Coating

Coating (コーティング) is a process in which a ship is coated with special resin from the Yarukiman Mangroves, enabling it to survive the crushing depths of the ocean, such as at the bottom of the Red Line.

Overview
Coating has so far been seen performed at the Sabaody Archipelago, where the Yarukiman Mangroves reside and Fishman Island, where the roots of the Yarukiman Mangroves, and the Light tree Eve, can be found, and there is an as of yet unseen location on the New World side of the Red Line that allows for coating, which so far Whitebeard and Lola's crews have made use of offscreen. It is done to allow ships to bypass the Red Line, which is otherwise impossible to cross, through Fishman Island. Not even the most astute submarines are capable of such a dive, since Fishman Island rests on the sea floor. Private vessels can bypass this and do not need to be coated because they can get clearence from the World Government to pass over the Red Line.

A coating surrounds a ship in a bubble-like membrane which renders the ship less buoyant than the water around it, causing it to sink. Coating is a very delicate procedure and must be done carefully, as any error in its application could compromise the bubble during the trip, causing the ship to be crushed by the pressure if it is deep enough.

Coating Mechanics
A coating mechanic is a person who coats a ship with the special resin that allows it to submerge. It is an expensive job and can take several days to complete. It is unknown how one goes about coating a ship, though Silvers Rayleigh was shown carrying several tools presumably related to the procedure, including oversized paint brushes.

On Fishman Island the use of the resin is taken one step furthur, and the ones who do this are called Bubble Craftsmen. They are responsible for the over water highways, and possibly for other unique structures involving the Yarukiman resin.

Using a coated ship
Once a ship is coated, it loses the ability to stay afloat. Until the ship is ready to depart, an air-filled 'floating bag' is used to keep it on the surface. Once the ship is ready to leave, a valve connecting the bag to the resin bubble is opened, transferring the air into the bubble, causing it to cover the ship completely in order to provide breathable air for the crew.

The completed 'bubble roof' also serves to protect the entire ship from the extreme water pressure beneath the sea. The bubble is permeable, just like the bubbles of the Saboady Archipelago, and will retain its integrity if objects pass through it, even underwater. This includes people and even cannonballs if necessary. However, if punctured in too many places at once, the bubble will pop.

In the anime, the bubble is shown to pop when a ship reaches the surface once more, though this may have been done intentionally by the crew. Assuming the bubble pops as a result of surfacing, this would suggest that coating only lasts as long as the ship remains beneath the surface.

Navigating a coated ship
Once the floating bag is removed, the ship starts to sink. However it does not mean it will sink straight down. The ship is to be navigated by using the underwater Sea Currents as it would use the wind on the ocean surface.

Another way to do so is by using a sea creature to pull the ship. This is (relatively, depending on the crews skill) much simpler as all that needs to be done is to capture a Sea Monster, tame it, and then put a leash on it which is attached to the ship. The sea monster is then used to steer and propel the ship into the depths. It has been said that the mark of a "pro undersea traveller" is to have a beast pulling the ship like that. The main fault with this technique is actually trying to conquer and tame a sea monster that is large and strong enough to pull the ship. However, once it is done, it is smooth sailing ahead, unless the sea monster in question is spooked.

Due to the bubble coating's nature, the ship can fire cannons to defend itself from sea monsters without compromising the barrier. However, the bubble's strength is not absolute. It can be compromised if the ship is bitten by a large animal (such as a Sea King), hitting rocks or a trench that cause the ship or mast to hit the bubble, or if sliced by a sword (such as Zoro did).

According to a sheet of instructions left by Rayleigh to Nami, 70% of all ships that head for Fishman Island sink before reaching their destination.

Coated Ships

 * Moby Dick and Whitebeard Pirates' four paddle ships
 * All of Whitebeard's allies' ships
 * Kid Pirates ship
 * Hawkins Pirates ship
 * Drake Pirates ship
 * On Air Pirates ship
 * Bonney Pirates ship
 * Firetank Pirates ship
 * Fallen Monk Pirates ship
 * Thousand Sunny
 * Unknown pirate galleon cut by Roronoa Zoro
 * Caribou Pirates ship
 * Gyro's ship
 * Flying Dutchman (limited)
 * Noah

Flutter Kick Coating
Flutter Kick Coating (バタ足コーティング), just like with normal coating, is the coating of a person to give them a bubble diving suit. When a person is coated, the bubble forms a spherical shape around the person from the knees up, with a thin coating from the leg down.

Just like with Ship coating, the people are able to withstand great pressure as long as they're in the bubble, but the air they have is limited. Flutter kick coating allows people to leave the ship, to do things like engage someone or something in combat. It was also shown that a small group of people can share a single bubble.

This coating can benefit Devil Fruit users by enabling them to move and fight underwater, although this may be somewhat compromised if the ability user's combat style requires a part of their body leaving the bubble, as Luffy's punch strength was decreased.

Coated People

 * Monkey D. Luffy
 * Roronoa Zoro
 * Sanji
 * Vander Decken IX

Other Uses of Coating
Strictly speaking, the following processes are not used for the same purpose as ship or Flutter Kick Coating, but still involve the use of the Yarukiman resin. So far two locations have adapted the unique properties of the resin for everyday needs, though mainly for transportation. These islands are Sabaody Archipelago and Fishman Island.

Housing
The people of Sabaody use large bubbles, mainly when making hotels. By taking large bubbles, constructing solid surfaces within and furnish them, one can quickly create living quarters.

Helmets
The Tenryubito use bubbles as helmets to keep them from "breathing the same air" as the "commoners." It also allows them to touch their own face since it won't pop easily, allowing them to eat, or in some cases, pick their nose.

Overwater Highways
The citizens of Fishman Island have constructed virtual highways of water that rise above the surface.

Inner tubes
Used mainly by merfolk with un-split tails and fish, the inner tubes allow those who wear them to lift a little off the ground, with mobility supplied by the tail-fin. With enough propulsion, the merfolk or fish are able to ascend even higher. These work well underwater as well, allowing humans riding on a fish to be dry and able to breath.

Bubbly Coral
There is a portable device that can create bubbles made from coral, similar to Milky Dials, called Bubbly Coral. It is used mainly within Fishman Island by citizens and soldiers alike, for transportation purposes above dry land and air.

Bon Chari
These bubble bicycles allow faster propulsion across surfaces by installing a special apparatus that propels a bubble across surfaces when using the bike pedals.

Shopping Bags
By simply attaching a solid bottom to a small bubble with a string attached to it, the bubbles will simply float and one can put various items in it and drag it around.