"Nothing's been located, which is uncommon,'' Mr Klinker said.
"I can't say (it is a hoax) but it's certainly on the list of possibilities.''
The search was continuing in case it was a genuine incident.
Six helicopters and several fire trucks and other emergency vehicles were dispatched and waited for victims to arrive, but so far they had not treated anyone, NJ.com reported.
"At this time (the report of an explosion) is unfounded. They're still treating it as if it's real, but they haven't found anything,'' the website reported emergency medical technician Max Ross as saying.
New Zealand engineer Matthew Edwards was listed as among the crew aboard the US$40 million vessel.
Jamie Lowe was the former captain of the 50m motor yacht in the Caribbean and Mediterranean until last July when he settled in New Zealand, according to his LinkedIn profile.
The vessel was sold in June last year and Mr Lowe carried out the professional training of the crew.