Thursday, February 24, 2011

Movement rates in BRP need repair

I've started disassembling the Basic RolePlaying rules in anticipation of my upcoming campaign with an eye toward establishing any quirky bits that will grate on my OCD tendencies if not fixed. Some can be dealt with using various optional rules (of which, BRP is amply endowed), but some require house ruling. The first is movement rates. A fit, unencumbered human is expected to be able to move 30 metres in a 12 second combat round, assuming he is performing no other actions. This is a movement rate of 2.5 m/s (5.6 mph) and is represented by a MOV characteristic of 10. A top sprinter can move four times as fast, but we're not talking about a world-class athlete under ideal conditions, so I accept that movement rate to be reasonable. However, once you start looking at the MOV rates of other things in the game, it goes off the rails a bit. For example, two things I'm interested in for my campaign are horses and tanks. A horse has MOV 12 which corresponds to a movement rate of 3.0 m/s (6.7 mph). Now I know horses aren't the most sure-footed of beasts and their size means they need a few seconds to get going, but an average horse can run about 25 mph (to say nothing of a thoroughbred). So, even if you cut their speed in half, they should still have a movement rate twice that listed. Incidentally, all the other large mammals listed in the BRP core book have the same MOV 12 (or less) save one, the bear, which has MOV 14.

Things really get wobbly when you look at vehicles. A "vintage" tank is described as a WWI-era tank and has MOV 42. This works out to 10.5 m/s (23.5 mph). Yet, the fastest tank of WWI, the British Medium Mark A Whippet, had a top speed of 8.3 mph. The blinding speed of the vintage tank is closer to a Panzer IV which has a top road speed of 26 mph, but even the Panzer IV could only manage about 10 mph off-road.

Based on this analysis, I would suggest the following changes. A human MOV 10 serves as a baseline for a speed of about 6 mph. A horse can sprint about 12 mph, so it will have MOV 20. A WWII-era tank such as a Panzer IV or a Sherman can move about 18 mph if we simplify things and average its road and off-road speeds, giving it a MOV 30.



Derobane-bane said...

How are the rules in regard to the range in which vehicles can travel? Do they also need a house ruling?

Rognar said...

They don't have stats for that. It's something you just look up, I guess. A Panzer IV has an operational range of about 200 km (120 miles), so I'm guessing that's about as far it can go and return on a tank of diesel.