Boats, just like an automobile, depreciate instantly once purchased. I recently attended the Atlanta Boat Show and all makes, sizes, etc., were drastically reduced from last year for same. Year is important when financing but the "big" number is "hours". The average hours during boat season in America is 50. Extremely Important, have the boat detailed, looking new, no mildew, nice clean cover, trailer cleaned, etc., this will sell a boat quickly.
In America we are "holding on" to our money. Luxury items, such as boats, once thought to be a nice weekend activity is no longer important. Gas prices alone have changed the minds of many. In Atlanta our lakes due to drought and too many homes were extremely low with levels currently improving. This housing market effects the way we purchase as well, "weighing" our responsibilities and maintaining our homes.
When I sold boats we used NADA for pricing on used. NADA is used by banks in the Atlanta area as well. Insure the publication you use is current. I believe most are monthly updates. Check with a local bank as well and ask for their input on pricing. At the bank you want to know what they value your boat at, not the maximum amount of a loan, these are different.
Another way to market your boat is through a "boat dealer". We did this and sold many and is on a "consignment" contract between you and dealer. You agree to a minimum price, but can be sold for more of course, you will accept and the dealer with "potential traffic" can offer. The dealer handles sell and financing as well. Best to use a "SeaRay" dealer because this is a name people know and come to a "SeaRay" dealer for name brand.
The low hours your boat has is a "deal" , and many are looking for a "deal". Practically new $21,500 should be a good pricing point with trailer. Again, check NADA as well. When a potential buyer comes to look have someone with you due to many "crooks". Also have "title" accessible to show you are the owner and can sign over, very important. Provide where you have serviced and show, in neat order, service done.
Once a purchaser is ready DO NOT accept personal checks and/or any check from a bank unless the exchange is at their or your bank to insure checks are GOOD. If this is not OK with them, "CROOKS". Boat theft is very common. If they want to go to the water first, you tow and stay with them.
Good luck, go to "marina's" and network. Use "Boat Trader" magazine as well. The internet may work but do not expect much in an acceptable offer. Talk to freinds, family, co-workers, etc. Someone always knows those looking for boats and your boat is great for first timers. Question always asked, why is this boat being sold with little useage?