The Ropewalk, by Phil Krol

Posted: Mon Jul 24, 2006 6:21 pm • Post subject: The Ropewalk, by Phil Krol

I've bounced a couple of emails back and forth to Phil Krol of the Nautical Research Guild, in relation to his superb ropewalk. As I thought it may be useful to both scratchbuilder and kit basher, here is a copy of the document which Phil has granted us permission to use.

Phil Krol Ropewalk HERE

Nautical Research Guild http://www.naut-res-guild.org/

Has anyone had any experience of rope walks, or made the Phil Krol one?

Thought this might be an interesting discussion point.

Posted: Mon Jul 24, 2006 7:55 pm • Post subject:

Here is a photo of my rope walk.

It is made from legos and basswood. I have a small wooden egg with three grooves cut into it that I use as a bobbin. I use Gutterman linen thread to lay up my ropes. Here is a photo of one of them attached to the stone anchor and another woven as the basket.

Scott

Posted: Mon Jul 24, 2006 7:59 pm • Post subject:

Any chance of some assembly plans Scott, such as the lego areas? I have a ton of Lego technic stuff which I'm thinking may be of use.

Nice looking rope!

Able Rate Joined: 18 Jun 2006 Posts: 4 Country: canada

I second that...more pictures, perhaps of the whole unit in use would be great.

Any chance to play with my Lego (my old modelling medium) would be great.

Posted: Tue Jul 25, 2006 1:35 pm • Post subject:

Jim,

I'll be happy to post more photos on the rope walk as well as an explanation of how these work.

Scott

Posted: Tue Jul 25, 2006 4:26 pm • Post subject:

I don't consider myself to be an expert on rope walks but I'll pass along what I've learned. The key to rope making is "balance." To understand this concept, first look carefully at a piece of thread (non-monofilament that is). You'll notice that it is made up of several fine strands of fiber that are all "twisted" in the same direction. What a rope walk does is take several threads and "over spin" or "over twist" them in the same direction that they are already twisted in. When this is done, the strands naturally want to "untwist" themselves. What the rope maker does is allow them to untwist by untwisting around each other. When this is done, there is a balance that takes place between the multiple strands, each individually wanting to untwist themselves in one direction and the rope, made up of multiple strands, wanting to untwist in the opposite direction. These two opposite sets of forces cancel each other out and a stable rope is made.

A rope walk consists of three basic parts. The first is a multi-headed (usually three) machine that can spin multiple strands of thread in the same direction. The second part varies based on the style of rope walk but often times is a single-headed machine that can rotate all three (or more) strands at the same time in the opposite direction. Some machines use a fishing spinner in place of this single headed machine. This spinner will allow the strands to twist by themselves once enough tension is placed on them (this is what Phil's machine does). The last part is a bobbin that can move along as the rope is laid up.

To use my rope walk three or more strands are tied to the multi-headed machine and then are tied as one to the single-headed machine. The single-headed machine is clamped down, a bobbin is placed between the strands and the multi-headed machine is cranked. What happens is that the two machines will want to move towards each other as the individual lines shorten because of the twisting taking place. Once the proper amount of twisting takes place (this takes experimenting), the multi-headed machine is clamped down and the single-headed machine is cranked in the opposite direction. The three strands will twist around each other, the distance between the machines will lengthen slightly and the bobbin will move from the single-headed machine towards the multi-headed machine. Once all of the rope is laid up, the ends are cut free and the rope is removed from the machines.

Here are a few observations from my trials and errors.

The size of the rope is dependant on the size and number of threads used (pretty obvious). You can double up the number of threads on the multi-headed machine and make six (or greater) stranded rope.

The type of fiber in the thread can make a difference in the appearance of the finished rope. Some cotton and polyester threads are fairly "hairy" and make "hairy" rope. These hairs can be waxed or burnt off. I admired the ropes made by Greg (from DDM) and he introduced me to Gutterman linen thread (made from flax). I've tried many different threads and I like this one the best. This is purely personal preference.

The "pitch" of the rope is dependent on the amount of twisting of the individual strands and the amount of tension on the bobbin. If the strands are twisted more, the rope tends to have a steeper pitch to the strands as they wind themselves around each other. On my machine, the bobbin is allowed to move by itself down the line as this happens. If you restrict the bobbin's motion (like Phil's machine does with its weighted bobbin car) then the steepness of the pitch can be controlled (more weight/steeper pitch).

The bobbin bounces around as it moves down the line. Phil's machine uses a weight and rail car the restrict this.

On my machine, the pitch of the strands sometimes lessens at the end of the rope because the resistance to the bobbin's motion lessens as it approaches the multi-headed machine. To correct this I restrict the bobbins motion with one hand at the end of the run.

It is important to note that is you don't like how the rope is laying up, you can always crank in the opposite direction and undo what you did.

Cable is laid up just like rope except that instead of using thread on the multi-headed machine you use individual ropes instead. Because the ropes are tensioned up in the opposite direction of the threads, the cable lays up in the opposite direction. This is why cable laid rope has an opposite twist compared to hawser laid rope. It is possible to continue the process and lay up cables on each other etc, etc.

The length of the rope made is dependent upon how far apart the machines are placed. Because the machines in my rope walk are not fixed in any way, the length of the rope is not limited. Some fixed machine walks get around this by running the individual threads through tubes set in the centers of the gears in the multi-headed machine so that rope length is not limited by the distance between the machines. Pretty clever!

Lastly, every different kind of fiber used (cotton, linen, polyester etc) has different stretch characteristics. It is possible to make ropes that have some give to them and some that don't. Linen has little/no give which I think is an advantage in rigging. The drawback is that if you over tension linen with the multi-headed machine it will snap and a rat's nest will ensue!

Sorry for the length of the explanation, I'll post better photos once I take them.

Scott

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THE ROPEWALK

IN that building, long and low,
With its windows all a-row,
Like the port-holes of a hulk,
Human spiders spin and spin,
Backward down their threads so thin
Dropping, each a hempen bulk.

At the end, an open door;
Squares of sunshine on the floor
Light the long and dusky lane;
And the whirring of a wheel,
Dull and drowsy, makes me feel
All its spokes are in my brain.

As the spinners to the end
Downward go and reascend,
Gleam the long threads in the sun;
While within this brain of mine
Cobwebs brighter and more fine
By the busy wheel are spun.

Two fair maidens in a swing,
Like white doves upon the wing,
First before my vision pass;
Laughing, as their gentle hands
Closely clasp the twisted strands,
At their shadow on the grass.

Then a booth of mountebanks,
With its smell of tan and planks,
And a girl poised high in air
On a cord, in spangled dress,
With a faded loveliness,
And a weary look of care.

Then a homestead among farms,
And a woman with bare arms
Drawing water from a well;
As the bucket mounts apace,
With it mounts her own fair face,
As at some magician's spell.

Then an old man in a tower,
Ringing loud the noontide hour,
While the rope coils round and round
Like a serpent at his feet,
And again, in swift retreat,
Nearly lifts him from the ground.

Then within a prison-yard,
Faces fixed, and stern, and hard,
Laughter and indecent mirth;
Ah! it is the gallows-tree!
Breath of Christian charity,
Blow, and sweep it from the earth!

Then a school-boy, with his kite
Gleaming in a sky of light,
And an eager, upward look;
Steeds pursued through lane and field;
Fowlers with their snares concealed;
And an angler by a brook.

Ships rejoicing in the breeze,
Wrecks that float o'er unknown seas,
Anchors dragged through faithless sand;
Sea-fog drifting overhead,
And, with lessening line and lead,
Sailors feeling for the land.

All these scenes do I behold,
These, and many left untold,
In that building long and low;
While the wheel goes round and round,
With a drowsy, dreamy sound,
And the spinners backward go.

Henry Wadsworth Longfellow

Posted: Fri Jul 20, 2007 5:34 am • Post subject:

I built a ropewalk back in the '80's but gave it away when I went to live in Brazil for a time. I really need to build another now, but I have no idea where to get the gears I need. Both Lego and Meccano seem to have degenerated into instant gratification kits to build specific 'things'. When I built the first one I got gears from my local model shop. There are no model shops anywhere near where I live in Portugal. Does anyone know of an online source?
Cheers,
Fraser

Posted: Fri Jul 20, 2007 6:43 am • Post subject:

guillemot,

You can try http://www.hpcgears.com/ in your home country. They probably ship out to Portugal (but at what price ?).

Scott,

Is something wrong with your (or my) browser ? All the special characters, such as inverted commas, are screwed, making your contribution difficult to read.

8) wefalck