ANNAPOLIS, Md.—The years haven’t been kind to Richard Phillips’s 60-foot Striker yacht. After working as a fishing boat in the Dominican Republic, “Big Dog” has sprouted mold, the hull is damaged and the engine needs work.

Sales price: $129,000. “It’s a total piece of junk,” said Edward Ennis, CEO of Striker Yacht Corp., who recently had it inspected.

There...