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.

Beam Tops

After removing the laminated beams from the mold, tops need to be fitted. These are the 2 aft beams which areslightly shorter at the tip than the forward pair.

The mold for the beam tops is made from the 2 cut-off from the beam mold itself. i.e the opoosite curve
I thought I would vacuum bag these as it only needs a small alteration to the mold to give a flat surface.

The mold is just made from slats running from side to side. I added this piece of 6mm ply to give a surface to bag on.

To hold it in place a few  right-angled brackets were needed around the curve. Otherwise the slats were pulled out of the chipboard sides.

Positioning the foam. The black tape is covering another removable strip, which will be dug out from the otherside later on. (Same as in the beam bottom.) The slits for the strip should be completely sealed with putty before laminating. The gap at the front is where the top goes over the reccess mold. The smaller rectangle higher up is where the highest part of the UFSR will go.

Holding the faom in position without screwing from the otherside (will lose vacuum) was a bit tricky. I ran a bead of hot glue right down the sides whilst clamped down, and this was just about enough to hold it in place. ( I did have to use some screws from underneath on the bend, but I put some hot glue down the holes before screwing them in and it did not seem to affect the vacuum too much.)

 

Vacuum bagging

 

Oops ..Disaster! I did not seal the slits for the removable strip well enough and the mold itself was too rough.The resin stuck well.

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I remained fairly calm under the circumstances else there would be no photos!. I just cut it all up and quietly put it in the bin.It put up a fair old struggle before breaking considering it was less than 24hr old, Even so it is a reminder of how brittle resin can be after it is just cured. I though afterwards that it would have been more economic to smash up the mold and save the part, but it did not occur to me at the time. (So far, I'm glad to say this is the only part I have completely wrecked. I hope it will be the last as well!)

 

Repaired mold this time totally covered in plastic tape!

Finished beam top.

 

Carbon anchors postcure

The carbon anchor strips need to be postcured at this stage. I thought about using my domestic oven for this but found that the temperature was very variable. Ampreg 22 postcure is 16 hours at 50C or 8 hours at 70C. The higher temp is no problem for the resin, but it is too much for the Core cell A foam which I am using. I spoke to SP Systems who manufacture Core cell and they were not keen for the foam to go above about 55C.

I built a simple oven from a box, some light bulbs and a dimmer switch.  A couple of old computer fans helped to distribute the heat evenly.

I gave them about 16 hours at 55C. You can certainly tell the difference with this resin as to wether it has been postcured or not. After postcure when the anchors are knocked together they sound very like ceramic/china.

Beams -Carbon Anchors

Ian Farrier's later beam designs incoporate carbon anchors in place of the usual metal parts.

Getting ready to laminate the assembly. If you don't get the carbon UD started EXACTLY perpendicular across the assembly, each wrap will move sideways until it is falling off the assembly.. The sides  help to keep things in their right place to a certain extent.

 Anchors peel-plyed and drying. The longer one at the bottom will be made into the carbon anchors for the hull

Each anchor blank needs to be cut ino to 8 strips. The plans say to use a bench saw with a diamond blade, but I found my bench saw was not up to the job really. On top of this it was carving out about 5mm per cut. That would end up turning 35mm of precious anchor into dust! (There is about 20mm of anchor to spare which includes any edge defects). I opted to have them cut by abrasive water jet in the end. It was expensive but worth it, and they turned out very well. Even the foam did not get damaged by cavitation from the cutting jet.

Beam mold continued

The mold needs to be quite strong and sturdy. By the time it comes to take the beam out of the mold, it is heavy and awkward. I reckon it must be in excess of 20Kg, on top of which they are an awkward shape. (When you lift them up from both ends to get them out,  they immedialely try to fall over sideways) I could not get them out of the mold without assistance. Recess mold at far end, as positioned by the template mentioned  above.

To make sure I did not have any extra proplems with sticking resin, I opted to entirely line the mold with parcel tape. It could well save a lot of agro, -the last thing you want to have to do is bash the mold around to get the beam out. That would be a sure fire way to upset the alignment.

Mold is about 3m long in total. I put it in the only available space I had, but it would have been a whole lot easier if I could have walked all the way around it more easily.

Mold lined with foam. I chose to line the Recess mold  with a loose fit resin proof plastic cover. In practice, when it came to getting the beams out of the mold, it was actually easier to unscrew the Recess mold from underneath and lift it out while still attached to the beam. It could be removed later easily. The central strip  towards the outer end of the beam is where 2 cuts have been made. This strip of foam is removed later from underneath for further lamination to be done.

 

Beams -mold making

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Doorway/passage way

Both of the Fwd beam bulkheads have doorways in and 1 of the Aft ones has a passage way to allow access to the Aft cabin. A flange is formed around the doorway cut out ( on one side only)  - many wraps of UD fiberglass which is bonded to the bulkhead with tape on both sides of the bulkhead . Photo shows the mold for the flange. The peel ply will save me having to sand shiny epoxy later when I need to tape around to the other side..Photo shows Stbd b-head.

Lamination finished and mold removed. (Port b-head).

Finished flange on Stbd FWD beam bulkhead now trimmed to size. This bulkhead now finished and ready for bonding into the hull at a later date. Extra layers have been built up around G10 pivot pin tube.



AFT beam bulkhead with passage way. (Sorry poor photo) Also a flange has been added which runs from the outer edge of the slot across to where the cockpit sea will bond later. Another 12 layers of UD! Beam bulkheads are now quite heavy and awkward to move with all the layers of glass and resin which have been added. Other photos show close up of flange area which is now very thick with solid laminate. Also collection of bulkheads ready for fitting to the hull

Bulkhead lamination

8 layers of fiberglass are needed over the mold and flanges, each slightly smaller than the one before. Strips of  Unidirectional fiberglass (UD) also go in this area and down the outer sides of the bulkhead. Cutting the glass for these shapes is a bit tricky. I made this weird looking template to speed things up.

Laminating the layers. Perhaps I should explain the different resin colours. The resin I am using Ampreg22 comes with different coloured hardeners. Yellow is fast/ Purple is standard and Green is slow. Because of my previously mentioned problems with the distorting plastic on the mold sides, I used slow hardener for these layers. The downside of the slow hardener is that it has to be postcured, whilst standard and fast do not. I prefer to use the standard hardener when ever possible.

Photo shows the UD point reinforcement  layers sandwiched in between the other layers. 5 wide strips and 8 narrower ones.

Partially finished bulkhead slot area with the mold removed. A mock up strut seems to go up and down centrally in the slot which is a good sign!