Thursday, 28 January 2016

How I Learned to Embrace Encumbrance

Encumbrance is a tricky issue – it promises realism / believability but tends to feel like an accounting exercise whose only effect is to give a penalty to players – and who wants to keep on calculating a penalty?

I place a lot of store in the realism camp – and if I'm going to have it for the sake of realism then I want some attempt at realistic results, not arbitrary penalties. This helps get over the first negative aspect of encumbrance – at least when you've calculated it you feel like that the penalty is deserved.

The next aspect is the ease of tracking the total weight characters are carrying – I've found that by splitting equipment into carried / with your horse / at home, and then further dividing each section into major / minor items (not tracking the weight of minor items unless you’re going over the top with them), and with a column in the list for weight then there’s only a small amount of adding to do, it’s easy to do when neatly arranged, and (importantly) I've found that players change what major items they’re carrying quite rarely in practice.

Next up is the feeling of being penalised, with no way round it except to leave stuff behind. By basing encumbrance on the amount you can lift, then you get a choice when you improve athletics (which you will do as that improves your damage bonus) - you can either improve your raw speed, or you can improve your power and thus reduce the encumbrance penalty on your speed.

Encumbrance In Practice
In the last session the players encountered a 5’ wide chasm across the corridor; all except the Dwarf could jump it, whereas he had to take off his armour and throw it across first. The jump distances and the effect of encumbrance all felt right, and the lack of rolling to see how far the PCs could jump felt right – it all made sense in the fiction of the game. Flairin did offer to jump across holding Kazem's armour but the Dwarf likes to be self-sufficient. He could even have jumped a 4’ chasm giving Kazem a piggy back – but if that had been sufficient somehow I think the offer would not have been accepted!

The Rule
Given the weight carried and the character’s Lift, look up the penalty on the table below.
 This is then applied to move/jump (see this post) - table reproduced below:
For example suppose you have STR +3, AG +2, Rank 4 athletics (Power 2, Speed 2) – so one rank short of Gold Medal Olympian ability – which gives you Lift 5 (600 lb), Run 5 (110 ft/rnd, max 10 mins) as per the char sheet calculations below.

Suppose you want to run carrying 110lb: 

The enc penalty is from the 100lb row and the Lift:5 column to get a penalty of -4, so you are reduced to Run 1, which is 72 ft/rnd.

This is tracked / calculated together with the Athletics skill on the character sheet as below – the encumbrance is just the extra column at the end. If there’s no penalty then just leave that section blank:
In practice it is very quick to update this when necessary, or look up a result for an ad-hoc situation such as "Can I jump the chasm holding that sack?". In total Athletics and Encumbrance take up one twelfth of the character sheet, which is a reasonable amount.

Originally this table was a single column and each +1/-1 lift moved you one row up/down. In play however this became another rule you had to remember, and it’s clearer as this table. For example, if you have a -12 penalty, then +1 lift makes it -8 (one row up) NOT -11, but it’s easy to forget that.

Speed or Power – which is best?
Players have a choice of where to put their points – into Speed or Power. In the example above, the athletics of 4 was split into Power 2, Speed 2 – what if it was a different split?

If instead you had Power 3, Speed 1 you’d get Lift 6, Run 4, Enc -3, so Run 1 again which is 72 ft/rnd.

However with Power 1, Speed 3 you’d get Lift 4, Run 6, Enc -6, so Run 0 which is only 64 ft/rnd.

So for any given weight there’s a sweet spot for power versus speed, and the heavier the weight the more it leans in favour of power.

If you ever have an encumbrance penalty of -6 or more then you improve your speed more by improving your power. That’s why I’ve shaded those cells in the table – that’s where a lack of power hampers you.

How does this measure up to real life?
I want a baseline of what effect carrying large weights has on people’s speed. Fortunately some nutters in Gawthorpe having been conducting experiments!

Every year (since 1964) they hold “The World Coal Carrying Championships”
The event consists of Men’s, Women’s and Children’s races that take place on Easter Monday. Men carry 50kg of coal and women 20kg in weight.
Adult races start from the Royal Oak public house, Owl Lane, Ossett and continue for a distance of 1012 metres to the finish line at the Maypole Green in Gawthorpe village.
(Please note your time will be recorded when your sack of coal hits the green).
So that’s a weight of 110 pounds carried for 3320 feet. How fast can they do it?

David Jones holds the record – he did it in an impressive 4:06 in 1991 and 1995, so that’s 3320/41 = 81 ft/rnd. 4 minutes is between a run (10 min) and a sprint (1 min) in my system, so I extrapolate that the record for 10 mins would be 72 ft/rnd, which is Run 1.

Astonishingly this is the same answer as my example above (almost as if I engineered it that way).

What is the formula behind the table?
The penalty is logarithmic, doubling every other row. The weight on the other hand doubles every four rows. That means the penalty is proportional to the Weight/Lift squared – which was the initial version of the rule. You could have a formula instead of a table - everyone would have a Carry value (approx. 1/10th the weight) and the penalty would be Weight/Carry squared. This would give a more fine grained result, but…

Why have a table instead of using the formula?
When you use the formula do this some values round up, some round down, and the effect of +1 speed or +1 power varies slightly. For example sometimes +1/+2/+3/+4 sometimes gives you a progression -8/-6/-4/-3 and sometimes -8/-5/-4/-3 and sometimes -8/-7/-4/-3. I like the outcomes of player choices to be clear, and the regularity of the table gives a clarity with observations such as “if your encumbrance penalty is -6 or worse then power is better than speed” is lost.

So in the end I opted for the table – you only have to look it up when the amount you’re carrying changes significantly, and you only fill in the values when you need them. The athletics and encumbrance tables fit onto one sheet of paper, and these are the only tables you need when updating your character sheet.

Why this formula?
The old version (the flawed one I referred to in the last post) was linear, not squared. That was simpler, and doesn't need a table, but the predictions it gives don't match with expectations. 

When I go for a run (or a walk) I can carry quite a bit before it starts to slow me down. Carrying more weight has a little more effect, and a little more, until it suddenly starts too feels too much, and then you find that it’s a real struggle. The straw that broke the camel's back?

The simplest way to model that is a squared rule, and it seems to give reasonable answers.

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