I've said this on another thread... The boat market is like the housing market. There are some great deals out there. Then there are those who want to sell their boat at what THEY think it's worth so they can run out and buy one of these great deals.
i.e.: The housing market is still in the tank, yet there are houses out there that are over priced and the owners are just hoping some idiot will come along and bail them out so they can move to FL and buy a house with a dock for 175K.
Offer what YOU feel comfortable paying. All they can say is no.
I know several people who have made offers at 50% of the asking price and got the boat. It's simple, they sell the boat, sail it or it sits there. If they sail it, good on them. If it sits, every month it's 30 days closer to becoming a project boat.
Three years ago I had an offer of 18K for my boat. Due to piss poor communication from my broker and the fact that I had plans that month for a cruise it ended up making it very difficult for the buyer and he walked away. I happily left it listed and sailed it. Finally I gave up on brokers and Last month I sold the boat for a MUCH less.
Two years listed with brokers and two people looked at it. Two months on Craigslist and one person looked at it.
Bottom line is that unless it's the lowest priced boat on the block, there won't be offers.