Along the journey of the Strawhats we've seen some of the most magnificent ships from the titanic Moby Dick to the much smaller yet advanced Sunny Go. After doing some research, I've come up with this list of some of the biggest ships to ever set sail. Disclaimer: The ancient weapon Pluton won't be included since we've yet to see it in the story.
1. Noah
The biggest known ship in the show, with the size of about half of the entire Fish Man Island. The Noah is an wooden ark constructed during the Void Century, much of its origin is still a mystery as it's true purpose is still unknown. The ship is so huge that it can only be pulled by multiple Sea Kings.
Height from the Mast to the ship's Hull: 2500m/2.5km
Reference: 25 football fields
2. Thriller Bark
To call Thriller Bark a mere ship would be an understatement, it is literally an island that was converted to a sailing ship. It's the base of the Thriller Bark Pirates lead by the former Warlord, Gecko Moria. In terms of it's length and width it is even bigger than Noah.
Height from the Mast to the ship's Hull: 2038m/2.038km
Reference: 20 football fields
3. Gran Tesoro
Formerly owned and built by Gild Tesoro, Gran Tesoro is a massive cruise like ship with a metropolis built in it. Due to it being the no.1 entertainment hub and it's wealth, it is acknowledged as an country on itself by the World Government. I mean it holds 20% of all the world's circulated money. It is longer than both Noah and Thriller Bark combined !
Length from it's head to tail: 10000m/10km
Reference: 100 football fields
4. Queen Mama Chanter
Helmed by the infamous Big Mom Pirates, the Queen Mama Chanter is the flagship of the Big Mom grand fleet. It is an colossal of a ship and honestly the anime dosen't do it's size a justice. The Thousand Sunny looks like a small boat compared to it. As a homie, the ship itself is alive and it's figurehead is capable of singing.
Height from the Mast to the ship's Hull: 600m
Reference: 6 football field
5. Yonta Maria
Okay this might be a bit obscure one as it was only shown in Dressrosa. It's the flagship of the Yonta Maria Grand Fleet, commanded by Orlumbus. Now it is part of the Straw Hat Grand Fleet ! It's massive size is shown by how Hajrudin a giant was able to get on board and completely dwarf him.
Height from the Mast to the ship's Hull: 200m
Reference: 2 football field
6. Island Ship
As the name suggest, the ship is literally composed of an island. Just like Thriller Bark the island was modified to become a pirate ship, except it's capable of flight. The ship's flight capability is sustained by Shiki's Float float Fruit.
Size: ???
Unfortunately I can't grasp the exact size of this said island nor find over the internet.😔
7. Moby Dick
Moby Dick was the main flagship of the Whitebeard Pirates. As the battleship of the Yonko, it completely dwarfed every other pirates and marines vessels. The ship itself is powered by paddle system capable of sailing the Calm Belt and coated with special resin from Saboady, which allowed her to submerge all the way to Fish Man Island.
Height from the Mast to the ship's Hull: 160m
Reference: 2 football field
8. Wind Granma
Representing the theme of an dragon, the Wind Granma is the main ship of the Revolutionary Army and it's captain being Monkey D. Dragon. It's an indefinitely large ship as it dwarves even the Red Force.
Height from the Mast to the ship's Hull: 100m
Reference: 1 football field
9. Red Force
The Red Force is an absolute behemoth of a ship as it dwarves even the marine ships. Belonging to the Red Hair Pirates and Yonko Shanks, it has a heavy viking theme. The ship was capable of surviving confrontation with the Beast Pirates and later arriving at the Marineford looking unscathed and still top of it's shape.
Height from the Mast to the ship's Hull: 98m
Reference: 1 football field
10. Oro Jackson
The only known ship to have sailed to the end of the Grand Line. Oro Jackson might not be the biggest or most intimidating ship of all but it is sure the most legendary ship to ever sail. Carrying the crew of the Pirate King Gol D. Roger himself, it survived countless clashes with other powerful pirates, marines and the harsh weather of the New World. The ship was built by Tom for Roger in Water 7 and one of the only known ship built from the wood of treasure tree Adam, the other one being Thousand Sunny. Adam wood is said to be toughest wood in the world.
Height from the Mast to the ship's Hull: 96m
Reference: 1 football field
Afternote: I myself am finding all this out now, after doing all the digging. The scale of the One Piece world is just huge. If you think these ships were big than here's the height of Zunesha.
Height from head to lower body: 35000m/35km
Don't even know how many football field is that.😅 Honestly it could be even taller than that.