In addition to the advice above I would add that it makes sense to try to sell on your own if:
1. The boat is popular and a known model (yours is!)
2. You use the broker fee you are not paying to make your deal irrisistable. Don't plan on pocketing it!
3. You understand what boats like yours have SOLD for...not the listing price and are prepared to undercut that SOLD FOR price.
4. The boat is in a PLACE that is easily seen and visited by prospective buyers...like Annapolis, SanDiego etc. . If there's foot traffic, that's even better. No one is gonna visit "Hicksville" to see just ONE Catalina.
5. Spend some $$ to advertise her in the local sailing rags...Spinsheet, Soundings etc. Not everyone shops on-line and those that do will gravitate towards yacht-world which you can't use.