No. But I think a broker would work to sell a "rare boat" in very good to excellent condition. I know if I had a $1M listing I'd work it hard. Only 8 boats of that class in the world; maybe nearly as few buyers. You can always try to split the sales commission with the other guy.
Just remember; it's
always a buyers' market. Most owners are more in love their boats than potential buyers and tend to over-rate them. (Your muse that the boat could sell itself is indicative.

) They may find themselves "offended" by a lowish offer as they perceive it which actually reflects the market value--
if the owner really wanted to sell it. This tends to make direct face-to-face (i.e., buyer to seller) negotiations tough. (A buyer looking for a boat over time will likely know the market better than a one-time seller.) There are literally
thousands of "large" boats up for sell every day over the range of prices to your ask; many of them quite nice. That's what I reminded the seller of, of the last boat I bought, every time we "talked."