I snipped the support piece out of the rear cabin wall before sanding here, to add some excitement to the process.
Saturday, 21 November 2020
Upper Hull | Sanding & Patches
I snipped the support piece out of the rear cabin wall before sanding here, to add some excitement to the process.
Rub Rails | Gluing Scarf Joints
While doing all this it became very obvious that there was not enough room in the workshop to glue up the third piece, to make the full length laminate. So that would have to take place inside the house.
This time I found that it helped to clamp the straightest pieces on both sides of the scarf, to steady the now very long lengths of wood and stop them wobbling.
I left the laminates to cure for several days, to be sure that they would be strong enough to move back into the workshop for fitting.
Sunday, 8 November 2020
Rub Rails | Cutting Scarf Joints
The day finally came when my next activity was making and fitting the rub rails which run along the sides of the boat.
Like the toe rails, I started this while covering the upper hull with fibreglass, and waiting for resin to cure.
I broke out the lengths of Sapele hardwood supplied for the rails.
Each rail is made from three laminates, fastened one at a time to the full length of the hull. And each laminate consists of three pieces of Sapele, scarfed together to make a single length.
That's a lot of wood, and a lot of work!
Scarf joints are made on a 10 to 1 basis for the length of the scarf and the thickness of the wood respectively. I hope that makes sense.
Our Sapele is 20mm thick, so each scarf will be 20cm long. Simple.
It is essential that that the scarfs are accurately made, so it takes a lot of time to mark them up and cut them out.
Here I am marking out the length of the scarf, using a metric steel rule and an engineer's square to make sure that the joint is exactly 20cm long and square.
Next the joints are marked out using a steel rule and a marking knife, like this.
The steel rule is held firmly in place with a couple of spring clamps, which allow it to be positioned very accurately. You can't hold it in place by hand - it doesn't work.
Then the joint is firmly but carefully marked up with the knife. I have got a fancy Japanese marking knife but I found in practice that a craft knife with a new blade was easier to use and very effective.
The rule needs to be as heavy and stiff as possible, which is why I like the rule in the above pic. I stole it from the metalwork shop when I was at school - it's so old it predates the metrification of the UK, and is only marked in inches. I love it!
It's important to use a knife rather than a pencil, for the reasons given in the previous post. A pencil line is not visible on the dark wood. The knife cuts a deep line which is easy to see and shows as a bright stripe when the plane blade reaches it.
I devised a method for labelling each piece so I would know which laminate it belongs to, and which of the three constituent pieces it is.
All the scarfs must slope in the same direction, fore and aft, for looks. And the pieces must be numbered and labelled Port and Starboard, pointing forwards.
This will avoid much confusion later, with 18 pieces of wood to handle.
The pieces were bundled together to await the cutting of joints, with one bundle for each laminate.
I planed the first four joints before deciding that there must be a faster way of doing this.
So I fitted a rip cut blade to the Japanese saw and used it to remove nearly all the waste, like this.
This is very quick and achieves a clean and accurate cut. As seen in this pic.
The scarf is then clamped in the vice and planed down to the line with a jack plane, as here.
Finally, the scarf is moved to the other end of the bench and clamped in place to be finished with the block plane. Like this.
This results in accurate, close fitting scarf joints.
Here are the scarfs all cut and ready for gluing, stored in bundles for each laminate.
That was a lot of fun!
Toe Rails | Making & Test Fit
Then it was planed to a straight edge with the jack plane, and finished with the block plane. Like this.
The blade cuts a fine line along the grain, as deep as you wish to make it. This is much more visible than a pencil line on the dark wood, and it is very easy to know when you have reached the line because it shows as a bright stripe along the edge of the workpiece when you hit it with the plane blade. That's enough about the cutting gauge ...
The manual shows that the builder used seven temporary screws in his rails, but I felt that the curve at the forward end was a bit too stiff and needed another screw in the Dorade box area.
And here is the front end of the rail, showing the three screws holding it in place on top of the Dorade box.
Saturday, 7 November 2020
Fibreglass | Transom Inboard Panel
When I 'glassed the footwell I omitted to add an overlap from the rear face of the footwell up onto the transom, to accept the final panel on the inside face of the boat's stern. By the time I realised this it was too late ... the footwell was all 'glassed out!
So before adding 'glass inside the transom I had to make an overlap with a scrap of cloth.
Here is the overlapping patch, wetted out.
When cured I sanded and feather edged the patch.
I had previously made a pattern for the inside face of the transom and transom skirt, and used it to cut out a 'glass panel.
Finally I carefully wetted out the panel with a disposable roller, working down from the top edge and from the middle outwards so that the cloth would not sag or drop.
Here is the finished article.
Looking nice, and hopefully no more fibreglass work until the boat is turned upside down to finish the lower hull!
Fibreglass | Seatbacks & Cockpit Deck
You can see that the pattern continues out across the cockpit deck, covering the outboard edge of the deck and overlapping onto the single full width sheet of cloth laid fore and aft along the centreline of the deck.
Fibreglass | Topsides & Seatback Tops
Patterns for the topsides were made by laying paper along the panels and scribing in the curves and overlaps.
Next the patterns were taken inside the house to cut the 'glass panels. There isn't any room in the workshop to do this.
While marking out the cloth for each rear topside panel I added an overlap of 15cm to the top edge, so that the same piece of cloth will cover the seatback top and overlap down the seatback into the cockpit.
In the following pic you can see where the topside 'glass panel extends across the seatback top and overlaps down onto the seatback itself, in one seamless layer.