Ian_Grant

On 8/28/2023 at 9:29 PM, bcochran said:

Well, the decks are finished and mounted to the hull.  Time to give the boat a gloss coat at this stage.  Also, time to go back over what everyone told me about the electronics. 

 

I bought a carry/stand to use to take the boat to the water, so I better get the motors to work.

It's always the man who wants to drive...............

5 hours ago, Bedford said:

On the subject of rudders, I wonder if they were, in reality, more trim tabs than actual rudders, as is the case in tall ships in which the set of the sails does most of the heading work.

 

Having had the helm on a 4 man row boat I can tell you the rudder only has any real effect when the oars are out of the water so you end up with a segmented turn.

I suppose they could have told oarsmen on one side or the other to "ease up" in order to steer, who knows now? My plan was to use rudders for slight/gradual course changes and leave the counter-stroking as an ace up the sleeve; I'm not sure they could even do that in reality. One gets far less power pushing an oar than pulling it.....

During our week's cruise aboard "Royal Clipper" a 5-mast square rigger I had the opportunity to steer her one evening. What a rush! Five thousand tons under my helm control. If she was drifting off course, and you moved the rudder, her inertia slowed her response dramatically but once she was turning that same inertia made it hard to stop......took some getting used to anticipating it ....

4 hours ago, Jack-in-the-Blue said:

What a fabulous project!
 

The sound of the motors perhaps simulates the wheezing breath of the oarsmen. 😁

Yeah, the servos are noisy. I'm hoping the full deck will muffle them.

1 hour ago, Hubac's Historian said:

Fabulous progress, Ian.  It is mice to hear your  voice in the videos.

Thank you Mark!  I only wish I could stop the stammer which only started in my late 20's for some reason.

I'm looking forward to adding the steering platforms and decorative trim, and painting of course....

1 hour ago, BANYAN said:

That's incredible work Ian; that appears to be a very effective mechanism.

 

cheers

 

Pat

Thanks Pat!  Another challenge will be adding steering platforms and twin rudders controlled by a servo linkage through the hull sides, beneath the platforms. I already have the hardware parts. Need to determine suitable size for rudders.

Thinking of using the library's laser etch/cut machine to etch the deck planking on the steering platforms, and if successful on the main deck and even the tops of the outriggers.

Looking really nice!  You should get her onto some water this fall by the look of it!  🤞

21 hours ago, gjdale said:

Amazing work Ian. Congratulations on achieving a successful first sea trial. I wonder if you really need to increase the oar blade size though - with an extra bank of oars, would the speed actually look about right for the scale?

You may be right ..... another trial with extra blade area rubber-banded on should give an indication, although I must say the blades look teeny when you view them against the large hull.

Thank you for following thus far, and your good comments!

20 hours ago, Bedford said:

I was thinking the same as Grant, once you get the second tier of oars it should speed up, yes it's slow off the mark but then it should be.

Before worrying about oar size I'd suggest you work out the theoretical hull speed "Hull speed can be expressed as a simple mathematical formula 1.34 X the square root of the length of the waterline (HS = 1.34 x √LWL). For instance, if a cruising sailboat has a waterline length of 36 feet, she should be able to sail 1.34 x 6, or approximately eight knots." 

Then work out the scale speed of the boat and take it from there, mind you it's doubtful such a big rowing boat would have ever attained hull speed.

 

As for the amount of ballast, I'd leave that as is too for now because water doesn't behave in a scale fashion so if you make it lighter it might get tossed around like a cork. The ballast helps her ride in a more scale manner. 

Looks like it's time for some more math .... 🫢.  Thanks for following from the beginning!

15 hours ago, Glen McGuire said:

That is absolutely amazing work, Ian!  Congrats on a successful test run.

 

In the first video when you said, "Something's gone wrong" all I could think of was "Houston, we have a problem."  But you get her fixed and cruising across the water.  Awesome!!  

HaHa!  Thanks Glen. I really don't know what happened which is worrying. Is the 2-year old battery feeling the strain? Did the Arduino burp? Battery cable too long? Needs investigation.

"SEA TRIAL #1"  !!!!!

Tweaked the software to map the servo signal pulses to appropriate limits and polarities to suit the actual physical setup. For example, the two sweep servos drive their associated mechanisms using opposite ends of their arms, so giving the same PCM signal to both would drive the oars in opposite directions. One pulse stream has to be "inverted" i.e. pulse width is "reflected" about the 1500 usec midpoint e.g. if one servo is at 1700usec (1500 + 200), the other has to be at 1300usec (1500 - 200) which results in both sweeps moving the same way. This is very easy to do using the Arduino "map" command.

I made up little "sacks" for lead shot ballast using cut up envelopes wrapped in packing tape. They fit nicely in the hull bottom between the bulkheads. At our new pool, it became obvious that the bow is much more buoyant than the stern, so bow needs more ballast. There is an awful lot of ballast...an awful lot...haven't weighed it but it is many pounds. My hull weight estimate was far too high, my resulting u/w hull has far too much bilge. In the videos below, you can see that moving forward and back is pretty slow since all that dead weight must be moved; but with oars stroking in opposite directions it turns in place not too badly, since the weight is not having to be actually moved along. Question is whether she will move better with more oars of the same blade size.

As mentioned in the video, the next step is to rubber-band larger oar blades on to try to predict the effect of 42 more oars in the second tier. I am thinking of making new partial oars with a bigger blade, then cutting the existing oars and scarfing the new ends on. This would be easier than trying to cut out exactly the old blade notches to add new blades.

I also conclude that a central handle is absotively a requirement. Hefting this thing around is a chore even without the second tier of oars sticking out even further.

Evidently she will not be finished this year. That being the case, I am wondering if over the winter I could cut out the bilge curves and form a new u/w hull with less volume (😒) thus less ballast required and more responsive operation. Very painful sounding especially as the u/w hull is epoxy-resined inside and out. Will have to mull it over given results of the next trial.

Here's the first video:

Then I realized I forgot to demonstrate the effect of opposite stroking. As a refresher, when software sees a "hard over" rudder signal, as currently written, it reverses the oars on the inside of the turn. Obviously she has no rudders, or indeed steering platforms, yet, but the software still reads the signal indicting position of my transmitter's rudder stick. Looking back, I think she spun to port when I "applied" hard-right rudder and vice-versa. That's a matter of more simple software tweaks in the unknowable future.

Here's the "spinning" video:

Very nice model....!

Hi Kevin, it was a rafting trip, three rafts, four guests and one guide per raft. Guide is at centre with oars, two guests at front and two back, guests can paddle if they like (or to keep warm!). All we really had to do was pitch our tents and set up air mattresses etc, pack them in the mornings, and take a turn doing the dishes. As they said, "It's your holiday so don't paddle unless you want to". The chief guide was a chef for seven years, the second guide was a sous-chef, the third loved to bake at camp. The meals were fabulous eg arctic char, thai curry chicken, fresh-baked brownies or cake. Only two of us opted to swim amongst the icebergs in Alsek lake, it was REALLY bracing!!   Great trip, but next time we think we'll go with canoes to be more active.

We were lucky to pick this trip as some other rivers had too much smoke and trips were cancelled. And the Dempster highway was opening and closing seemingly at random.

By the way, we met a few Brits in Whitehorse who had their motorcycles shipped to Anchorage, rode to Prudhoe Bay on the Beaufort Sea, had come down to Whitehorse, and were en route for Cape Horn; yes, THE Cape Horn. What an epic trip!

4 hours ago, schooner said:

<snipo..snip>

 As far as the motor goes I don't know if it is brushed (I threw the box out and I'm a total RC newbie), it is geared.

Yes, your MACK 1885 motor is brushed.

Since you're a newbie, a warning about batteries - I don't think it's the case here (your battery looks like NiMH cells) - but if lithium batteries are being charged it's best not to leave them in the boat due to fire risk. 🔥

Look forward to your launch video! Wish I was as close ...... 😣

Nice neat installation. Looks like a mini servo on the rudder. I only seem to see two terminals on the motor so I assume it's brushed? Is it geared down?

Nice model by the way...... if I ever build a tug I'm quite taken with the "George W Washburn" by Dumas.

Congratulations on a superb model!!

Glen, this is your best SIB yet!!!  Can't wait to see it hooked up at the sea wall............. 👍

Glen, she looks incredible!!!!!.....better than mine......love the oars.....

On 7/29/2023 at 10:30 PM, Glen McGuire said:

Enjoy your vacation, Ian!  And I'm sure you won't think about your quadrireme while you are gone!!

I spent not one nanosecond thinking about it while passing down the Tatshenshini and Alsek Rivers from the Yukon to coastal Alaska. What a trip - grizzly bears, bald eagles, mountain views, hikes, glaciers calving into Alsek lake (where a polar bear swim is optional). Plus we got to fly back to Whitehorse in bush planes.

Unfortunately I did not get the boat to the pool for a water test today so it must wait until we return from our trip in two weeks. The mechanical setup is complete ie. all the servos have their mechanical links to the oar mechanisms and the 2nd lower oar bar is fixed via the requisite hinges to its beam. I also added the aluminum rods at the stem for mounting the printed ram when available, and also to prevent water reaching the wood interior of these holes.

We need to finish packing so there's no time to install the Arduino, fire it up, and tweak the software to the actual physical connections of the servos in this final configuration. I expect the water test to be underwhelming. I plan to make the oar blades larger, but they will move just below the water surface. Deeper would be better but that would mean the loom ends would be higher and be interfered with by the deck beams. I can just see me reworking the mechanisms to shorten the oar looms (which would reduce their ultimate height) , if that is possible for the upper remes since they must reach the wall of the outrigger. Time will tell.

I used the shortest arm possible on the sweep servos, to get the two inch stroke at minimum torque load using a reasonable total rotation. The arm must move over 120 degrees; looking at this I recalled Bedford's comment of long long ago when he suggested linear servos which would give constant sweep speed. Since my sweep servo arms are rotating, and the software as presently written generates a steady rotation of the arms, the sweep speed along the boat's axis decreases as the angle of the arms increases. I'll need to change the software to accelerate the sweep servo arm rotation as its angle increases, to maintain a constant "delta-x", if you will, forward and backward. Haven't looked at the math yet, should just be some basic trig.

Here are a couple of shots of the boat "ready to go"; just needs electronics, updated software, and ballast.

Bill, have a look at the latest few posts on 72Nova's "Wasa" build. Rigging doesn't get much better than that! You will see realistic block spacing etc, but the exact number of blocks involved in the crowfeet varied over time. See Andersen pg 127; "The sprit topmast backstay was one of the places where the early 17th century rigger really let himself go." I love that sentence. He shows many variations by nationality and year ..... just look at that "backstay" on "Sovereign of the Seas" and thank your lucky stars you're not building a model of her! 😉

Good luck Bill!! 🖖

Michael, as always, fantastic model! I can't get over how your crowfeet don't distort the run of the stays. Beautiful.

By the way, what are you using for ratline thread?

Held my nose and ordered another aluminum channel beam from ServoCity, paying the usurious shipping rates to Canada and the inevitable "brokerage fees", shipping taxes, brokerage taxes, and Canadian taxes on the sum total ie taxes on taxes. I have some tea in the pantry; where's the nearest harbour?

Making slow progress on the 2nd mechanism. I want to make a second water test with all lower oars this week because we are leaving on the weekend for two weeks in the Yukon and NWT.

Here's a pic of current state.........

Really like your stand, Bill. And the ship, of course!

1 hour ago, Hubac&#x27;s Historian said:

Thank you all for the vacation well-wishes.  I am looking forward to some time away from NYC.

........ and smoke from Canada ...... 🫢

Over here, waterproofed matchsticks for camping are generally green.

Glen, what can I say?  I'm running out of superlatives for this build. Your scorpios are Aaah-maaaaziiiing!!!!

Looks great Glen! Must have been very fiddly. Just a note that they weren't actually made of stone, just sometimes painted to resemble it. They had to be very light weight wood and canvas affairs to not affect stability. In fact they were later made to be collapsible and stored flat on deck during heavier weather.

Agree with George....and I love the brass etch trailboard decorations ..... day and night compared to the decals.....keep up the good work .... I admire your commitment.....

1 hour ago, Glen McGuire said:

 

One thing on my list of deck fittings that I did not see in the video is a corvus (bridge) mounted between the mast and the bow.  I'm working on the castle right now, then probably move on to the ballistas and then the corvus.           

Yes, the corvus was a Roman invention for the first Punic war. They soon discovered that the additional weight, and possibly the removal of forward bulwarks to allow deploying it at various angles, made the ships even less seaworthy so it was obsoleted. The new solution was a lighter-weight "boarding bridge" which could be manhandled over the side, and was stored lying athwartships on the forward deck, between new bulwark openings used to deploy it. You can see it sitting on the deck around the 21 sec and 53 sec marks in the following video (I meant to send you this video earlier, not the short fast one but couldn't find this at the time). That's a really beautiful model; I'd love to buy one but they are out of production, very difficult to find, and presumably $$$$. There's another video before this one showing his stages of the build.

I'd love to know where he found his crew too!

By the way, looking forward to seeing how you represent scorpio artillery at your miniscule scale. I'm wondering how to make them for mine!