The Great Sea refers to the vast body of water that surrounds the island that Uzushiogakure resides on. The Land of Whirlpools was restructured along with its surrounding area; allowing for the Great Sea to exist the way it does today. The seas are always calm and made to be that way, patrolled and protected by Uzushiogakure. Various posts and miniature pieces of land are spread throughout the span of the Great Sea and are used as stations to use for security and surveillance. Much of the water surrounding the island is used to supply it with water, as various tubing and lines were created underneath the land in order to create a water system with a never ending flow of water. This filtration adds to the purity of the water and makes the Great Sea so beautiful and serine. The water is crystal clear as it shines and reflects the skies, remaining calm and rarely stirred up or tense. It is known to harbor many resort island and vacation getaways, having a large tourist attraction; especially for the elegant beaches it makes on the island.
Many wildlife and marine animals live in the depths of the Great Sea, often large creatures are hunted and combated with between sailors and sea-travelers due to their natural instinct to protect their homes in the seas. It is evident that the destruction of the island in the past has left ancient relics and treasures to be scattered and sunken to the depths of the ocean; making some travelers interested in finding lost treasures where the wild sea animals live. They protect the ancient relics as well as their own homes, known to be ferocious and terrifying sea monsters. One of the reasons the Great Sea's is patrolled is to keep travelers away from such vile creatures, knowing disturbing their own peace would not serve well. Some islanders are known to harmonize and become friendly with the various creatures at sea, yet they know of their protectiveness as well.
Whirlpool system.
In order to protect their island from being approached by evil forces out of the blue, Uzushiogakure has created an artificial whirlpool system. Meaning they had various navigation routes that stray away from the whirlpools they set up around themselves. This is done and put it in place, in order to prevent those who aren't from Uzushiogakure or for the island to reach the island safely. Making it much more harder to infiltrate through any meager means. The seafarers and merchant ships are given specified routes in order to avoid the whirlpools as they aren't normally shut off and effective indefinitely. Little is known but they are also a power providing source to the island in terms of water, swallowing and storing large amounts in tanks set up beneath them.
Whirlpool system in effect.
no matter the boat, these whirlpools will stop at nothing until anything that roams across them is swallowed whole. The whirlpools are line up strategically so that invaders will have a nearly impossible time pushing through. The currents would be strong enough to push a boat any direction into a the whirling vortex. There are a select few known granted access to the mechanism that controls these whirlpools. Only they could shut or alter the system set up in any given moment; through the activation a specific seal set of hand signs one activated, the user can control them in anyway and may even combine them.
Ship sailing the Great Seas at night.
The seas are also maintained by a vast band of pirates, hired by Uzushiogakure. They roam the seas, making sure all is order for their village and cause, as well as preventing anyone from plundering but them.
One of the many lookout towers out in the Great Sea.
They are there to protect merchant ships as well as provide safe access through the water ways in events that the sea monsters strike against innocent ships passing by. Due to constantly roaming the seas, various ports and islands have been set up to be created as checkpoint stations for the pirates to link back to the village of Uzushiogakure. It has even become evident that various beacon towers are set up throughout the great sea known to hone the hiraishin marker setup by the Shiokage. From such there are teleportation systems setup along the seas. This helps send fleets or ninja to a certain area of the ocean with much eases, especially in the case of a storm.
A clear view of the Great Sea.
The Great Sea is a vital source of energy for Uzushiogakure and the island, pumping its waters through various filtration systems and energy mills in order to power the island. This natural usage of the water, allows for a less hazardous method of energy as well as keeps the island with a flowing cycle of pure water. Its depths have many wonders, being barely ventured and only a mystery. Although one thing, the islanders will always know that they are protected if the great creature of Charybdis is healthy and roaming. This sea monster was tamed by the previous Uzumaki Leader and used as a natural defense of Uzushiogakure's great waters. The fearsome sea monster, known to devour islands in seconds roams the deepest and darkest sections of the Great Sea, lurking for hostile ships and evil doers in order to feed itself and protect the island. It is known to live within a deep sea cavern directly underneath the island and has been affected by a sealing technique that forbids the beast to turn on the villagers and island. This beast is known to bring ultimate destruction and death the second it is sent out as well as known to cause voids in the oceans from how much its mouth can swallow up. If ever needed, the Shiokage can unleash Charybdis and send him out to assault an incoming invader, if they were to get past the intricate whirlpool system that is.