Huge ships are very heavy. However, they become even heavier once they sink. They fill up with water, mud, some sea creatures make themselves home in those shipwrecks. This is a big problem if they decide to salvage the ship – how do you recover a sunken ship when it‘s so big and heavy? Well, you cut it into pieces, but that is just half of the story.
There some very powerful sea cranes in operation. Some of them are floating, some of them are mounted on giant ships and some of them actually brace themselves on the bottom of the sea if it is not very deep. There are options, but none of them matter if the ship is under the water. Ships are very strong when they are intact sailing on the sea. But they become very brittle once they sustain some damage and sink to the bottom in some unusual position. This makes recovery very difficult.
So what do they do? Well, a simple solution is to just let the shipwreck be. It is a giant piece of junk at that point and it is not great for the environment, but sometimes recovery efforts may be even more damaging and simply too expensive. If the wreck is not in the way of other ships and is not posing any further damage, it may be left to rest where it went down. Sometimes, if it is possible, the recovery crew will salvage some parts and fuel, but the bulk of the ship is going to remain on the seabed forever.
However, in those cases when it is necessary to recover the ship, the best bet is to cut it into pieces. They are more manageable, easier to raise and take to some scrap metal company. But how do you cut a giant ship that is entirely under water? The best, most efficient technique to cut a shipwreck may actually be known for some camping enthusiasts – they use a cutting wire.
A film about removing Baltic Ace from the bottom of the sea
A cutting wire for ship salvaging is a big thick cable with some segments of abrasive materials – ceramic and some synthetic diamond. Cutting wire is passed under the shipwreck after all its fuel is removed. Preparations take some time, because condition of the ship has to be taken into account. This cable is then stretched between two platforms that can be floating or fixed to the seabed. Then it is moved back and forth with a huge amount of pulling force. It easily slices through the ship from the bottom to the top, leaving a relatively clean cut.
After the ship is cut into pieces separate parts have to be raised to the top, which is also quite difficult. They are heavy and lose a lot of structural integrity. These pieces go straight to a company that deals with scrap metal. Then the seabed has to be cleared from the remaining debris. This takes some machines and a lot of manual labour.
The entire process takes months to complete. It is also quite expensive – 150 people and 18 boats and ships participated in the salvaging operation of the car carrier Baltic Ace. However, it is unavoidable if you want to have a clean seabed without any threat to wildlife and marine operations.