Anyone on the Merlin site remember this 

Quote from the BBC comparing 2010 to 1963

"Amid the hardship however a new sport took off - ice yachting.
Pam Gershon, from Harrow, recalls land yachts on wheels being sailed on the frozen Welsh Harp reservoir in north west London".

If you saw the BBC news yesterday morning there was a shot of two young dinghy sailors of the time sailing a home made ice-yacht on Oulton Broad with Firefly sails and a Merlin Rocket mast.

IIRC there were stories of Fireflies being sailed (on ice) at Welsh Harp in 64/5.

Apparently the bilge keels took a bit of wear, but the keelband took most of the strain. (and I've no idea how you steer one!)

Colin