Buying a boat is easy. Selling can be a nightmare. There a number of different ways in which it can be done.
The most sensible approach is probably to use a broker. They can give you advice on the best price, on the local market, and whether your boat is suitable for the international market. If your boat is relatively small, then you are probably looking at a local buyer, and a local dealer is probably the best bet. However that local dealer should have access to, and be using the internet directories. Even local buyers browse the yacht search engines to compare yachts and boats around the world.
When my father's Hurley 30/90 was being sold by Euroyachts in Largs, we were disappointed to see that it was not listed in the main directories at Boats.com and Yachting Monthly.
Using the internet alone is unlikely to be successful, as you will want the dealer's help in arranging viewer, and getting the boat ready for surveys and inspections.