Research questions about Sailing Characteristics of an old Cog Ship

Discussion in 'Sailboats' started by SanderV, May 26, 2018.

  1. SanderV
    Joined: May 2018
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    SanderV New Member

    Hi,

    I am a Post Doctoral Fellow and doing research on an old 15th Cog Ship found in the Netherlands. I have made a reconstruction of the ship (see image below) and we are interested in its sailing characteristics. We use Orca 3D software to perform various hydro-static and stability analysis such as (Holtrop) speed/power analysis, but we have no tools to calculate the propulsion forces by the sails.
    I found some information on the website (Horsepower/Sail Area equivalence https://www.boatdesign.net/threads/horsepower-sail-area-equivalence.28551/) about the sail generated forces, but it seems quite general. The Cog ship is a single square rigged boat and I am not sure if the described theory is accurate enough to get a good sail force estimate. We would like to calculate the maximum sailing speed of the ship.
    My first question is which forum at boatdesign.net is most suited for this question. Secondly I would like some advice how to approach this question in a (semi)realistic way.
    Kind regards, Sander
    upload_2018-5-26_12-44-51.png
    upload_2018-5-26_12-57-46.png
     
  2. SanderV
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    SanderV New Member

    The estimated sail area is 60-80 m^2.
     
  3. Angélique
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    Angélique aka Angel (only by name)

    Hi Sander, welcome to the forum . . :)

    I think Boat Design, or the Sailboats forums.

    You can ask the Moderator to move this thread to the forum of your choice, you can do so by clicking on ‘‘report’’ below any post in this thread, and then post your request to the Moderator in the window that appears.

    You can also start a new thread on your prefered subject forum, and then post a link to the new thread here.

    Good luck with your Cog Ship research . . :cool:
     
    Last edited: May 29, 2018
  4. PAR
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    PAR Yacht Designer/Builder

    It may help to know that in force 4 winds, about 50 Sq. ft. of sail area is about 1 HP. Given the extreme burden that hull form carries, you could surmise slightly less, per sq, ft.
     
  5. Angélique
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    Angélique aka Angel (only by name)

    Here's a Dutch government article (auto translate to English) about this thread's 1415~1420 built historical topic ship, which was found in 2012 and lifted in 2016.

    She's in the special frame in picture 1, and kept wet in pic 2 . . .

    [​IMG]

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    [​IMG]
     
  6. wet feet
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    wet feet Senior Member

    I don't know how faithfully the Lisa von Lubeck follows the shape of the true cog,but they might be worth speaking to on the topic.
     
  7. Angélique
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    Angélique aka Angel (only by name)

    I've just looked her up Wet Feet, she certainly looks to be worth a chat for the researchers about her sailing characteristics . . :)


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    There's a in 1994 to 1998 built Dutch reconstruction of a Cog ship from Kampen, which is also the place where in 2012 the one of this topic was found, so I'm sure Sander knows about it, and the ones from Bremen as well, so those are just posted here for general interest...

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    Kampen Cog <aka> Kamper Kogge | Website | (these two links are both in Dutch)

    Zwarte Dame - = - Black Lady
    [​IMG]

    Kamper Kogge a 1998 Dutch reconstruction of a Cog Ship from Kampen in the Netherlands.jpg

    Zwarte Dame Black Lady​ Kamper Kogge 1998 Dutch reconstruction Cog Ship Kampen the Netherlands.jpg

    She seems to be straight downwind motor sailing there Dutch link, note the direction of the flags, and also note the aft starboard cooling water squirt from the engine . . :(

    It looks like she's going upstream the river IJssel there, with a fresh breeze (± force 4~5 Bft ?) against some current, in front of her home port Kampen, while a lot of rain upstream the river Rhine can cause much more current there than is shown in this picture.

    Oh well, that's just something for Sander to research why the engine was running there, and whether she can or can't do by her sail alone under these circumstances, and how they did this 600 years ago with these sailing craft . . :)

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    [​IMG]

    Ubena von Bremen
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    Roland von Bremen
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    At their own websites... | Lisa von Lübeck | Ubena von Bremen | Kieler Hansekogge is the below picture source | Poeler Kogge | Pommern Kogge | Kamper Kogge |

    [​IMG]
     
    Last edited: May 29, 2018
  8. SanderV
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    SanderV New Member

    Hi,
    I would like to move this thread to the Sailboats forum.
    Kind regards,
    Sander
     
  9. SanderV
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    SanderV New Member

    And thanks for all the suggestions. I will contact the different Cogship organisations to get an idea of their sailing characteristics.
    The Cogship (as far as we know) is quite a late model and differs quite a lot from previous found ships. I would therefore also like to pursue the more mathematical approach.
     

  10. Angélique
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    Angélique aka Angel (only by name)

    You can also run the asked for mathematics on an existing Cog ship reconstruction, so you can compare the outcome with performance in reality, and maybe fine-tune the calculation method with this.

    I'll quote your post #1 main request to the forum, since I've drifted quite a bit away from that...
    [​IMG]
     
    Last edited: May 29, 2018
    Doug Lord likes this.
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