Late in 2002 we started looking around for a boat to build. Ideally it would be something that two adults and two children could sail in, or row. As this would be my first boat-building project, I wanted something that would be relatively straightforward to build. Stitch and tape plywood construction seemed to be ideal. One of the pram designs seemed to be the simplest to build, but I preferred a rounder hull - perhaps harking back to the Heron we had when I learned to sail as a kid.
Eventually I narrowed my choices down to one of the boats by Paul Fisher, of Selway Fisher Designs, and decided on one of the Northumbrian Cobles. The prompt, courteous replies from Paul regarding changes of the rig on a Coble, and the existence of a Yahoo Groups forum for Selway Fisher sailors and builders, reinforced my decision to go with one of his designs. Another Yahoo Group that I subscribed to was Wooden Boats Australia. Through these groups I met Alan Chinn, an invaluable source of boat-building knowledge, and discovered Australia's Wooden Boat Association, and joined the Victorian branch.
The plans were bought as a present by Kirsty's parents, and so, with no excuses left, I started building my first boat.
Futher down this page are some notes I made while building the boat. Another pages is devoted to sailing and handling notes.
We sold this boat in 2010, only because we had outgrown it as a family - two adults and two teenagers is really too much for this boat in anything but sheltered waters.
What is a Coble?
Cobles were used for fishing and foying (tending shipping) in the rugged conditions of the English NE coast and North Sea. Typical boats would be 30 feet long, with a beam of 8 feet. Apparently they borrowed much from the designs for the Viking boats. Selway Fisher's 12'6" version normally uses a Gunter rig and has a beam of 4'11". She uses 6mm (1/4") ply - around 5 sheets and has an approx. weight of 120 lbs. I preferred a Sprit rig to a Gunter, mainly because of concern with small children in a boat with a boom swinging above their heads - I remember being hit in the head by the boom on the Heron a number of times. Having a boom at the top of the sail means that the foot of the sail is soft, and a lot easier on the head if it comes in contact with you. Paul generously provided another set of plans, for a dinghy that used a Sprit rig, and calculated the changes in the mast location. Another advantage of a Sprit rig in a boat this size is that the mast is freestanding, requiring no supporting rigging. You may have seen photos of Cobles without knowing it. Many of the photos by Frank Sutcliffe, a well known 19th Century photographer, show Cobles being used for fishing or tending shipping. Take a look at some of Sutcliffe's photos to see Cobles from an earlier time.
Links to more information on Cobles
- The Raven and the Rose - The Coble
- BBC - h2g2 - Cobles
- Bridlington Sailing Coble Preservation Society
- Mast & Sail in Europe and Asia
All of the planks are now in place. Dad holds the transom in place while I thread wires through the planks and the transom from underneath. William is very intrigued by the whole process, and looking forward to getting onto the water.
Copper wires are used to stitch the planks together prior to using epoxy to glue it all together. The wire was stripped from electrical cable. Holes were drilled at 20 cm intervals, 6mm in from the top side of the bottom four planks. At points where there was more stress on a plank, due to increased flex, the holes were drilled every 10 cm. Then, starting at the stern, corresponding holes were drilled along the bottom edge of the next plank up. We only drilled about 4 or 5 of these holes at a time, to ensure that they matched properly. Lines drawn across the planks indicated where the frames/bulkheads would be located. It was important to check that these lines matched the lines on the planks above and below.
Towards the stern, the first few planks needed steaming to allow them to be brought together. This was achieved by wrapping the area in towels and pouring boiling water onto the towels. Repeating this a few times resulted in planks that were, for a short time, relatively easy to bend. All the planks are in place, and the frames/bulkheads are being wired in as well.
Now that the bulkheads/frames are all wired in place the boat is nowhere near as limp and flexible as it was. Getting the frames in place took quite a bit of time - particularly the forward frame, which puts quite a lot of strain on the hull. The hull planks had to be steamed and soaked in boiling water again to ease the fitting of this frame, and I had to use a heavier gauge wire to keep everything pulled in tight.
The for and aft frames will be the walls of watertight compartments, which will provide buoyancy for the boat in the event of a capsize. The access hatches are RWO type circular openings with an O-ring seal. I found these at CH Smith Marine - one of the line suppliers I used when making kites. They now have an excellent range of chandlery.
The forward frame is only loosely fitted here - note that the access hatch hasn't been fitted as yet. I had to clamp a length of timber across the frame to stop it from flexing too much while getting the hull planks to take the correct shape. Once the hull planks were all wired I removed the forward bulkhead and cut out the hole for the access hatch.
This series of close-ups shows the wiring together of two planks. We used a pair of aviation pliers to twist these wires. Once they were clamped on it was just a matter of pulling on the back of the pliers to twist up and tension the wire. It was considerably faster than manually tightening each wire, and a lot easier on our wrists as well.
Some of the people I talked to suggested leaving the wires in place, which is why the loop is on the inside and the ends are on the outside, making the wire on the internal chines easier to cover with epoxy.
I decided to follow the other suggest course of action - apply a dob of thickened epoxy between each wire, let it dry and then cut out all of the wires before running an epoxy fillet along each chine. I was able to remove almost all of the wire this way, but the few wires that remained were easy to file down flush with the hull.
While waiting for epoxy to dry, there are plenty of other components to start working on. The rudder and the rudder cheeks had to be laminated, routed, sanded and epoxied. The top of the cheeks have been routed to accept the stock, which now fits into this opening, but is yet to be fully shaped. The centreboard has been cut to shape, laminated and sanded. In this photo I'm using the centreboard as reality check for the measurements for the centreboard case (one part of the case is under the centreboard). Due to a mistake in adding up distances, I drilled the pivot point in one half of the centreboard case 5cm too far from the forward edge. I noticed this when checking to see if the case was the right length for the centreboard. The errant hole was filled with thickened epoxy and a new one drilled in the correct location. Better to find out now than once it had been fitted to the boat....
She is starting to look like a real boat now! The internal chines and bulkheads have all been epoxied and fibreglass taped. The epoxying got better as we went along, and the next boat would (or perhaps I should say will) be better, with neater fillets, and fewer jagged edges. In this first photo the seats and decking have been laid in place. It will be a while yet before they are all screwed and glued. I'm assuming that it will be easier to work on the internal surfaces without any more clutter than absolutely necessary.
The bulkheads are now in place, the inwale and outwale have been steamed, glued and nailed, and the supports for the seats have all been added. To add strength to the bow, a number of small pieces of hardwood have been cut to shape and laid in a bed of epoxy, from the forward bulkhead up to underneath the inwale. Extra epoxy has been added each side of, and over, these strengthening pieces.
The inwale at the bow has been routed to accept the bow decking. The cross beam to brace the freestanding mast has also been fitted and glued across the top of the front bulkhead. The centreboard case was fitted to the hull shape and then the internal surfaces were given multiple layers of epoxy before being glued and screwed together, and then then fitted into the boat.
The side seats were fitted and used to brace the centre support while the epoxy fillet that attached the support to the hull dried. The internal framing for the stern seat has been glued and screwed in place. The pieces running along the sides of the hull were cut half way through in several places across the supports, to ease the bending of the supports. The transom stiffener was cut to the shape of the top of the stern, and the corners of the stiffener and the inwale were routed out to accept the corner braces.
William and Amelia have been keen helpers! They have both done quite a lot of filing, rasping and sanding. Here, William is sanding the gunwales and side seats. Will is a dab hand with a rasp now, and it is amazing how long he will work with me. Amelia and William both spend a lot of time sweeping and vacuuming, and generally cleaning up after me.
We've just turned the boat over and have started filling the external chines with epoxy. Most of this will be filed and sanded off again, once it has hardened sufficiently - at this time of year it will probably be a week or two. We'll then run glass tape along each chine and wet out the tape with epoxy - the same process that has already been completed inside the boat.
Where do the months get to? Since August I've sanded the epoxy filling the external chines back to level with the ply, and run fibreglass tape along each chine.
Once the epoxy over the glass tape had cured, I filled covered the entire external surface with epoxy and sanding filler. The first pass with the filler was applied with a serrated blade. This built up the surface to the necessary height. Once this cured it was sanded until all of the tops of the ridges were level. A second layer of sanding filler was applied, filling in all of the gaps. This process filled the hull to the height of the glass tape over each chine. I used a longboard to sand the hull to a smooth finish. This is a sanding board about 10cm wide and about 50cm long. It is used to sand only the peaks from the filler. The length of the board means that a smoother finish is made as it averages out the variations in heights or depths of the filler. When I was happy with this finish I coated the hull with two more layers of clear epoxy.
The same process was carried out inside the hull as well, although this was not done with the same attention to detail. The variations in the fillets along the internal chines meant that a large amount of filler would have had to be used to smooth the inside of the hull.
The seats and decking are now glued and screwed or nailed in place, and the watertight inspection hatches have also been fitted. The final coats of clear epoxy have been rolled on. I found that the cheap yellow rollers that I bought at a "two dollar shop" disintegrated pretty quickly, but I did want to use a roller because of the finish it gave. I still had lots of the high density foam tubes that I used when making handles for dual line kites, and these, when cut in half, slipped over the yellow rollers perfectly. Because they are a high density foam they don't leave anywhere near as many bubbles in the epoxy surface, and I found that, unlike when using the yellow rollers, I didn't need to follow up with a brush to remove bubbles. The high density foam that I used for kite handles was intended for use as foam handlebar covers for bicycles, but it is absolutely perfect for rolling on epoxy!
A 14mm stainless steel pin has been used as the pivot for the centreboard. I had originally planned to use an half inch pin, and had drilled larger holes in the centreboard and case, filled the holes with epoxy, and then drilled out half inch holes before fitting the case together and fixing it in place. The increase in size meant using a round rasp to gently ease the size of the holes until the pin fitted. A dab of clear epoxy to reseal the edges completed the revision. Once the centreboard is in place the pin will be flush with the outside edges of the case. A layer of silicone will be rubbed over the ends of the pin and surrounding case, and a plate will be screwed over the hole. This should prevent any leaks.
While letting the final layers of epoxy cure for two weeks prior to painting, I worked on the mast and sprit. During September I used my saw bench to rip the square sections for the mast and sprit into halves, reversed one half of each pole so that the grain ran in the opposite direction and then epoxied them back together. This is done to prevent warping in the future. In early October I rounded each pole. This is done by marking lines along each side at a point 3.5 twelfths of the total width of the edge. This area is planed away from each corner, and then the new corners are planed, and so on, using a combination of electric planer, hand planer and eventually an electric sander with increasingly fine papers. Last week, once the poles were rounded, the ends were tapered to reduce weight, using the same sort of rounding procedure. Wooden blocs were screwed to the mast to locate the strop for the braille line and the snotter (which will hold the sprit under tension).
We bought a Dunbier Nipper 4M-10 trailer for the boat, and have started adjusting the trailer to suit the boat. This has been put on hold at present, as we have finally turned the boat over again and started painting! Following advice from Paul Fisher and Alan Chinn, we are painting the boat with an oil based undercoat, and then a gloss enamel house paint. Haymes Paints have been suggested as a good paint to use in Australia, for boats that will only be in the water for one or two weeks at a time. The first layer of undercoat has been applied with a brush to the outside of the hull, but I think that I will try a short nap roller for subsequent coats. There needs to be at least 24 hours between coats, and as I intend to sand lightly as well, it is probable that I will only be applying a coat every second day.
While this is progressing, I will also start working on the sail. We bought the 5oz sailcloth from the very helpful people at Contender Sailcloth in Sydney, who shipped it down to us within a couple of days. In keeping with the traditional design of the boat, the sail is tanbark in colour.
During late October and early November, two undercoats were applied, three topcoats of white gloss for the hull, two coats of Treadgrip for the areas inside the boat where you could reasonable expect feet to be placed, and three coats of blue gloss on the seats, gunwales and forward decking. I was surprised how long it took for the topcoats to cure. Even a week afterwards it was easy to damage the topcoats. When I judged that the paint had cured sufficiently we turned the boat over and put her back on her trailer. Then I was able to start fixing hardware in place. Some will have to wait until we've sailed her a few times - such as quick release cams for the main sheet, which will be fixed inside the gunwales once I have worked out the best location for them by seeing how the sail reacts to the sheet being hauled in and loosened off while at various points along the gunwale.
The pintles have been mounted on the hull and the gudgeons were fitted loosely to the rudder while we moved the rudder back and forth, to let the pintles and gudgeons find the best orientation against the other. Once this was achieved everything was tightened up.
The gate for the mast has also been fitted. I've sewn a leather pad that will fit around the mast and prevent wear against the gate. Once the mast is dropped into the locating hole at the base, a pin is pushed through the holes in the gate, preventing the mast from coming out again. The snotter (the line that hold the sprit boom under tension) runs through a single block and back to a quick release cam on the centreboard case. This line, under tension, will hold the mast into the boat. The mast is unstayed (no supporting or bracing rigging), and is intended to rotate as the sail moves.
We finally have the centreboard in, and holes have been made for a pin to hold the board up while traveling and the shock cord to hold the board down while sailing. These have been epoxy coated and were left to cure for a couple of days. There is probably a little too much slack around the centreboard, but this will have to be checked while sailing. A couple of CDs were used as broad washers, as they were exactly the right size for the pivot pin, and I just happened to have a few of them lying around :-) The stainless steel pin that the centreboard pivots on sits flush with the outside of the case. A thick layer of silicone was applied to both ends of the pin, and the surrounding area, to stop leaks, and a wooden plate was screwed over each end, to prevent any movement.
The mast and sprit, which were shaped during October, have been coated with Deks Olje (pronounced Decks Olya), an oil that can be used instead of varnish. This is a two part process. #1 is an oil that is brushed on, and on, and on, until there is still oil on the surface after a break of ten minutes. Four days later you start on the second part of the process, a single coat per day, for five or six days, of the #2 oil, which gives a gloss finish. The benefit of this treatment is that the finish is quite durable, and touching up only requires a light sanding and then another application of the #2. I probably used about 750ml of the one litre can of the first solution, and less than 250ml of the one litre tin of the second oil, so there is plenty left for touching up later.
The sail is complete, and is awaiting attachment to the mast. I have to wait a couple of days for the final coat of the mast to harden, and then I can test the sail on the mast and sprit. The most charitable thing I can say is that my sewing improved during the building of the sail! If I were still making kites for a living this wouldn't have been something that I could have sold. Having to work on a small sewing machine again made me wish that I hadn't sold my old industrial machine. Still, the sail will certainly be strong enough, and there are only a couple of seams where the stitching is a bit crooked. Paul Fisher's book on sailmaking was invaluable while making this.
The safety gear is all ready to go, the sail should be rigged and tested by the end of the week, and the weather isn't looking too bad for the weekend! With luck, Saturday 22 November will the launch day, at Williamstown, with a second launch on Sunday at Albert Park Lake, for a Wooden Boat Association day.
Go to the Sailing Notes for our 12'6" Northumbrian Coble.