2007 building logs

Jan 07 New work on boat

Happy New Year to all. Now that the hulls are completed, I can now look forward to new things to do on the boat. This makes the work more challenging and more fun as new tasks mean having to think about how things are done as opposed to the fairly tedious nature of making the second hull. As I wont be joining the hulls for a while, this month I will start to fabricate parts of the boat that I would otherwise have done later, such as the forward beam, the daggers and cases and the rudders and rudder boxes. I am sure the forebeam and the daggers will keep me busy all of January.

6th Jan 07 Forebeam mold

The forebeam is the front span that joins the bows of the 2 hulls and is the place where the front of the trampolines (and catwalk) is attached among other things. Because we have decided on the bi-rig we wont need to make the striker or any of the bracing, webs and composite fittings that would be needed with a standard rig with a forestay. About the only serious load bearing fitting will be the eyes for the anchor bridle and storm para-anchor and the anchor chain roller. We will still build in all of the strength of the original design but skip the un-needed fittings.

The forebeam is strip planked. It is shaped like a wing with a blunter rounded leading edge and sharper trailing edge and is curved so that it is higher in the middle by about 200mm. It is made by strip planking into (or over) either a male or female temporary mold but the kit provides female bottom half and male top half mdf molds which makes life a lot easier. In the past the plans provided the profile of the beam on paper and you had to cut the molds yourself from them. The molds are now cut with a cnc router the same way that the duflex panels are cut.

The only requirement for me is to make legs so that the curve of the beam is accommodated by the different height of the legs. The plans tell you the heights and spacing of the molds. The first step is to mark a line at the same place on each mold so that you can run a stringline to line them up. Then make the legs at the correct heights and attach them to your table so they are solidly in place. I used two 3 meter timber planks (the same ones I used to stand on when making the hulls) joined in the centre by screwing a plate of mdf to them. Then it is a matter of attaching the legs with the molds attached in the correct positions and making sure they are plumb, square and straight with a level, square and stringline, just as I did with the bulkheads. There are 4 planes that need to be adjusted. Everything is screwed in place so it can be moved if needed.

Once the bottom half of the beam is made (glued and glassed) using the female mold, the male molds are used to create the other half and they are glued to each other (with a web frame inside for added strength) and glassed shut to form the finished beam.

The cedar planks need to be scarf joined so they are long enough to make the beam. I need a 6.2 meter beam and the planks are between 3 and 4 meters. A scarf joint is a stronger joint than a standard end to end butt joint because the surface area of glue is much larger and also spreads the breaking strain along the plank more effectively making for a much stronger bond. The longer the scarf the stronger the join. I can easily cut 50mm scarfes using my circular drop saw but the plans call for a 10:1 scarf, and the planks are 10mm thick so the scarf should be 100mm. I can cut 100mm scarfes but they must be cut one at a time rather than both planks together which is more accurate as the cuts are made at the same time at the same angle. I did manage to make 5 fairly good 100mm scarfes (if the cuts are not at exactly the same angle the 2 halves wont meet correctly) and made 3 50-60mm scarfes for the other 3 planks for this half. (there are 8 planks in each half, I will make the other 8 after I have glassed this half)

As our beam wont be subjected to the same forces that a standard rig has I am not too concerned about having some of the scarfes at 50-60mm and when I plank the beam I will stagger the joins and alternate the planks with the shorter scarfes to ensure there are no weak spots. In the end the planks are again just a core for the glassing that will take place over them so I shouldn't have any concerns with them.

Once I had cut all of the scarfes for this half I glued and clamped them together. I used offcuts to spread the pressure of the clamps along the joins.

Tomorrow I will re check and re adjust the legs and molds, clean up the glue on the planks and start planking. I will dry fit them first, and screw them into place, number them, remove them and re-attach them with glue. You can also fit them with spacers (usually icy-pole sticks) and glue them after but I think I will glue as I go after a dry fit.

6th Jan 07 Forebeam half glued

Today I plumbed the legs properly and screwed the planks down for the bottom half of the beam, and glued them so that tomorrow I can remove it from the jig, and start sanding it ready to glass.

I started the planking at the top of the leading edge of the beam and worked back from there. I placed a screw into each leg. On the first plank I pre drilled the holes through the cedar strips but realized that I could send the self tapping screws through the cedar into the mdf molds without pre drilling (I thought that without pre drilling the cedar may split but this didnt happen). This saved some time as in order to drill the cedar I first had to mark the position of the mold then move away, drill the hole and return it to the mold. I quickly attached the 8 strips. My original intention was to mark the planks, remove them and re attach them with glue applied to each strip as I went.

But I quickly saw that the joins on the inside of the beam were very tight and not much glue would penetrate and I decided I would carefully turn the whole thing over and glue from the other side where the plank joins are more open. In the original idea I would have had to glass in between the screws, then when that was set fill the holes and glass the voids, this way I will be able to remove the screws before glassing, the glue will hold the beam in place while I run the glass in 1 continuous length of the beam. The only downside to this is that I had not yet applied any sticky tape to the molds (I intended to do it after I removed the planks for gluing in my original method.) It meant I had to be careful not to get any glue touching the molds. I can back fill this with glue later.

The advantage of making the jig on the planks the way I did was that it was very easy to turn over, and with the planks all screwed down it was fairly stable. Once upside down I had the advantage of gravity and the open side of the plank joins to fill with glue. The result will mean that tomorrow with the glue set I can turn the whole thing back over, remove the screws, fill the holes and start glassing the internal joins. Once this is done I can turn it over and glass the outside. I think this will result in the half becoming a stable rigid shape faster and more reliably.

I applied the glue using a filleting scraper. First I brushed resin into the joins so that it could seep into the grain of the timber, then I applied the glue and pressed it down into the joins stopping about an inch from each mold. Once I had glued all the joins I used a piece of peel ply to wipe away any excess glue making the surface a lot smoother for sanding and sealing the timber with glue. I was going to use just any rag but was scared of rubbing on any potential contaminant and decided better to be safe than sorry.

So except for glassing I have half a forebeam. Does that mean I have a two-beam? I know, I should stick to boatbuilding!

9th Jan 07 Uni glass cut for beam

I had to cut some glass from a roll of a different type of glass, uni directional. In places where there are particular loads uni directional glass has all its strength woven in just one direction instead of 2 directions in double bias (or 3 in triaxial) glass. The weight of the glass is 450g per square meter but would be twice as strong as equivalent weight double bias in the direction of the weave but half as strong as the double bias across the weave.

I used my temporary cutting table (sheets of mdf, over sheets of duflex on 44 gallon drums) and hauled over the 50kg roll of 450g uni glass. The roll is 1220 wide. I rolled out the 6.6meters I need and cut it off the roll (I think the roll is 50 meters). I then marked out 300mm and cut if off the length, then I repeated the process making another 300mm width length for the top half of the forebeam and leaving a 620 width that I will use on the outside of the beam. I rolled each of the lengths up ready for use.

14th Jan 07 Forebeam glassed

I didn't manage to get anything done on the boat yesterday due to having to help Jo get a waterbed and then moving stock from the warehouse to the shop until mid afternoon by which time I was exhausted so I didn't have the energy anyway.

Today I glassed the forebeam with 1 layer of 450g unidirectional and 1 layer of 450g double bias. I started by sanding the inside as smooth as I could get it and then vacuuming it clean. I decided I would also fill some of the uneven heights of the planks but that I could then glass onto it wet. It is not so important how it looks but still important the glass has a smooth surface to adhere to. Once the gaps (and screw holes) were filled I started with the uni, I rolled out about 3 meters of it and started to wet it out with a brush. After a while I realized it was easier to pour out some resin and spread it with the brush. I thought at first that I was using too much resin, but as I am going to place the next double bias glass onto the wet uni I was not so concerned.

Once I had finished the uni glass wet out, I immediately started on the double bias glass wet out directly on top. I didn't have to cut this from a wider roll as I have a 300mm roll of 450g double bias so I simply measured off 6.4 meters and cut it to length and rolled it up ready to apply.

The wet out process was identical for the double bias but having an already wet surface below meant that it was faster and used less resin to wet out. The double bias is also much easier to wet out than the equivalent weight uni, I guess because the strands of glass on the double bias are much thinner than on the uni.

Now that the beam (half) is glassed I can start on cutting the 12mm ply web. I need to shape it to the shape of the curved beam before glassing it in. I have the shape from the plans, so I will draw it onto a template of cardboard, which I can check for fit and add or trim where necessary, then once satisfied I can transfer that to the ply. I have a 2400 x 1200 sheet of ply so I will need to cut that down to 3 planks of 400mm each and then scarf join the 2400mm lengths into a 7200mm length. I can then cut out the curved shaped web to the same curve as the beam top and bottom, top is easy once I have the bottom as it will be a uniform height so have the same curve as the bottom. Then once cut I glue it into the beam and cove and glass it in place. Then I can glue the top on once I have that made.

It should take me another couple of weekends to finish the beam. So basically the rest of January.

18th Jan 07 Forebeam web cut

The forebeam is hollow and made up of 2 strip planked halves glued together. To provide extra support in the middle there is a plywood web. The web is cut from a sheet of 12mm ply and has to have the curve of the beam cut into it so that it can be glued on its edge, it cant be bent to fit on its edge. I am cutting it out of the edge of a 1200mm x 2400mm sheet. In order to cut the correct shape I decided to make stencils out of 3 sheets of 3mm mdf that came as packaging material with the kit.

You might think that cutting the mdf stencils is an extra set of cutting, why not just mark the ply and cut that. I decided that the mdf was free but the ply is expensive so it was worth the extra cutting to get it right. Also because I want to cut the 3 pieces of ply from the long edge of 1 1200mm x 2400mm sheet but that I have 3 sheets of mdf it was far easier to join the 3 sheets of mdf and mark the full length of the beam. Then I could use the 3 stencil parts to mark just 1 edge of the ply sheet and cut all 3 pieces to the correct curve without having to mess around with marks each time I have cut a piece off. In fact I think doing it this way was actually faster, the mdf took about 10 minutes to cut and then it took about 2 minutes to use the stencils to mark the ply. To mark the stencil, I transposed the measurements of the beam onto the sheets and using a piece of cedar strip I marked the curved shape. I then used a jigsaw to cut the stencil. Once I had the stencils and made sure the curve was correct by dry fitting it to the beam, I transferred the shape to the ply and cut them out with a jigsaw. I then dry fit them also and trimmed here and there where my jigsaw cutting drifted a little from the line.

 

With the ply web dry fitted to the beam, I am ready to glue it in. I will do that on the weekend. I have decided that instead of a scarf join to make the 3 pieces into 1 long web I will butt join them with ply plates overlapping the join on either side. This should be stronger than a scarfes and also provide extra surface to glue the top of the beam to. I also need to run a stringer for added gluing area along the length of the web and for this I will use either more ply cut to the same curved shape or cedar strips bent to shape. To glue the web in I will glue the 3 pieces together first (probably tomorrow so they are set for the weekend) then glue the whole web in. Once it is set I will run a cove along both sides and glass it in. Enough glue and I should be able to fill all of the voids made by my crap jig-sawing!

Then I start on the top and cover up the evidence!

20th Jan 07 Forebeam web glued in

I glued the ply web parts together yesterday so that today I could glue the web into the beam. I simply applied some glued to the plates and screwed it back together to set overnight. It took less than 15 minutes to mix the glue and screw the plates back on. Today I removed the screws and then placed the now one piece web into the beam. I marked the correct position and screwed it into place. I marked each side of the web so that I could see where I would need to place glue. I then removed the screws again and piped (remember the piping bag method I used on the hulls) glue along the lines ready for the web. I placed the web over the glue and screwed it into place. I then smeared the excess along with my finger, filling any voids and creating a small cove either side of the web.

Once the web is set it will be coved and glassed in but before I do that I will plank the top half of the beam. To do that I have mdf molds that sit in the bottom half of the beam either side of the web, but in order for the molds to sit in place I will have to make the top half before I cove and glass (or else I have to take a piece out of every mold so they sit over the cove). I have glued the planks with scarf joins ready to plank tomorrow.

I will be gluing the top half of the beam onto the bottom half by gluing the first plank to the edge of the bottom front plank, this will save me having to fill the shape in at the front in the void that would be left if I start planking from the corner edge the way the back will join. I will then round off the sharp front edge with a router before glassing the beam. At the back edge I will be gluing in a 1/2 inch (12mm) electrical conduit. It fits perfectly as does the planking, the back plank finishes corner to corner if I start the front one flush along the face of the front bottom plank. I couldn't have planned it better! The electrical conduit is for the trampoline to attach to and fills the void perfectly. After I have glued it in I will fill and sand it smooth ready for glassing.

21st Jan 07 Forebeam top planked

Today it was a 40 degree C (about 104 F) day. Regular readers will know that on really hot days my work rate halves. And I also cant sustain a long work day. To compound matters Jo and I woke early and went for a walk along a local beach and I forgot to wear a hat and I think I got a little sunstroke. Anyway I managed to get the temp molds in place and planked the top of the beam. I had also intended to glue the planks together so that I was ready to glass it inside next but the heat was too much for me to continue.

I also trimmed the ply web so that it is the width of a cedar strip (12mm) shorter than the temp molds so that after I glue a stringer of cedar to the web the top face of it will be at the height that I have planked to. The purpose of the cedar stringer is to increase the surface area that the top can be glued to. The top will be glued to the stringer on the web and at the front and back. In the trimming I also cleaned it up so that it is a lot more even than it was so that the stringer will have a better surface to adhere to.

Once I had the ply web trimmed I attached the temp molds to the beam. I simply used sticky tape. This held them in place while I screwed the planks to them and also ensures that the top beam can't stick to the temps when I glue it. Then I can easily remove it, turn it over and glass it inside in the same way that I did with the bottom of the beam. I can sit it in the jig to do that but I will have to rearrange the legs. I may just sit it on the drums.

As I mentioned yesterday, I started the planking with the forward edge of the first plank flush with the front face of the first plank on the bottom half so that they glue to each other and the front edge of the beam will be the rounded edge of this first top plank. I will round it with a router. I then planked the next 2 planks in the normal way. So that the planking ends in the exact position I need it to so that the gap that is left is the correct size to glue the conduit into I planked the last plank next and then worked back towards the middle, spacing the planks as I went to ensure even spacing between them. These planks were not as tight up to each other as they were in the bottom half of the beam but it wont matter. Glue will fill the gaps and then the glass on both sides will complete the structure and such gaps wont matter, in fact some builders use icy pole sticks to deliberately keep the planks apart so that glue can properly penetrate the joins.

The beam is now the shape and size it will be when complete. It is satisfying to build another part of the boat and have it looking like it should and like all the other beams out there on Schionning cats. This was my first attempt at strip planking and it has worked fairly well and it was another of my fears before starting. I am sure most first time builders reading will be a bit daunted by strip planking so it was nice to pass another hurdle.

As I didn't glue the planks today I may get a chance to do that tomorrow. This is a relatively quick job, maybe an hour. Then once it is glued it is time to glass the inside.

22nd Jan 07 Forebeam top glued

As predicted, it only took an hour to glue the planked beam top. The method of gluing is quite simple, I trowel the glue in between the planks and remove as much excess as I can from the plank faces so that I don't have as tough a job later sanding it smooth for glassing.

Tomorrow I will remove the screws and turn the top over ready for glassing. I may even get the glass in.

23rd Jan 07 A fun diversion

I virtually had a day off work (job) today and whilst I was building a boat it wasn't MM. A friend and I are making 2 dinghies out of scrap duflex. But first a little background. One of the great things about building a catamaran is the camaraderie among builders and ex builders. One such ex builder is a guy I met here at Gosford. Warren has built a 40ft strip planked Crowther cat and I saw his cat tied up at the marina at Gosford so I introduced myself and told him what I was building. We instantly struck a friendship and Warren invited me on board to see his boat and has visited my shed to see my progress.

We had a plan to make Warren another daggerboard at my shed after he had one stolen (off his ute) and in the process show me how they are made and get me started on mine but that plan was shelved in favor of another project. The waters around here abound with oysters and they grow on any jetty pylon. The problem with this is it punctures inflatable ribs easily. Warren has a rib that has more patches than original rubber surface and is finally sick of repairing it. We have decided to build 2 dinghies based on the shape of a rib. Rib's great feature is their stability. When someone gets into one it doesn't tip at that point and become an unstable platform. like a V bottom boat would and doesn't have the drag through the water that a flat bottom boat would have. Like most cats it should have stability and be easily pushed through the water. That should mean good speed with a small outboard and made out of duflex it will be strong and almost indestructible and fairly light. Besides how could we have a cat and a mono! One of the great things about this plan is that I get to practice techniques that will come into play in the building of the MM. The other great part of this plan is we are making them out of offcut duflex.

Warren drew the plans (well you couldn't really call them plans, more sketches on the back of napkins!) and took the design from Thunder Cats, a rigid inflatable type boat raced in the surf. There were a couple of important measurements such as the angle of the keel of each hull to ensure the boat easily planes and the curves of the hull in and up to form the pointed bows and the length and beam overall but otherwise it was a lot of what looked right by eye so far.

We started by scrounging all the offcuts we could use to make the various boat panels. We needed to glue some panels together here and there but we have managed to find enough offcuts to make 2 dinghies with a length of about 3.5 meters and about a 2 meter beam. The first panels we made were the inside panel in each hull and we had to make 4 identical panels. These are the longest panel on the boat. We then cut 4 mdf temporary bulkheads and 2 duflex bulkheads and attached them to the first hull panels. The bulkheads were made to the exact size and shape we wanted the hulls to be.

We had to join 2 pieces together for the inside hull panels on the second boat. We will let them set overnight and join the bulkheads to these panels in the morning. One of the panels we made needed us to make our own z joins which we did with a router (the other offcuts had the factory z joints in place).

Next we started making the keel panels. We knew the width at the stern to about mid boat that we wanted it to be at the stern based on the size of that face on the bulkheads but the shape of the panel as it narrowed into a point we made up as we went along and was decided by eye to an extent.

We attached the keel panel to the bulkheads and then marked the panel for scoring. The scoring is a method used to curve the flat panel over a short distance. A place where this occurs on the main build is on the bridgedeck at the front where it curves up to the deck. You run a circular saw (or router) through the inside glass and the balsa. The tighter the curve the closer the spacing (and frequency) of the scores. There is no formula for the spacing as far as I know, you just learn it by trial and error so what better place to trail it. Once you have appropriately scored the panel and achieve the curve you want you fill the scores with runny glue and set the curve to the panel and let the glue dry. When it is dry the panel will hold the curve and you can glass it to seal the panel and return the strength to the panel.

Once we had scored the panel and attached it to the pre shaped bow of the inside hull panel we had an idea of the shape that the final outside hull panel should take and also the shape that we needed to cut the keel panel to at the bow to create the sharply pointed bow shape we were after. We marked the panel with a line then carefully took the scored panel to the bench to cut. In order to move panels that have been scored you really need to clamp a rigid panel onto the scored section so that it cant break. We cut the panel to shape and then used it as a template for the other 3 matching panels for the rest of this boat and the other boat.

The middle picture above shows the starboard hull curved to show the upward curve of the keel but before we shape the inward curve of the hull. The right hand pic gives an idea of the overall shape of the dingy based on the beam set and the shape of the bulkheads. This may be a little too wide we will set that tomorrow when we make the transom bulkhead and the forward bulkhead. We have glued the curve of the starboard hull and will glass it tomorrow. We will also start making the other 3 hulls (the port hull of this and the 2 hulls of the second boat).

I will not add the time spent on this side project to my build hours as it is not related, but so far we have each spent 6 hours. So 12 man hours but we will be making 2 boats. So far this little project has gone very well and should result in a fun little dingy each for Warren and I.

Once all the hull panels are cut and glued together (the top of each hull last) we will cove and tape (glass) them and then set the 2 through bulkheads and also tape them before finally setting the deck. We can cut some hatches into the hulls, I am a fan of having the outboard gas tank inside a lockable hatch so it cant easily be stolen. We also have to set the transom height and add bollards and other attachments before fairing the hulls ready for a final finish. We will give the hulls and underside of bridgedeck a couple of coats of resin to fully seal it but I am not sure yet what we will do about painting them. We hope that this project only takes us a week or 2 before at least the first boat is on the water.

24th Jan 07 More work on dingy

We spent another 6 hours working on the dinghies today (so in all we are up to 12 hours each). We have managed to cut the 2 rear transom bulkheads (one for each boat) out of 25mm duflex. We have the inside hull panels for the second boat cut and also the temp and small bulkheads We also have the bridgedeck for one of the boats cut, and we have glued the 2 hulls together with the rear bulkhead on one of the boats. We have not cut the side panels or top panels for either boat yet. So that just leaves the bridgedeck for 1 boat and the outside and top hull panels for both boats and the forward bulkheads on both boats.

We are planning to finish the first boat before assembling the second boat but we are cutting the panels so that we are ready to go. The reason for this is that if there are any mistakes or adjustments to be made we can make them to the second boat rather than making the same mistakes on both boats. We are also keeping the panel templates so that if we want to make another it will be a simple task.

So on the first boat we joined the inside hull panel to the keel and bulkheads on the port hull including the scoring curved bow. Once it had set a little we then had the 2 hulls to the same stage, we clamped them together to mark the rear bulkhead transom slot. It is canted backwards. We have to be sure that both slots are in exactly the same position (angle of cant and position) on each hull. With the slots cut we glued the bulkhead in and plumbed the hulls, ensuring they were square to the bulkhead, level and running parallel to each other. We then braced the hulls to ensure it sets in the right position. 

 

With the hulls joined we cut the bridgedeck for the first boat. We have yet to decide if it will be easier to attach the bridgedeck before or after the forward bulkhead. We will cut that on Saturday out of 19mm duflex offcuts. We have used 16mm duflex on the hull panels and 25mm duflex on the rear transom bulkhead. The bridgedeck will be scored and shaped upward about 3/4 of the way and then a similarly shaped panel will start at the forward bulkhead to the front of the deck and curved down to meet the lower bridgedeck. The nose cone space that this encloses will become the anchor well with a hatch cover and be self draining. We wont attach the side hull panels until after the bridgedeck is in as it is easier to get to the inside of each hull to run the holding screws into the deck (and remove them again).

After the sides of the hulls are in place we will start to glass the joins inside and outside the hulls. We will cove the joins inside before taping and on the outside we will have to take the sharp edges off the hulls with a router to glass effectively but we actually want a sharp keel line on the hulls so we may rebuild that sharp edge with bog over the top of the glass.

Then finally once this is done we can make the hull tops and glue them down before glassing them on. Then we will start on the fairing. Yes the fairing. Oh how we love it. We may add a small chine (about 100mm) to the top outside hull side to top join to give the hulls a more rounded look but it is extra work and purely aesthetic so we have yet to decide that. Then finally we will fit all of the deck hardware we need and any hatches we may want cut into the hulls and hatch covers made and re attached. The last thing we will do is to decide how to actually finish the boat. We will resin coat the first boat and then test it. Then we may paint it. The final picture above is the plans we are working from. Yep that's it!

26th Jan 07 Back on the big boat

Happy Australia day to all the Australian readers and to those overseas, well you can always migrate to the greatest country on earth. This morning Jo and I went for our morning walk to Gosford Marina and visited Warren on his cat. He invited us to spend some of the Australia Day celebrations aboard his cat. That consisted of a sail past regatta and water bombing other boats in the bay, then Warren was able to raise his huge ex Australia 2 Americas Cup spinnaker with the boxing kangaroo on it (I hope to have a photo soon), which was a highlight. Then after watching some of the raft races and other fun we left Warren and his other guests on board who were going to sail the bay the rest of the afternoon because after spending the morning on someone else's boat I wanted to get on with mine. The sooner I finish the sooner we are on the water on days like today.

So I returned to building MM today. I glassed the inside of the top half of the beam. Because the planks were spaced a little less tightly than the bottom I had glue oozing between the planks and set hard which I had to sand down before I could glass. I did this and then prepared to glass. I still had an uneven surface with some planks a little higher than others so rather than keep sanding the rounded area I decided it would be better to smooth it out with filler. I decided it would be better to use glue rather than filler for strength and settled on a mix with both microspheres and microfibres in it. The strength of glue with the viscosity and consistency of filler. I was pleased with the mix.

My method was to apply the filling mixture to about 2 meters of beam, then wet out the uni glass to just before the end of the mix, then fill 2 more meters then roll out another 2 meters of uni glass and wet it out. I continued with this until I completed the uni wet out, then applied the double bias and wet it out rolling out a couple of meters at a time and sqeegeeing the excess resin as I went.

The first layer of uni glass took about 40 minutes to wet out, the combination of filling and wetting out taking a little longer.

The second layer of double bias glass took about half the time of the uni, so about 20 minutes to apply. Add to that about an hour of preparation, and it took about 2 hours to glass the inside of the beam top. Tomorrow I will start around 9 am and hope to get the ply web coved and glassed in by about noon, when Warren and I will return to the dingy project. Then on Sunday, I may be able to glue the 2 beam halves together.

27th Jan 07 More work on beam

I didn't get to do any more work on the dingy today but I did do more on the beam. I coved and taped the web in place and glued a stringer to it, ready to glue the top on. Before I do that I will attach 2 stainless steel u-bolts that will be the anchor bridle points.

I bought the u-bolts today. It was the first spending I have done for the boat in over 6 months except for the odd consumable (drill bits, sand paper, etc). The last boat purchase was the highbuild I think. I could have bought galvanized u-bolts the same size (boat trailer winch bolts) for a third of the price but opted for stainless steel because it is so much stronger than galv steel and the constant rubbing of rope against the eyes would probably wear the coating away on the galv where as stainless is not a coating and is stainless all the way through. In the end our boat will be held by these 2 bolts so the stronger the better!

The tapes (100mm double bias) for the web were applied directly to wet coving and wet out manually (paint brush) in the same way I have for the other glass in the beam, by rolling out a couple of meters, wetting out and rolling out a couple more. The coving was also applied in the usual way, by spreading the filler along the join with a rounded spatula.

After I had attached tapes to both sides of the web and resin coated the rest of the ply to seal it, I smeared thick glue along the top of the ply and attached a cedar strip along it and screwed it down. I then smeared the excess glue that was squeezed out into a cove along both sides of the join with my finger. When this is set (tomorrow) I will remove the screws and then all I have to do before gluing the top of the beam to the bottom will be to attach the 2 stainless steel anchor eyes. I will build a timber pad for each and glass them into the beam and drill out the holes from which the eyes will exit the beam so that the 2 halves still meet cleanly for gluing.

Then I will glue it together. Maybe I will also get a little more done to the dingy.

28th Jan 07 More work on dingy

Apart from a dry fit of the top to the bottom of the beam I didn't do any work today on MM. I will try to fit the u-bolt into a timber pad and glass that in tomorrow. But today, Warren and I did some more work on the dingy.

We decided we did want to add a chine. It added a bit of work (about 4 man hours, 2 hours x 2 people) but only on the first boat because we had to work it all out and establish the size and shape of each panel. The extra chine really does make the boat look better. It takes the hard edge off and softens the look of the boat.

We started by cutting the chine into the bulkheads (including the temps). We then made the now smaller hull side panels and scored them for curving. I remembered today that the proper terminology for this is Kerfing. The scores are kerfs. I had some fear about kerfing. I thought the kerfs had to be properly placed on the panel and that there was some formula for working out where they go. Not only is it not so scientific, you can just run saw cuts at guessed spacing and angles and you should be able to form the curves you want. Once you have kerfed the panel you can dry fit it and if needed add more kerfs. Once you are happy with the curve, take the panel off, fill the kerfs with sloppy glue, be sure to get the glue deep into the cuts and glue it to the bulkheads. Remove the excess glue and you have done it. A kerfed panel.

Once we had the hull sides on the boat we started to shape the new chine. We made a template from the 3mm mdf and trimmed it to size to make sure that we cut the correct size and shape chine panel. Once we had it right we transferred the shape to the appropriate offcuts and made our chine panels. We made them oversize and trimmed them with a plane just to be sure, but on the second and any subsequent boat we can cut it exactly to size and know that it will fit. We also made some modifications to the back of the hulls to give them some shape by tapering them down from the top. We didn't alter the length of the hulls at the waterline but we did shorten them at the top.

As with the hull panels on MM we used blocks to pull or push protruding panels into line with each other. In this case we only needed 3mm mdf to pull them into place.

With the hull sides and extra chine glued onto the boat the next step is to glue the forward bulkhead in and then the bridgedeck (floor) or visa versa. It may be easier to glue the floor in first and then fit the bulkhead to the hull. After that we will start taping the joins from the inside of the hulls before finally gluing the hull tops on and taping the joins on the outside of the boat. Today we spent another 6 hours each on the boat for a total of 18 hours each so far.

31st Jan 07 More work on dingy

Today we managed to tape the joins on the inside of the rear buoyancy compartment. We also managed to clean off the glue from some the joins ready to glass them. And to glue the floor into the hull. That is the most visible of the work on the dingy.

I coved and taped the bulkheads and hull panel joins in the rear compartments. This is the compartment bordered by the transom bulkhead and the internal bulkhead. This compartment will be sealed for buoyancy. The middle compartments between the internal bulkhead and the forward bulkhead will become storage compartments for the petrol tank on one side and life jackets etc on the other side and will have hinged hatches. The bow compartments will also be sealed for buoyancy. The hull overhang behind the transom bulkhead will also be built into a buoyancy compartment to stop the bow lifting and to give the boat higher floatation at rest to counter the weight of the outboard. We will also have an anchor locker in the curved bow section of the bridgedeck in front of the forward beam bulkhead. We haven't quite figured out how we will hatch that one yet.

We then turned the hulls over and trimmed the overhang of the hull side panels. They were made slightly oversize. We will be able to make the second boat more accurately so that such trimming wont be necessary or at least not as much. Warren used an electric plane to trim the bulk of the overhang and then used a sanding disk with a soft back to sand the rest down smooth. We have used a router to round the sharp edge off the keels and will sand them smoother before glassing. We will also need to round the keel to outside hull panels a little rounder, I will use the random orbital to do that next time I work on the boat.

To fit the bridgedeck we marked the line from the bottom of the transom bulkhead along the hull and screwed an mdf board into each hull as a platform for it to sit on. We then dry fit the bridgedeck and marked the kerf lines for the curve we wanted it to take. We then removed it and cut the kerfs and glued them and also the edges of the panel and refit it. We then screwed the panel in place through the hulls to pull the join tight. We then removed the mdf panels and left it to set. There was not much more we could do as we couldn't move the hull until the bridgedeck was set. So we called it a day and relaxed with a couple of drinks to enjoy the achievement so far. We spent another 4 hours on the dingy today for a total of 22 hours each. It does not equate to 44 man hours on the boat as we are building 2. I will calculate a build time once we have finished the second boat.

I only managed 32 hours on MM this month but have also done about 22 hours on the dingy project so in all I did about 54 hours work, which is not a bad month.

February will be an exciting month. We should have both dinghies launched, I will finish the forebeam and get a start on the daggerboards and start to finalize where I will move to in March.