I'll try not to be too much "tongue in cheek" here, BUT ...
Irrespective of what channel you use to market your boat for sale, nothing is more important than the price vs. time equation.
I have seen many boat-selling dock neighbors price their boats at the higher (or even higher) end of what they deem is the "market" price. To their dismay, 12 months later (and now having spent 12 months x say $400/mo. in dock fees = $4800 plus $500/year insurance plus say another $1000 for registration and other incidentals) they have let go of another $6000 - $7000 in holding costs. And their boat has suffered another year of depreciation and degradation of curb appeal. And to add insult to injury, maybe they haven't even used the boat at all during the year.
What I am saying is that if you want to sell your boat, price it so that it will go TOMORROW! That is much more important than deciding whether to consign it to say a broker (one of whose interest's is to keep used boat prices propped up), or eBay, or Craigslist, or just hanging out a sign. And then recognizing 12-24 months later and the bank account being depleted of another $7000 - $14000, that the boat is still unsold.
For each person the calculation is different ... But just do the calculation of price vs. time vs. likelihood of making a sale scenario.
When I bought my bought, I made a vow to myself that I would not forget that I was engaging in a hobby. My $ value/investment was my enjoyment of owning a boat, a floating condo, and the experience of it all. But that I would never have any expectation of getting a return on my monetary "investment".
And that when time came to let go of my hobby (or upgrade to a new/bigger boat), my current boat (which I prize highly) will be priced for a new hobbyist to start enjoying within days after I list the boat for sale.