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One more small cog by silverman834 - scale 1:13 - c. 1410

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So, I have just finished my¬†build of a small 15th century cog and while I am pleased with the result, there are¬†some things I wish I¬†would have done differently.¬† The only reasonable thing to do is to start over again ūüėõ

Old build:



I guess most people would start with a new ship, but I don't feel like I'm done yet with NZ43 and would like to fix some issues, and I would like your help to find them. Here is my list of changes, and I would very much like to hear your thoughts on them.

The old model used fir and it it was just as bad as everyone here told me. I will look for pear, but I guess I will not find it and use birch instead.

I bought the old wood in planks, but now I have space to buy a small tablesaw and saw my own wood. But before buying it I will try sawing it by hand and see if it would be feasible as I like the idea of it.

I don't liked how I soaked the planks in hot water, I think I will try a steambox this time.

One thing I really wanted to do with the old build was to use functioning nails, but the scale proved to be just too small. I think it will be better if I now make it 50% bigger length wise. (I thought 50% bigger than 1:20 would be 1:15, but apperently it is 1:1333... Not as a neat and round number as I had hoped. Calling it scale 7.5% sounds better.)

I didn't much care in the last build about where the joint between futtock and floor timber was and I built it frame first.

Now I will build it bottom first, ie the bottom will be frame first and the rest shell first. This way the floors will be shaped and attached to the keel plank and the futtocks will be shaped and attached afterwards. I do not know how to do it, but I'm sure I will find a way

The hold was way too small in the last build. The layout was like this


Red - decks
Green - ceiling
Blue - large beams and masts
Pink - bulkheads

My new proposal is like this instead


The fore deck was way too big and it can be cut down a lot and lots of cargo can be stored there.

The bulkheads are moved to where the decks begin and will be like this with twin stanchions, vertical planking and a door. This design is from the Almere 13 wreck. Perhaps a bulkhead also under the beam aft of the mast to seal off the ceiling area?


And yeah, the bipod mast was a fun build, but I will ditch it for a normal single mast with a normal mast step. And I guess the lifting boom will also have to go.

The old decks were not waterproof, but the new ones will be.

The old cleats were thought of in the last minute and just wrong. I think I will integrate them in the knees on the decks.

Sheer height over decks
I have no clue of what this is called, but I'm talking about this measurement


It is so small on my build. But increasing it means smaller decks and less storage space. How much bigger must this be? The Almere 13 wreck seem to have double the height, but that ship is also a bit bigger than mine.

Any thoughts of other things I should fix?

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    From one cog-man to another, well done!!! and good luck with your new build.  :cheers:


    WOOD:  I have used cherry for internal framing in the past.  It is strong and works well.


    FRAMES:  Attached is a link to the building of the Viking longship HARRALD FAIRHAIR.  You may have already seen it.  While the longship and cog are not the same, construction appears to be similar.   Perhaps it will give you some ideas.  Reminder: on a cog the first three strakes (garboard plus 2) are NOT clinker, they are caravel.


    I look forward to your progress.

Edited by Chuck Seiler
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Thank you @Chuck Seiler for the clip! I havn't seen it before and it was interesting. Fascinating that they didn't steam the planks. And what a massive ship! I had not understood that vikings built that large.


My cog is a bit special as the first strakes becomes clinker towards the ends. This was very clearly seen in the wreck.

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  • 2 weeks later...

@Chuck Seiler thank you for the tips! I've learned a lot of the videos of how square sailed ships sail, most videos I've seen before was multimasted ones.


Tonight I imported the ship plan into cad and made the hull. I tried to stay as close as possible, but had to stray in some areas, and that is the same areas as I strayed in my other build when I used much more lowtech ways of doing my drawings of the frames.


I did a quick check to see that no strakes would be forced into strange shapes.



Red curves are my new sections.



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Change of strategy, it will all be built shell first. I really disliked how 'artificial' the frames in my old build was. Photographs of finds always shows much more 'organic' shapes and I see that look in builds here that are built shell first.


The mold will be in 6mm birch plywood




The mold will be adjusted in the ends as I build the stem, sternpost, hooks and keel plank.



But I can start in the middle and see how it works out

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  • 2 months later...

After building some furniture for the cats in the new apartment I finally have time to build more on this ship. First off I ordered some pear wood from Germany. Now I understand why people said that I shouldn't have use fir in my last build! This wood is just fantastic! Almost no grain and makes really crisp edges.


I ordered 2mm sheets for the planking and 12x25mm (1/2×1") for posts etc. It saws really nice with my fine pull saws.


The mould for the hull is built and the backbone of the ship - stem and sternpost, hooks and keel plank. They are held to the mould by removable wire with shrink tubing and two screws through the keel plank.


I used dry heat to bend the keel plank and will try it on the planks as well.






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On 7/1/2021 at 5:39 PM, silverman834 said:

I used dry heat to bend the keel plank

Hi Silverman.


Nice clean work there. I also used dry heat to bend timber, mainly with a hot air gun. I did use boiling water once because it had to be softened along it's full length at once - but I don't think the timber was more flexible from that technique than just dry heat.  For planks I would look at the twist required & then clamp one end of the plank, then apply hot air & twist the timber with the other hand...let cool & check...twist some more etc.



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  • 2 weeks later...

@Chuck Seiler Thank you, and yes, it bends so much easier! At first I thought something was wrong as it was so easy.


@Mark Pearse Thank you for the great advice! Now I first soak the planks and then hit it with the heat gun. I feel like I get more consistent results by soaking them first, but I guess one could just use dry heat with training.


The planking has started and I'm most impressed by the work they did on this ship. The largest planks are gigantic and it is so hard to imagine them heating them over an open fire before clamping it in place.




The planking is quite special on some cogs as it generally is clinker built, but has a carvel built area where the hull contacts the beach at low tide. And it is also flush at the posts.


This transition between carvel and clinker is sometimes mid-plank and sometimes at the scarf joints.






The ship feels stable and I'm able to remove it from the mould to attach the nails. It's much easier to clench them now instead of waiting 'til the hull is finished.



the clenched ends are a bit long and I'll try to make them 1mm shorter in the future. 

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@Mark Pearse I've tried a couple of different ways to clench the nails, and right now I start the bend by pressing with a left over plank and then complete it and push the head into the wood using a polygrip with brass plates to protect the wood. I think this gives me more control then using a hammer but we'll see if I find a better way

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Five out of nine strakes done. These are the strakes that is carvel built midships. And now I will take a break from planking and do some frames. Most of the frames are of three parts; floor and two futtocks. Looking at the drawings of the wreck I see that one could say that the floor parts cover the carvel built areas and the futtocks are used for the clinker built parts of the strakes.




I enjoyed making the cargo in the last build and I have already started some of that work by reading books with titles like 'The ploughs of medieval Denmark' and such like. I never thought the history of ploughs was this exciting! My partner is amazed of how I seem to be able to be enthral by almost any subject...





Edited by silverman834
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So I started doing the floors. The ceiling covers eight floors in the middle so that's a good starting point. As I remove the hull from the mould there is a slight deformation, but nothing to worry about there.


I copy the hull shape using this method I've seen here and it works out nicely and I spend a couple of days of the vacation almost finishing all eight floors.







It looks pretty good and I clamp some of the floors to the hull and put it back on the mould.




It doesn't fit!!!


I was ready to throw away the floors and do at least a couple of them with the hull on the mould (I made it quite spacious with this in mind...), but after I have stepped back for a while and taken a fresh look I will try and bend the floors sligthly to get the correct shape. The plan is to have the hull on the mould and then clamp the floors to it. Let's see how that goes. 


Post script: I think this error was always there when I removed it from the mould, but it was so easy to bend it back that I didn't think so much about it. But the floors solidified the error and now it took a lot more power to bend it back.

Edited by silverman834
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All visable floors are done. The aftmost is shaped to the hull but not treenailed as I want to make the futtocks before finishing it as it will have a bulk head on it. The foremost of the visible frames will perhaps only be futtocks and also have a bulk head why I'm also waiting with it.





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  • 4 months later...

It's almost half a year since I last posted here. You see, I got a bit tired of the planking and took a break to make something to use as cargo for when it's finished. So I made a plough. It can be disassembled to take up less space. It's based on a danish find from this period.




But as I browsed through books in the library for inspiration for ploughs (all Swedish university libraries are free to the public) I found a picture of a medieval rope that I couldn't wrap my head around as I couldn't see how it had been made. So I fell down another rabbit hole investigating rope making before the rope walk was invented. This resulted in this video if you are interested.



And then I got energy for finishing the planking!





The remaining strakes were clinker built and I finished off the sheer with a clamp like in the find. This clamp is attached with treenails. I placed these treenails between every frame, but they should really be placed every 12 cm (5")! And I also made them thinner as they really were up to 5cm (2") thick!


I placed blocks in the end of the clamp for reinforcement. The one in the bow is based on the block from Almere Wijk 13 and it has a cavity for the bowsprit. This block and both posts will be adjusted in size later.


You really can't turn your back to the kittens without them finding something new to use as a bed!


Next up is finishing the seams in the carvel built section as these were caulked with mosslaths between the planks.

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You saw in the last post that the cracks between the planks in the flush carvelbuilt section were uneven and they now looks nicer after I inserted the laths between the planks. I hoped the walnut strips would show up a bit more, but I guess it's nice that they are discreet.



These laths should then be protected by iron clamps called sintrels. Here is a picture from another ship from the same period.




I have looked into manufacturing them by photo etching brass, but I think it will be hard to secure them without gluing and it would look very busy so perhaps I will omit them.

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