This is John Ashworth and the shallow-water quarter rudder for his proa "Z" 
first launched in 1979.
30ft loa
26ft waterline length
14ft from centerline of hull to centerline of ama
1700lbs weight overall
hull ~500lbs
xbeams ~100lbs
ama ~110lbs
The hull is western red cedar covered with versatex fabric and westsystem epoxy
The spars are aircraft spruce and aluminum              
The trampoline extends beyond the ama.
He originally built it with a flat leeward side.
It generated much lift, actually in his words "crabbing to windward"
Then he redid the hull, copying the windward side, so now it's symmetrical.
And is a faster boat now than it was then.
With the flat side the waterline beam was ~18"
Now it's ~24"

The sail is a conventional cambered battened sail, the foot of the mast is in a track 
on the deck. From now on I'll call this mast the yard just to be confusing, but 
it looks like a mast.
Cuz there's also the mast support, or "mast" in the interest of confusion.
It is stepped on a dolphin-striker type beam between the two akas.
To shunt he would unhook a leash that limited the mast rake, and pull the yard t
o the other end on its track.
The mast would rake the right amount automatically.

There's a buoyant sponson on the lee side of the hull like on a Russ Brown boat.
John says "no proa should be designed without one".
The boat came through several knockdowns just fine.

There are two centerboard rudders a la Newick , and
also a popup tiller to use for shallow water or other maneuvering.
He's happy with this arrangement.

There are small "dolphin fins" on the stems to keep the bow from diving.
Kind of like on some Santacruz proas.
They work fine.

The first ama was too small, now it has a larger one,
with a thousand lbs of buoyancy or so.
It has a flat spot on the bottom and skips along the top of the water
very nicely.
The trampoline extends a couple of feet beyond the ama.
He keeps his boat in a narrow tidal inlet - the Ipswitch river, and has to sail 
a few miles
up it to get to the ocean. So he tacks his boat as well as shunting it.
Getting caught aback is also no problem.
He thinks it might actually be faster as an atlantic proa than pacific, and the 
acceleration sailed
on a new "atlantic" tack is particularly impressive.

His first proa was a dory to which he added an outrigger.
The sail was a double-luffed jib, like the "bolger openmind proa" sail
without the battens. The sail worked well for him.
One thing he liked about this proa-dory was you could get down in the hull.
In rough conditions on his big boat it felt exposed being up ontop the hull and 
He felt the need of a lifeline.

Things he would change: 
He'd put more rocker in the hull, put cockpits by the stems to steer from.
Especially in strong winds the crew always ended up moving as far aft as they co

I took a bunch of pictures, they won't be great cuz the boat isn't all put toget
her, but they'll show the shape of the hulls at least.
He's got good pictures, I plan to scan in some of those eventually.

He's interested in talking to likeminded souls, he doesn't have email but he has
 a fax. He's putting the boat back in the water this year, is looking for people to help
 him work on it and sail it.

John Ashworth 
(978) 948-7007 
465 Main St
Rowley , MA 01969-1115