"I've spoken to other people who have saved other ships, and you're talking millions [of pounds]," he added.
He said LV72's "biggest problem", because she was towed everywhere, was that she could not be used to take people out on trips, unlike the Medway Queen or the MV Balmoral.
"Those ships can cruise," he said.
"It doesn't make a lot of money, but you can cover your ongoing costs.
"If [Juno] did get saved, what do you actually use her for? Because inside, she's very small, like a terraced house."
He said Juno's condition was "getting worse", but said there was still a long time before she would be at risk of collapse.
"As sad as it is seeing LV72 deteriorating over the last few decades, she's still hanging on," he said.
LV72 Juno's owners have been contacted for comment.
