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Bridgedeck Construction
This is where you can get more information on the construction and fitting of the cross beams, the building of the bridgedeck
coachroof and the construction of the cockpit.
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The polytunnel looks rather empty after the hulls have been moved out, but we are rapidly filling it up. Owen is working on the coachroof jig and Mac is working on the aft beam. The Jig is a facsimile ( see this detailed drawing) of the hulls on which the coachroof will eventually be fitted. If this was being done in a boat yard, you would probably be building the coachroof on the actual hulls, but this can't be done with Swing Cat since it would create too wide a load for transportation. Top of Page 
The frames are in position and 3 out of the 5 frames have plastic strips stapled to them ready for strip planking. The plywood panels are cut and fixed in position; they will be glued together with thickened epoxy and the joins covered with 2 strips of glass. Top of Page 
The planking is almost finished. The Plans call for the planking/coachroof joint to be reinforced with strips of glass/epoxy. We are worried about taking out all the screws holding the front of the planking at once, because there is a lot of curvature, and hence strain, at this point and we doubted the ability of Gorilla Glue to hold it all together. That is why Owen is following a strategy of removing screws from non-contiguous areas of the join, leaving others in place; sanding and glassing therefore proceed in alternate areas, as you can see. Top of Page 
Here you can see some flexible solar panels. I am just trying them out for size. Each panel is rated at 68W, very similar to the semi-flexible panels installed on the hull decks, which could not be used here because of excessive curvature. I am relieved to see that there is plenty of room, forward of where the mast footing will be. These panels are considerably cheaper than the GB-Sol semi-flexible solar panels. They are also built using amorphous silicon, rather than monocrystalline silicon, so it will be interesting to see how the two types compare in practice. Top of Page 
We are putting on the last length of glass. The groove inbetween the first two lengths has been filled with epoxy thickened with colloidal silica. When the screws holding the front of the coach roof were removed, it sprung up leaving a gap of about 4 inches between it and the jig. We had to screw it down and glass over the screws - we will remove the glass covering the screws when it has gone leather hard, so we can remove them when hard. I hope the front of the coach roof will then stay put - otherwise we will have difficulty fitting the coachroof to the hulls later. Top of Page 
Turning the coachroof over on a wet, cold, grey, winter's day. It is still quite flexible, but not heavy. We had six people, but four could have done the job. The main worry was it being caught in a gust of wind since it is so large and flat. Top of Page 
Glassing finished. Notice the extra glass over all seams. The glass strips across the bridgedeck are allowed to overlap here since the overlap will not be seen once the headlining is up. The overlap is in the same place the groove is cut on the outside of the bridgedeck, so giving extra reinforcement at that point. Note also the cradle the coachroof sits in - this gives a lot of support while moving around inside. Top of Page 
While the wet resin on the coachroof was curing, we could get on with the cross beams. You saw the aft beam being constructed earlier. We also did the mast beam. Here is the bridgedeck beam which forms the leading edge of the bridgedeck. We chose to make this out of douglas fir sandwiching a strip of plywood. Lengths of wood were scarfed together and all joins were staggered. Top of Page 
After several hours aligning the hulls, holes have to cut in 3 hull sides so the main beams can be slid in from one side. The holes for the aft beam are shown here. The top of the beam needs to level with the top of the gunwale, but this would mean cutting through the rubbing strake which I could not bear to do; therefore the beam is inserted and then lifted into place. Unfortunately, the holes on the inner hull skins ended up much bigger than the beams themselves, because of having to get the best alignment with the bulkheads as well as having to satisfy my requirement not to cut the rubbing strake. Top of Page 
The butt joints on the inside of the hull give something solid to attach hull pieces to from the outside. In this way, each beam is surrounded by a solid lamination of epoxy and marine ply approximately 30mm thick - a good basis for the further reinforcement to come. Top of Page 
The bridgedeck coachroof is a bit to heavy to manhandle into place, so here a crane is lifting it off its cradle. Top of Page 
Perfect alignment is possible with little effort - you have to have worked out your hand signals with the crane driver though. Top of Page 
... it actually looks like a catamaran. The coach roof fitted perfectly across the hulls, but it looks as if there is going to be a large gap between the front of the coachroof and the decking between the hulls. More on this later. Top of Page 
One of the benefits of being in a Shipyard is that there is always a lot of interest going on. Here, being refitted in the dry dock, is MV Balmoral.This used to ply between Southampton and Cowes, on the Isle of Wight, in the 50s and 60s when I was living there as a boy. Top of Page 
Another wet-day job is to make the recessed hatch coaming into which the flush-with-the-deck hatch covers will fit. The moulds for these are shown here upside down. Bead and cove strip plank is glued to make the required shape and then covered with gaffer tape - which I had previously determined did not stick to epoxy. Four layers of 300 gm/sq m biaxial cloth tape were then laminated together to create the coaming. Top of Page 
Wedge shaped pices of Douglas Fir have been fixed to the foredeck to support extra 12mm plywood panels which will close the gap and make the bridgdeck watertight. Note the bits of copper pipe sticking out of the lockers. These drain the locker coamings. Only one per locker is shown, but there will be two per locker, positioned in the two lowest corners. They won't guarantee to keep the lockers dry since they could be overwhelmed by a big wave. However, the lockers will also drain from their lowest points - to cope with gas leaks in the gas locker and wet anchor rodes in the anchor locker. Top of Page 
However, we noticed a "tear" stain beneath the eye-shaped patch where the netting beam had been inserted. As we watched, a globule of water formed underneath the eye and Swing Cat shed a tear! This was on a hot dry day and the inside of the port hull was bone dry - yet there was water coming out of my boat! I was tempted to re-name the boat after a religious icon, claim a miracle and charge for admission! It turned out rain water was getting into the horizontal mast track in the beam, running along it and escaping at the ends into the beam itself. Once inside the beam it was trapped. It was a good job the patch-up job was imperfect so we spotted it! Top of Page 
The net is tensioned from each corner and by lacing along each side. This means the net is held in place by 8 individual pieces of rope so, in the event that one fails, the net will not collapse catapaulting someone into the water or, worse, onto the hard. A014 sail slides (obtained from Bristol Sails) are used in the netting beam and lacing eyes are used to give a total of 108 attachment points to take the load. The lacing eyes were screwed to the hulls with the help of epoxy - for details see construction_details.pdf. The lacing chord was 6mm braid-on-braid for strength and low stretch. Top of Page 
We have become more sophisticated in our casting. Gaffer tape works but one gets a cleaner cast, which comes off the mould more easily, if a mixture of wax and PVA (Polyvinyl Alcohol) are used as release agents instead. If the mould was very smooth - i.e. finished using 400 grit sandpaper or finer - just wax would do but the rougher mould of our construction required a liquid plastic on top of the wax as well. Top of Page 
Mac is now back at work after an absence of 16 weeks - he fell off a ladder and badly injured his back. He is just working half days for now
so he doesn't over do it. He is installing drains in the corners of the recessed coamings to direct the water from the locker lids to the
cockpit drains. You can just make out the copper pipes being used for this task.
Note that the aft beam now has a box-like superstructure added on top of it. One can just make out the bolts sticking out of it. The bolts secure the mainsheet track. The construction of the mainsheet box is an example of how much care was taken to ensure that bolting deck hardware to the boat did not allow the ingress of water into the plywood core. Top of Page 
The race is now on to get the mast erected before Christmas. The first step is to laminate together a post about 4" by 6" in cross-section and about 5' long. This is the "king post" which will fit between the mast beam and the coachroof and will take the compression load of the mast. Laminating it using epoxy out of many bits of good quality Douglas Fir makes for a very strong result. It needs to be strong as the compression load is about 5T. Top of Page 
To the left of the king post is a newly installed wood burning stove. A twin wall flue is used to go through the deck to prevent the glass/resin/cedar composite from getting too hot. The stove is from Windy Smithy,who also supplied the flues, the cowl, two deflector plates and the flashing - in fact everything necessary for the installation. The wood burner is the Louis model with a rated output of 4kW, easily enough to keep us warm through the winter! There is a fiddle rail going around the hot plate so we can boil a kettle, or heat up some food, with out the risk of it sliding off. The two aluminium deflector plates, painted black, were mounted 13mm away from the bulkheads to create an insulating air gap. Top of Page 
An air rivet gun makes short work of riveting the "gull striker" to the netting beam. The mechanical alternative of a lazy tong riveter would struggle with the 18mm by 6.4mm Monel rivets. Monel is higly resistant to corrosion. The stainless steel of the gull striker has been insulated from the aluminium of the netting beam with a thick layer of polysulphide, to prevent galvanic corroision. Top of Page 
Here is a view showing the wire passing over the gull striker....
A view of the masthead showing: the electronic wind speed & direction indicator, a lightning conductor, a VHF aerial and the LCD tri-colour navigation lights. The halyard coming out the front of the mast is for the drifter. Top of Page 
The mast is now up - and by Xmas, as planned! Feeling pretty pleased. It is tall isn't it? The spar is 13.5m long and the top is about 16m off the ground. Top of Page 
The very last thing Mac did was make this wet locker. As always, some excellent work. I will really miss his craftsmanship and attention to detail. By the way, notice the smart teak effect floors constructed by Owen in the same way as we showed before. Top of Page 
The same teak effect flooring
has been laid in the cockpit, using iroko, with the spacing between strips filled with epoxy mixed with a black pigment
(rather than the white pigment used inside).
Owen is also putting in place the iroko capping over the edge of the bridgedeck coachroof. We tried to do it before, when the coachroof was being built (see further up this page), by steaming a long length of iroko, but we couldn't get the wood to be sufficiently flexible. Now, we are laminating much thinner strips onto the coachroof using epoxy and a lot of clamps. Top of Page 
Now that the rudders are supported by uphauls and downhauls, the
cradles,have been removed.
This feels like a major milestone - Swing Cat is finally standing on its own two feet! Or, at least two beaching keels.
The cradles have been in place since the begining of 2012. The black lines show where they were. They did amazingly well: supporting each hull while they were being constructed, rolled over a farmyard on fencing posts,lifted by a forklift thrice and towed by a tractor from Malmesbury to Sharpness. They took about half a day for Owen and I to remove, so they were still pretty solid. Top of Page 
The foredeck after installation of all deck hardware. Fairleads and 12" cleats can be seen on each bow. In addition, a massive cleat admidships is used
to secure the anchor rode. Also of interest is the fitting for the inner forestay; the forestay can be detached and moved to one side when not in use - which
is most of the time since it is only used for a hanked-on storm jib.
The "new generation" anchor and its windlass is labelled. I decided on a manual windlass to spare the batteries, to save weight and to provide me with a bit of exercise. Provision to fly a spinnaker with the guy attached to a windward bow, rather than a pole, is also provided - standard catamaran practice. Top of Page 
The gas bottles are in the outside starboard locker on the foredeck. It serves three appliances: an oven, a hob and a water heater. Each applicance has its own isolating valve right next to it but, in addition, the pipework to each appliance can be isolated in the gas locker; this is to aid the finding of any leaks which may be indicated by the bubble tester. After using an appliance the gas can be burned out of the pipes by shutting off the gas using the electrically operated gas solenoid valve. In case of a power failure, the valve switches the gas off. The switch for this valve is in the galley. Details of the gas installation are in the plumbing documentation. I found Will Hayward of www.whayward.comto be very helpful and knowledgeable. Top of Page 
The electronics systems are connected to either an NMEA 2000 (N2K) or NMEA 0183 bus. Both busses are connected together. The busses ensure that navigational information from various sources, such as the chart plotter or the boat's heading, can be overlaid on the Zeus 9" multi-function display. For example, the photograph shows the VHF radio with an AIS receiver interfacing to the chart plotter. If you look carefully you should be able to see a black triangle in the middle of the screen - this represents a ship travelling up the Bristol Channel. The systems interfaced can be seen in Swing Cat's electronics schematicprovided by Richardwho did an excellent job installing and commissioning all of the electronics. Top of Page 
One of the unforeseen problems with Swing Cat was the lack of a secure steering position in the cockpit which gave a good view of the bows. You could sit or stand on the aft decks but would have to clip on and were exposed to the elements. You could stand in the cockpit, which gave some protection, but had nowhere to brace yourself, to avoid being thrown off your feet in a big sea. If you sat in the cockpit, the only view was of the bridge deck bulkhead. This problem was unforeseen because I only had experience of sailing a monohull with much smaller cockpits and good views forward from port or starboard. The answer was a central steering position affording a good view over the coachroof with both protection and security. Here is the design for Swing Cat's steering position. Top of Page 
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The aft beam is 5.8m long, although we have made it a bit longer so it can be trimmed to fit exactly when on-site. This photograph shows the construction - the marine plywood is 6mm and timber 32mm x 45mm Douglas Fir. The timber is scarf-jointed and the plywood butt jointed (with an overlapping piece of plywood screwed and epoxied to the inside of the beam). All joints are staggered and glue is epoxy throughout. The inside of the plywood is coated with epoxy. Here, Mac is using the router to round off the edges so the beam can be sheathed in 600 g/sq m biaxial cloth. Behind Mac can be seen the frames which will shortly be added to the jig. Top of Page 
Planking has now started. The polytunnel is filled with the smell of cedar again, which is lovely! The most forward frame (Frame 5) has had its leading edge chamfered, to make it easier to bend the strip planks where they join the plywood panels. The joins between the panels have been filled and sheathed with 2 overlapping strips of biaxial 600g/sq m glass tape impregnated with epoxy. Top of Page 
We were right to be worried. Owen has removed too many screws and the planking has sprung. It is my fault, not Owen's
since I insisted he remove a couple more screws against his better judgement. Serves me right for trying to hurry. It
took Mac and I standing on the planks to get them back into position, while Owen put in place battens to keep them there
while the glue set - this time we used epoxy!
Top of Page 
Grooves have been cut into the coachroof to bury the edges of the glass cloth. I learned of this technique from Howard,but started off using the trimming method advocated on page 24 of the West System User Manual and Product Catalogue. Unless you catch the epoxy at the right moment, after application, it will either be too soft, or too hard, to easily peel back the epoxy-impregnated cloth without distorting it. When the cloth is replaced, a right mess can be produced, which is hard to remove by sanding and fairing - one can still see a faint line, or two, on my hulls despite a lot of effort. The method I now use is to bury the edges of the cloth in a groove like this; the groove can then be filled flush with the weave using thickened epoxy. A router with a convex bit is used to make the groove with the edges chamfered by sanding. Top of Page 
The outside of the coachroof after glassing, filling weave, fairing, sanding and rolling on two coats of resin containing white pigment. We will paint it once it is fixed to the hulls. Top of Page 
Mac, taking a well earned rest whilst cleaning up the inside by scraping off the Gorilla glue. The curve of the bridgedeck is so comfortable - just like a hammock! Top of Page 
With the interior glassed there is much less flex in the coachroof. One can walk around inside with almost no give underfoot. The window surrounds are now being attached; they will give the same look to the fixed portlights as we achieved here in the hulls. Most boats fix the acrylic or polycarbonate glazing over the opening in the coachroof so it stands proud of the coachroof outer surface; in our case it will be flush with the outside. Top of Page 
Here is a typical scarf joint. Like the other ones on all the cross beams, they were cut by hand. Since thicknesses of wood varied, it was not worth making up a jig. To finish off, all beams were sealed with 2 coats of epoxy. Top of Page 
My solution is to provide butt joints, overlapping the the 9mm hull skin and butting up against the beam. The insulation between the stringers is cut away and replaced by marine ply, all around the beam. To give a flat surface for applying glass cloth and resin, two pieces of plywood are laminated together to give the same thickness as the stringer - 18mm. Top of Page 
But there are more important things to do than finish reinforcing the beams. The coachroof needs to be attached to give us a waterproof space between the hulls in which we can work. The hulls are joined together sufficiently for this, I reckoned, once three beams are in place, even though plenty of reinforcing still remains to be done. Here you can see, going forward: the aft beam, the solid wooden beam at the front of the bridgedeck and the aluminium mast section, which forms the netting beam. Beyond is the coachroof, waiting patiently. Top of Page 
After putting it down and re-adjusting the straps, the coachroof is now horizontal. This crane is overkill, but it makes it so easy. Top of Page 
The Coachroof transforms the build. No longer does it look as if we are building two large kayaks ... Top of Page 
Before we can make Swing Cat water tight we need to put on the decking between the hulls and from Bulkhead 3 to the Bridgedeck Beam. But this can't be done
until the gas and anchor lockers are constructed and the shelving for the forward cabins. The plans allow a choice for either a flat or a
curved front to these lockers. I have gone with the latter since it makes it possible to carry large gas bottles.
Top of Page 
One of the disadvantages is that we are outside in the open. We often have to find jobs to do inside our container/workshop when rain prevents us doing what we would really like to be doing. Here Owen is making grab rails out of Iroko. The template is on the right and made out of 9mm ply. The inch thick Iroko is first drilled and jig-sawed to rougly remove the waste material. A flush trim bit is then used with the template to create the desired shape. All edges are rounded off using another router bit. Finally, the table saw cuts down the middle to give 2 (fairly) identical grab rails. Given that my router bit is rather blunt some sanding was required to remove a few scorch marks! Top of Page 
Here is the recessed coaming in the hatch to the gas locker. Beyond, the hatch cover for the anchor locker is in place. Hinges and catches will be added later. The inside of both gas and anchor lockers are heavily glassed. The last bits of deck are now in place and one can see the big gap between the front of the bridgedeck coach roof and the foredeck - far from ideal since there should be no gap at all! If the bridgedeck had been made in situ, then we would have achieved a better fit. This is what the plans direct. However, the tension in the strip planks where the curvature is greatest is such that, if the coach roof were removed and turned over to glass the inside, as the plans suggest, it would probably have sprung open a bit. The only way to get a perfect fit, I think, would be to glass the coachroof both inside and outside in situ: this would mean glassing underneath a horizontal surface - not nice! Top of Page 
Watertight at last! The tarpaulins are off and the bridgedeck is heavily glassed to the decks - all around. The extra panels to the front of the bridgedeck coachroof look almost as though they were meant to be there. Only another Eclipse builder could say - "that looks like a bit of a botched job". The daggerboards were inserted in their cases with some fear and trepidation - would the cases have been distorted during installation? Would the boards have warped during their long period of storage? They slid in beautifully and give Swing Cat a Batman-like look, I think. Top of Page 
It was decided to install the trampoline net at this stage to make working on the deck safer. There are many styles of nets but nets made out of
webbing are the strongest and can be walked upon and used for sunbathing. A UK supplier could not be found so the net was ordered from
Sunrise Yacht Productsin the USA.
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The cockpit framing is almost done - for a drawing see
construction_details.pdf.The sloping bridgedeck floor is constructed
from 4 panels of 12mm plywood, butt-jointed. The glassing of these panels was done before fitting. There is a false cockpit sole with the floors
(joists) sloping slighly aft so water drains away from the cabin.
The rail going around the cockpit forms the inner edge of the cockpit seating; it is rounded for comfort and re-bated to take plywood sides and tops. The tops will have locker lids constructed in the same way as for the gas and anchor lockers. Top of Page 
It is the beginning of October 2014. After a long spell of dry and fine weather, the first gale of winter shreds our cockpit covering. Fortunately, we are now in a pretty good state to cope without a "tent". Bulkhead 4 is now completely filled in and watertight. The inside of the lockers are complete and have been coated with epoxy. The cockpit floor is in place, fitted with drains and epoxied. Top of Page 
The next job is to put in the bridgedeck floor. Here, the mast beam is in position. The sheet of plywood behind is a hefty 12mm thick and will be used for the floor.We are about to lose the large cavernous space between the hulls which has been a very useful workshop for a while! Top of Page 
The king post is now in position. It flares a bit at the top to counteract any tendancy of the
mast to rock back and forth under load. It is bolted to the Mast beam with the help of two bits of angle iron.
Note the stable door, beautifully made by Owen out of solid Iroko. The bridgedeck floor has also been completed, so we are now fully enclosed. Top of Page 
The cockpit now with door and flue topped with a cowl. Top of Page 
The bridle wire passes over the gull striker and down to bridle plates fixed to the hull. Details of the construction can be found in the
document:
construction_details.pdf.
... and here is the reinforcement on the other side of the hull to support the bridle plates; stainless steel backing plates are supported by 9mm of hull plus 18mm of plywood pads, a "mini" bulkhead and plenty of glass and resin. Top of Page 
The mast being raised into position. Chris Clyburn from
Pro Yacht Masts and Rigging is guiding the mast into position, Mac is on the furling forestay,
Owen is looking after the trailing shrouds and George is working the crane.
I was worried about losing the wind indicator to the strop on the hook of the crane but George re-assured me by saying, "I've never lost one yet" - his record remains unbroken. Note the radar which is one of these new "broadband" radars, rather than a pulsed radar; the benefits apprear to be: lower power, instant power up, no dangerous microwave radiation and better near-to resolution; one drawback appears to be a shorter range. We shall see! Top of Page 
Here is the very wonderful chart table built by Mac. The lid is made out of American Ash. It is a full size table with plenty of storage space underneath.
Unfortunately, this is one of the last jobs done on Swing Cat by Mac. He has handed in his notice and will be much missed. Top of Page 
Richard has also been doing some excellent work on the Galley. The micorwave is already in regular use, as are the cupboards. We don't yet have a gas supply so the oven is installed, but not connected to any propane gas cylinders. Top of Page 
The inside of the port water tank showing the fittings. The approximate internal volume is 185L. The starboard tank is the same size and has all the same fittings as well as the filler tube. The hand pump attached to the port tank is by the basin in the heads and the hand pump attached to the starboard tank is beside the galley sink. The blue colour is the Armourguard resin, especially formulated as a coating for potable water tanks. Four coats of Armourguard were applied over glass and normal resin. Full details of the tanks' construction are in the plumbing documentation. Top of Page  
This photograph shows the plumbing underneath the false floor in the bridgedeck. We are looking across the boat. We have a high pressure system and a low pressure system - the high pressure being provided by the pressure pump. The accumulator contains an elastic diaphragm which maintains pressure in the cold water high pressure system inbetween pump cycles and reduces the frequency of said cycles. All fittings are JG Speedfit using PEX pipe. One can just make out the colour coded collets on the fittings, to stop them coming loose, which indicate whether the pipe is for hot (red) or cold (blue) water. The fall between the galley sink and the grey water tank is small so the sink drains by gravity only slowly - hence the need for another grey water pump. Full details of the plumbing can be found in the the plumbing documentation. Top of Page 
An "artistic" view across the coachroof showing a winch and a bank of clutches. All halyards and sheets are led aft to either of the two cockpit winches. The only exceptions to this are the topping lift and the lazy jacks which are cleated individually on the mast. The 3 reefing lines, boom outhaul and furling line are also led aft. At the bottom of the mast I have 9 turning blocks for:
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The top photograph shows the gas supply to the hob and oven in the starboard hull. Note the compression fitting into the hull is high up in the locker. Drain
holes are in the bottom of the locker so any LPG gas (which is heavier than air) leaking from the installation can escape overboard.
The bottom photograph shows the gas supply to the Morco water heater disappearing into the anchor locker, en route to the port hull. Note that:
As we approached the end of the build, the most difficult and time consuming job was fitting the headlining. Nowhere was this more difficult than for the coachroof where flexible plywood sheets were coerced into compound curves and screwed, through insulation, to the coachroof. The idea was to have headlining which could easily be removed if new deck hardware was needed, or the existing h/w started to leak. These large sheets of ply had to fit snug enough so that the gaps could be covered with trim - a tricky task. Fortunately Owenwas up to the job! The headlining in the hulls was more straighforward - mainly flat sheets of ply were called for. Once the headlining was up everywhere needed decorating. This was another time consuming task requiring enormous attention to detail. I was very lucky to have my daughter Hennie to help me, who was in between jobs. Her husband Jules also had time to help me whilst starting up his new business Around & About Bath. Finally my other daughter Leo, occasionally with friends, were able to muck in. Decorating is painstaking business and I am lucky to have some perfectionists in my family who achieved the high quality results you can see in the tour of the finished catamaran. Top of Page 
As proof of the concept here is Nicky steering. Although a bit below average height she could easily see where she was going. Even someone above average
height can sit with their head a some way below the boom. There is also room for two people to share the seat which is useful when changing the helmsperson.
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