"It's an important find," said Peter Norman from The Swedish National Heritage Board. "Three of them are three whole hulls. They are standing straight up, 100 metres down on the bottom of the seabed. They are now sealed off and are really of great historical value."
The discovery was made when the company Nord Stream filmed the bottom of the sea, east of the Swedish island of Gotland where parts of the gas pipeline will be laid.
The state's Maritime museums have analysed the pictures and found nine of the artefacts to be of real value.
"Some can be from medieval times and some are from the 1600's. Most are from the 1700's to the 1800's," Peter Norman said.
The wreck, which lies inside the so-called Swedish economic zone, is not in the way of the gas pipeline and Ekot says that Nord Stream has promised not to disturb the wreck site.
The gas pipeline is being built by the consortium Nord Stream and stretches from Vyborg in Russia to Greifswald in Germany. It'll supply Western Europe with gas from Russia, without having to go through transit countries such as Ukraine.
The gaspipeline will run under the Baltic sea and will cross Finnish, Swedish and Danish waters. It's been hugely controversial with environmentalists who say Nord Stream has only carried out cursory checks on the environmental impact of the pipeline, a claim denied by the company.
Due to its low temperatures and oxygen levels, the Baltic Sea is known as an ideal environment for conserving shipwrecks, which can remain virtually unblemished for hundreds and even thousands of year.
According to Norman, some 3,000 shipwrecks have been discovered and mapped in the Baltic, but experts believe more than 100,000 whole and partial wrecks litter the sea bottom.
"What makes this discovery so unique is that these wrecks have their hulls fully intact," Norman said, adding however that there were no plans to raise the wrecks, which lie at a depth of more than 100 metres (328 feet)
