2017.02.11 - The Boom Crutch Proper
The first task of the day was a visit to our local woodyard where I bought the softwood required to make the crutches. With all planed wood, either Planed Square Edge (PSE) or Planed All Round (PAR) the dimensions are for the original size, not the actual size after planing. So, if you buy a piece of timber that is marked as 25mm x 75mm what you will get is a piece of wood that is less than this. It could be 22mm x 72mm, or 19mm x 69mm or something else depending on how much wood needed to be planed off.
So, if you want a finished piece of 25mm x 75mm, as I do in this case, you have to select the next size up, in my case 100mm x 38mm which actually measures 95mm x 32mm, and then cut it to size. I rummaged in the stack of timber to find a piece that was suitable with no cracks or splits and no major knots that would weaken it.
Here is the timber I bought.
Time for a coffee.
Continuing on then, here the timber has bee cut to length and run through the table saw so that the width is slightly wider than required.
At this point the legs have been planed to the correct thickness and width, a curve cut into the top section, the edges rounded and the bolt holes drilled. Two washers are used between the legs, or a very thick washer is used, to give a gap.
You can see the gap here. The bolt I am using is just a temporary one, I'll buy a bolt, nut and washers later.
When the crutches are placed in position, the curved section is where the boom will rest.
Leaning back a little in the brackets due to the rushes and tarpaulin, but this is how they are used.
Two more holes were drilled so that a rope can be used to tie the crutches down so that when the boom is lifted prior to raising the sails, the crutches are not able to be knocked overboard.
The router is used again...
...to round the edges of the hole so that there are no sharp edges to wear against the rope.
So, the completed crutches except for the bolt. Now they need to be varnished.
Time for a break, my feet are cold from spending 2 1/2 hours standing on cold concrete. It is just 2 Celsius today. There's no chance of getting any epoxy work done unless the workpiece can be taken indoors to warm up.
I'm beginning to run out of essential things to do because of not being able to use epoxy. The spacers between the chain plates and the hull need to be redone, the holes for the tabernacle bolts drilled, the rudder needs to be completed, the skeg fitted and that is the end of the construction necessary to get Naiad in the water. The rest is painting varnishing and fitting out.
I think I may have to start measuring up and preparing the wood for the spars.
The forecast for next week is for much warmer weather and I expect to be frantically epoxying, varnishing and such like to get as much done in the warm. I have a deadline now. The Boat Safety Scheme surveyor will be coming to examine Naiad for her BSS Certificate on 13th March and she must be fitted out by then, that's just 30 days away. All the certificate essentials must be in place before 13th March.
For the final tasks of the day I decided to fashion the bronze top of the rudder stock in which the tiller will be placed and the chain plate spacer replacements.
The bronze sheet will be inset into the rudder stock which meant that a thin piece of the wood needed to be cut away.
Both sides received the same treatment using a router to do the job.
The bronze sheet was bent, cut and drilled and here is the almost final thing. The bare wood underneath will need to be treated before the bronze is bolted in place with some sealant under it as well.
The tiller slides into the tunnel formed by the bronze.
The new chain plate spacers and the old Oak spacers they replace.
One thing I want to do is to form a shape of epoxy under this gammon iron mounting so that it flows into the shape of the hull. At the moment it ends somewhat abruptly.
The sides will also flow into the curve but since it will be made from epoxy it will have to wait until the temperature rises a tad.