Have you ever heard of these? Even better, go watch the 1-2 minute video to be found here. Wow--that blows my mind. Can you even imagine that?
So why are those ships a big deal? I've spoken earlier of my interest in naval campaigns, i.e. whole campaigns centered around exploration of seas and oceans. (A fantastic Greek Isles would make an amazing campaign--obviously!) But I've always felt that such a campaign would seem 'small' in some way--typically as a result of the small size of the vessels of the day.
Most D&D campaigns that I know of exist in that pseudo-historical period between 1000 and 1450 AD or so. And to my knowledge, before coming across the above, most common sea going vessels were shorter than 100 feet long and 30-35 feet wide. While I could easily imagine larger and even much larger ships in my fantasy settings, they didn't seem realistic (used in the loosest sense of the word) enough to warrant existence.
I realize that the entire above paragraph might rub some people the wrong way. (It's fantasy for goodness sake!) But I have always felt that some level of reality or at least verisimilitude was appropriate. Now that I know that wooden ships as long as 450 feet and almost 180 feet wide actually existed in the world in that time frame, I feel freed to include them in a campaign. Of course, the possibilities are endless.
But that is a topic for another time...