Draft dragons - a question

It's been determined that draft dragons are able to pull some pretty darn fantastic loads. How do those harnesses work?

A hawser heavy enough to pull a 25 ton load over a road is going to be a nightmare for humans to handle, in order to connect them to loads and beasts of burden. I can imagine ways that it might be done, but I'm wondering if it's already been discussed?

Do the dragons use a simple back strap and chest strap setup like elephants do?

Cheopis wrote:A hawser heavy enough to pull a 25 ton load over a road is going to be a nightmare for humans to handle, in order to connect them to loads and beasts of burden.

I don't think you'd need a hawser big enough to lift 25 tons, because you'd only be dealing with rolling friction.

From personal experience, I know towing a 40,000 gross weight articulated lorry (an eighteen-wheeler if it had been back in the US) with a single 1/2inch wire rope is a piece of cake, no strain at all on a level road. (the cable was a nominal 10K-lb test winch cable.)

I think a double-shaft rig, like a one-horse buggy uses, would be the best choice for a single-dragon hitch. Attachment to the Dragon could be to an Ox-Yoke or Horse-Collar via steel-thistle cables of nominal 10K-20K test strength -- the equivalent of 1.5-2.0 inch hemp rope or thereabouts. With multiple attachments between the "Dragon-Collar" and shafts, no single rope will take the full strain even on steep grades.

Weird Harold wrote:

Cheopis wrote:A hawser heavy enough to pull a 25 ton load over a road is going to be a nightmare for humans to handle, in order to connect them to loads and beasts of burden.

I don't think you'd need a hawser big enough to lift 25 tons, because you'd only be dealing with rolling friction.

From personal experience, I know towing a 40,000 gross weight articulated lorry (an eighteen-wheeler if it had been back in the US) with a single 1/2inch wire rope is a piece of cake, no strain at all on a level road. (the cable was a nominal 10K-lb test winch cable.)

I think a double-shaft rig, like a one-horse buggy uses, would be the best choice for a single-dragon hitch. Attachment to the Dragon could be to an Ox-Yoke or Horse-Collar via steel-thistle cables of nominal 10K-20K test strength -- the equivalent of 1.5-2.0 inch hemp rope or thereabouts. With multiple attachments between the "Dragon-Collar" and shafts, no single rope will take the full strain even on steep grades.

I think, given the state of engineering and the state of textile industry prior to Merlin, you would have to assume significant grades and hemp ropes (at least not steel thistle ones). But it does sound like those ropes could handle those grades from what you've said. (I have no towing experience to draw on myself.)

Would you be able to work up a harness that pulls on both forelimb shoulder and the midlimb ones, to spread the burden around? If so, the six-limbed dragons may have an edge as draft animals, both for pull and how much strain is put on the harness and the ropes, over our four-limbed ones.

This is a really interesting questiion.
I've never been able to envision how a six-legged draft animal would walk, or for that matter, look. We know the treecats' upper pairs have different paws so would the dragon, which does not move around in trees, have big differences between the forelimb and the middle limb? The shoulder joints might be different if the forelimb had much lateral movement. I've also assumed the mid and forward pair would have to move in unison which implies the mid limb would be shorter otherwise the animal would have a sort of rocker motion.
The shoulder width wold seem to very important. From a top down viewpoint the animal could be diamond-shaped, figure-eight shaped. rectangular or maybe even triangular with the rear limbs (hips?) wider than the shoulders. I'm thinking (guessing) that four-legged draft animals have hips slightly wider than shoulders.
Any xenobiomechanic specialists out there?

Cheopis wrote:It's been determined that draft dragons are able to pull some pretty darn fantastic loads. How do those harnesses work?

A hawser heavy enough to pull a 25 ton load over a road is going to be a nightmare for humans to handle, in order to connect them to loads and beasts of burden. I can imagine ways that it might be done, but I'm wondering if it's already been discussed?

Do the dragons use a simple back strap and chest strap setup like elephants do?

I don't think we know enough about dragon anatomy to guess.

Since we don't have to lift the 25 ton load, only pull it, I expect you could do wagon shafts (works with elephants!) or trek-chains (works with 40-mule teams and big hitches of oxen) just fine, but precisely what has to depend on the dragon anatomy and I don't think we know anything about that at all.

Graydon wrote:I don't think we know enough about dragon anatomy to guess.

Since we don't have to lift the 25 ton load, only pull it, I expect you could do wagon shafts (works with elephants!) or trek-chains (works with 40-mule teams and big hitches of oxen) just fine, but precisely what has to depend on the dragon anatomy and I don't think we know anything about that at all.

We know they're six legged.

But given how many things on Safehold have "Lizard" in their names, I'd assume that alot of Safeholdian native fauna is at east vaguely reptilian at first glance (although at least some of them are noted to have fur), with the largest fauna getting the "dragon" appellation.

Really though, all that's required for a dragon harness is a design that puts the bulk of the load on the dragon's shoulders. A reptile-like body plan (plus being bilaterally symmetrical) would suggest a head separate from the torso by some kind of neck structure, and that having paired limbs at all guarantees some kind of shoulder structure.

With regards to how the dragons might walk, what about looking at the AT-TE from Star Wars?

OK, it's a fictional machine, but Lucasfilm did give it six legs.

Mike.

Michael Riddell wrote:With regards to how the dragons might walk, what about looking at the AT-TE from Star Wars?

OK, it's a fictional machine, but Lucasfilm did give it six legs.

There are all sorts of terrestrial hexapods; insects. So we know six legs is an easy walking pattern because you can always have a tripod of legs that aren't moving.

Left front and rear, right middle, or right front and rear, left middle; move them alternately, you're never unbalanced. This made six legs popular with early mechanical walker researchers because there was a control problem they didn't have to solve. If you can solve the control problem, four is more interesting because lighter, cheaper, etc. (Though the third pair of legs and implied length might be where dragons get the room to store their extra-long and thus efficient guts.)

We don't know if dragons walk like that, or pace (all left forward, all right forward) or do something disturbing like front feet forward, middle feet forward, back feet forward in a galumphing gait. A gait like that would probably affect harness design.

Graydon wrote:

Michael Riddell wrote:With regards to how the dragons might walk, what about looking at the AT-TE from Star Wars?

OK, it's a fictional machine, but Lucasfilm did give it six legs.

There are all sorts of terrestrial hexapods; insects. So we know six legs is an easy walking pattern because you can always have a tripod of legs that aren't moving.

Left front and rear, right middle, or right front and rear, left middle; move them alternately, you're never unbalanced. This made six legs popular with early mechanical walker researchers because there was a control problem they didn't have to solve. If you can solve the control problem, four is more interesting because lighter, cheaper, etc. (Though the third pair of legs and implied length might be where dragons get the room to store their extra-long and thus efficient guts.)

We don't know if dragons walk like that, or pace (all left forward, all right forward) or do something disturbing like front feet forward, middle feet forward, back feet forward in a galumphing gait. A gait like that would probably affect harness design.

Anyone remember the mech-spider in the movie "Wild, Wild West."

Graydon wrote:

Michael Riddell wrote:With regards to how the dragons might walk, what about looking at the AT-TE from Star Wars?

OK, it's a fictional machine, but Lucasfilm did give it six legs.

There are all sorts of terrestrial hexapods; insects. So we know six legs is an easy walking pattern because you can always have a tripod of legs that aren't moving.

Left front and rear, right middle, or right front and rear, left middle; move them alternately, you're never unbalanced. This made six legs popular with early mechanical walker researchers because there was a control problem they didn't have to solve. If you can solve the control problem, four is more interesting because lighter, cheaper, etc. (Though the third pair of legs and implied length might be where dragons get the room to store their extra-long and thus efficient guts.)

We don't know if dragons walk like that, or pace (all left forward, all right forward) or do something disturbing like front feet forward, middle feet forward, back feet forward in a galumphing gait. A gait like that would probably affect harness design.

Thanks, this is plenty informative - although it does raise a bunch of questions.

Do you suppose it makes much difference that the draft dragons are (1) warm-blooded (I'm pretty sure they are, anyway), (2) so very much larger and bulkier than insects, and (3) endoskeletal?

The bulk may mean that while balance could mean maintained with three legs on the ground, it may be dangerous or exhausting to walk with less than 4 or 5 grounded at a time. (For all I know - presumably comparing gaits of tiny mammals and huge ones could suggest an answer. I'm just betting I can find out from one of you more easily and soundly than researching it myself.)