Try researching similar recreational businesses. If there are any larger companies which happen to be publicly traded, you may find some market information in their reports or reference to where to find it.
You could also look for pulbic records of similar businesses. I expect there is some liscensing involved or maritine records which would indicate how many similar businesses are based in a particular harbor.
There may be a local trade or government tourism organization which could be helpful.
Good Luck!Posted on 05/31/16