The new design

The design of the new, unnamed boat is very similar to Aerie’s: marine plywood, v-bottom, four strakes per side, 176 inches long. It has some important changes in the structure and sailing equipment, all born of experience:

1. It is built around a three piece backbone consisting of keel/skeg, keel/stem and centerboard trunk all joined together, with the keel made of two layers of 12mm (half inch) plywood. Instead of a keel batten, garboard cleats are glued and nailed to the keel and CB trunk. 
2. Another important modification is the design of the centerboard, whose pivot bolt is positioned on the keel under the hull, to prevent leaks through the pivot hole. The centerboard is wider and the CB trunk is almost completely enclosed, with a small corner opening for the line and blocks for raising and dropping the centerboard. This will prevent water from splashing into the boat. The centerboard will be weighted with lead, both so it can drop easily and for ballast below the waterline when lowered. The CB was designed in tandem with the sail for a balanced helm, using techniques learned from David Nichols' The Working Guide to Traditional Small-Boat Sails.
3. For simplicity, the boat will be a cat with a single sprit sail. This way there will be no halyards (the sail will be permanently laced to the mast), no boom and only three lines: a sheet clipped to the clew, a snotter for the sprit and a brailing line for dousing the sail in rough weather. Again, thanks to David Nichols for many ideas. This being a sea-going vessel (albeit in the Mediterranean and very close to land for beach hopping only), a small outboard and oars will be on hand for when the wind is too weak or too strong.
4. The fact that I am building a cat means that there is only one forward bulkhead, at 28 inches (711mm) aft of the stem of the boat. The mast partner will be secured to this bulkhead and the foredeck.
5. The new boat has a bit less freeboard. I found that Aerie had too much, especially for the purpose of fitting an outboard. An added bonus is that the long hull pieces (garboard & strakes) will fit on two pieces of plywood (scarfed together) per side.
6. There will be a bit less in the way of seating and no lockers (again for simplicity). Instead there will be four storage compartments with open access ports cut into the bench risers. In addition, there will be three buoyancy compartments (fore of the transom and under the foredeck and rowing thwart) filled with expanded polystyrene. I got tired of relying on watertight compartments for buoyancy: they never are fully watertight and are a pain to drain and dry after water gets into them. I will make sure that the compartments have drainage holes. 
7. There will be no floorboards, which proved to be an annoyance on Aerie. Instead I will reinforce the bottom with extra plywood strips and finish it with anti-slip grit.

Acknowledgements

Now that virtually everything, including rigging details, has crystallized (if not writ in stone--that won't happen even after the boat's launch), it's time for some acknowledgements.  In designing and building my boat, I drew inspiration from a very wide range of sources, some of which were anonymous, some which I have forgotten.  The amateur boatbuilding community is very generous with ideas and advice, and inspiration and emulation is widespread and natural—after all, it’s been said that imitation is the sincerest form of flattery.  I did not copy anything specific in detail, I just used well-known practices (and quite a few improvisations) to achieve what I wanted, based on the many inspirations.  All calculations and decisions, all errors and corrections, and even some small innovations are mine.

Even so, I would like to gratefully acknowledge the following people/businesses for inspirations and influences by subject (a specific boat design is listed as appropriate). 

• General lapstrake hull design: John Welsford, François Vivier, B&B Yacht Designs (Lapwing)
• Broad lapstrake hull design: Iain Oughtred (Caledonia Yawl)
• Cat ketch basics: B&B Yacht Design
• All manner of stuff on traditional sails, helm balancing, marlinspike skills, etc.: David Nichols
• Sprit booms: B&B Yacht Designs, David Nichols
• Lug sails: David Nichols, Jim Michalak
• Standing lug/sprit boom combo: John Welsford (Houdini)
• Sheet arrangements: B&B Yacht Designs
• Halyard arrangements: François Vivier, Michael Storer (Goat Island Skiff), David Nichols, Jim Michalak
• Broadseaming: Todd Bradshaw

You probably already know that I did not buy any plans for this boatbuilding effort.  That was obviously not for reasons of economy (even though some people think I am cheap): buying plans would have saved me countless hours of planning, calculating and improvising.  As I explained in my two earliest posts, I did not find a design that fit all my needs, and I greatly enjoyed the whole challenge of designing from scratch and building on the fly by the seat of my pants.  For people who are less crazy than me, I would heartily recommend the plans and/or books of the fine naval architects listed above.

Design quirks

A bit more about the design and planned building method:

The Carlson hull design software builds up a hull over four polygonal (straight-sided) transverse bulkheads, including the transom.  It gives the dimensions and coordinates of these plus other frames specified by the user.  I divided the 176 inches into 8 sections of 22 inches each, so I have coordinates for 8 frames.  The program also calculates the flat profiles of the strakes that wrap around the frames, and allows you to place the pieces on 4x8 sheets, giving visual printouts and coordinates.

Here's the standard three-view as created by the software.  As you can see it has the basic outlines, without seating, decking, floor, thwart, skeg or anything else.  The rest needed some work.

There were many more things to figure out, such as the shapes and sizes of the bench risers, seats and skeg, the depth of the floor, the angles and overlaps between strakes, etc.  I worked all that out by plugging  coordinates into Excel and working out formulas.  High school trigonometry helped a lot!  I also converted everything to millimeters just in case--Excel does not like fractions and 5.81 inches is hard to measure.

Because the program assumes carvel-built design (with the strakes flush against each other), I have to add enough extra width to the strakes so they can be beveled and glued together.  I will have to bevel the plywood (after scarfing pieces together--more on that later) using hand planes I bought cheap at an antique store.  I plan to use epoxy and bronze ring-shank nails that will be set (recessed) and clenched on the inside, then the indentations filled before painting.

I also had to figure out some basics about the centerboard and the sails, to make sure everything fit around the frames, decks, etc., and that the centerboard and sail placement was correct for a balanced helm, not only for the chosen rig but for the three alternatives. It all took a fair amount of pencil-and-ruler-on-paper work.  I will post a more detailed drawing of the design with the extra features, but it will take some time because my pencil sketches need detailing and prettying up.

Next time, a few more design details.

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Design Choices

What went into the design you say?  Well, it was meant to be an open boat, about 15 feet, with plenty of stability and freeboard, and pretty dry in a chop.  It needed to be a capable sailer (including single-handed sailing) and easy to row.  Preferably it would look old-timey, but not be impossibly hard to build.  I would have a short unstayed mast or two, but the rig would be flexible.  It would have adequate storage, plus extra buoyancy in case of swamping or capsizing.  The oars had to be stowable out of sight, and the floor had to be flat.

That's a pretty complicated combination.  What I settled on was a lapstrake design (nice and traditional looking) with a V-bottom (ditto, and less slappy on the waves), with four strakes per side (easier to build but still nicely rounded), built around a total of eight frames, including transom and two full-size bulkheads.  Unlike regular lapstrake forms, the frames will be permanent and will increase rigidity.  The boat will have side benches all the way from transom to main forward bulkhead, with storage and buoyancy built into them, and large storage lockers fore and aft.  It will have a foredeck and side decks for dryness, and a removable plank floor with room under it for oar stowage and lead shot ballast in a special compartment.

The hull will be built upside-down over two sturdy sawhorses, connected with wooden runners on wheels, so the whole thing can be moved in and out of my small, unheated garage.  Most of the work will have to be done in the warm season, because epoxy doesn't cure in the cold.  The vertical risers of the side benches will sit on top of the saw horses, and the frames and bulkheads will interlock with them like three-dimensional puzzle pieces. 

The other decision to be made was the rig.  At first I thought that it should be switchable from cat to sloop, the latter with a jib and a bowsprit.  But that would have meant a tall mast, which I dislike.  I then considered a yawl rig, which I rejected for various reasons.  The chosen rig was a cat ketch with a balanced lug main and a standing lug/ sprit boom mizzen.  For more on all these old-timers, you could read David Nichols's book.  Still, there will be four different possible mast steps that can accommodate all four possible rigs.  I like the cat ketch design, because it is stable, has two smaller and more manageable sails, and is very easy to tack and to sail single-handed.  It also means that a mast hole goes through the rowing thwart, and the centerboard case has to be slightly off center.

So there you have it.  Next time I'll talk about the mechanics of the design and planned building techniques.

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Some history II

Anyway, I was talking about a sliding Gunter (BTW, it does get a little arcane, but Wikipedia and Google are great for explanations for those who need them).

That wasn't the end. In search of an ever better rig, I replaced the regular boom with a sprit boom. I finally decided I didn't want to mess with either the jib (too small to matter, too picky for single-handed sailing), or with stays  So I modified the sail to a bat-wing with full-length battens, and replaced the 14 foot mast with a 10'8" unstayed one.  This final rig served me well for a while.

Then we moved to Ohio, and the little boat was fine for the city reservoir, but too small to risk on lake Erie, where big waves can come out of nowhere. A one-mile-square reservoir gets a little repetitive, even though it has plenty of wind, being 20 feet above ground level.  I got bored and decided to build a bigger boat, still small enough to fit on the small trailer, but with side decks, more freeboard and more stability.

I shopped around for plans, but I couldn't decide on what I wanted.  None seemed to have the right combination of features, size, versatility, old-timey look, relative ease of building, etc.  I had already figured out from experience that plans may need a lot of tinkering, or may be poor designs (especially after building an unbelievably tippy plywood canoe, whose designer shall remain nameless, for fear of possible lawsuits :-)).  Being a fearless tinkerer, I decided to look for ways to design my own.

My inspiration came from many fine naval architects, and I owe a debt for ideas especially to Francois Vivier, John Welsford, and B&B Yacht Designs.  I used the free hull design program from Carlson Design to test my ideas and come up with dimensions and shapes of bulkheads, frames and strake panels.  For more of what went into the design choices, check the next installment of 176Inches.

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Some history

This blog will be about my (still theoretical) 15-footer sail- and row-boat.  It's called 176inches because that's the exact length in the plans, which I designed myself, in my first such effort.  Whether I will regret such arrogance remains to be seen.  You, dear readers, and the elements will be the judge of that.

Yesterday I ordered my first materials for my putative boat: 2 gallons of epoxy, 2 lbs bronze ring shank nails, three boxes bronze screws, gudgeons and pintles and some other stuff.  I haven't yet ordered the 12 sheets of marine plywood.  But first, some history.

Many months of  thought and design went into this project already (and it was all great and totally free fun).  My history with boats all started with a little 11 foot 6 inch dinghy I built several years ago.  It was a very old British design, called the Siren, still available from Clarkcraft.  It arrived on old-fashioned (actually blue!) blueprints, and I believe it was influenced by the ubiquitous Mirror dinghy.  By then I had heard about stitch and glue techniques, which I thought would be easier than the hard chine construction described in the plans.  I had to modify them significantly, but eventually I built a nice little sloop in marine plywood and mahogany, complete with home-made spars, rigging and sails I sewed myself.

The proof of the pudding is in the eating, as they say.  The boat proved to be wobbly, but hard to swamp nonetheless.  The biggest problem was the rig, with something called a pivoting Gunter mainsail and a tiny jib.  The pivoting Gunter proved a real pain: its impossible to reef, all or nothing nature forced me to launch with the full canvas on, which is pretty dangerous on a stiff wind.  On the first serious sail, first the centerboard got stuck.  I had to return across Indian River lagoon in the teeth of the wind, and tacking was out of the question.  I tried wearing (turning the boat 270 degrees through a jibe), something I knew from reading the naval adventures penned by Patric O'Brian of Master and Commander fame, but I was making very little headway.  Then the top of the rudder delaminated and the tiller came off. My brother-in-law and I had to beach it, walk to a phone and call for help.

So I had to do some repairs, but I finally realized how bad the rig was when the feeble remnants of hurricane Ivan reached a South Carolina lake just as we were launching, capsizing us about six times before we got under way.  So I changed the rig into a sliding Gunter, which boat designer and traditional rig booster David Nichols did me he honor of highlighting in his very nice book on traditional rigs and this e-zine article.  You can find David's designs (all lapstrake) for sale here.

For more of the plans' history, check the next installment of 176inches.

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