Understanding how the boat operates and how the river behaves are essential to successful swift-water rescues
Of all the technical rescue disciplines, I find swift water to be one of the least forgiving. Rivers are incredibly dynamic environments with an unlimited supply of hazards that can change a seemingly uneventful rescue sequence into a nightmare.
Each boat will perform differently in the water as the loads within the boat change. I have observed two prevalent mistakes that novice boat operators and rescuers make. First, they simply do not understanding the performance characteristics of their boat and motor. Improper operating techniques may result in rotational capsizing or sudden surges or losses in position in the river. Either of these actions can put rescuers in the water. Second, they develop tunnel vision on a specific problem and forget about the river. The river never stops coming at you and losing sight of it can result in rapid loss of position and an ill-advised ferry angle.
For the purpose of this article, we will be discussing the most common river-based boats within the rescue service – 3.6 metres to 4.9 metres crafts including standard inflatables, tunnel hulls (a boat hull that uses two typically planing hulls with a solid centre) and jon boats (a flat-bottomed boat constructed of aluminium, glass fibre, or wood with one, two, or three bench seats). Before effectively operating these boats, we need to have a firm grasp of three basic factors:
- Load capacity.
- Performance characteristics.
- Immediate actions.
Boats may be equipped with a load-capacity placard that displays the maximum allowable weight and/or persons that can be in the boat. This calculation is based on a standard U.S. Coast Guard formula that multiplies the length of the boat times the width of the boat and divides it by 15. For example: in imperial measure, a 15-foot-long by 8-foot-wide boat would result in 120/15 = 8.
This formula is based on a 150 lb (68 kg) person, and I do not know many rescuers that weigh 150 lbs. So, use a coefficient of 20 to be on the safe side. This would result in a maximum person load of six as opposed to eight. You also need to consider the increased drag and weight that is generated as you approach the maximum load.
I am a strong advocate of keeping boat personnel to a minimum in swift-water applications to ensure optimal performance of the craft. The best layout for a boat rescue team is an operator or pilot, a primary rescuer and a secondary rescuer if absolutely necessary.
It is important to know how to trouble-shoot and take corrective actions when things do not go as planned. Know your motor inside out. Have a systematic and rapid checklist that you progress through to correct the problem.
Once the load capacity is known, it needs to be applied on the river to analyse its relationship to performance characteristics of the boat. Generally, inflatable crafts are much more stable than jon boats. This allows more personnel to be placed in the boat with less concern for placement or position. Jon boats can be highly unstable and require great attention to load positions in the boat to prevent taking on water and capsizing. This principle is particularly important when turning the boat or applying sharp ferry angles.
During these manoeuvres, it is imperative that the crew understands how reactive the boat is to load placement near its sides. In unstable boats, crews should shift their weight to the downriver side when performing turns if the goal is to maximise boat stability. However, the result is a wide turn radius. If a tighter turn is desired, the crews must be aware of their particular boat’s reaction to inside loading to ensure that they do not overload it and allow water to rush into the boat and cause a rotational capsize.
Each of the primary boat types turn very differently. Standard inflatable boats typically perform a sliding motion across the surface of the water. Jon boats and V-bottom boats slide less and will naturally turn tighter. Tunnel-hull boats have two rails in the water that produce extremely tight turns that generate up to four Gs when performed at maximum operating speed.
When setting up a boat, the motor must be set at the appropriate angle with the appropriate propeller to ensure that maximal water is drawn through the propeller and not an air cavity.
It is often impractical to adjust the trim of the motor while on the river by any means other than load positioning. For example, many tunnel-hull boats need to have as much load in the rear as possible to generate enough initial torque to react with maximum propulsion. If a crew knows they are going to perform a peel out or a tight down river eddy turn, they should shift their weight just prior to performing that manoeuvre. Bringing a boat to plane or maximum operating speed may also be impacted by load distribution in the boat.
The last component to be evaluated is overall capability of the boat as it relates to CFS or water movement. Boat crews must know the limitations of their boat – especially how much current is too much for the boat configuration. This will be based on the load in the boat, the drag of the boat design and construction, and the horsepower and prop setup of the motor.
The key to successful boat rescue is to develop refined operating skills through repetition and exposure to different water conditions, as well as strong situational and environmental awareness using all senses. Boat-based rescue operations can be tremendous assets or liabilities to rescue operations.
When Things Go Wrong
It is also important to know how to trouble-shoot and take corrective actions when things do not go as planned. Know the motor inside and out. If propulsion is lost or the motor dies, have a systematic and rapid checklist that you progress through to correct the problem.
The crew should also have a course of corrective actions to try to maintain a safe boat position in the water with paddles. This is one example of immediate actions, which should be rehearsed and performed with great repetition to develop muscle memory.
Once the boat itself has been addressed, operators and crews need to understand the dynamics of swift water. Rescue sequences typically require a large array of boating skills from ferrying, hovering and peel outs to river reading, avoiding and identifying hazards and victim retrievals.
One of the hardest disciplines to develop in novice operators is the ability to keep the nose of the boat up river with no ferry angle and maintain position in the river while a victim is being loaded. This is commonly referred to as hovering.
Operators will naturally want to shift their focus towards the rescuers and victim during loading. This generally results in an accidental ferry angle being set towards the victim because the operator is staring at that receiving point on the boat as opposed to looking up river to hold position.
In a narrow shoot with fast water, even a 15-degree ferry angle can cause a boat to careen towards the bank and the operator may not be able to recover boat position in time to avoid further injury to the victim and damage to the boat and crew. Conversely, an operator who is completely honed in on a hazard in the river but has lost focus on his rescue crew and the victim may fail to respond appropriately to their needs.
We address this dichotomy during training by encouraging operators to divide their senses. They are instructed to keep their eyes on the water and their ears attuned to their rescuers.
One of the best drills or events to apply this is in victim pick-ups. The boat will always approach the victim from the down river side. We require operators to maintain boat position and hover during a victim pickup as well as capture the victim and perform a down river peel out with the victim on the down-river side of the boat.
In more forgiving water conditions, operators should always bring their motors to neutral during victim pickups to negate the possibility of a prop injury to the victim. In swift water however, losing operational control of the boat by going to neutral could be catastrophic.
We train our rescuers to convey specific verbal commands to the operator when they grab, capture and pull in a victim or command a peel out. If the rescuer is losing the victim, he or she communicates to the operator to either “peel out” to come around and relieve current pressure on the victim or “kill it” to bring the motor to a neutral or zero energy state.
The key is to develop refined boat operating skills through repetition and exposure to different water conditions as well as strong situational and environmental awareness using all senses. Boat-based rescue operations can be tremendous assets or liabilities to rescue organizations.
Get the boats out of the bay and onto the water to insure they will be an asset.
This article appeared originally in the June 2013 edition of FireRescue1. The FireRescue1 website is at http://www.firerescue1.com
For further information, go to www.rescuemethods.com