I remember using them a couple of years and they performed very well with, or as an alternative, to Google AdSense.
AdSense wins, though, if you're looking for one or the other.
Always start with Mobile first if possible, this will ensure that you don't run into difficulties once you've built a stunning desktop site and try to bring it down to Mobile.
Speak with the boat companies directly?
But as Chris suggests, always write about them even if you can't link to them. Thin affiliate sites get destroyed by Google these days.
Honestly, it's not great.
It needs structuring a little better - better defined menus, clearer product layout / titles and possibly lose the boring slider which takes up so much valuable real estate.
I wouldn't bother with any books if I were you - waste of time.
Focus on your website and provide visitors with exactly what they're looking for and in-turn you will perform much better in Google. Find a couple of great blogs and frequent them - things like MOZ and SEL are great starting...