This may be information overload, but fun

[Trés 30]

This is one heck of a rabbit hole.
Some of the links are dead, but that's bound to happen with this many.

http://www.boat-links.com/boatlink.html#top

[hanleyclifford]

That's more than a rabbit hole - most of the animal kingdom could get in there.

[Al Schober]

That site has been around for about 15 years (my guess) - and yes, I've spent some time lost in that rabbit hole. Haven't tried it lately, so no guess how good the present links are. My guess is that the average link has about a 5 year half life.