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Towards the end of the 12th century, a number of German maritime trading towns in the Baltic began to join together in order to serve their common interests. The resultant Hanseatic League soon dominated maritime trade in Northern Europe. In the interest of economy they developed a new type of ship - the cog.

The earliest mentions of the cog in written sources date way back to the 9th century, but the earlist excavated example dates to 1226.

We see here some representations of cogs that appear on the seals of towns belonging to the Hanseatic League. These date to the 13th and 14th centuries.

All cogs have:

It is possible that the rise of cogs had a lot to do with the development of the stern rudder in Northern Europe.

Here we see that these cogs were not just for merchants. They were used as warships too. Note the diagnostic features again: straight stem and sternposts, nearly vertical clinker planks, and a very full midsection that is quite flat, made for carrying cargo.

 

Main Point Review

  1. Bottom strakes were edge joined on each side of a keel.
  2. Strakes were nailed to inner frames.
  3. After the chine, the sides of the vessel were lapstrake or clinker built.
  4. Not riveted like Scandinavian vessels, but clenched nails.
  5. Extremely high sides with throughbeams to strengthen the upper hull.
  6. Nearly flat bottoms - originating in the shallow waters of Holland and Germany.

The Bremen Cog

Here we see the Bremen Cog - the best-preserved cog in existence. In building this cog, the stern, sternpost and keel were first assembled. Then the other bottom planking strakes were laid out edge to edge to either side of the keel plank. All the bottom planking was held together by being fastened to frame floors that were next installed.

In the past, it was suggested that the cog may have developed out of a type of dugout with flat bottom and hard chines, and a steep straight bow and stern, still in use in the low lands area in modern times.

After installing edge to edge planking (carvel) the sides of the hull were shell-built in the lapstrake or clinker fashion. Planking was not riveted together as in the Scandinavian tradition, but was just nailed together using iron nails. The iron nails were driven in from the outside and clenced on the inside. The extremely high sides were held in place by an ingenious combination of Mediterranean through-beams set at a level midway up the sides of the hull surmounted by Scandinavian vertical knees.

The origin of the cog is as yet, uncertain. It probably came into being along the low lands of Holland and Germany where their vast areas of shallows that left ships high and dry during the low tide. Obviously, flat-bottomed ships would be far more convinient in such places.

The pieces of the Bremen cog have been reassembled in a maritime museum at Bremerhaven, Germany. The conservation began only after the hull was reassembled, with a conservation tank built around the reassumbled hull.

This cog had been under constructino in a shipyard when she was swept away from her slip in a storm and sunk. Some shipbuilding tools were found a with the ship, as well as a shoe and a ship's toilet. The ship was clearly not finished when she was lost. The sterncastle was not quite finished, and the forecastle was not even started yet.

The vessel was 77 ft long and 24.5 feet wide, with a vertical height of 24.5 feet, and an estimated capacity of 130 tons.

The mast step extended the entire length of the hull, making it a true keelson. Notice also that in the bow there is a through beam above the level of the deck. This is called a riding bitt. An anchor would have been tied to it originally.

On the main deck underneath the stern castle was a windlass. It was used for hauling in anchor cables, and for raising cargo.

On the stern deck there is a capstan used primariloy for raising the sail, as well as cargo.

Dendrochronology of the throughbeams from the hull freveals that the oak tree was felled in AD 1378 in an oak forest 200 km upstream from Bremen on the Weser river. The ship probably dates to 1380.