Let's go everyone...!! Back to the sea of adventure again!! I came to take you home!!
The Going Merry was the first full-sized ship owned by the Straw Hat Pirates, a caravel that served as their main transportation through the East Blue, and the Grand Line up until Water 7. It was often affectionally referred to as simply Merry (メリー, Merī) by the crew.
The Going Merry had a jib and a central steer rudder. The ship's armaments consisted of four cannons, one in the bow pointing forward, one in the stern, and two pointing to either side. They were rarely used, as the Straw Hat Pirates usually preferred to run away or engage in hand-to-hand combat. After the Arlong Park Arc, the Going Merry gained three tangerine trees from Bell-mère's orchard, a memento of Nami's home. As the crew traveled through the first half of the Grand Line, the ship received more and more damage and gained several metal patches to hold her together at places that could not be nailed back together: prominent examples are Merry's figurehead and the mast, which was torn off several times. Several spots of the guardrail were damaged and missing, leading the crew to patch them up with wood-boards, which was done rather crudely due to their lack of experience in carpentry. By the time it reached Water 7, the keel was damaged, which was considered to be irreparable in the long run, thus dooming Merry. In the Skypiea arc, the body of the ship had wings and the sheep figurehead was dressed as a chicken.
Despite the incredible amount of damage, the ship accumulated over its travel through the Grand Line, it had a miraculous resilience in that when Kaku released it to drop down a waterfall, it did not smash apart, but instead landed on its side, undamaged from the fall. With Iceburg's expertise in patching it up to extend the limited time it had, the Going Merry was able to sail through the treacherous storm of the Aqua Laguna, all the way to Enies Lobby and back before finally succumbing to its limits.
In volume 11 of the manga, Oda presented various schematics and explanations of each part of the ship. These included everything from Merry's figurehead to the kitchen.
This is the room with the most functions in the entire ship. It serves as the meeting room, lounge, kitchen and helm. Here the whole crew can do a number of things. Temporarily, Usopp used this room for his Usopp's Workshop.
The steering pole used to maneuver the ship is located in this room. It has a sheep's head similar to the one used for the ship's figurehead. By tilting the pole left or right, the rudder at the stern will move in that direction.
The men's room of the Going Merry is located below the deck of the ship right below the mast. It is quite large and untidy. This room is normally crowded due to the fact it is shared by Luffy, Zoro, Usopp, Chopper, and Sanji to sleep. It is accessed through a hatch next to the mast. There are a total of five hammocks located here to sleep on. There is an emergency exit that connects to the women's room in case something should happen.
A storage room and a cannon deck are located under the lounge of the Going Merry. This is where the crew keeps all their cargo such as beer barrels, water barrels, rations, and treasure boxes in storage. Any treasure that Nami cannot keep in the women's quarters is kept here as well. The room also houses two cannons facing each side of the ship.
The bathroom and the women's quarters can be accessed from here. Some towels can be found next to the bathroom's entrance for when one finishes taking a bath. The hatch going down to the women's quarters had a latch to keep out prying eyes.
The steering shaft that is used to steer the ship can also be seen located above this room.
The women's room of the Going Merry is located under the storage and cannon deck. This is where Nami and Nico Robin (and for a time, Vivi) usually sleep. It was originally designed by Merry for Kaya's use, resulting in its beautiful and well-decorated design. The room is accessed through a hatch that leads to the room above. This hatch had a lock. There is an emergency exit that connects to the men's room located here in case something happens. This hatch, however, is not normally used and is usually locked.
After the Arlong Park Arc, a bar was added here by a carpenter from Cocoyasi, Teru-san.
A cannon deck can be found below the front deck of the Going Merry. It also serves as the room where the anchor is stored. Various weapons such as swords can be stored here. It also contains giant oars and life preservers for use when called for.
The cannon here was notably used to fire at Laboon before the Going Merry rammed into him and broke her figurehead.
The bathroom of the Going Merry is located below deck, next to the rudder of the ship. It is accessed through a door leading to the storage room. This door had curtains for privacy.
The bathroom features a shower, a bathtub, a sink, and a toilet. When Robin was frozen by Aokiji, the bathtub was used by Chopper and Usopp to thaw her out. The water in the bathroom is drawn up by a special machine located underneath the stairs on the top deck. There used to be two of these machines, but Luffy broke one.
Care must be taken after using the shower. After cleaning themselves, the crew must make sure to thoroughly clean the bathroom with a rubber wiper in order to prevent the ship from being weakened by moisture.
The figurehead of the Going Merry is a sheep. This is where Luffy likes to sit most of the time while sailing. Why he likes to sit there considering his inability to swim is a complete mystery. When the figurehead was temporarily broken upon impact with Laboon, Luffy expressed how mad he was and attacked the whale. The figurehead is also found on top of the ship's steering pole in the main room. This design is also used for the figurehead of the Mini Merry II.
Throughout the series, the figurehead would sometimes show signs of expressions like a regular person. These have ranged from comical to sad.
After the Arlong Park Arc, three mikan trees from Bell-mère's grove were added to the top of the Going Merry. The fruits they bear are satsumas (Citrus unshui) but are usually translated as tangerine or oranges. Nami treats them with care, as they are mementos of Bell-mère. They provide the crew with Vitamin C as well as serve as decorations for the ship.
Aside from Nami taking care of them, Sanji also protects these three trees from those who might otherwise harm them or steal the fruit (e.g., Luffy).
After Luffy and Usopp's battle in Water 7, these trees were moved to the hotel room where the Straw Hats were. They were luckily found by the Galley-La shipwrights and moved to a safer location before the Aqua Laguna hit.
They, along with the rest of the Straw Hats' belongings, now reside on the Thousand Sunny.
On board the Thousand Sunny, Franky announced that the Thousand Sunny will carry on the spirit of Going Merry. This is shown more literally when Franky later introduced the Straw Hat Pirates to the soldier dock system and it was revealed that channel 2 houses the Mini Merry II, a four-passenger steamboat almost identical to the original Merry, so much that Usopp declared that she was Merry's "reincarnation"; the main differences are that it is much smaller and has a steam engine with paddle wheels.
Usopp, who was so dedicated to saving Merry that it blinded him from the truth to the point of nearly severing his ties with the rest of the Straw Hat Pirates, came to realize his mistake upon Merry's funeral. Although difficult, he accepted that he had to let the ship go, and eventually went to apologize to the crew before being re-accepted.