KOGGE van Tartane-schaal by tartane - FINISHED - 1:87 - reconstruction

[tartane]

In 2023 bouwde ik een model van een kogge, een schip dat van belang was voor de handel tussen ca 1250 en 1450.

Ik bouwde hem, niet vermoedend dat het Stedelijk Museum in Zutphen daar lucht van kreeg. Men vroeg mij het model onderdeel te laten worden van een expositie over de Hanzetijd, waar dit schip een grote rol in speelde.

Het verslag ga ik laten zien in drie delen. Ik maak op voorhand excuses voor mijn niet perfecte kennis van de Engelse taal, maar ik koos er toch voor dit in het Engels te doen. Er komen veel termen in voor die niet goed in computertaal in het Engels zijn weer te geven.

 

RECONSTRUCTION OF A COG

Scale 1 : 87, Built in 2023

 

 

This reconstruction is exactly based on the measurements and construction of

an excavated shipwreck in Holland in 1983, registrated; Oz 36, known as Nijkerk II.

 

The results were in 2021 published by the archeologist Karel Vlierman in 2021 ;

  “Coghen, kleene coghen ende schuten”.In this publication you find detailed drawings of the excavated parts and a reconstruction of the hull.

The German book: ; “Die Kieler Hansekogge, der Nachbau eines historischen Segelschiffes von 1380”, written by Uwe Baykowsky, 1991, was a great help especially for the rigging and the missing parts of the ship such as the mast and the yard.

 

The wreck is until now the most complete cog which is excavated, The starboardside of te hull was almost complete.

A lot had to be reconstructed on paper but the result is very satisfactory.

Combined with remains of other excavated cogs it was possible to build this model

 

Dendrochronologycal the ship was build in 1320, and wrecked around 1355.

 

No remains werd found of the mast, rigging and rudder. Only a few marks point to the posibility of a castle on the stern.

In the publication of the excavation nothing is mentioned about the sailing capabilities, also the lenght of the mast is not reconstructed.

 

Before I started I did a lot of investigation to Mediaeval pictures  Mainly concerning the rigging, the mast and the sail. 

 

Planking the hull

 

The model is made of Mahogany vener. Attached on a frame of triplex. The keel, bow and stern are made of pearwood, attached to the long middle frame of triplex

 

 On the middle frame I attached the frames at first on the righet side and filed them in the correct shape of the hull. After that I made exact copies of all the frames on the left side and attachede them also on the middle frame.

 

I started planking at the keel. All excavations show that the first three planks near the keel were carvel built connected, but only in the middle. Going to the stern and to the bow this construction changed in clinker built  planking. The rest of the hull is entirely clinker built.

The wreck showed that the hull on each side consisted of 15 planks, clinker built. I made this amount also on the model.

 

Every plank consists of three or four parts, just like the real excavated planks

 

The bow during planking before sanding and filing

 

 

 

On the sternpost curved timbers were nessesary. Here the timbers in paper, before making them in wood. Most wooden constructies on the deck  consit of several layers of veneer, glued upon each othter until the exact thicknesses.

 

 

Above the deck the planks are attached on a number of frame timbers which are visible above the deck. In the model I made the same amount as found in the real ship. The upper plank was needed to attache them.

 

 Before placing the frame timbers I removed stsp by step all the temporary upper triplex parts of the frames.

 

 

[tartane]

 

The deck

 

On two places I made openings in the deck. The deck itself consisted of a frame of beams with were formed in a rectangular pattern. Most rectangulars were planked, but a number were hatches used for loading  the vessel. Probably these hatches were caulked during the voyage, to prevent overcoming water in the ship.

 

The walnut shape of the deck which is characteristic for all cogs in that period.

 

In the bow a part of the railing was missing. Probably to guide the anchor cable in a low position. This prevented damage on the upper part of the railing. A cleat on the foreside prevented damage of the anchor-cable.

 

 

 

Th castles.

 

In the wreck were remnants of the vertical beams which once supported a castle in the stern.These wooden castles were common on these ships. The ships company could defend themselves against attacs during the voyage. In none of te wrecks of cogs were sufficient remnants found of such castles.

So we have to look at old illustrations on coins and document-seals of the cities which committed trade with these ships.

Fortunately there is a large number of these old seals, on which  castles can be seen.  Sometimes there was only one castle but other seals show two of these structures.

I chose for two castles, according to the seals of the city of Damme 1300 and the seal of Rye 1400.

On the reconstruction on paper in the archeological publication are drawn two castles. The castle on the stem and a very large castle on the bow. The last one could impossible have stand on this place. It stands in the way  of the sail when the wind blows  in it. On all  seals on which two castles are depicted it is obvious that the castle stand as far as possible near the bow, sometimes even on the bow.

 

 

 

     

Two document-seals with cogs. Above the seal of Rye (1400) and under the seal of Damme (1300).

I chose for these constructions.

The back of the tower on the bow must stand at least on the half length of the yard before the mast, otherwise the sail could not be braced in the proper position during sailing.

 

 

 

 

The mast and the yard.

 

The mast and the yard were not found on the wreck. There are two reconstructed cogs on full scale on which the lenght of the mast had to be calculated. Both cogs are fully documented. So I took  the three lenghts of the ships and the two lenghts of the masts of the reconstructed ships. After some calculations I found a hight of 17,3 m. above the deck.

The construction of the mast is exactly as made on the two reconstructed ships.

 

The sail.

 

Cogs had only one sail. How this was made is not exactly known.  Different solutions can be seen on the document-seals, but the details are very small and hardly recognisable. I did some research on larger illustrations, mainly before the year 1400. Even pictures dating from the Roman times. There I found ships with only one mast with a very detailed rigging. I decided to use these details on my model. Surprisingly some deatils are the same as depicted on several seals from about 800 years later.

 

The sail I made consists of twelve horizontal strips and six vertical ropes. Each rope is led throug rings on every second horizontal seam and finally attached on the lowest seal. When you pull the ropes the sail will fold up until the entire sail ends under the yard.

This  construction can be seen on a reconstructed  pre-Roman vessel which sails in the  Mediterranean the ”Kyrenia Liberty”. The sail is horizontal longer en verical shorter than the sails which are used on the two reconstruced cogs.  On both ships the sails are the results of exeperiments. On my model I used the proportions of the sail which can be seen on old original mediaeval pictures and according to the measurements of the Kyrenia Liberty.

For this reason the yard is also very long. 

 

 

Every rope leads through a bloc in the top of the mast and ends on a jeer bitt on deck.

[Seamus107]

I appreciate and admire what you are trying to accomplish with this model, because I model small open boats with some sort of historical significance, many of which do not have published plans.  You are creating something special from scratch, based on lots of research and considerable ingenuity.  Excellent work!

 

james

[tartane]

Hi James,

 

Thanks for your compliments! I made several historical boats which require a lot of research. Ik build them all on the same scale so it is possible to compare each other. On my website you can find some other boats;    www.constantwillems.nl

Constant

 

[GrandpaPhil]

Incredible work!

[tartane]

The rigging.

 

The rigging is less complicated than the rigging on more masted ships, but is basically the same.

A big difference is the absence of lanyards and deadeyes. During my research I came to the solution that this construction is an invention which dates from the first half of the fifteenth century. Original mediaeval pictures show everywhere an other construction which is surprisingly the same as used on ships with latin sails, which were used until the last part of the nineteenth century. This cog was build in 1320, so long before the invention of lanyards and deadeyes.

 

One of the reconstructed cogs was build in Kiel in Germany. While testing  its sail capabilities it appeared the ship could sail up to 70 degrees by wind abeam. In this position the sail would grate over the shrouds. The shrouds on that ship are equipped with lanyards and deadeyes, which I believe is not correct, so the shrouds could not be removed in case of grating.

Shrouds on ships with latin sails can be removed while sailing. A part of the shrouds on leeward can be removed while the ship is sailing abeam. This is possible with the help of the construction as drawn in the sketch nr 1. A stick (Dutch; knevel) can be pulled out in the connection of two parts of the shroud which both end in a noose. On both sides of the ship are mostly four shrouds as drawn in nr 2. The shrouds windward can of course not be removed, but with some of the shrouds leeward it is possible.

 

 

 

1                                                                                                                                                  

 

2

 

The model without the yard, but with the shrouds.

 

On port-side the four shrouds are all fastened, on starboard only two. The other two are hanging alongside the mast. In this case the wind will come abeam the portside.

This construction is on ships with latin sails always usual, but it is also possible on cogs. Old mediaval illustrations of ships show this solution.

Ships with latin sails have a different rigging because of the possibility of setting the sails and yards in other positions which move around the foreside the masts. But the shroud construction is the same as on cogs.

It is obvious that ratlines are impossible with this type of rigging. Ratlines in shrouds can not be found on ships before the first part of the fifteenth century.

 

The rest

 

On the model I made two anchors. Made of brass. I sawed them from brass plate, thick 2,5 mm. After filing and sanding in the correct proportions,  blades of thin brass,  were soldered on it. After that I painted them in colour Matt  46, from Revell. All iron pieces on the models I make are painted in this color. Never black.

 

The sailors on the model are from “Lehman HO pirates 90-2025”. Usually I do not place figures, but this model goes to a museum here in town. For visitors it is in this way easier to compare the human proportions.

 

I never paint my models, only the sails.

 

The finished model gives an impression of how those ships looked like. It is a reconstruction, so there always will be the possibility of other opinions.

 

The following pictures give an impression of teh finished model.

Cogs had an unsusual construction of the hull. The ends of the  beams inside the ship came out the side of the ships hull. This can be seen on the next illustrations.

 

 u