BigDreams,

A combination of need influenced by aesthetics. People in general are trained to think that boats have to be pointy and curvy and that if they're not then they're "scows", "barges", "bathtubs", look funny, etc. There's also some fear that the flat bow transom will crash against waves.

To get around all that baggage there has to be a strong justification for that bow transom. That usually ends up being mostly increased capacity for a shorter length. As soon as the small size constraint is removed, the bow transom is replaced with a "real" bow. That's why prams tend to be on the shorter end of the scale.

Even so, some designers have made a commitment to bow transoms in the size range that you mention, but they tend to be in the minority. There's Herbulot's Caravelle at 4.6 meter (15 feet) which is technically just below your range, but it has 16-ft knock-off from Mertens that matches your range.

Jim Michalik has made a serious commitement to larger prams. He offers the 16-ft Blobster, Deansbox, and Scram Pram, the 17-ft MikesBoat, the 18-ft Hapscut and the 19-ft JewelBox.

If you really want a large pram but don't like the ones that are out there, CLC can custom design you one, but they will want a living wage for their skilled design work.

And for all those people who just can't wrap their heads around how a boat with a bow transom looks, CLC offers this kit. At the moment it's just for Welsford's SCAMP, but I'm sure that with enough demand they'll expand the product line.

Laszlo 

...and let's not forget Howard Chapelle's "22 Ft. Dutch Scow Sloop" from his book Boatbuilding. I've day dreamed about that one since I first stumbled onto that book in the library as a youth.  Also, Sam Devlin's Lichen 20 comes to mind, see here:

https://devlinboat.com/lichen-20/

Then there were the New Jersey sailing garveys, used by waterfowl hunters, later adapted to power. I believe Reuel Parker designed a number of garveys, both sail and power, in various sizes.

Ah, yes, there's something about the way a square nosed boat schooms along with foam on her chin rather than a bone in her teeth....

.....Michael

   You're both right.  I had forgotten about Merten's Caravelle; it's funny how I keep coming back to his designs.  I built a Prameke 78 a few years back, but sold it before we moved to Mexico.  We had a blast using it on a lake close to where we used to live.  I'll definitely check out that Caravelle again.

I still think there is something very valuable in the prams' stability and seaworthiness in a smaller craft.  There's so much bouyancy in that bow that, with a nice angled bow transom, it seems to pop up instead of stuffing.  Maybe it's my Dutch blood bubbling out.

On a separate topic (but while I've got you here), Laszlo, are you still enjoying your faering cruiser?  Do you think the rudder is sufficient?

There are a lot of cool larger prams out there. Get to a certain size, and in this country they start calling them "scows." 

Ages ago I was hired to draw an 18-foot version of the Passagemaker Dinghy and to cut a kit for it. The rig in the drawings is as requested by the builder. As far as I know it got built, though I never got a performance report. I'd expect it to be stiff and fast and fun to sail.

Mercy, John, you are killing me with boat lust here!  My drool list is getting longer:

• Eastport Ultralight Dinghy - truly a serious, minimalist impulse boat capable of carrying a good load.
• Chester Yawl - a real pulling boat for those who love to row in which one could cover a lot of miles with sleep aboard potential, given the thwart-less interior and some awning work to tent her in snugly.
• Mill Creek 13 - another good impulse boat, a great way to sneak up on birds with serious camera gear right in front of you in the cockpit ready to put down the paddle to take up a camera for a quick shot at target of opportunity.
• Nesting Expedition Dinghy - minimalist cruiser for those short on time, money and storage space, good for getting off for solo adventure over a long weekend on short notice.  For a capable couple, have two and make it a fleet action, rafting up for meals, swimming, overnights, etc.
• Southwester Dory - maybe the closest thing in the CLC lineup to my old Sea Pearl 21, another good adventure boat for beach cruising or carrying some passengers (really needs no crew) for a daysail around the harbor.  Would row better than my Sea Pearl ever did, no doubt, and the motor well is a much better arrangement, for those so inclined, than the jackleg business of hanging a 35# Honda 2 off the rudder as with the Sea Pearl.  Not that'd she needs a motor, of course.
• Faering Cruiser - sometimes a body just has to get away on their own for a while, and this would be a good way to sneak off somewhere they'd need helicopters to find you and drag you back to work, with a lot of adventurous sailing and rowing before they caught up with you.
• Autumn Leaves Canoe Yawl - another good boat for gettin' off by yourself, perhaps in a bit more comfort than the Faering Cruiser.

...and now this!  What a great boat for taking a passel of grandchildren out for a bit of a sail and maybe an amphibious landing for some beach combing!  Of course I want one!

Too many boats, not enough time....

.....Michael