The Skol was a British production fiberglass Moth from the late 1960’s / early 1970’s. The Mk 1 SL was a deep cockpit design developed in foam/glassfibre in early 1969.
The Mk2 was a production fiberglass Moth built by Rondar Boats from 1970 onwards. The Mk II SD had a self-draining tub cockpit with a back tank and was very popular, but rapidly became uncompetitive when wider winged designs rose to prominence.
The big change with the Mk 3 was the removal of the back tank and the full self-draining cockpit through to the open transom. Later boats featured owner added aluminium wings to compete with the wider winged rival designs from Chris Eyre and also Mervyn Cook’s Chelsea Morning.