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Ian_Grant

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    ian_h_grant@hotmail.com

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  • Gender
    Male
  • Location
    Ottawa, Canada
  • Interests
    Cycling, Nordic Skiing, Back Country Canoe Camping, Pets, Ships

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  1. Generally conditioners are called for for soft woods like pine, or fir plywood, which otherwise can absorb stain unevenly and give a "blobby" appearance.
  2. Hi Steven, yes they used sheaths as you describe, apparently called "askomata". I wondered about doing something similar, but how to attach to hull in some way to allow replacement, also there would be 44 or 60 of them....😅.....plus the oar slides back and forth a little through the stroke as distance to loom mounting point varies.........something like the rubber bulb on an eye dropper comes to mind 🤪😵........trying to think of something..... By the way, your dromon is AWESOME!!!! Love the scenic backdrop!
  3. I attached longer arms to the "sweep" servos to get a decent length of sweep at the (non-existent right now) oar blades. In doing so, I realized that the oar motion was in part being constrained at the holes I drilled for oar ports. I did "bevel" the hole edges from the inside using a countersink bit but they were a little too snug. This applied more to the upper reme than the lower, because of the higher oar angle when "in the water". Another little lesson learned! I have been wondering how to construct oar ports on a real model. Wouldn't want the oars rubbing away at the necessarily thin skin and making the holes ever bigger! My current idea is a drilled hole, with a suitably dimensioned brass "chicken wire staple" for the oar to rub against. Real galleys apparently lashed the oar to a single thole pin, but this doesn't seem practical in a working model. The lower reme's ports need to be pretty snug because their scale freeboard will be less than one inch from the water - remember, literally whole fleets of these things were sunk by sudden storms. Here is a brief video showing the moving mechanism. As I said before, with my two channel RC set I can only power one side; that's where the Arduino comes in! The last part is me trying to row by twiddling both sticks, not very successfully. Arduino will provide consistent motion. Next step is to go to Digikey and order the servo connectors I will need for the Arduino daughter board, plus I think some DIP switches in case I need a "Cal" test case or whatever. I was also thinking of using a 3-position switch channel on my nicer RC transmitter to provide a signal to the Arduino to (a) stop all oars in water, (b) row normally according to throttle and rudder signals, (c) stop all oars out of the water. https://www.youtube.com/watch?v=ivhx3jbQ4p8 Let me know if this link works or not 😉
  4. Thanks Steven, I saw this before but you are right, the stroke is very flat. If this project proceeds to fruition, I expect to be modifying the oar code pool-side during trials to get the shape right, and also to decide at what point the rudder needs the assistance of stopped or backward-going oars on one side.
  5. Funny you should mention Fusion360. I've only used tinkerCAD which seems to be at a rather "for children" level. There really are no accurate plans extant for any ancient galley; having purchased both "Age of the Galley" and "Roman Warships" I am amazed at how little we actually know. Knowledge of Roman galleys is gleaned from coins, a few uncovered fresco paintings in Pompeii or Herculaneum, and some stone relief carvings on Trajan's Column among others. That's it; that's all. Contemporary historians never seemed to include descriptions when mentioning galleys, assuming their contemporary audience had actually seen them already. "Roman Warships" provides an "educated guess" at the various ships but drawings are pretty much limited to a side view, top view, and single cross section in the "engine room". Oh, and they're about 4" or 5" long. Anyway I was wondering how to modify and marry the bow and stern lines from "Olympias" (as an approximation) to Pitakis's extended engine room cross section and Fusion360 came up in my thoughts. But what a learning curve! Oh, for my old drafting machine and table.........
  6. The great advantage of the Arduino language is that you can write programs without having to understand and control all the register bits in the microcontroller, and more especially how to use all the timers. For example, the PULSEIN command returns the duration of a pulse occurring at a specified input pin in microseconds; the compiler handles setting up a timer to count clock cycles during the pulse. For another example, the SERVO library provides the writeMicroseconds command which outputs a pulse of specified length on a specified pin i.e. to a waiting oar servo; the compiler picks a timer and sets it up to time out after the desired pulse length. In fact, using the servo library one can control up to 12 servos with the compiler employing only a single timer. I won't need to worry about timers at all, because I know that each time the program receives and measures the "throttle" and "rudder" pulses from the RC Receiver, 20 msec has elapsed since the previous pulses. I can derive the stroke cycle timing in terms of "number of 50Hz RC cycles elapsed". I think 🤪. You can find a list of the standard Arduino commands at https://www.arduino.cc/reference/en/ . Arduino provides a free development environment which one uses to write, compile, and easily download programs to the target board. Please note that though I seem to wax eloquent on all this, I have never actually done it 😁. That said I have done some reading, and though I was a hardware engineer and never a code developer I have been mulling over various ways to structure the code, while walking the dog etc. Looking forward to trying it.
  7. Dale, there is something or other awry with your main channel deadeye placement. The deadeyes should be in groups such that the chains, when extended in a straight line from their respective shrouds from the masthead, do not interfere with the guns and port lids. From the forward end of the channel, there should be: a group of three (2 shrouds, 1 topmast backstay); gap over gunport; a group of five (4 shrouds, 1 TM b'stay); gap over gunport; two shrouds, space, one shroud; gap over gunport; two shrouds. Here is a Figure from Longridge showing the starboard side main channel. Notice how the chains and preventers are at larger angles moving aft, since the shroud angles change, and how none interferes with a gunport. The smaller topmast backstay deadeyes have shorter chains here, as you noted. I don't know if your deadeyes are just too large, or the channel is a bit too far aft, but you might want to investigate before moving forward. Regards, Ian.
  8. You mean the lower deck port lid? No, I just drilled holes and rigged the port lid ropes. You mean the middle deck port right forward with the two half-doors? I did nothing here. Some people open them; I believe they are at the sick berth.
  9. This large model deserves, nay demands, extensive rigging. It is an undertaking, but well worth the time.
  10. Dale, she looks really good! It's a bit late as I just happened on your log now, and I hesitate to say, but looking at your photos ...😔..... your waterline is quite low...in actual fact the waterline (and thus the copper) reaches the main wale in the midships area. Since you coppered from the keel up, using adhesive tape, you could possibly add a couple more rows. Your decision I know, but if you decide it is do-able her hull would look more true to life. Sorry, I hope I have not offended, at this late date....😟
  11. Just to say that Smithsonianmag.com is an excellent site; you can subscribe for free and receive a daily email with several story links. There is a vast range of topics and there's always a story of interest.
  12. https://www.smithsonianmag.com/smart-news/divers-find-second-century-military-ship-sunken-egyptian-city-180978244/?utm_source=smithsoniandaily&utm_medium=email&utm_campaign=20210721-daily-responsive&spMailingID=45337671&spUserID=OTY4MjUzNzkyMTQ3S0&spJobID=2045187682&spReportId=MjA0NTE4NzY4MgS2
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