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This website documents my progress in building a Farrier F-85SR trimaran.

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Buildlog 2012

19 dec 2012

Although the rudder molds were ready I still had to perform some additional work. After gluing together the rudder halves the leading edge has to be laminated with carbon tape to prevent splitting. To keep the rudder shape intact, I put some vinyl tape into the mold. Afterwards I applied packing tape to the mold. This is flexible enough to get a seamless application and epoxy does not stick to it. To ensure a good release I also added some wax.

Several builders apply the laminate and core in one go. I wanted to be sure of equal distribution of the vacuum over the laminate, so I chose to work in two steps. After laminating the rudder halves I trimmed the cores to size and glued these in place under vacuum. A little bit of sanding had the cores level with the mold so I could take them out. This went really easy. The halves are now ready to be glued together, but are waiting for the HD insert. 

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1 dec 2012

After returning from work I found out that the rudder plugs had warped considerably. I had not expected this as the MDF should be free from internal stresses. I glued the plugs to their base boards under vacuum to get them into shape again. After 3 layers of mold release wax I applied my homemade 'gelcoat', a mixture of graphite powder, aerosil and epoxy. Just thick enough to still be applied with a brush. Next came all glass layers, beginning with 25gram glass and progressively heavier layers. Total glass weight is in excess of 6 kg/m.
At intervals I let the layers cure to avoid thermal problems. After the last layers had cured I was able to pull off the plugs. 3 layers of wax probably is a bit minimal as both plugs did not survive. On the right mold some gelcoat had managed to creep under the plug, damaging the leading edge. As the plug had come loose I was able to use this for the repair job, just before I had to get back to work. The left mold looks very good.

As the shed keeps getting colder, I started to work in a tent again. To work on the floats I first need to warm up the shed for at least an hour after which the floats need time to adapt to the temperature. Part of the port float needed some more compound, as I couldn't get it into the right shape. I used a slightly thinner mixture this time, to get it to flow better. When I've sanded that back into shape the floats are ready for the finishing compound, but that has to wait until after post curing.

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14 nov 2012

This time as well, the majority of my building time was spend on filling and fairing the floats. I've now switched more to contouring, trying to get both float shapes optically symmetrical and pleasing. As I was making a lot of dust anyway and needed some diversion while the bog was drying, I started on the rudder. A lot of MDF had to be routered away there.

There are 2 ways to make the rudder. The positive and negative build. If you build the rudder from the foam core up, laminating the reinforcements and skin on top, it's called a positive build. I will do that with the board, like here. For a negative build you need a mold, where you build the rudder starting from the outside shape, which gives better shape control. The easiest way to make a mold, is to cut it directly out of MDF, like here. That doesn't work with me, as my router does not have the required accuracy, so I'm building a plug first and will make a mold from that.
 
Before cutting the plug I routered a flat base in a thick MDF sheet, to be sure the rudder will have constant thickness. As I don't master 3D CAD, I routered the plug halves in 2 D. First in height steps of 1 mm. It was my intention to make a second pass for half mm steps, but the edges began to warp so that was only possible for the thickest part where it had the largest effect anyway. Afterwards I also cut the foam cores. I had already made these to size, with all HD reinforcements in place. An hour of sanding, and everything was shaped nicely. The rudder plug halves now have a layer of PU sealer on top and await final sanding. I forgot to bring my phone or a camera on the last day, so no pictures of that.

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28 oct 2012

This time my days off partly fell into a school holiday, so I couldn't do very much on the boat. What I did consisted of filling and fairing, which takes quite a bit of time. I started with grid 60 and am down to grid 80 now. I can still continue this for some time. Before the last phase, however, I first have to post cure the epoxy at something between 40C @ 24hr and 60C @ 16 hr. I already asked around at a car paint shop, but it looks as if I have to wait until a hot period next summer. With a tent of black plastic it should work. Problem however is my work schedule. This year, during the only few hot days of the year I was in South America....


11 oct 2012

After my previous update I had a holiday so I enjoyed continued work on the boat. Both floats are now fully covered in a layer of compound. Fairing is an art I must say. The bog will sag slightly after filling the ridges, so you should add a second layer before the first layer has fully hardened. That's the theory anyway.

To try this out, I started with the deck as it has the smallest area. Bringing up the bog is not too difficult. I use a putty knife to spread the bog and use a 30 cm trowel to scrape off the excess. The ridges are still visible then. After partial curing, I sanded away any new ridges, which are unavoidable. In practice it is very difficult to bring up a second coat of constant thickness. A 1mm layer over both floats requires 30 liters of compound, most of which has to be sanded away. And if you don't you are stuck with 12 kgs of extra weight.

I found out that, if you keep the bog quite thick ( not runny ) and the trowel at a shallow angle the sagging is not too bad. You need quite a bit of pressure and work slowly but that is easy to control. As I hadn't sanded the ridges completely back to the laminate it should be possible to sand most parts back and only fill a few local areas where needed. I'll see how that works.

To keep the work from being tedious I also continued work on the beams. Making different small parts takes a lot of time. Halfway the building of the beams the aluminum parts have to be ready and they have to be anodized first, so time to get started with those.

All 4 beam tops have been laminated. I'm starting to get laminating with carbon under control. It's a lot trickier than with glass. It's also more difficult to get a good fiber/resin content without vacuum. I'll probably retry laminating the beam undersides under vacuum, even though I had decided not to after 2 failures back in April.

As the value added tax soared to 21% last week, I ordered all remaining foam, glass and epoxy just in time. Now I've worked with both PVC foam and Corecell, one thing is clear: Corecell is worth the higher price. The only disadvantage is that it requires more heat for forming. Also I will use 2 layers of 300gr glass cloth for the main hull, in stead of the woven cloth. More expensive as well of course.

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20 sept 2012

It was great to be back at work on the boat. The floats look like zebras. All ridges of bog have been laid down and sanded back again. Time to start filling. There was one tense moment when I took the wooden plug out of the chainplate. I had waxed it well, so the hammer was not really necessary. Next to the bogging and sanding I also resumed work on the beams. The third beam is taking form in the mold and the first beam top has just been made under vacuum.

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3 sept 2012

It's been a while since my last update. Due to work and school holidays I haven't been able to work on the boat. Last week I enjoyed sailing my catamaran and helping my son to learn to sail. Very important as well :-). Also I crewed on the 'Trillseeker' while racing for the Henk Eggink Trofee which was really motivating. I'm itching to have a go at the boat again, but I have to wait another week before I'm back from work.

Ian Farrier indicated he will stop sales of his building plans per September 25 so he can devote his time to production of the F-22 and later the F-33 as well. So, if you have a desire to build your own farrier, you still have 3 weeks to decide!   

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14 july 2012

Even though I had used peel ply, I still had spots that had a glassy look, especially in between the fibers. The glassy coat has to be sanded away, but that is impossible between the fibers. I read here that sand blasting works really well and I decided to give that a try and rent some equipment. In practice it worked, but not as good as I had hoped. I think it works better on a finer weave. The 600 gram cloth is quite coarse and I didn't dare bring up the pressure too much. It makes an incredible mess, but the heavy compressor makes easy work of blasting the shed clean. :-)

After repairing the imperfections in the cloth it was time to start bogging and sanding. For applying the bog there are several methods. It would be nice to apply one layer in a single go, but I think that is not easy on a compound curved hull. Most people make ridges of bog, each about 5cm apart. Much of the material will be sanded away and it is easy to see when you are getting close to the hull. The space between the ridges is filled after the sanding.

On Internet blogs I generally saw 2 ways of applying the ridges, using a 30cm wide notched trowel or a candy bag. I tried both methods. With the notched trowel I had the problem that ridges were curling up. With the candy bag the thickness varies and the bog doesn't stick to the laminate very well. A lot of material is used, most of which has to be sanded away.
In the end I decided to apply the bog with a candy bag and finish it with a notched putty knife. This works really well. Thickness is constant and the ridges attach very well. As the resulting layer is quite thin, ( about 3 mm ) sanding the ridges down again ( 36 grit ) takes less time than applying them  :-).

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22 jun 2012

And then the time arrived to put some laminate on the outside of the floats. I made all preparations to use vacuum bagging. After laminating the first float half I couldn't get any vacuum however. And I couldn't find the cause either. After some time I ran into the time limit for applying vacuum, as the epoxy continues to cure. Even without vacuum the laminate looked quite acceptable. The floats do not have any hollow shapes and that makes it easy to pull the glass tight, so I decided to laminate the rest without vacuum as well. I rather spend my time perfecting the laminate than hunting for leakages that I can't find. It doesn't mean I've given up on vacuum, but I thought it was better this way this time.

While laminating I ran into another problem. I'm using stitched fabrics i.s.o. woven fabrics because of their strength. On a few spots part of a yarn is missing so that the stitching releases the crossing yarns and causes them to curl up. This causes local delamination and weakening and requires repair. A pity, as it makes the laminate thicker and requires more bog = weight.

To avoid runners of epoxy, I taped the hull with painters tape, which had some plastic attached to it. This worked well.

Next up is finishing. Final finishing will be completed after post curing, but I can make a start now.

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5 jun 2012

All laminating jobs have been finished. I'm now bogging and sanding the floats so they're in good shape before I laminate the glass on the outside. Part of the bog is for closing and fairing the gaps between the foam strips. Besides this there are a few spots with scalloping in the curve from deck to hull sides, especially in the rear. Float half #4 has the least spots, which proves that the foam oven was a good idea. It does mean a bit of extra work and weight though, although I will probably need less than 1 kg of bog to fair it out.

Small imperfections can be sanded away, but I don't want to do that too much, as it thins out the laminate. For the bog I use a 50/50 mix of brown and white micro balloons and epoxy with a slow hardener. It means I have to exercise patience before sanding. The advantage is that the epoxy now has a low viscosity and allows me to almost add 40% micro balloons in weight. The bog is light and sands easily. During spreading and scraping it off again, it dries out a little, so I keep some epoxy on the side to mix through the bog. Disadvantage of the brown micro balloons is visibility. The floats look like they've been sailing through a minefield. scratch 

The deck is slightly curved while the inspection hatches are flat, so I sanded a flat spot. To reinforce the opening I added a ply ring.

While gluing the bow bumper to the hull, I lined it up with my laser leveler. Works great.

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18 may 2012

Sanding the second beam flat showed that the carbon had a good wet out this time, so that problem was solved. At the same time the temperature finally went up and allowed me to continue to work on the floats. This allows me some breathing space to think about the next steps on the beams.

The floats still had some lamination jobs to go. I want to laminate the bow eye into the hull, just like Phill did. Also for gluing the bow bulkhead into place I used the same procedure; a strip of carton which keeps the glue in place and ensures a nice fillet.

Laminating the chainplates in place was tricky. I first glued them in place and clamped them, with the hulls upright. I then turned the floats upside down and lifted them up so I could work at it from the underside. Access to the front side was easy through the float hatch cutout. Laminating the rear was much more difficult as it had to be done though the inspection hatch cutout. The fact that the chainplates have been moved further to the rear didn't make it any easier as it was very hard to make the glass follow the shape of the chainplate.

For closing up the transom I use the same method as Henny. This is only possible if there is enough room for access so I doesn't work for the narrow bow of the F85SR. Works very well. 

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28 apr 2012

In the last couple of weeks I was able to spend quite a few hours on the boat. Initially I made good progress and both beams were soon ready to be laminated on the underside. As I couldn't source any 320 gram unidirectional carbon, I use a combination of 250 gram and 300 gram uni. The total laminate weight is slightly higher than required. The 300gm cloth is easier to handle but more difficult to wet out.

After I had laminated the first beam and taken off the vacuum, I ran into a problem. I had made an insert for the upper folding strut recess. This did not fully fill the recess so I could finish the laminate properly. The indent probably had caused some stresses in the vacuum foil leading to wrinkles in the laminate. Not a good thing and I had to grind of the carbon. While grinding down the carbon uni I found a few spots that were dry inside the laminate, so I'm glad I did that. It creates a lot of carbon dust though...

For the second beam I decided to lay a piece of mylar on top of the bleeder cloth and raise the insert for the UFS recess. To prevent dry spots, I not only wet out the cloth on my laminating table, but added epoxy as well when I applied the carbon to the beam, carefully working the epoxy into the carbon. Also I used a slower and thinner harder mix.

After putting on the vacuum, everything looked good. The next day however, I found that the laminate wasn't smooth at all. The use of mylar on top of the bleeder cloth didn't work out. On this beam I will have to grind the uni carbon off as well.... Allows me to check for dry spots again.

This is no way to make progress however. Advantage of these setbacks is that my laminating technique is getting better. I haven't had any success in using vacuum on unidirectional carbon until now. I had the same problem with the chain plates last year, so from now I will laminate the unidirectional cloth on the beams without vacuum. In the mean time I'm waiting for the temperature to finally go up and let me resume work on the floats.

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11 apr 2012

This week I laminated the inside of the second beam. The preparations for vacuum bagging take quite some time but give a good result. Before I applied the carbon I wet it out on the laminating table, to ensure a good laminate. I also was able to do a bit more finishing on the first beam. Space is confined inside the beam but I make good use of the flexible extension of my dremel.

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25 march 2012

Many other builders already wrote that building the beams is very time consuming. I can confirm that. Internal work on the first beam is ready. I combined a few steps so I could laminate everything under vacuum. To be sure the carbon fibers stayed in place, I put a mylar sheet under the vacuum foil. This worked very well. Work has now started on the second beam.

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7 march 2012

This time my days off coincided with a schoolholiday so I couldn't spend much time on boat building. I did however cut parts for the folding mechanism and the beam pads.

The time that I spend in the shed partly was lost in realigning a part in the mould as I was not satisfied about it. When all preparations were ready, I was just able to laminate the first carbon parts before duty called.

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20 feb 2012

When I came back from a trip through sunny South America it was a bit of a shock to see -17C ( 1F) indicated in my car. Luckily the shed was still just above zero.... By building a tent around the laminating table and using 2 electric heaters I was able to create a workable temperature of 18C. This allowed me to continue work on the boat. While the tent was heating up, I kept myself warm by sanding the floats. ( yes )

Before I could make any parts for the beams, I first had to laminate some panels, like a solid glass panel from which the CNC-router made several parts.

I chose to cut the foam parts by hand with the template that I had cut for the beam mould. The parts can be spaced closer together this way. For the beams I had chosen to use PVC foam i.s.o. Corecell. I'm glad I didn't do that for the hulls as it's a lot more brittle. This is not so important for the beams, as the foam will be surrounded by a lot of carbon cloth. It's easier to cut though.
As I want to vacuum bag the beams as well, I routered rebates in the edges of the HD inserts so the seams can be bogged close. This takes a bit of extra work and by the time I was ready to lay the foam into the mould, time was up!

The interior plan of the F-85SR is different from the F-82R as the cockpit floor and bunk height have changed. Settees are not included. F-82 settees can be used but it is no longer possible to extend them under the cockpit seats. With some fiddling I was able to think up a new interior using cushens of different height and a pull-out kitchen. I have adapted the drawings on the F-85SR page.

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31 jan 2012

When I'm enroute for my job I always try to prepare the tasks for my next period off. Sometimes I also make a workorder. This way, when I'm at work on the boat I don't have to spend time working things out. Last week I made the beam mould, beamtop mould, beam stand, beam template and CMM mould. Work on the floats was limited to some sanding. The temperature in the shed slowly follows the outside temperature... It should stay above freezing though.

Ian Farrier finished the lines for the main hull and the sailplan. Luckily the chainplates do not need to be moved. I'll have to change my ideas for the interior though.

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13 jan 2012

The temperature in the shed dropped to about 8 C. My epoxy needs a mimimum of 15C for application. Still I was able to work without problems though, as two 60W lightbulbs keep the epoxy at about 20C in the heater box and an electric heater keeps the inside of the floats at an acceptable temperature. Smaller jobs on the outside kan also be kept warm by building a temporary tent, but that is not as easy.

Except for the chainplates all internal work on the floats is now ready. Also the cutouts for the deck hatches are finished. I can't place the chainplates yet, as Ian is still finalizing the sailplan, and they may have to be placed further aft then initially intended.

Except for some sanding and a few small jobs, work on the floats will now rest until temperatures go up again. I don't want to heat the whole shed each time I need to epoxy something on the outside of the floats. The beams are not so big and I can build a tent around it which is easily kept warm. So, I have now started to cut the moulds for the beams and the Central Mounting Modules ( CMM ). The ash wood blocks for the beam pads are now ready to be glassed.

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