Mast base

This (part) of the rotating  mast base is one of those maddening little pieces that is difficult to get right, because of all the shallow angles. If you get one bit correct and nicely fitting you then find another bit has gone slightly AWOL! Very frustrating.

 

It did not take too long to make the individual bits, but fitting it all together and working out 'how' to hold the parts in place for  welding (without loosing the pin alignment for the sheaves) has been quite tricky. The sheaves are running on a 1/2 inch stainless steel rod. I will drill sideways  holes either end of the rod and fit  clevis pins to keep everything in place, and allow for replacement of the sheaves if neccessary in the future

  

Sheaves fitted and now ready for welding.

Beams -Foam fill and top fitting

I have opted to foam fill the beams with a 2 part expanding polyurethane faom. It will add a bit of weight to each beam unfortnately, but hopefully not too much. I think I have used about 6/7 kilos per beam

It is a bit of a messy and laborious business. If you keep the 2 components at the optimum temerature for maximum expansion (least weight), then you do not get very long ( 45 secs) to mix well. i.e you have to mix lots and lots of small batches. The foam produces exothermic heat on expanding so it expands well, but then has an annoying habit of shrinking back slightly, leaving gaps around where it is touching the inside of the beam sides and bottom. Fortunately the next liquid pour and gravity  helps to fill these in.

If you spend too long mxing,  this happens! To get the foam into all the nooks and cranies, it reallly needs to be poured in whilst it is still completely liquid.

Here, I am cleaning up. I have tried to keep the foam off the areas that will later be usd as glueing surfaces for the lid.

Ready for the lid. This has been prelaminated already on the inside face.

Lid fitted.

Daggerboard Case continued

Now the cheek block has been trial fitted to the case, the sides can be joined. The insides has been coated with several layers of antifouling, as this area will be inaccessable once it is joined together.

Glueing together.

More layers of glass are then added along the hardwood sides.

Despite the core of the side panels being made from end grain balsa, this is now a large and pretty heavy piece. I can just about move it around single handed, but I doubt I could lift it.!

Case is now ready to be fitted in the hull at a later date. It will be trimed off at an angle either end to match the hull.

Daggerboard Cheekblock/Some metal parts

Before putting the daggerboard case sides together, I have to fit a cheek block which will be needed to lower the daggerboard. (Might be worth mentioning that the pairs of holes at the top and bottom of the Barton block, are NOT the same distance apart. I almost ruined the backing plate by not spottig this!)

Cheek block is bolted to a backing plate which is attached to the side of the control line slot

!0 bolts are neede for the plate.The bolts are pushed through from the inner side, and the heads buried in epoxy putty.


I thought I would make some of the simpler Aluminium parts myself. I have had to buy some large blacksmiths drills and some hole-saws  to make these parts, but they will also be needed later on to drill matching holes in the hull  and beambulkhead flanges.etc

Drilling Aluminium is easier than I thought, even 12mm plate was not too difficult. I already have a small pillar drill which seems up to the task. The cutting and shaping I have had to do is on a small band saw with a bi-metal blade.It is slow going to cut but still easily possible. A bench sander also rounds of corners and edges very easily.

These parts  are for the kick- up rudder box. The 4 large holes will have a plastic bush fitted and then a 16mm bolt. Plans specify a 16mm ID by 19mm OD plastic bush, but I found that from Igus GMBH   (suplies acetal bushes as used in folding system) that they only have 16mm ID by 18mm OD. So I have drilled 18mm hole and not 19mm. (Could be worth checking that you can get the bush specified Before drilling hole!)

These are the beam bolt backing pads for the folding system - made from 12mm Aluminium plate.

Carbon chainplates and forestay bracket

Carbon chainplates are formed from a stainless steel thimble and clevis pin, glued to  foam strip and covered in multiple layers of Carbon UD and glass

Laminating. Difficult to keep them still!

Finished- will be trimmed to final size and shape later

The forestay bracket  also serves as the sleeve for the retracting bowpole.

Attaching the foam and thimble to the carbon tube. (at the correct angle) The bowpole will be a sliding fit into the sleeve.

Building up a cone of foam around the tube

Laminated with multiple layers of Carbon UD

Daggerboard Case

This can be constructed either from Marine plywood (heavy) or end grain balsa. I was lucky to find a supplier in the UK who would sell individual sheets of balsa. Normally you have to buy a full case which is expensive and more than you actually need. The panels are supplied as 4'x 2' sheets with the balsa blocks attached to a flexible backing scrim.

Assembling the sides. A plywood insert is added in the top section  for the compression loading from the mast. 2 layers of glass are laminated either side of the balsa sides. I vacuum bagged the layers after making a small extension for the table, as this is a long piece, and would not quite fit.

After laminating and attaching the down pieces (Ash) , I coated the inside with several layers of epoxy. The down side of balsa is that it would soak up water if there are unfilled gaps or holes.

Photo shows the rope channel for pulling the board up and down. This has been laminated over and sealed, after digging out the balsa around the edge and replacing with solid putty. Before I can do anymore on this I need to find a suitable cheek block....

Beam fairings

Made using molds traced from Full size patterns and. constructed from foam strips about 25mm wide. It is hard to get them to stay in place. Beacause of the shape of the fairing, (deeper at the outer end than at the inner end) the strips need to bend backwards and forwards, up and down and twist as well.

 I ended up having to hot glue each strip to the lower strip and hold every strip in place with screws in every single mold!  After that  right angled brackets were used from the outside, to hold it all in place, and the screws on the inside removed before laminating. Just make sure there is enough room to get your screwdriver in to get the screws out. By the time the sides have been built up, there is not much space left inside.

The end result is rather "gappy" on the outside. It is virtually impossible to get the strips to align nicely along their entire lengths.  I will have to try and squeeze some resin/putty into these gaps later. The shape is not that good either with a lot of ridges to be sanded. I think that there ought  be a better way to make these. It has taken a lot of time and the results are not that impressive really. (i.e you have just created more work for yourself!)

After a bit of sanding/fairing they look a bit better. Pity I forgot to put any peel ply on the inside after laminating though..


I am going to leave the beams at this stage for the moment. There is still quite a lot more to do but I am running out of space in my current workshop. Interestingly I had an update to the F-39 plans recently form Ian Farrier, and he mentioned that several builders or potential builders had enquired about purchasing ready made beams from Farrier Marine. I can certainly see the appeal of that. It is too late for me, but if I had a choice I think it would be well worth it.