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Richard Braithwaite

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Posts posted by Richard Braithwaite


  1. Starting to plank the canopy today. Olympias's canopy was constructed from a number of sections so that the delicate structure would not be damaged by the hull girder stresses as the long thin ship flexed at sea. The sliding joint between each section is shown in the extract from John Coates Plan No 23 (Quarter Deck) below:

    566931102_Slidingjoint.jpg.b0e54dd3c46be896f2564bc58ddc2df9.jpg

    The start of this joint is indicated by the arrow on the following picture of my model:

    1510311497_PA271455small.thumb.jpg.dd35ce8e16e6b5ec3fa97814a138789f.jpg

     

     


  2. Since this is intended as a model of "Olympias" rather than an updated attempt to model an Athenian Trireme, I shall stick to the Olympias Ram. As a parallel project, I am also working on a software simulation of the maneuvering of oared warships, which I am validating against the sea trials of Olympias. One of the original ideas was to use this model for testing to find some of the coefficients for the software simulation. Must admit that I got a bit carried away with the model. Rather more detail than would be strictly required for a tank test model... I (sort of) justified it to myself on the basis that If I built it to the full size drawings, from wood of the same density, then the weight distribution would be about right.... But there are easier ways of doing that. Probably also easier to use Computational Fluid Dynamics Software to derive the coefficients. Anyway, I thought it would be fun to see if I could build an accurate enough model of Olympias at this scale and fit a rowing machine in it.

    Haven't yet decided how I will make the ram...

    John Coates "Plan No 20 Trieres Ram" drawing shows details of the wooden structure (which I have used for my model as you can see from the whole ship picture at the beginning of the blog) but does not detail the construction of the "Ram Sheath" other than to say that is based on the Athlit Ram as described in the Mariners Mirror , August 1983. The views in the drawing suggest that it is fabricated from plate. Part view of Plan No 20:

     

    1899602628_Plan20Rampart.thumb.jpg.ff4e91d398f33941d4b34d1b4f032d6d.jpg

    Ill need to do some more research...


  3. On 10/1/2019 at 1:03 AM, Louie da fly said:

    That's a pretty amazing machine, Richard. I was hoping to do a similar thing on my dromon model in the early days of the build, but I just don't have the mechanical skills and I gave it up as a bad job.

     

    However, as I'm putting little guys on my model I studied what the oars did in the video of the full size ship's sea trials, and I found it was quite different from some of the oar motions I've seen on video of other mechanised model galleys. I'd be interested to know if the motion of the oars on your model ties up with what's seen on the sea trials.

     

    Steven

    Yes, remains to be seen whether I can achieve the required level of accuracy. Placement of the thole pins in relation to the oar ports is critical to achieving the required length of stroke. The following photos show the approach I used:

     

    1. A jig used for drilling the thole pin mounting blocks to ensure that the hole is in the right place and angle:

    jig-for-thalmian-thole-dril.jpg.1e5241c30fc0bddf84336742baa209ac.jpg

    2. Some pins installed on their blocks together with a jig for installing at the correct angle in the boat:

    jig-and-tholes.jpg.a54532673df8ea3be051cde894ee304c.jpg

    3. Installing the pin in position using the jig:

    installing-thalmian-thole.jpg.d66a6c3d6122fefa71d5509c3e8c0414.jpg

    4. The pin in position:

    thalmian-thole.jpg.d346c1ec285e491681573fd3dae47f2c.jpg

    5. Finally, a check on the clearances to give the required stroke angle:

    thalmian-oar-sweep.jpg.251b8527c88284b72d0a7afa75d22f63.jpg


  4. Before I embarked on this project I built a section model to see if I could fit machinery below the central walkway to operate the oars. This remains an option for this model which is why the canopy and internal hull structure is removable (see bolts in the above pics). The machinery is quite crude (I would aim to improve on that with the full model) but did demonstrate that independent control of port and starboard oars would be possible with machinery that would give an elliptical oar path with the right stroke length.

     

     

     


  5. Several years ago (quite a few in fact...) I started building a 1:24 scale model of a reconstruction of an Athenian Trireme. The model is based on drawings produced by John Coats for building the full size reconstruction ("Olympias"). A number of trials were conducted with the ship in the 1980's, which have been published in a number of sources by the Trireme Trust. Well worth looking up. A fascinating example of experimental archaeology.

    I did have a blog running to record the model build (on this site I think?) but have not updated for a long time and I think it is no longer there. I have now reduced my working hours which has given me more time to progress the model over the last few months, so I thought it would be worth restarting the blog.

    I have just completed the framing for the canopy.

     

    P9130994small.jpg

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