This owner wished to have a yacht similar to a Swan 48 (design #2079), but slightly enlarged. She was built by Steel Yachts & Launches Shipyard, but I confess I can't figure out where that yard was located. She was constructed of aluminum and launched in 1974. Otherwise she is based in great part on sailing yacht Noryema IX, design #2148.
Here are the plans.
Displacement 30,575 lbs
Ballast 18,000 lbs (outside) 1,000 lbs (inside)
Sail Area 1,107 sq ft