(My apologies for the coloured dots in the photos on this page, back in the 70's colour film was expensive, so I used up some outdated film....)
An Uncle of mine built this Mermaid from a kit back in the seventies.
It was plywood 'stitch and glue' construction, of very similar dimensions to the Mirror Dinghy produced in the same era. It wasn't as popular though, which was a shame, as it was better in many respects, including the proper stem, (rather than the Mirror's bluff pram dinghy shape).
It had the same wooden spar gunter rig, so that all the sailing gear could be carried within the hull, with no overhanging.
Beam: 4ft 7in
Hull Weight: 115lbs
Sail Area: 70 sq ft
PY: 127 (mk 1)
Designed by Roger Hancock in 1972
(not there any more though)