## 2017-05-11

### OED Wilderness Rules Draft: Carrying Capacity

More suggested refinements to OD&D wilderness adventuring mechanics. Notice how in this installment we use modern research to establish a mathematical formula between real-world creature weight and carrying capacity (in line with our observations last week). So: It's simultaneously more realistic, and also (perhaps more importantly) simpler to judge and to generalize. Comments?

### Carrying Capacity

Animal carrying capacity is shown in the table to the right, as well as average weights for such mounts. All weights are given in stone. Light load (full move) is considered to be up to 20% of the animal’s weight; heavy load (half move) is set at 40% of animal weight.

Vehicle and ship capacity is given in the next table; units here are in tons (160 stone). Note that as a convenient rule-of-thumb, the capacity of the vehicle is its cost (from Vol-1), divided by 100, in tons. Galley types are the exception, with a capacity half normal by this rule (or in other words, about 1 ton per crewman; see Unger p. 176). Do not count normal crew against the cargo capacity given here (although any added soldiers, pilgrims, horses, etc., will be counted). Treat longships as small galleys, and warships as small merchant ships for this purpose.

Of course, in reality both animals and ships vary continuously in their size, weight, strength, carrying capacity, etc. As DM you may wish to permit a range of sizes for each (and load capacity can be fairly easily found by the rules-of-thumb above). This is easier to do with ships (likely only one owned by a given party), and harder to do with beasts (where many may be owned per party). Maximum constructable size for a merchant ship (cog) may be up to around 400 tons capacity in this time period.

For simplicity, assume that an unarmored man weighs about 10 stone, and medium or heavy horse with one week of hay and water weighs 1 ton.

### Update

After great observations in playtests from our patrons, we revisited the issue of horse carrying capacities and became convinced from modern research that 30% body weight -- or say, 1/3 for a simple fraction -- is a better cutoff for the point where horse mobility starts to fall off. (Or in other words: the modern 20% rule-of-thumb is highly conservative, kind to the animal, and has a large safety overhead built-in). This results in our 60-90-120 stone horses having light-load cutoffs at 20-30-40 stone, which seems to work pretty well, and happen to be quite close to the Original D&D numbers. See here for more.

1. I'm loving these wilderness rules. I'm going to be straight-up stealing them. Thanks!

1. That is the best!

2. I am liking it,
Only thing I see off the bat is some sort of guideline for non-beasts of burden. "How much can my summoned bear carry?"
Always with my corner cases.
Any thoughts on "pulling" capacity vs carry?

1. Assuming a wagon or cart with nice big wheels, I would divide pulled weight by 5 on dirt, and by 10 on a paved or "metalled" surface, to find the effective carried weight.

2. Hmmm, that's an interesting point. I was just looking at mounts on the D&D list (as you can tell).

3. Here's some interesting data on pulling capacity by teams of two horses (http://www.humanist.de/rome/rts/load.html). I'm tracking down other sources.

4. Wow, that's a nice article! Thank you. (The funny thing is that my father and a friend of the family are world published experts in teamstering and yokes, but not in terms of ancient/medieval time periods.)

5. Whoa! That's kinda cool!

6. The Medieval Horse and its Equipment (edited by John Clark) corroborates the numbers that LWSCHURTZ's article arrives at, estimating average pulling loads at 500-600 pounds per horse.

Also of note is that you might be overestimating the weight of your medium and heavy horses. Your 120 stone figure would be reasonable for a very large modern draft horse, but based on the size of historical horse armor, knightly warhorses were closer to the size of a modern Friesian, in the 90-100 stone range on average. It's less certain, but something similar is probably also true of medieval draft horses, as people only began to develop the truly massive working breeds in the Late Middle Ages and beyond with the increasing importance of cannons in warfare.

7. The figure for horse weight I got comes from the Wikipedia link in the notes; Horses in Warfare: Heavy-Weight, indicating for middle-ages Europe 1,500 to 2,000 pounds (100 to 140 stone). Cites Clark's Medieval Horse and Prestwich's Armies and Warfare in footnote.

If it's even roughly in that zone I like having the game rule be a linear sequence 60/90/120 for the different horse weights. For example, I did intentionally boost the medium horse weight a bit to make that happen.

8. I unfortunately can't remember where I read it, but basically what it came down to when looking at the size of barding and how it fit on modern horses, the only stuff sized for what we'd nowadays call heavy horses was jousting armor from the tail end of the Middle Ages. All the earlier equipment measured pointed to a slightly smaller and faster horse being the norm, even for the heavy cavalry.

9. Also, if you want a sequence you could always do 60/80/100.

3. First off: awesome on all counts.

Second: do you have objections to folks (me) putting your modified encumbrance rules into their own publications?

: )

1. Please do that, that's ideal! A short credit note is always appreciated. (Dan Collins, oedgames.com)

2. Of course.
: )

4. Great, concise work! Thanks for all of the excellent references on this one, especially; exactly the kind of logistics information that feeds my tinkering instincts.

1. Thanks so much for the kind words! I think I had a revelation recently that references like that need to be included so we can all build on each others' work and not keeping reinventing and re-researching the wheel over and over.

5. One thing to consider is that in general, a mount allows you to carry more, not travel farther or faster. Something that's often missing in overland travel rules. Mounts need regular rests, and that usually means removing their burdens. That's one of the reasons why wagons are more efficient - you don't have to unload and reload a wagon when you stop to rest the horses.

You'll also find that in general, horses were used as beasts of burden, not as mounts. That is, if you were traveling long distance, they were to haul or carry your gear.

Obviously, when regarding a knight, they would ride a horse. But a knight would typically travel with several horses, would not be riding while fully armored (unless heading into combat), and had additional beasts of burden to carry or haul their equipment.

All great stuff, though, I love these posts.