In my experience, it’s product-related blogs that tend to do best with Amazon. Most blogs probably have at least some possibilities (for example here on ProBlogger I occasionally link to a book that relates or a computer or electronic tool that I think might be useful to bloggers) but the reality is that this blog will never convert as well on Amazon as my photography site.
As an affiliate for Boatbookings, you will receive 20% of their revenue - effectively meaning your commission will be about 4% of any sales from your referrals. You also receive 10% of any commissions Boatbookings make on repeat customers who were your referrals. They do have a minimum charter value of 3,000 ($/€/£/etc) before commissions are earned.