More Brooding - 20th December 2009

Much as I grumble about the use of bewildering nautical jargon I have to admit that much of it is very rich and colourful, my current favourite being 'Tumblehome' - I mean, I'd really like a dog or a girl friend called Tumblehome. However, its actual definition is a bit more prosaic, meaning that the beam at the gunnels is less than the beam below the gunnels - and it's typical of cobles. I'm not sure what function or advantage it has though - possibly can get away with shorter oars as the beam narrows and the boat would be more stable when leaning over the gunnels hauling pots, etc. Anyway, the practical result when building is that the completed hull won't separate from the mould. Jordan Boats suggest that you wobble it about a bit and the mould should come away; Selway Fisher say split the moulds (now they tell me!). Seven of the nine moulds have this tumblehome so, having now cut them out, I'll cut a small removable section from each - held in place during the planking. Once this is removed, the two halves of the mould should draw in towards the centre, to release the hull. Can't go wrong! The alternative is to simply destroy the mould in order to remove it but with the risk of damage to the hull. (Voice from the future: No, the mould didn't lift out!)

Another thing I've noticed is that the transom dimensions are for the aft face but, being raked at about 35 degrees, there will be a considerable bevel needed - I'd guess up to 25mm wider in places on a 18mm transom. So what size do I cut it out and, given that the bevel will vary from one plank to the next, what's the best way to form these? John Leather says some builders just make it well oversize and then hack it down to size as each plank is fitted (he also says that if you do this, you're a BAD person!).
I'm thinking that what I'll do is fit a false 6 or 9mm transom (as Thom Hill suggests), and then transfer the angles between this and each of the ribbands, onto the 18mm transom (the ribbands being the strips of timber that run the length of the hull at the plank positions to make the mould a rigid structure). I confess I've also worked out these angles with trig. but have doubts about my figures. We'll see . . . .
I'm constantly having to guard against a techy desire for precision of measurements, at which times it's refreshing to read about the old time boat builders. Some history of the coble is given by the Hemlington Nautical History Society. It seems that the last East Coast coble was built around 1932 by Angus Hopwood who built boats at the rear of his house in North Marine Road, Flamborough and that he dismantled an old coble on the beach, noted the parts, and then went home to become a famous coble builder. It's even rumoured that he didn't possess a ruler at all but measured the rough proportions of his boats using a smoked herring! But then, you can't believe anything these days!

Options: 29th November 2009

The Selway Fisher Coble plans offer a number of design options: a 14ft or 15ft version - the former having a less raked transom; a 5 or 9 strake (plank) hull - the latter intended I think for clinker construction; and various sail layouts. Construction can be either by stitch and glue (ugh!) or glued clinker. To be fair, stitch and glue is a quicker and probably lighter process but uses masses of epoxy and involves struggling with a huge wobbly pea pod of a hull before it looks like a boat. I'm frightened the pea pod might win one day - and anyway, it's just not cool. The clinker procedure, however, does require building a mould around which to lay the strakes - which is all extra time and material - but personally I just like doing it this way. The mould itself is quite attractive - just doesn't float well. The pic. shows the mould for the MacGregor canoe.

So I opt for clinker which I think would suit a 9 strake rather than a 5 strake design, the 9 giving a more rounded and stronger hull. The 5 strake option would use planks up to 300mm wide which would probably suit stitch and glue rather than clinker. The instructions suggest either 6 or 9mm ply for the strakes and the 9 strake version would be strong enough with 6mm, whilst the 5 strake option might need 9mm - especially if the builder is going to risk using exterior rather than marine ply. Marine ply is a lot more expensive but stiffer and nicer to work with: 6mm marine has 5 ply where exterior has 3. However, Alex Jordan of Jordan Boats in Fife sells a kit of planks and moulds and he uses 9mm (he says he feels 'the boat deserves 9mm' - I like that) so who am I to argue?
The downside of the 9 plank version is that the S.F. plans only give profiles for the 5 plank version; admittedly for stitch and glue construction but they can still serve as guidance for the clinker method. I've searched around for software to produce these 3D to 2D projections but with no luck so it looks like the plank profiles will have to be taken from the mould. The pic. shows the profiles for the 5 strake coble.
The size of boat is usually limited by the size of your workshop - I use a 20ft x 10ft polytunnel - but there's also the problem of getting it out onto the nearest road or track. This is a big problem for me and I'll need a load of helpers to move the boat out on its side. It may not make it - we'll see . . . .
I'm promising myself to keep track of the costs this time. I kid myself that I'm saving loads of money by building a boat - it's what I tell other people anyway - but I sometimes doubt it.
So, the running costs are as shown top right.

Looking ahead a bit, I've discovered a source of low price marine ply but may have to buy a trial sheet to see what it's like . . . .

Initial thoughts: 1st November 2009

I was surprised, the other day, to uncover a set of boat plans which I must have bought some 30 years ago - a 17ft Coble by Ditchfield Designs in Southampton - doesn't seem to exist anymore though. I can't remember why I didn't build it; I only know that I ended up tackling a 15ft Island Plastics design instead (they don't exist anymore either) resulting, after about a year, in an incredibly seaworthy little gaff rigged cruiser that took me on great adventures around the West and East coasts of Scotland (before eventually sinking in Dunbar harbour during a force 9 easterly!).

Then other life stuff intervened - as it does - and years passed before I got the boating itch again. Starting small, I completed the very pretty Esk 14 kayak by Selway Fisher - although I have no particular interest in kayaking - too close to the water for my liking! My friend Angela is looking after it at present but I guess I'll have to sell it soon.

Next, was the more challenging MacGregor canoe by Iain Oughtred - a 15ft clinker design with 6 strakes per side, and a yawl rig. Most builders start off slavishly sticking to the design details (for about a week) and then start modifying! I was no different. The suggested lee board was replaced by a Rushton type swivelling dagger board; and then I couldn't resist adding outriggers modified from a design I bought from Fyne Boats near Kendal. Again, it's a very pretty boat but what began as a car-topable canoe has become so elaborate and heavy (complete with an outboard) that I've had to build a trailer. Things can get out of hand like this sometimes - well, quite a lot actually.I had good fun in this boat too but, at the end of the day, it's not the sailing or being on the water that I like; it's simply the building. Projects like this can be totally absorbing - to the point of obsession in fact - the downside being that no one invites you round anymore in case you start going on about your boat. Odd that! (There may, of course, be other reasons!)

So, anyway, the next project is a 15 foot Northumbrian coble with 9 strakes a side and a nice 5ft 10" beam; again from Selway Fisher (Study Plans are available which is a great help before committing to any one design). But there's this thing about boat plans - no matter where you get them - they are daunting and you might, like me,  find yourself staring at them for weeks before things start to make a bit of sense. Also, if you hope that the instructions that accompany your plans will help, you're in for a disappointment. The exception is Fyne Boat's own designs which come with very detailed instructions - but others offer rather sparse guidance - I even read some Welsford instructions which said at one point: 'Now cut out the parts and assemble.' Like, yeah! For clinker construction of the Northumbrian coble there are just two lines of instructions suggesting you buy Thomas Hill's book (which I did and didn't find helpful) but there is now an excellent range of instruction manuals from Selway Fisher which cover most of what you need to know.

Some additional refs:

Clinker Plywood Boatbuilding Manual by Iain Oughtred - the layout is a bit chaotic but there's a lot of useful stuff there.
Clinker Boatbuilding by John Leather - something of a classic if perhaps more traditional than needed by most builders these days. This is the one I started off with years ago.
The Working Guide to Traditional Small Boat Sails by David Nichols - helps sort out your dipping lines, thimbles, thumb cleats, cheek blocks and so on . . . .

So, anyway, getting back to the Northumbrian Coble . . . .