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Hi, thank you very much for your input. I think Linda meant that adding "something about how each alternate choice is similar to/different from the original boat" would be labour intensive (which is correct for 2k makes and 8m models!) but we already have logic to get "similar boats" so we'll be able to auto populate these pages with some content.

I have run into this same problem in multiple industries. John Mueller at Google has answered my question multiple times on this subject saying that internal duplicate content is NOT an issue and especially if you can justify it being there a manual review of sorts would not identify a problem. Google will make a judgement call on what the best page to serve is by the users query. In your case you are doing what should be done, the least helpful page is the actual product page and in many cases in the past I have no indexed them. This same problem arises for many industries, real estate, office space, used cars etc...