Day Sailer Class specs say the CB must weigh less than 25#, but I think mine is a bit more (Not a problem, I don't race).
The DS CB is fiberglass, unballasted, and on hte DS II and DS III it is raised and lowered by a pair of lines (1 pulls CB up, the other pulls it down) the DS I and hte DS IV use a bronze lever on the side of hte CB trunk to raise/lower the CB. The DS IV is the one built starting in 1991 by SUNFISH-LASER and now built by Cape Cod Shipbuilding. The DS II and DS III have theoretically self-bailing cockpits even at rest. they also have lockable cuddys. The DS I and DS IV have deeper, but not self-bailing cockpits. The cuddy on hte DS I is totally open to the cockpit, the DS IV has a bulkhead sealing the aft end of the cuddy with a small, watertight hatch for access (CCSB has enlarged that hatch, but it is still not as open as on hte DS II and III).
Basically, in hull design, the DS is a bigger (mostly longer) version of the Javelin with the addition of a cuddy.