Expedition Fuel Planning Tool

Measuring the weight of your equipment, food, fuel, and clothes is an absolute necessity.  The more weight you need to move, the more energy it takes, and the more money it takes.

Yes, I said money.  Airlines charge by weight.  If your baggage is over their limit, you will be paying by the kilo or pound.  That is money and that is a cost for your expedition planning.

Base weight system

In my opinion, the “base weight” system is probably the worst way categorize weight.  For anyone familiar with basic accounting, the base weight system reminds me a lot of transfer pricing.  Basically, it has a high potential for abuse.

Transfer pricing is how a company sells things within the organization.  Thus, this is a major system for allocating profit to different departments.

Base weight is subject to the same kinds of games that we see in transfer pricing.  For example, if someone wants to reduce their base weight, they simply remove the item from the pack, and place it in a pocket or in their hands, and just like that, base weight is reduced.

This is useless for anything other than trying to entertain yourself with pissing matches about who has the lowest base weight and what base weight is considered light or ultra light or super light or amazingly light.

Fixed and Variable system

The system I use is very simple, much like a managerial budget (cost accounting).  I have two types of weight; fixed and variable.

Fixed weights

Fixed weights refer to the weight of things that will not change for the trip.  These are the weights of items like boots, backpack, sleeping bag, sleeping pad, rope, carabiners, crampons, etc.

For a given type of trip, no matter the length, these items weigh the same over the entire trip.

To continue to use the accounting analogy, this is like the fixed costs associated with making something.  You have a lease for your factory building.  That cost is fixed over the term of your contract, you know exactly what it will cost you, no matter how productive you are (or how much time your expedition will take).

Variable weights

Variable weights are for items that change depending on the duration of the trip.  The easiest examples are food and fuel.  But, another example is first aid equipment.  Using the accounting parallel, variable weights are just like variable costs. . .your electricity bill is a variable cost.  It varies as you use more or less electricity.  If you run an extra shift at the factory, your electricity bill goes up as you keep the lights and machines on for that time.  If your trip goes an extra day, your food weight goes up.

The weight of antibiotics, pain meds, altitude drugs, etc for a 3 day trip is different than the weight for a 28 day expedition.  The same effect is seen with gauze.  To be able to change the bandages on someone during the course of an expedition requires much larger quantities than for a weekend trip that has easy evacuation possibilities for very minor injuries.

Another tricky variable weight is fuel bottles for liquid stoves.  With an MSR style stove, 1 fuel bottle is a necessity and should probably be logged as a fixed weight, as part of the stove system.  But as the duration of the trip increases, so too does the quantity of fuel needed.  This requires more containers for carrying the fuel.  These additional containers, whether they are plastic bottles or additional metal fuel bottles should be logged as a variable weight.

Water, of course, is another variable weight, as are the containers for carrying the water and, perhaps, chemical treatments for purifying the water.  In many areas, there is little concern over availability of water.  Following rivers, fishing on lakes, or in mountains with an abundance of glacial streams, water is everywhere and makes up a relatively small amount of variable weight.  There is just no need to carry a large quantity.

However, in desert areas, water can be a significant portion of variable weight, when water suddenly is measured in days rather than in hours between streams.

Batteries are another variable weight.  A lot can be done to minimize the weight of these energy sources, however, they still vary depending on the length of the trip.

Conclusion

Using a simple model for weight accounting results in several useful advantages.  First, it is quite easy to know exactly how much weight you will be dealing with, and plan for weight decreases each day, which can correlate to mileage increases over the course of the trip as well.

Second, using this framework, it is possible to plan for expeditionary expenses, like the costs associated with shipping your gear to the destination.

Third, using empirical data, it is very possible to plan expeditions with a high degree of accuracy.  Variable weights are tricky to master, as every person has preferences for how many hot meals they consume each day, what kinds of food they will eat, how they respond to altitude, how many calories they need to eat, etc.  This is why experience is such a major factor in planning well.

I’ll cover more about weight accounting, cost accounting, and expedition planning in the next few weeks.

Tags: accounting, expedition planning, lightweight, planning, weight