Entry 7

EuroPig – a Pirogue 

By Lew Clayman, lew_clayman@yahoo.com

EuroPig is an anagram on pirogue, and I chose the name because it’s the silliest anagram I could make out of that word.  “Pig Roue” might have been more appropriate (look it up) but for some reason I just like EuroPig better.  If you find a more fitting anagram, send it along.

EuroPig is a flat-bottomed calm-water one-person craft, although with kids or other lightweight crew it might take two: the nominal displacement of 325lbs leaves something in range of 275 lbs over the empty hull weight.  As such, it could carry in addition to most adult crew, such cargo as fishing gear, light camping gear, and the like.  Although I have not designed such, I think it could readily take a canoe sailing rig, a small outboard or trolling motor, and fabric decks.  I have shown it with a double paddle, but I’m certain that a single paddle or oars could readily be used.  The narrow side-decks give it a bit of extra “tip” before it ships water, and add greatly to its strength; more about them later.

At the specified displacement, it shows a buttock angle of 2.8 degrees, and shows a D/L limited speed of  9.63kts (S/L=2.51) against a hull speed of 5.13kts, suggesting that with a generous rig or the right motor she could plane readily – but prepare for a wet ride, as she’ll only have about 5” of freeboard.  More sensibly, this all suggests that she’ll glide well to a paddle stroke.  Sailing, the skipper might not want to hike out – but seriously leaning to windward should accomplish the task; once again, expect to be damp.

The key to the design is contained in two features, which are perhaps most easily seen in plan and elevation views.  The plumb stem and stern define the ends of a boat with a flat bottom and laterally-flat side-decks, both with the same curve as viewed from the side.  The outside curve of the bottom just matches the inside curve of the side-decks.  These two facts mean that, when developed and plotted on the material to be cut, the side-decks exactly abut the bottom, making good use of the material.  When assembled, the bottom is entirely, and exactly, visible from above.  The thickness of the side-decks therefore defines the flare of the sides.  Kept low and to a moderate flair, as here, the side decks come from the same two sheets of butt-jointed ply as the bottom and side-decks.

In effect, EuroPig is just one of an infinite family of designs which observe the above constraints.  This basic idea can be stretched or shrunk or otherwise distorted without violating the previous paragraph.  Indeed, I had it at one point as a 7’10” skiff, bottom and decks from one sheet and sides from the other.  In many of the possible proportions, it produces a lot of boat from the given materials, which was a major part of the contest challenge

The stern, here, is cut from 1x lumber; however the ply purists may prefer to shorten the whole thing a few inches and get the stern from the ply also.  Similarly, the breasthook is of lumber, but might be made of the excess ply by the fastidious user of all scraps.  In a sailing application, the breasthook might be holed to serve as a mast partner.  I have claimed the scraps for paddle blades; the motivated will find lots of leftover lumber in the given list from which to fashion foils, steps, tillers, and what-not.

Some possible variants, which I have not explored in detail but which I am sure can be made to work, include the following:

  • There is no reason why a double-ended form is impossible, within the “concept” outlined.  In this size, I found no advantage to the pointy-stern, but clearly nothing forbids it.  It produces an open-topped kayak, which is not to my taste.  In other proportions, using more material, I see no reason why not.
  • Similarly, a scow form using the same constraints is quite possible.  The sides will tend to be straighter in plan view, leading to a slightly longer boat; but the bow transom and foredeck or quarterbraces or whatever would have consumed additional materials and, more significantly, eliminated the nice pointy front.
  • The bow and stern here are both plumb; more generally they only need to be parallel.  Picture in your mind’s eye the same boat, with the decks and so forth moved forward say 3 inches.  The top and bottom curves, in elevation, still match – they are however offset from each other.  The bow now has a jaunty, wave-cutting look to it, and the boat has acquired a counter stern.  In some resizings, this could well have advantages; for the present pirogue, I liked plumb better for its useful interior volume, especially aft, and for the extra inch or so of overall length from the given materials.  Done thusly, the sides take on a bit of twist, usually showing hollow at the bow and, depending on the width of the side-decks aft, anything from hollowness to convexity to even a smidgeon of tumblehome aft.
  • In an related form, the top can be significantly longer than the bottom, but match the curve of the bottom over the length of the bottom - obviously, the “ends” of the deck would, in elevation, continue the curve smoothly.  Less stingy in the use of materials, this approach might produce a very fast and seaworthy kayak, with a v-bottom interrupted only a small flat under the cockpit.  In another proportioning, a dory might result, or even a chined interpretation of something like Alerion.  She might look identical as a silouette on a late-afternoon horizon, but would in fact be very different.  The “chined Alerion” is definitely not for those who become squeamish about torturing wood!

I make no claim that this automatically produces the best boat; merely that it produces a lot of boat from given sheet-goods.  The relationships noted above do not guarantee very much else – the constraints are in fact not very constraining, and there were uncountably many designs along the way to this one which I simply hated, but they met the “rules” above.  EuroPig is, IMHO, the best one I came up with – not in any sense the best possible.  Play with the form, it’s simple enough, but let your eyes guide your hands.


click to enlarge




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