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


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Build report 2014

1 jan 2015
The wax has a melting temperature of 80 ºC. I was just able to fit the rudder case into our oven. After some time the wax went soft nicely and it was easy to remove the wax from the inside of the case with a paper towel. A small residue remained however. Luckily we have a Quooker tap, which produces boiling water. Together with a brush I was able to clean the inside completely. The rudder also had some glue residue which was easily removed with 'Goo Gone'. The last remains of the wax were also removed with the help of the Quooker. Side effect was that a few pinholes blew open, so that has to be repaired.

During the Christmas holidays I was able to do a few more jobs. The rudder control horns are made of 7mm HD foam with 1.5mm carbon on both sides. Very stiff. The pop top pivot arms are made of 15mm foam with 3mm glass on both sides. By clamping these panels together with a bunch of glue clamps I get a lot higher pressure than with vacuum. The result is a nice smooth finish with a very high fibre - resin ratio. After that the shapes are cut out by the router. Also I have all parts for the pop top mold cut out now. Finally I was able to pick up my curved foils from Arno. I had ordered them from Ian some time ago already but we combined transportation to reduce cost.

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9 dec 2014
It's four years ago that I stood in an empty shed and shortly after posted the first update on my website. My boat building project has really moved on since then and the shed is almost full now. On my website I've now started on part 7. I try to limit every page to about 6 - 7 MB.

When I came back from work last week, the temperature had dropped too much to continue work on the main hull. I set up the party tent again. For this situation I had several smaller projects in mind. In the coming months I will spend time on the rudder case, traveler bridge, water ballast sheave blocks, cabin 'pop top', and the settees. If I have some extra time at the end, I can start fairing the beams. Also I still need to produce a few parts for the beams.

It looks like a lot of builders use the cabin roof hatch to make modifications and deviate from the design. On the F-22 Ian changed the construction slightly from the F-82/F-85SR design. I have some changes as well, will try to stay as close as possible to the design in the build book. The pivot arms will not be aluminum but composite and curved to allow the hatch to slide further forward. I want to mount the instruments on the pop top, so it will be a bit higher as well. 

Work on the rudder case needs several steps. The first two are now finished. Using vacuum was not an option, so I used the 'poor man's vacuum' method by adding some vacuum foil on top of the peel ply. Then by scraping with the epoxy spreader you can remove all bubbles and get a very nice and smooth finish. The rudder was wrapped with 3mm thick sheet wax before lamination. After the epoxy had cured I heated the set up and easily removed the case. Now I still need to remove all the residue from the rudder and the case ....scratch. Not much visible progress on the other projects, just a lot of preparation work. 


23 nov 2014
The forward part of the hull is another big job to laminate. This time I kept record of the time it took me. I'd already cut all the glass and other stuff to size. On arrival in the morning I started up the heater, vacuumed the foam and degreased with acetone. Next was applying the tacky tape to the vacuum foil which I always do last. This took about an hour and gave the foam the time to get to the right temperature. Then I started mixing epoxy and laminating, 2½ hours. Applying peelply, bleed foil and bleeder cloth, 1 hour. Taping the vacuum foil to the foam, 1 hour. Lastly connecting the vacuum pumps and kneading the tacky tape with a roller and by hand. The funny thing is that you don't hear any leakages yet, but you do notice when you've stopped one. The foil is compressed a bit further and makes a crackling noise. After half an hour the meter began to register a vacuum and I began to hear the first leaks hissing. That makes it easier to spot the leakages. Another half hour left me with just one small leak in the foam and 0.9 bar suction. 6½ hours of work.

The drawings show the possibility to use water ballast in the rear of the hull using bailers. It was always a mystery to me how to operate the bailers. Tor Rabe told me he is very happy with the Andersen super mini special bailers, which can be remotely controlled. I chose not to wait and build them in now. This bailer has been made for a maximum skin thickness of about 5mm, so I cut out 2 pieces of the hull and glued in some glass sheets. I still have to laminate them in place though.

Just like with the port hull, I hand laminated the uni kevlar. This is a tricky job, as kevlar is difficult to wet out with epoxy, even though this kevlar has had special treatment. With that completed I lowered the port half and aligned it at frame 5, which is the most important frame. It is very easy now to align all bulkheads. I glued a ridge where the main bulkhead comes as that will be glued into place last.

The cockpit floor and bunk lines were easy to copy with the laser level. First I checked if the hull was exactly vertical. This was a good thing, as the gunwales were 0,2º out. This doesn't seem much but with more than 2m hull width it makes a difference of almost a cm. I would have liked to finish the job, but I got hit with the flue instead.

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4 nov 2014
My daughter had a few extra days off from school. Forming the foam and screwing in place is a lot faster when working together. We had the foam in place within a few days. I had renewed the insulation of the foam oven and that really helped. 90 minutes after start up the oven was at 85° C and in the end the temperature reached 100° C. Together with the 3KW paint stripper bending the foam in place went very smooth. At the end I only needed an hour of sanding to get the hull into a perfect shape.

Placing the HD foam strips and plugging the seams took an equal amount of time. I calculated that I needed to close 50 meters of rebated foam. Again I worked in two steps. The first time really working the bog into the seam and making the bog as fair as possible in the second pass. The chance of having a leak in the same spot twice is about nil. Just before my holiday was over I was able to laminate the rear of the hull. 

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17 oct 2014
After returning from my job I started preparation for the final lamination on the port hull half. The lamination itself was my biggest until now. In the morning I started by cleaning and degreasing the hull, applying the tacky tape to the vacuum foil and then sticking the bag to the hull in two parts. Around noon I mixed the first batch of epoxy. Five hours later I closed the bag and applied the vacuum. The hunt for leaks only took half an hour this time. Even though I used a slow harder it was just in time. It was also just in time before the autumn school holidays. My kids were eager to help me and they were very welcome help in lifting the hull and setting up the frames for the starboard half.

In between I also did some more work on the cockpit floor. That is finished now. For now I can continue working on the boat as I have the rest of this years annual leave alotted to me.
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29 sept 2014

Before laminating the outside of the hull I want it to be as fair as possible. This will eliminate a lot of filling and fairing later, so it's no problem if this takes up some time now. I divided the laminating in two tasks as it is too big a job to do in one go. To prevent epoxy creeping where the tacky tape needs to go, I place one side of the vacuum bag on the low side of the hull before laminating. I already laminated the aft 1/3 and got a perfect vacuum. For the forward part I will divide the bag into two segments. 

For the floats I used a coarse 600 gram knitted fabric that I didn't like. For the main hull I switched to a double layer of 300 gram woven cloth. Disadvantage is that it is only 100cm wide so I need more overlaps. On the other hand the overlaps can be staggered, so fairing will be easier. This fabric is easy to lay down using the wet method. I'm leaving the bottom 40cm free, so that later after joining I can laminate top and bottom with one full width piece. This way ensures optimal use of the fabric.

In between I've also started some work on the underside of the cockpit floor. An electrical conduit, a reinforcement for the tiller bearing, some composite anchors and three cut down pieces of sewage pipe for storing fishing rods, a boat hook and the mast raising pole. These are easier to glue into place now than after the floor is glued into the hull.

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21 sept 2014
My previous work period was quite short as I took a couple of days off and got into a good working rhythm in the shed. That is why this update is earlier than normal. After taping the cockpit seat and the main bulkhead I was ready with the port hull inside. To improve rigidity of the hull, I added some stiffeners which I glued on some foam offcuts that I glued onto peel ply to make it easier to remove later.

And then it was time to get the hull out of the mold. First I needed to unscrew about 2000 screws. The hull released easily but it was suite an effort to pull up single handed. Not because of the weight. It's just too big to handle alone. I just managed to get it up enough to get the lift strap underneath and then it was a piece of cake. The hull turned out to balance nicely around frame 7, just like the floats. Before removing the mold, I marked all frames and battens, so I can make the starboard side exactly duplicate. Turning the hull with the tackles was easy as well. Next step was some sanding ( not much, as the hull is very fair ) and removing foam for the HD inserts, as well as cutting a rebate for the windows.

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I don't like the standard F-85SR window design so I had already drawn up something myself, but Ian came with very good looking windows for his new F-33 and F-22 production models. He was very friendly in sending me the F-33 CAD files, when I asked for them. Problem is that the F-33 is a lot bigger than the F-85, so I had to reduce the length of the window to 70%. This makes the window quite narrow, so I did some experimenting with window height. Standing on a ladder I then made pictures to check the looks. In the end I found a good result with a window height 85% of the original. Then I used the negative cut out to router a 6 mm rebate in the foam. This will let the window stick out by about 2mm and give enough room for expansion around the window.

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10 sept 2014
As the deck is quite flat, finishing didn't take long and soon I was ready for laminating. Beforehand I had to decide how to route the vacuum bag. Either over the just laminated cabin side or a bit wider, but also higher up. I decided to lay the tape over the cabin side as otherwise I would have to walk over the tape area while laminating. However, I got some epoxy leaking under the tape where it crossed the gunwale and this made vacuum impossible. Too bad. I quickly mixed some extra epoxy to make sure all peel ply was saturated and got a good laminate. The only downside is that it's a bit heavier.

With the last major lamination completed I could finally start fitting the remaining panels. The rear wall of the anchor locker will be placed after joining of the hulls, so I laminated a ridge now. I checked the fit of the daggerboard case and the cabinet. It only needed a bit of sanding for a perfect fit!

Near the bow the hull gets very narrow and it will be very difficult taping the parts together. Ian suggest making a fibre reinforced ridge for that. I combined it with the reinforcement needed for the bob stay of the bowsprit.

I laminated the jib track reinforcement under vacuum and the glued the main bulkhead and the cockpit seat into place. Everything fits perfectly. Only the main bulkhead has some space on top. This is probably because it is placed at an angle ( like on the F-82R ), although I did make allowance for that, but probably not enough.

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23 aug 2014
After a building holiday of almost 7 weeks the schools have started again and it was great to start building again. The foam for the hull side only needed one more piece and a little finishing before laminating. With the new tacky tape, again, I got fantastic vacuum. I then moved up to the deck. I could make the bow part in one piece. Even though there is only a light curve, it is too much for the screws to hold, so the foam needed some persuasion with the heat gun and the bending mold. It now fits with almost no tension. The rest was laid down within only a short time and I was just able to apply the first layer for the foam joins.

As a test I laminated two of the composite anchors for the wallas tank with vacuum. Of course this takes some extra time, but it looks great.

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30 june 2014
This week I wasn't able to do very much. It was my intention to have all the foam for the port hull half in the mold before the summer holidays. That's not going to happen and I hope it won't harm my planning for this winter. I made a glue ridge for the front bunk and the settee. Together almost five meters long. These panels also fit very well. Also I glued in few bulkheads. The tank for the wallas will be held in place using composite anchors. I want to minimize the use of fasteners.

I did start with the foam for the hull sides. I'm using 15mm foam here as I want to rebate the windows. Because of that I'm a bit short on 15mm foam and I initially used some left over Airex for part of the hull sides, but I was not satisfied with it. This means I will have to get another sheet of 15mm foam. The curvature of the sides is only minimal, but up front a twist is introduced, so I need some smaller pieces there.

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latest update 13 june 2014
After discussing the issue of the sealant tape with a few other builders and on advice of Bouwmeester Advanced Composites I switched over to Tygavac Sealant Tape AT 90B. At temperatures just under twenty degrees Celsius this tape is more flexible and sticks much better than the Airtech Airseal 2 that I used until now. This gave me new confidence to start the big project of laminating the front side. It took me 6 hours in total. Getting vacuum was the easy part and that was a big relief.

I still had to laminate a 6 meter long strip of Kevlar along the keel. Kevlar is very hard to cut. You won't get it done with normal scissors or a sharp knife. That is the reason you can buy special ( and very expensive ) Kevlar scissors. There is a trick however, by sanding a small 90º edge to the cutting edges of a cheap pair of scissors with a whetstone. This way cutting Kevlar is easy.

The cockpit floor and the front bunk will only be glued in place after both hull halves are glued together. The join needs a few lamination steps and several spots will be really hard to reach if I laminate them in place now. The same applies to the aft bulkheads as well. To make it easier to glue the panels in place I started making glue ridges. Everything is still easily measured and aligned with the laser level and easy to reach. The fit  of all panels and bulkheads is very good. Before I started gluing I also checked the fit of the important beam bulkhead.

The fuel tank that came with my second hand Wallas 95 cooker and heater was made for an F-9, but is an exact fit on the spot that I intended. Easiest to do now as well.
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29 may 2014
This time I had a few extra days off, so I could speed up progress. Within a few days all foam was laid down into the mold. I was very satisfied with the result. Only a little sanding was needed to take away a few edges. With the föhn I was able to make the tight curve until almost at the bow. Further forward I made some kerfs and in with the first sheet I used a piece of 15mm foam, that I later sanded into shape, as the curve is too tight there.

Thereafter I closed the seams in two steps, as I did with the floats. The first step with a thin mixture to really close off the gap and the second to fill up. It's important not to fill too much. The mixture is much harder than the foam, so when sanding you run the risk of making 'valley's' in the foam. All around I added a foam strip, made of cut offs, for attaching the tacky tape.

In the mean time I had my router cut foam for the daggerboard of Arno's boat.
Finally the big day came to laminate the rear part of the hull. The hull is too big to laminate in one go. After laminating I ran into problems while trying to get vacuum. I couldn't find any leakage and had no vacuum at all. In the end I pulled away the vacuum foil, but the epoxy had already started gelling too much to do any hand finishing. The result was a few no-bond spots. This was caused in part by the S-shape of the hull. It makes it hard to get the laminate to lay down well and even harder to get the peel ply correct. You pull in one place with the result that the laminate gets loose in another place.

Lesson for next time: Use an even slower mix of hardener and apply the peelply in narrower strips.

Next to that, I'm going to use another type of tacky tape. The present tape, at low temperatures ( 15- 17 °C ), doesn't stick well. I went along the tape several times, while heating it and pressing it down, but it is my impression that I had air leaking along the whole length. 

Where I had hoped to continue directly with the hull front side, I had to repair a few spots and sand the laminate as the peelply had not attached well. As I have to wait for the new tacky tape, I already started drawing lines for the bulkheads. The laser level works perfectly for this.

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08 may 2014

When I got home, a school holiday had just started. There is no way daddy can lock himself up in the shed in such times, so we enjoyed a nice week away from home. Afterwards there were still a few hours left for me to work on the boat.

First I redid the bow as I was not happy with its shape. The battens stick out quite far in front of the forward frame. To get the shape nice and even, I screwed on a cross batten. To get the bow the correct shape, some of the battens have to be concave. To achieve this I tied a line from the battens to the strongback. After a final check, I was finally able to start planking. I used the same procedure as with my last float half. The foam strips are about 30cm wide with 10mm rebates that are glued together with PU glue. I first heat a strip of foam in the oven to about 75° C and add heat with the 3KW föhn where needed when bending into shape. This works great and quite fast. In a way, planking the main hull is easier than the floats, as the curves are not as tight.

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22 apr 2014
After returning from my job, it was time for the last beam lamination. The CMM bearing area still had to be reinforced. As the load can be quite high, I used vacuum here. It was the first time that I split the vacuum into four bags, but that gave no problems. It was tempting to continue with filling and fairing, but that can wait until next winter.

The temperature is rising, and that means that I could pack the party tent, clean out the shed ( high time for that ) and clear the strongback for the main hull. It took me two days.

As I work alone, I used offcuts from the frames for the initial set up of the form frames. In principle the frames are aligned by the centreling string on the strongback. As supplied in DXF the width of the form frames is not equal. As I'm using an laser level, I changed the frames to all have the same width on one side. After individually setting each frame, I used the laser to align them vertically within a mm. After that I adjusted the alignment lengthwise. Only took a few hours

My son had a day off from school. What is more fun than helping daddy setting up the mold? nodding The hull will be laminated first. For better access the deck is still free of battens.

I did not like the Alkyd paint that I wrote about last update ( now in Part 5 ). Some searching on the Yahoo F-boat forums gave me a new idea: PU reinforced Acrylic paint. It is a professional paint that can be used indoors and outdoors and should be quite hard. As it is water based, it can be used safely in an enclosed area. I tested this paint and like it. The carbon washbasin is now ready for assembly.

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1 apr 2014

After laminating the beam tops of the forward beams, all major work on the beams is now ready. I'm quite happy with the outcome of my hand lamination. Had I used vacuum it probably would have been a bit lighter. Now I was able to stretch out all uni fibres to the same tension. When the beam is loaded all fibers will be equally stressed. As the carbon follows a curved area, using vacuum gives the problem that the outside fibers are compressed to a smaller radius. In that case the forces will not be distributed equally accross the laminate. The effect is much less than with the chainplates ( see the update of june 26th 2011, part 1 ), but it is still there I think. After some cutting and sanding I still had to do one job that was still waiting. Reinforcing the UFS recesses. Only one more lamination to go.

In between I also applied some glass tapes on the kitchen cabinets where needed and I started filling and fairing. The wash basis can not be glued together yet as I first have to paint the inside of the drawer, so I have to look for paint. For the outside of the boat I want to use a two component PU paint. Very hard and UV resistant. For the inside I want to use an egg gloss paint that is easier and safer to apply inside the cabin. I'm now testing an Alkyd urethane paint on a test piece. This paint is advertized as a concrete floor paint, but also can be used on wood without primer. I'm open to any ideas and suggestions.

The wallas fits nicely in the drawer. By taking over the bolt holes, I can now reinforce them on the inside.

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15 mar 2014
It was time to continue work on the beams, but I first had to take a few decisions. The design asks for the tops to be rounded with quite a big radius of about 60mm. This leaves only a narrow flat part on the top. Too narrow for my liking. I found out many Australian F-82 and F-85 builders use a smaller radius and I ended up with a radius of about 45mm which will make it easier to walk on the beams. Another point was the wing net attachments. I had to grind away quite a bit of the aluminium strips on the inside and, even though I'd filled up the void with JBweld, I was looking for a solution. I found the solution on Ian's production F-22 progress webpage. Great looking aluminium beam eyes. It won't be difficult to make these on a lathe.

While I was shaping the beams, my router cut the form frames for the main hull. These have been reinforced where needed and are ready for use. It is tempting to start with the main hull now, but I first want to finish the beams.

I was unsure whether to use vacuum for laminating the beams tops. For the beam bottoms it gave me a lot of trouble and I had to sand away a lot of carbon twice. Arno put the whole beam in a bag for his F-32 beams.
An easy solution. However, even with only 0.5 bar vacuum the beams have to resist a crushing force of more than 3000 kg. So, I chickened out, even though it worked quite well for Arno. In the end I decided to try vacuum with the bag attached the normal way on the bottom of the beam. After laminating the first beam I got attachment problems with the tackytape. As I was quite happy with the layup, I did not even try to get vacuum, but ripped away the bag. It is better to stick your energy into getting a good finish of the laminate and I'm quite happy with the outcome even though my beams will be a bit heavier now. Two beams have now been laminated.

In the mean time I also glued together the rest of the kitchen parts and started finishing and taping them where needed.

20 feb 2014
It is funny how a couple of small jobs can take a lot of time. Cutting and glueing the laminating table. Cutting glass, peelpy and vacuumfoil etc. In the mean time making some preparations for the final lamination of the beams. And some finetuning of the panels for the drawers and cupboards. Gone were two days.

One drawer has been glued together. The other three parts are are ready to be glued. All parts fit together like a jigsaw puzzle. Laminating the cockpit floor with all reinforcements is a big job and was the last panel to be laminated. It just fit on the table. And so my three days of boat building came to an end.

7 feb 2014
When I was browsing through the build book, looking for any necessary reinforcements for the cockpit floor, I saw that I still had to make parts for the forward beam recesses. Ian hadn't supplied CAD drawings of these, so I made them myself. Like with the other panels, I laminated reinforcements into the panel when possible. Because of these panels I just ran out of time to laminate the cockpit floor. That is the last panel that I still have to laminate. I have cut out all other panels now. The only panels not made yet are the settees. Sitting position and height of the backrest have to be decided upon when the hull is ready for it, so they will have to wait.

In the mean time I also started on some small jobs for the kitchen cabinets. Last year I made a mold for a carbon washbin. I put it on a flat plate and made a nice radius with epoxy and microballoons. After curing and sanding I applied 3 layers of wax, which somehow wasn't enough as washbin did not release well. I spend almost an hour trying to free the mold. Part of the radius is still stuck to the basin and has to be sanded away. Too bad, as I wanted to clear coat the carbon and I don't think I can do that now as there are also a few scrathes and dents at the edge.
I had no idea how much carbon to use. In the end I decided to use 3 layers of 200gm, with some thin strips of foam between the second and third layer to increase stiffness. The endresult is very stiff and weighs ( with the peelply still on ) 440 grams. Not bad. A SS washbin is more than 1 kg.

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22 jan 2014

After the last posting, another F-85SR builder pointed me to a connector for more exposed spots: weather pack connectors. Thanks David.

Last week I was able to laminate 4 panels. The extra preparation work that I do takes more time, but I hope to profit from that later. For the cabinets and the kitchen drawers I use PVC foam that I had left over. When I used my 'nail bed' to make the hole pattern, the PVC broke in pieces. Sure proof that Corecell is much stronger. PVC is cheaper and a bit lighter, although I think it absorbs more epoxy, so there is no gain in that. As a result I had to manually drill the holes again. Drilling two panels at a time does save time though.

I hoped not to have to paint the inside of the cabinets by adding a white epoxy colour paste. It makes the epoxy thicker, so you need more to wet out the glass cloth. The vacuum doesn't pull out the epoxy very well, so you end up with a heavier laminate. Not such a problem if you don't have to paint the panel afterwards. But that's not the case. The green foam still shines through.

All the foam for the panels is now cut. The cockpit floor is too big to fit on my router bed, so I made a ply cutting guide. With a jigsaw pastern that fits well I don't have to glue the parts together. I the mean time I have started to cut out the cured panels on the router. Only takes a few minutes per panel!

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1 jan 2014

It was great to be home for Christmas and New Years Eve. Normally I'm away from home for either due to work. as my family had a school holiday as well, I didn't work on the boat very much. When I went to the shed, my kids helped me out. That was very nice.

Luckily the router had been repaired, so I immediately put it back to work. Initially on the mini table. The result only needs minimal fairing. I also continued work on panels and bulkheads. On some panels I first have the router draw the outline with a marker. This allows me to precisely place HD foam and rebate the foam where needed for taping. I want to build all flat panels and bulkheads before I start work on the main hull.

In the mean time I'm also preparing work on the electrical system. I found out that marine connectors are quite pricey. Good connectors have also been developed for radio controlled models. Gold plated, sturdy and a lot cheaper at hobbyking. The big ones are rated 90 Amperes. More than enough for my little system. Soldered connections are more prone to breakage than crimp fittings though. To prevent that, I will isolate and reinforce the connection by using Instamorph. An alternative is using a hot glue gun.

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