I have owned a 2005 R21 Classic for a decade and have seen a few others. My understanding is that they all came originally with a mast and boom. The mast height was consistent, but many have been shortened (or eliminated) over the years for bridge and boathouse clearance. A sail could be hoisted and would serve as a stabilizer, as these boats have a very rounded (full displacement) hull profile and roll like a barrel. The boom supports a canopy which is a very effective sun and rain shelter. The boom could also be used to hoist a dinghy, but I am not sure where it would be stored other for a short-term in the cockpit. The full-displacement hull is very easily driven with about 4 mph at idle, 7 mph at about 2,000 rpm and only a little over 8 mph wide open. My record speed is 10.5 (by GPS) surfing down a wave. At 7 mph, w get about 4 hours to a gallon of fuel. The Classic is very seaworthy and bobs like a cork, although you really gotta hang on sometimes.
The Classic and the EC are quite different, with the EC having a larger cabin and resultant smaller cockpit, relocated fuel tank and cabin amenities. The EC also has a semi-displacement hull with flatter aft sections, although they are still limited to about 9 mph. The EC's from the first decade of the 2000's had the same 30 hp Yanmar as the Classic. Later generation EC's have Volvo motors and I hear that some had a Cummins although I am not sure about that.
Check out my photo album...lotsa photos there of my 21EC and 25sc.
Cheers,
TK
