Graeme,
I am the lucky owner of  «American Small Sailing Craft», written by Howard I. Chapelle in 1951. One of the many boat types he describes is the Garvey. Built with strong topsides of moderate flare, and cross-planked bottoms, they were configured for rowing (long and lean) or sailing. Marcus’ Freebie would surely be called a garvey by Chapelle. This basic shape can probably be found everywhere (they do exist in Norway as well; hastily built craft for occasional transporting sheep or a moose carcass across the numerous small lakes in southern Norway).

The available material decides the shape of a vessel to a large degree. With plywood available, the 5-plank boats appear to be an easy-to-build upgrade from the 3-plank garvey or sampan. Suddenly one gets a boat which changes character in use: Row it when lightly laden, and they are very easily driven with their narrow waterlines. Load them down, or heel them over under sail, and the topsides of the beamy vessels will dip in and add a lot of stability. The challenge is to decide for the deadrise angle of that no. 2 plank.

Annie Hill reports that her FanShi is very easily driven in light winds. I think that is much because of the good 5-plank mid-section, which David Tyler gave that design. FanShi's overall beam of 2.97m versus waterline beam of 2.47m speaks for itself.

Pointy or square bow.
For some reason, western boat builders mostly cling to the habit of having at least one pointy end. Having played with the pram-type designs lately, I think the Chinese were smart to make their sampans with transom bows, in particular if they had sailing in mind. These boats have very straight sailing lines and low entry angles, and the hull shape contributes with form stability over most of the waterline length. The 5-plank version only makes it better. 

When drawing my small boats, I spend a lot of time playing around with different main sections before drawing any more lines. CAD is wonderful for this.

Arne

(PS: The three entries below dropped in while I was writing this. I only got to read them now...)

What it doesn't do is to make for a good sailing dinghy - only a 'good enough' one. The 5-plank types are better.

Well, I don't Know David, that depends on a lot of things. When it comes to very small boats, the beautiful ones are not always the fastest. This thing of yours (better give it a name!) might have the legs of Arne's 5-plank down wind. It will be stiffer initially, and upwind its surprising how much wetted surface can be reduced by shifting weight forward and inducing some heel. (Not talking from experience - I came last in the one and only race I ever entered - but the Aussi moth (moth Mkll we used to call them in NZ) was a pretty fast scow and that was one of their tricks. I don't think flaring sides helps in that case).

(Anyway, racing is not the point here, and as you say, it will sail well enough. Arne's 5-plank is a bit too beamy to be really fast, I reckon. Of course, load-carrying ability and stability for getting on and off is more important. Both should be lively and fun to sail, perhaps Arne's 5-plank slightly more so. I wouldn't bet on it. Arne's has the looks, I would grant you that.

"Sampan" is not the word which first springs to mind when you look at it - but I guess it fits the definition. It may not be a shanban - but it is clearly a sanban.

How are you going to get that rig down to a 2-minute assembly/disassembly? Lets tighten the screws and make it 1-minute. This is where the contest properly resides I reckon.

• In the Committee Dinghy Design thread, David wrote: The definition of a sampan is 'three planks', ie flat bottom and slab sides.  This grabbed my attention. Of course!  sān bǎn    三 板    "three plank"   Sampan would be a dialect pronunciation of "sanban". I never noticed that before. Many Chinese words have entered the Engish language, often from southern Chinese dialects, and their counterparts in Mandarin can be easily seen. (Examples: typhoon, coolie, canteen - and the good old cup of "cha". But not the word "junk", by the way) But wait - David, can you quote the source of this definition? If it is Worcester I wouldn't argue - different dialects, and Chinese language sound-ambiguity being what it is, I don't doubt it could have been true in the region in which he lived. Its certainly plausible. But the problem is, I looked it up in my modern standard Chinese dictionaries and it doesn't seem to be the case. San ban does not seem to be a word in Chinese (at least, not these days) - but the translation for "sampan" seems always to be given as shān bǎn 舢 板 The same "ban" 板 character is there, meaning "plank" - (notice the two components of it, 木 the tree character (squashed up a bit) which means its something to do with wood - and the other component which can often give a clue as to pronunciation, as it does in this case). But I can't find any meaning for that first syllable shan 舢 , it does not seem to have any meaning on its own, other than as an abbreviation for sampan. I wonder what its origin is? I've written away to our member John K in Hong Kong for his opinion. Could any native speaker of Chinese please comment? My only native speaker friend, who is well-educated but knows nothing about boats, had never learnt that "shan" character. Edit: I've just checked with my son. Despite that he knows little about boats, he wracked his brains for a moment and in the dark recesses of his memory, (he has a remarkably good one for matters linguistic) remembered the characters for sampan, and the fact that in mandarin it is shan ban, not san ban. He even remembered that incredibly obscure "shan" character. He thought it was probably a mandarin rendition of some dialect word for a specific type of boat. This character  舢 shan is made up from two components. Look closely, the first component is 舟 (zhou pronounced "joe") and as a stand-alone character it means "boat" so that tells us 舢 is probably something to do with boats. The first component is often a clue to meaning. The other component is easy - it is 山 shan which usually means  "mountain" or hill, but its role here simply as a clue to pronunciation. So, this "shan" character 舢, the first syllable of "sampan", is probably derived from some no-longer-used, or arcane dialect word to do with boats - and the second syllable of course still means "plank". At least shanban now makes SOME sense Perhaps "three plank" (sanban) is a plausible homonym - almost a pun - which is a very common thing in Chinese. (Or it could have just been a very reasonable but incorrect assumption on the part of Worcester - or again  it might have been a Chinese "spelling" mistake - the average Chinese person in Worcester's time would not have been very literate. Even today, people still sometimes get their characters wrong). Did anyone really want to know all that?  (In fact "pun" comedy xiàngsheng or "cross talk" is an art form in China. You'd better beware of homonyms if you are thinking to give your boat a Chinese name. The language is full of them. Occasionally unprintable. Yes, they have those words too, of course - and use them pretty frequently too). ...................................................  (thanks David) Now, this might be interesting. Let us take "3-plank" as at least a good working definition for what we today would call a sampan - simplicity itself, and just the very thing for a junk rig! (Mark, Dinghy Design Committee - it would be very nice if the winner of the dinghy design contest could be a Chinese sampan - after all, a 3-plank sampan would be easy to make and could make quite a good tender, being not unlike a Scandinavian praam dinghy. How about John K coming up with an authentic Chinese sampan about 8' ?  ) I don't think the Golden Bay or the Drake 13 (both 3-planked) could be called sampans - to me they belong with a class of American skiffs - but surely Freebie could be called a sampan. And surely Annie's cute little dink really WANTS to be called a sampan, even though she's 5-planked (No, Ratty, not Annie - the dinghy I mean!) I quite like the ideas of the late R. D. Culler who has designed some excellent 3-plank traditional American skiffs (one of which, his 13'6" Good Little Skiff, would make a nice junket boat). Culler also has a sampan in his delightful book Skiffs and Schooners. At 11' I think Culler's sampan is too big for a tender and too small for a junket boat, but here it is anyway. (Excuse the scribbles on the drawing. That's from 40 years ago when I was thinking of building one and now I can't erase it.) Culler liked a lot of flare in his flat bottom designs - same principle as Arne and David have applied to their 5-plank designs, I guess. I hope this is all good covid distraction.