Understanding the Capacities of the Mark III Pump and how this relates to the S-211 Course

There is a 12 page PDF file that was written to cover the relationships of the portable pumps & water use class to the actual hydraulic formulas the use in the class. Many many students over the years have stated to myself as well as others that the math in the class seems to be seriously out of step with the pump.  As a result of identifying through discussion with many of these past students what their frustrations were, all of them agreed individually that the main issue they had was “trying to understand how performing any math problem to determine a pressure for a pump that has no pressure gauge is an absolute waste of time and tells us nothing“. I AGREE!   


The main concept the S-211 portable pumps class teaches is two-fold, as follows:

  • A. The components of the portable pumps
  • B. The basic operating principles of the portable pump. Then the courses next major concept is to introduce hydraulics and feasibility that comprises:
  1. Determine the total distance of the hoselay.
  2. Determine the total elevation gain or loss of the hose lay.
  3. Determine the nozzle type and associated pressure for use.
  4. Sum these pressures up along with the flow to be used and then look at a chart to see if a pump matches.

As many students have stated, this is not only not practical, 99% of the time the flows are seriously deficient in the need for the tactical objectives being sought, and the pumps to few and far in between to make up any differences and third, the number of actual pump operators knowledgeable on how to determine the “TRUE” solutions are practically nonexistent. Many instructors simply do not even cover this important topic, however.

The portable pump course therefor still offers nothing as to how to properly conduct stage pumping. There is an example of determining distances between the pumps that is covered on page 6. Now the example used can be used in ANY scenario and the only caveat is that you need to know if the slope from the pump to the final destination should be relatively constant. If the distance and/or elevation between the sections is NOT the same , then you simply need to work out the head pressure and distance for that “Section”. However, myself personally, id not worry about such unless it was a section that would create a significant change in pressures. 

Slope vs distance will can very widely in a single hose lay.


This 12 page paper that was written explains the terms, how they are derived and then introduces the pump curve and how to use that pump curve as your guide to determining how to get a specific volume of water over a distance and how to determine the needs. 

There are many things that are NOT gone over in this paper. The pump components and its operating principles is left to the actual course instructor for the classroom and field portion and so would serve no benefit to this discussion. However, experience and time using the pump with other experienced operators can help in this manner and as the time progresses forward for these folks, the engine academy will hopefully help them out IF they have a very excellent instructor in hydraulics principles.  


Updated and Clarified pages 11-14 (1-21-24)

Free Documents NO longer available, but may be purchased.

Understanding the Capacities of the Mark III Pump Updated Jan 2024.

Mark III Pump Capacity Cheat sheet




Joseph Moylan


Please see the About me link on the wildfireengineer.com website.

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