I had to support each block on the pillar drill table so that its upper face was perfectly level. When drilled out and installed in the locker it must line up exactly with the tube coming down through the seatback deck, providing a perfectly perpendicular socket fitting.

Easier said than done. I settled on attaching each block to a piece of scrap ply with temporary screws, so that it could be clamped securely on the drill table and still hold the upper face of the block level for drilling.

This is what the solution looked like for the starboard block.

In this pic you can see that I have marked in the centre of the centre of the block, ready for drilling. The folly of this will shortly become evident.

I went to great lengths to ensure that the block was flat and level using a level, like this.

Then I clamped the block on the drill table, as here.

So far, so good. I'm feeling pretty pleased with myself at this point, so I drilled the hole to a depth of 1 1/4". Here is the beautifully drilled hole.

I had become so intoxicated with solving a real woodworking problem that I had completely overlooked that there is no reason why the hole will be in the exact centre of the block.

So it was a shock when I test fitted it, and dropped the dowel down through the seatback blocking to see how it fitted. Here is the moment of truth.

The hole is not in the right place. It was immediately obvious that I should have used the dowel to mark where the tube will land on the support block, which would inevitably not be in its centre.

The air turned blue for a few minutes while I thought about how to fix this silly but easily remedied mistake. I would permanently plug the hole with a piece of hardwood dowel, mark it out correctly, and re-drill the hole.

As I resigned myself to more work on this block a thought struck me. What if by some miracle the drilled block was suitable for the other side of the boat, without rework? With absolutely no expectation of success I tried a test fit in the port locker. Here is the result.

It was a perfect fit! What are the chances of that happening? Not one to look a gift horse in the mouth, the starboard block immediately became the port block and we moved on.

It was now time to drill the 'real' starboard block. This time I marked the location of the hole correctly and levelled the piece carefully on the drill table, as here.

The block was clamped in place, drilled, and test fitted.

This was the result.

A perfect fit. Checks with the level showed that the dowel was perpendicular, side to side as here.

And fore and aft, as here.

Finally I rounded over the edges of both blocks with a 1/4" router bit, on the router table.

This is what the port block looked like when test fitted.

I'm happy with that. Job done!

Friday, 24 July 2020

Boom Gallows Tube Support Blocks | Making & Test Fit

The bottom end of the boom gallows tubing would rest on the locker floor inside the seatbacks, and would require strong support blocks of some kind.

I decided to experiment by making a test block, and see what happened.

The first task was to find suitable timber for the blocks.

I had some Ash left over from my first boatbuilding project, but it is a rough sawn board and needs a lot of work to make it useable.

I did however have a big piece of Kauri which I had been saving for years, thinking it would be good for making strong fittings for a boat!

It is - or rather was - a chopping board for the kitchen. Here it is.

As I said, it is made of Kauri which is a giant member of the pine family endemic to New Zealand.

It is very slow growing and has a very tight grain. It is knot free and easy to work. No surprise that it was logged to near extinction in the last century.

Kauri is legally protected and I would be amazed if you could find any now, but some years ago things were still being made of reclaimed boards or salvaged logs, and I'm guessing my chopping board is such an article.

This is its makers mark.

It was made in 1976, so it's well seasoned!

It is also ideal for making some tube support blocks.

First I made a cardboard pattern, like this.

To get the correct curve to fit over the fillet on the hull I found a plastic pot in my cupboard with exactly the right diameter. This is it.

There is always something in my cupboard which provides an exact profile for any curved edge!

Then I cut off a chunk of Kauri and shaped it into a test piece. Here it is.

And here it is in place on the locker floor.

 This looked like it would work, so I went ahead and made a pair of support blocks for installation. Here they are on the bench.

They fitted nicely but it was immediately obvious that they did not have sufficient depth to provide a steady support for the tubing.

I therefore doubled the depth of the blocks by 'laminating' another chunk of Kauri on top of them. It worked really well!

Here is the resulting support block test fitted on the port side.

The piece of dowel shows where the stainless steel tubing will fit. There is plenty of depth in this block to provide solid support for it.

And here is the other block on the starboard side.

These two-part fittings are held together with screws at this stage, but satisfied that this was the solution I took them apart and laminated them permanently with thickened epoxy.

Here they are glued up and curing.

The next challenge will be to drill a deep and perpendicular 25mm hole in their upper face using the pillar drill.

But for now I was pleased with progress.

Seatback Blocking | Stanchion Holes

The seatback blocking was all installed, levelled and flattened. The next step was to make sure the stern blocking was ready for the boom gallows stanchions, which are 25mm stainless steel and will require very strong support blocks.

First, we have to bore a 25mm hole through the blocking at the stern of the boat. The exact position of this hole is not obvious in the build manual or the drawings, so I decided where it would go myself.

I marked in the centre of the hole 11.5cm from the transom skirt. This looks about right.

I used my UJK drill guide to bore perfectly perpendicular holes. I purchased this last year with just this sort of task in mind.

It is very difficult to drill a perfectly vertical hole by hand, and it is impossible to make large holes in this way.

But with a really good drill guide it is achievable.

First I set up the drill guide on the port seatback, fitted with a 25mm Forstner bit. Here it is.

I did the set up without the drill fitted, so that it was easier to manoeuvre. The base plate is secured to the blocking with a woodscrew, to hold it in place.

And here it is in place on the starboard side, with the drill fitted.

I used a level across the base plate to make sure it was level, like this.

Boring the holes was straightforward, but I think I will try the small corded Bosch drill next time.

This cordless DeWalt drill is very big and makes the drill guide top heavy and a bit hard to handle.

My small Bosch cordless drill isn't powerful enough for this, but I think its corded counterpart would be. We will have a test run at some point.

Anyway, I successfully drilled both holes port and starboard. They are very clean cut and perfectly perpendicular.

Here is the hole in the port seatback.

Very nice!

The next task is to install some sort of block on the floor of the seatback locker to receive the bottom end of the stanchion. That looked like it might be quite 'challenging'!

Seatbacks | Test Fitting

It was time to do a proper test fit of the seatbacks, to make sure they were ready to install when required.

First, now that the locker openings had been cut out, I made a quick fit to check that they look OK. They did.

Next I marked out where the temporary screws would be required to hold the seatbacks in place, and drilled all the holes.

I used 3.5mm screws, which are the right size for use on the relatively skinny stringers. I assembled a box of screws with plywood washers, and got out the drill driver.

Here is the starboard seatback, screwed in place.

I didn't use screws along the bottom edge. The screws driven into the seatback support frames hold the bottom in place very nicely, and a heavy weight closes any small gaps.

I'm happy with that.

The port seatback was a good fit too, as here.

Looking good!

Seatback Lockers | Gluing Flanges & Cutting Out

I would soon be fitting the seatbacks so needed to have them ready. Not much work was required and it was an easy background task.

First I glued the locker opening flanges in place, simply weighting them down on the bench, as here.

When cured I cleaned them up and cut out the locker openings. I used a Japanese keyhole saw which I purchased for making holes for inspection ports and portholes. Here it is is use.

Cleaning up the edges was quick and easy using a saw rasp and a Spiraband abrasive wheel in the drill, like this.

Finally, the edges were finished off in the vice.

That's it! All ready for a test fitting.