Crossing the Gap … Safely
January 31, 2012
There are many important factors to consider before conducting water-crossing operations. I would like to highlight a few best practices and lessons learned in an effort to shed light on how to mitigate risks associated with water crossings. Soldiers and Leaders may not realize the buoyant force on an object is equal to the weight of the fluid displaced by that object. A cubic foot of water weighs about 62.4 pounds. Vehicles displace a lot of water when they enter a river or creek bed, and the pressure exerted by moving water increases with the square of its velocity. The depth and width of the area to be crossed, the bank conditions and the river's current velocity are major factors to consider before attempting a water crossing. These factors will determine if equipment and personnel can cross by fording or swimming, if use of expedient materials is practical or if specific bridging assets are required.
Some common risks of trying to cross water include vehicles stalling or becoming stuck. Most times, when a vehicle stalls, personnel try to get out of the vehicle. Once outside, they are exposed to swift currents that may result in them falling into the water and being swept away or jammed into debris downstream.
Drivers and their vehicle commanders also must be aware of environmental conditions and other issues associated with water crossings. Water clarity and lighting circumstances could conceal the condition of the roadway beneath them. Floodwaters can also hide a damaged roadway. Generally, flash floods do not last more than an hour, so Soldiers should keep this in mind: Do not trade a lifetime for an hour. Act safely, remember your training and do not cut corners.
Other factors to consider before conducting water-crossing operations include:
•Follow all vehicle fording and swimming instructions in accordance with the vehicle's technical manual.
•During training exercises, ensure drivers and crewmembers wear personal flotation devices if the water is more than 4 feet deep.
Factors to consider during water-crossing operations include:
•Ensure the water depth at the fording site is below the vehicle's fording limits and the site is clear of submerged obstacles.
•Do not exceed 4 mph when entering and traveling through the water.
•Consider not wearing load-bearing equipment during fording operations. The equipment could snag on vehicle components and prevent crewmembers from escaping through the top hatches during emergencies.
•Consider leaving combat locks unlocked during fording and when operating near bodies of water.
•Store sensitive items and small arms inside the vehicle. If the vehicle sinks, these items can be easily retrieved during recovery operations.
•Attach dismounted troops to a safety line when crossing.
•Do not cross more than one vehicle at a time, and do not cross a vehicle beside dismounted troops.
•Ensure the fording site has adequate entrance and exit points and a firm bottom.
Analyzing wet gaps and using the necessary resources available should allow crossings of gaps to occur safely and minimize unnecessary risks.
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Did You Know?
Field Manual 3-90.12, Combined Arms Gap- Crossing Operations, focuses on the elements necessary for the forces to cross an obstacle, wet or dry? To view this publication and others related to equipment safety operations, check out our Driver's Training Toolbox at https://safety.army.mil/drivertrainingtoolbox/. Having a strong, solid foundation on the aspects necessary for the conduct of water crossing enables the personnel and equipment to be safely postured.