You must have bought the boat that was for sale in kingston. Apparently it was built by Holland boats in 1976, from a Vandestadt plan. It looks like it is actually one of van de stadt's Wibo series designs, that has been modified.
Van de Stadt Design - Wibo 930
Heres a full (and very impressive) list of VDS designs:
Van de Stadt Design
Holland Boats built a few of these steel designs, and seemed to have called them excaliburs, although VdS doesn't list any exaclibur in the design catalog except the fiberglass excalibur 36.