Roman Quadrireme Galley by Ian_Grant - 1/32 Scale - RADIO

[Ian_Grant]

4 hours ago, Ian_Grant said:

 (this thing consisted of five PCP's entirely built from MSI TTL) with ....

I should have mentioned these five circuit board prototypes covered in socketed TTL were entirely wire-wrapped (giving away my age here). That added another dimension to debugging/modifying.  Fond memories...!

[Ian_Grant]

Modified code again to replace the rectangular stroke with parabolic entry and exit on the power stroke with flat central portion. Now that I've seen rectangular, trapezoidal, and parabolic strokes I conclude that the stroke shape is not important; the vertical movement is so much less than the sweep movement that the eye cannot discern the difference.

 

Since I now had the parabola formulas in the program I decided to have some fun with the stroke as shown in this video.

 

 

I'm very happy with my code; it has been robust in the face of frequent changes and obviously is not a wobbly house of cards which is what I was afraid I would end up with. Perhaps "C" itself forces you to write in a structured way.....

 

I will now move on to a hull design and build (finally, I hear people saying......).  One last thing to show - I built a water tank to see the oars row in water. Not for long as they are glued with yellow carpenter's glue and are not varnished or painted as yet. I'll need to sand the corners off the blades before applying finish. Anyway here is a brief video. You can see where my garbage bag liner sprung a leak 😆. No danger of the mechanism flying off to the side..😄..I must say it's hard to imagine this having the power to move what will be a fairly heavy hull. I hope to God after all this effort, and effort to come, that it does.🤞✌️

 

 

 

Edited October 25, 2022 by Ian_Grant

[Glen McGuire]

That is beyond cool, Ian!  Looking forward to seeing you mold a ship around it.  Will you build the ship next or add the banks of oars on the other side first?

[Ian_Grant]

First the ship, then the second bank of oars. I'm finished with the software for now so I'm going to dismantle the oar bank to weigh the aluminum channel; if it's fairly heavy compared to plywood I will modify the bank to a wood plate sliding on Lee Valley "Slippery tape" and try that out. If successful I will go with that approach. As I mentioned earlier I need to beef up the u/w hull to displace the resulting expected weight of it all. What I am coming up with to attain the necessary volume is a most inelegant midships shape 😬. When I have a hull I will be measuring its displacement ASAP to verify. I'm even thinking about just covering the hull framing in two layers of plastic wrap or silkspan or something, just to try to make a quick measurement of weight required to get it to waterline.

 

Here is video of another model; 1.3m and 6.5kg displacement. Not sure if he has a propeller "assist" in her. My estimated hull is a couple of inches longer and 1.8 kg heavier, half of which is the darn drawer slides.

 

 

Edited December 10, 2022 by Ian_Grant

[Bedford]

I'm nobodys hydrological engineer (don't even think that's the right term) but I'd imagine that the oars sweeping in a fixed test like that will mostly stir the water into eddy currents and not result in much in the way of thrust but when on a floating boat they will work more as they're designed to which involves moving the boat rather than moving much water. I think it may surprise you.

[gjdale]

This is so cool Ian! Perhaps Glen (McGuire) can make you some miniature slaves to man the oars in the final rendition!

[Glen McGuire]

7 hours ago, gjdale said:

This is so cool Ian! Perhaps Glen (McGuire) can make you some miniature slaves to man the oars in the final rendition!

Mini slaves are probably out of my league, but what about a figurehead for the final boat?

Edited October 22, 2022 by Glen McGuire

[Ian_Grant]

10 hours ago, Bedford said:

I'm nobodys hydrological engineer (don't even think that's the right term) but I'd imagine that the oars sweeping in a fixed test like that will mostly stir the water into eddy currents and not result in much in the way of thrust but when on a floating boat they will work more as they're designed to which involves moving the boat rather than moving much water. I think it may surprise you.

I guess we'll find out!

 

8 hours ago, gjdale said:

This is so cool Ian! Perhaps Glen (McGuire) can make you some miniature slaves to man the oars in the final rendition!

Yes, a crew will be needed. I'd like to have the two helmsmen, some marines, an optio commanding them, a couple of archers in the tower, crews on the scorpios (artillery), commander gazing forward,.....

 

I've been talking to my brother, the 3D printer guy, about that. For example, I found this guy on the internet; he's "fully rigged" which Andrew says means you can pose him as you like before printing; as opposed to printing then having to cut him up to move his arms etc. You could even scale him to get men of different heights. For $40 you get the file then print as many as you like. He'd do for the marines and could be modded for the optio. I think I will be learning about resin molding in the future.

 

https://www.turbosquid.com/3d-models/maya-roman-legionnaire/371829

 

 

59 minutes ago, Glen McGuire said:

Mini slaves are probably out of my league, but what about a figurehead for the final boat?

 

 

Glen, that's hilarious! 🤣  But actually you have the little guy on the stern....😄

 

[Glen McGuire]

3 minutes ago, Ian_Grant said:

But actually you have the little guy on the stern....😄

Seriously?  OMG.  Now you know who not to ask for any help on this project.  

[mtaylor]

I suspect the aluminum will probably be lighter than ply.  Maybe not.  One way to cut weight is drill holes in the aluminum or wood.  In wood, too many might weaken it.  Aluminum, not so much and it's not affected by water so no need to add sealer which adds weight.

[Ian_Grant]

You're probably right; the aluminum is riddled with holes actually. And will never warp.

 

Possibly my best plan is to design the hull to give me the estimated displacement, then if the built hull turns out to be a bit heavier, eliminate the drawer slides thereby saving the 0.76 kg. If it's lighter, I could add internal ballast. Or eliminate the slides anyway and have more ballast.

 

I will probably be quiet for some time now. Need to review the library's materials on using their machines then get myself approved for them. Will post when there is something to show. Don't anyone hold their breath.....😵

[Ian_Grant]

It has dawned on me (God my aging mind is getting slow!) that I can save some weight on the slides. I only need them to move 3/4" each side of "neutral"; I'm not pulling out a deep drawer so I could cut off a lot of their ends. For instance here is a close-up of a 12" slide:

The actual BB carriage is only about 3.5" long, and if I move the metal slide 3/4" (say) the carriage only moves 3/8" in that direction since it is moving relative to both sides of the slide. I could in theory just cut the metal parts off 3/8" beyond the carriage ends with the slide  centred, and drill new mounting holes i.e. I'd be left with "mini-slides" 4.25" long thus losing almost 2/3 of the weight! Like having my cake and eating it too....

 

I won't cut it that fine but losing a little more than 1/2 the weight of metal is easy to do.

 

I'm going to the library tomorrow to take their one-on-one certification course to use their laser cutting/engraving machines. Just need to figure out InkScape to draw the ship's ribs 😬

 

 

 

 

 

Edited October 29, 2022 by Ian_Grant

[Ian_Grant]

In order to draw the bow and stern lines, lacking any knowledge of or interest in mastering 3D CAD, I needed a set of ship's curves which are now rare and pricey. Member iMustBeCrazy kindly supplied to me a pdf file with 4 pages of images of a ship's curves set. I used it and our local library's "Imagine Space" laser engaver/cutter to produce my own curves using 1/8" thick acrylic. These cost me a grand total of $12 which the Imagine Space charges for a 12" x 24" sheet of 1/8" acrylic out of their closet. A steal!

 

Edited November 6, 2022 by Ian_Grant

[Ian_Grant]

Welcome to those skipping straight here from the start instead of plowing through the prolonged history of the mechanism development. Finally getting started on actual hull development. Very little is actually known for certain about these ships, and of course there are no lines drawings extant. I'm using Michael Pitassi's book "Roman Warships" and building on his reconstructions. I also have on hand the lines for the "Olympias" which is a recently constructed full size trireme designed by a naval architect with archaeologist input. Unfortunately I already know my u/w hull needs to be much deeper than that of Olympias to support the weight so I cannot simply employ her lines. 😭

 

Galley Model Parameters:

 

1/32 Scale.  

Approx 54" LOA for a ship of about 145 ft.

Approx 8" WL beam.

44 oars per side, in two remes of 22, staggered.

Interscalmium 42" in accordance with Pitassi.  (this is spacing between oars in a reme).

 

Sea trials of Olympias quickly showed that her interscalmium of about 3 ft was too cramped for proper rowing. The archaeologist had used an ancient measure for which several values existed during ancient times and the consensus is the selected value was too small.

 

Powered by a 5-cell NiMH battery producing 6V for the servos, and a 9V battery to power the Arduino Uno and RC Rcvr.

Two oar servos per side, one for "Sweep" motion and one for "Lift" motion.

Lift servos are standard size; Sweep servos are "Giant Scale" for continuous torque expected, and heat dissipation.

 

Oars are approx 8" with loom 1.5".

Oar angles when in water are 17 and 24 degrees for the lower/upper reme.

 

Expected displacement approx 17 or 18 lbs.

Because of this the u/w hull will not be "realistic", it will need to be bulked up to provide the displacement volume.

 

I made a couple of mock-ups of the "giant" servos compared to standard-sized servos. I need these to make sure there is sufficient space at the bow to house them. Here is the Arduino "Uno" microcontroller board which runs the software to control the oars, with my servo interface board plugged into it; a standard servo; and the mock-ups.

 

That's about it for now. I'm sure I will be a while drafting.

 

Edited November 7, 2022 by Ian_Grant

[Dr PR]

Ian,

 

I sympathize!

 

Back in the early '80s another fellow and I were writing a C compiler for a new computer we were making. When I was testing the code I found something that just wasn't working right. It included some of the code the other fellow (a very experienced programmer) had written and I came to a single line with many statements concatenated using just about every operator in the language. Every time I read it I came to a different conclusion about what it was doing. So I took it to the other fellow and asked how it worked. He looked at it a while and said he had no idea what it did!

 

After that I broke everything down into simple statements on separate lines. It made the printouts longer but was easy to understand and significantly reduced debugging time.

[Glen McGuire]

10 hours ago, Ian_Grant said:

Welcome to those skipping straight here from the start

If anyone did this, they missed a fascinating design and build effort!  Such a cool project.

[Ian_Grant]

7 hours ago, Dr PR said:

 

<snip..snip>

After that I broke everything down into simple statements on separate lines. It made the printouts longer but was easy to understand and significantly reduced debugging time.

Yes, after a while I tended to put consecutive explicit IF statements, rather than IF....ELSE...ELSE...ELSE etc. It just got confusing to read, and hard to pick out which "}" applied to what section of code. Shout out here to the "Auto Format" tool in Arduino which indents "{" and "}" according to what it sees as the program flow. It can help show that you missed a "}" somewhere.

 

Thanks for your humorous anecdote!

[Ian_Grant]

1 hour ago, Glen McGuire said:

If anyone did this, they missed a fascinating design and build effort!  Such a cool project.

Thanks Glen; I just thought my log was a bit wordy when I look back. Will try to be more succinct from now on.

[mtaylor]

5 hours ago, Ian_Grant said:

Thanks Glen; I just thought my log was a bit wordy when I look back. Will try to be more succinct from now on.

It's all part of the process, Ian and documenting it will help someone else at some point in time.

[Lieste]

On 4/29/2022 at 10:10 AM, Richard Braithwaite said:

This document contains a bit more detail on the trails and calculations described above and application to a working model of Olympias using the elliptical machine shown in the video on a previous page of this thread.

 

Rowing Machine Calculation.pdf 987 kB · 3 downloads

 

One interesting finding is that with The top tier only (i.e. 62 oarsmen) the average speed is predicted at 6.53 knots, 

tis increases to  7.72 knots with all 170 oarsmen. So a significant increase in speed, but not as much as one might expect for all these additional oars. The main benefit would have been acceleration and maneuverability (very important in combat) which, I guess is why it was so important to pack as many oarsmen as they could into the boat.

Also long term endurance at the lower speed as the rowing can be shared out over time at a higher effort per group over a short time, followed by rest. This could be done by bank, by division or by files in an interleaved watch system. Those doing experimental archaeology with Danish/Norse warships have used various forms of watch system to provide long term rowing capability as well.

[Hubac's Historian]

This is a fascinating project, Ian.  I will enjoy watching your design evolution.

 

All the best,

 

Marc

[Louie da fly]

On 10/23/2022 at 12:59 AM, Ian_Grant said:

Yes, a crew will be needed. I'd like to have the two helmsmen, some marines, an optio commanding them, a couple of archers in the tower, crews on the scorpios (artillery), commander gazing forward,.....

 

I've been talking to my brother, the 3D printer guy, about that. For example, I found this guy on the internet; he's "fully rigged" which Andrew says means you can pose him as you like before printing; as opposed to printing then having to cut him up to move his arms etc. You could even scale him to get men of different heights. For $40 you get the file then print as many as you like. He'd do for the marines and could be modded for the optio. I think I will be learning about resin molding in the future.

 

 

Just don't carve all your oarsmen out of wood (don't ask me how I know) - 

 

 

Steven

[Ian_Grant]

Well I have discovered that my best effort cannot produce a fair hull on a drafting table. I thought if I had actual size profile, top, and cross section views all properly aligned on the sheet I could do it, but I can't. If for example  I draw fair looking curves in say the top view, they might look ok but translated to the cross section they are not fair. I did a lot of erasing then decided I do not know what I am doing. At least I got actual size bow and stern profiles and waterlines out of it.

 

I traced the bow and stern profiles onto some true 1/4" ply I had around. I will just cut these by hand instead of having to do the keel in 24" sections for the laser cutter. The bulkheads will be lasered for accuracy & consistency.

 

I reverted to the plan of carving half-hulls at the bow and stern which I will simply slice up and use to trace the bulkhead contours. I did the u/w bow first and quickly discovered that my waterline and u/w profile which looked ok on paper were way too bulbous; the effect of carrying on from the bulky midship section. I reduced it to what I think looks pretty good.

 

Then I glued up a blank for the above water hull at the bow. While hogging off the waste with my bandsaw I stupidly cut my index finger pretty good - the classic "following a curve then having the hand slip". I went to the ER last night and finally had five stitches this morning at 6am. I did not want to go there, knew it would be bad, but the bleeding just was not stopping. Let me tell you, I was pretty sick of sudoku and crossword puzzles after seven hours of waiting! 🙄

 

Rather than stress my stitches by using a hand plane today I thought I would sit quietly and have a crack at drawing a ram in TinkerCAD. Here are a couple of results. I added some decorations as found rams had some but TinkerCAD doesn't have such things as acanthus leaves sadly. I used the limited shapes available; not sure which I like better. The upper and lower horizontal vanes curve apart slightly. The front is about 1.25" on a side.  The angles on the sides are where the main wales come in, while the upper angle is for the stem. Don't know if the decorations would actually print, other than in resin. Oh well.

 

 

 

Edited October 12, 2023 by Ian_Grant

[Hubac's Historian]

Well, Ian, it was always a model, but NOW it’s a model; you bled on, or near it.  Congratulations!

 

Kidding, of course - I love your inventiveness and willingness to do difficult things.  I’m glad you are on the mend.

Edited November 21, 2022 by Hubac's Historian

[Glen McGuire]

Dang, Ian.  Sorry to hear about your finger, but glad it wasn't worse. 

 

What a way to spend the entire night waiting like that.  Ugh.  

[mtaylor]

I think one old saying applies to modelbuilding..."there will be blood".   I too am glad your injury wasn't more serious Ian.

[Ian_Grant]

Thanks, gentlemen.  The doctor asked how it happened. Went away and came back with the freezing stuff; asked if I'd had stitches before. When I said yes, she replied, "Yes, everyone that works with saws has had stitches"  Haha.

[Bedford]

3 hours ago, Ian_Grant said:

 "Yes, everyone that works with saws has had stitches"  Haha.

Now you've got me worried, band saw, chain saw, circ saw, jig saw, scroll saw, super sharp model making saws and various hand saws and to date, no stitches in 61 years. What's around the corner!!! Mind you I have left a few drops claret in most jobs in one way or another.

 

Glad your injury wasn't too serious though!

[Louie da fly]

It's not a ship model if you haven't bled on it. Welcome to the fraternity . . .

 

Steven

[gjdale]

Glad to hear the injury wasn’t more serious Ian. We must constantly remind ourselves that every machine in our workshops is actively trying to murder us! Maybe that’s why my wife is happy for me to spend so much time out there……..

 

And yes, it’s not a real model if it doesn’t contain your DNA.