She is the world’s oldest ship of any type still afloat, but how much of that ship is still original material? I believe there is a large area in Indiana called Constitution Grove where white oak is grown for the purpose of replacing planks on the U.S.S. Constitution, but how often are those planks replaced?
The estimates I have seen are 10-15%. I was reading about recently in fact.
As far as exposed decking goes, it is probably 0%.
To add to the above, the remaining original material is likely composed of interior bulkheads, cabinetry in the Captain’s cabin and the like. Everything else has been replaced by Theseus Ship Builders, LLC.
ETA: It seems that is a common question. Per Seaport Boston:
According to the Naval History and Heritage Command Detachment Boston, today’s U.S.S. Constitution maintains about 10 to 15 percent of its original wood, including the lower futtocks, keel and the deadwood at the stem and stern.
Strange trivia bit, the ribs of the great ship are live oak. When they needed to replace the live oak most recently the grandsons of President Tyler provided the live oak from their family estate that President Tyler had bought off Thomas Jefferson.
It gets stranger, the one grandson is still alive. Please keep in mind John Tyler was born in 1790 and was our 10th President.
I just find this incredibly strange.
At what point does it become a replica of the U.S.S. Constitution?
Never, but it will eventually qualify as a case of “my grandfather’s axe” or more appropriately a Ship of Theseus.
As someone that has worked on Navy Ships (well one) and many wooden boats, let me explain a little more. As long as the basic boat keeps getting repaired, it is still the same boat. The lack of original material will not matter.
But as a example where it is not the same boat, a bit of steel from the first Big “E” was used to build CVN-65 USS Enterprise and a piece of that Big “E” is being used to build CVN-80 The USS Enterprise. Those are 3 separate ships.
Your grandpa is Abraham Lincoln?
Not my grandfather, and that is one President that has pretty much nothing to do with the USS Constitution.
HMS Victory, which has just completed a £35m restoration is probably somewhere between 15 and 20% original.
Victory’s keel is made of English Elm from the forests near Portsmouth. It is believed to be almost entirely ‘as launched’, except for a 4.5-metre section that was damaged during a 1941 air raid when a 250-kilogram high explosive bomb hit the masonry steps of the dock and exploded.
USS Constitution is a smaller ship with fewer guns than Victory - a frigate rather than a battleship.
Here’s an article on that- they say 10-20% is original.
Rebuilt, Preserved, Restored - USS Constitution Across the Centuries - USS Constitution Museum
What I’d like to know is if they’re going to rebuild it periodically, why not REALLY rebuild it so that they can actually set the mainsails, not just the topsails? It would be so cool to have an actual functional sailing ship instead of the sorta-kinda thing they have these days.
But it did set all sails a few years ago. I’m confused by your post.
But what if we gradually, one by one, replaced pieces of Abe Lincoln with pieces of your grandfather?
Last time I saw anything about it, they had just set topsails. And I couldn’t find any pictures of anything else.
Good one!
It looks like you’re correct and I’m misremembering. 
Damn, I swore I saw clips of her under full sail.
Outstanding! Were the pieces melted down and reformed, or are they in their original state?
As I recall, it took them an hour, unlike the good old days when Captain Bligh could have the last man down lashed.
Yeah…
I mean, I’m truly excited that they can actually take her out and literally sail her around these days, but I do wish (like I was saying), that they’d do the refits/reconstructions properly, such that they could set full sails if they wanted to, and actually do it for a little while.
I’m sure they just set topsails to slowly cruise around the harbor, but how cool would it be if they’d actually sail out into the bay proper and set all sails?
I’m not sure they could manage it. It took them quite a long time to set what sail they did when she went out several years ago. Faced with the dreaded lea shore, they would call for tugs.