Reply to Caro Brooking: The scow schooner plans in your post of April 11 2017 (two posts back) are of two different designs, both by Brian Donovan.
The first of the two drawings is a 28' scow schooner which Brian Donovan designed during the time he was living in a caravan on a property my wife and I owned at Riverhead. The prototype was built next door. Brian was quite excited by the concept, which he believed could be built very cheaply, with a minimum of materials. "You can build it out of nothing" he said "with just a hammer, a skillsaw and a broad axe." He was building a little round bilge boat for himself at the time and he confided "I wish I had thought of this idea earlier." I think the materials which his neighbour was putting into the build were inferior (demolition timber for framing, and free "car case" plywood for the hull, sheathed with a thin layer of ferrocement.) It sunk soon after it was launched (the story I heard is that it sunk when it was launched at Riverhead, through sitting on something hard when the tide went out - but I did not see it.)
I always believed (and still do) that this was the one which ended up on the beach at the back of someone's property at Cox's Bay. I think this is the boat you are referring to, but perhaps there were two of them built. I do not recall if the cabin top profile was true to plan. I think that cabin was probably true to the first of the plans you posted (the one on the left, the 28 footer). One thing would identify it - it had a hand made wheel with turned spokes made from macrocarpa. It was me who made the wheel and I would recognise it, if it survived. I don't think any more were built, although the concept has since been proven. Typically, Brian just did the study plan/ sail plan which is the drawing you have posted - he did not get around to drawing construction details but just supervised and gave his neighbour verbal instructions. The neighbour (and Brian himself at the time) were close to penniless and Brian, perhaps over-optimistically, encouraged him to just go ahead and make do with what he had. Some years later a small company was formed to market some of Brian's designs, and one of the shareholders (Ian Baugh) completed the drawings, construction details etc. Ian did the construction drawings under Brian's supervision. I don't think any plans were sold and I am not aware of any further scows built to this design. However the ferrocement sheathing concept looked promising and has since been proven. Another of Brian's associates (Joe Buckton) ferrocement sheathed an old derelict launch hull, using the same layup as the scow (light gauge skeletal wire and chicken mesh) and if anyone is interested, I ended up owning that hull, and just recently (after it had lain derelict in the mud for a number of years and full of water) I broke open the ferrocement sheathing to inspect its condition. The ferrocement and its wire reinforcing was in the same good condition as it was 50 years ago when it was plastered.
I think the little scow would probably be still around today if the builder had used better framing and plywood, and heavier scantlings.
The second of the two drawings is a 33' scow which Brian designed for me. This one also was just the sail plan (drawn on the back of a calendar) and another sheet with some offsets. After discussion with Brian Donovan I decided to build this one heavier as I thought the 28 footer was too light in her scantlings (I started building the 33' scow before the 28' one was launched.) I used newly milled macrocarpa framing, and two skins of 3/4" macrocarpa planking, laid diagonally and fastened with clenched galvanised nails. There is a post which describes it in more details earlier in this forum, about page 5. The steel reinforcing for the ferrocement sheath was a good quality mesh known as Watson mesh, and some #8g rods were laid around higher stressed areas. After I built the hull, plastered the ferrocement sheath and gave it a coat of epoxy and rolled it into the water, I gave up on the project in order to go commercial fishing. It was taken over by Brian Giles, who built the topsides, installed the engine and completed the interior and the rigging pretty much as you see in the plan you have posted. It was pretty true to the drawing you have posted (the one on the right) except that there was no break in the cabin top, this one was built with the cabin top all on one level. It looked pretty good, with its schooner rig, fidded topmasts and all, and spent a number of years in Whangaroa Harbour under the name "Endurance". It went through another owner, then I re-purchased it and sailed it back to Auckland and lived in it for a number of years. (It sailed pretty well, too.) It is currently in West Auckland sitting on a mudbank about 20 metres away from where it was built. The macrocarpa hull and ferrocement sheathing looks pretty good from the outside, but no destructive examination has been done. The plywood cabin top has rotted in the damp conditions we have here, and she has narrowly escaped becoming a hulk. However she has recently been taken over by a new owner who has the enthusiasm and skill to rebuild the topsides, and very soon she will be sailed back to Whangarei to have a new lease of life - and a new rig. She is going to be converted into a Chinese junk rig, and I believe she will be renamed "Havoc" after one of the earlier commercial scows.
Just to ensure there is no confusion, there is a third ferrocement-sheathed scow which was even more lightly constructed from plywood, which was built in Thames by the late Ian White. It had no centreboard (instead shallow bilge keels) and in scantings it was downright flimsy. I can say that, because Ian was a friend of mine and I helped him plaster it and I told him at the time I thought it was pretty light. I don 't know what happened to that one, but it was about the same size and superficially similar to look at to the 28' Donovan scow which Caro is referring to. I think I saw it (unrigged) one day when I drove past Little Shoal Bay but never saw it again, and Ian White had since gone to Australia. I have no doubt it would not have lasted very long. I mention this in case there is any confusion with the one Caro is referring to. To the best of my knowledge those are the only three ferrocement sheathed scows which were ever built - except that I am currently in the process of building another one right now.