When planning a rescue, you need to inventory all of your assets and that includes people. More challenging rescues require a Rescue Leader. The rescue leader is typically the person with the most rescue experience, not necessarily the trip leader. They probably have more experience in boating, taken several SWR classes, taken part in previous rescues, etc. This person assesses the situation with the help of others, formulates and communicates a plan, tracks progress, and adjusts activities as necessary. Quite often, the leader does NOT perform the rescue themselves. Think of this person as a manager and not a worker bee.
The next order of business is the safety of the rescuers. When working with ropes, you need to place a person or two upstream of the accident site to warn off other boaters. For boat assisted rescues, we often need to let them go to manually assist the victim or wade/swim to them. It really helps to have someone in a safety boat below to retrieve our gear. Additional safety persons with throw bags can be positioned above strategic eddies in case either the rescuers or victim end up swimming.
Now that safety has been addressed, we turn our attention to the rescuers. People fortunately come in all shapes and sizes. Large strong persons are helpful for belaying tag lines. Small individuals with strong climbing and swimming skills are useful in the water or in vertical work. Anyone that is attached to a line MUST wear a rescue vest so that may dictate who goes in the water. Take a minute to verify that in water rescue persons have all the equipment they need like carabineers, pulleys, and a throw line. Other personnel can try to set up a stabilization line across the stream to assist in the rescue. If you have extra people, consider setting up a backup plan in case your initial attempt fails.
Eventually, you will get the person on shore. What if the person is injured? Is there someone in your paddling group with solid First Aid skills? Who has the best first aid kit? For that matter, you might as well have someone get all the first aid kits out just to be on the safe side since we each carry different items. The title of this person is the Medic. While you are at it, see if anyone has a cell phone. This may come in handy for requesting professional help. If cell reception isn't available and you need help, consider assigning someone as the "Runner". The Runner may be able to find a close by road or trail to get help. In some cases, you may need to send two paddlers downstream to get help. Riggers are often on the rescue team. They are very skilled with rope work and mechanical advantage systems. They usually carry a pin kit which includes pulleys, prussic loops, webbing, and carabineers. They probably have a full size (75' 3/8") throw rope as well. Other less skilled individuals can help out buy gathering firewood, setting up shelter, taking notes, boiling water, etc.
The key to making all of this work is a centralized command structure. The Rescue Leader needs to take charge and avoid conflicting activities. This is a full time responsibility which is why they typically do not take part in the rescue itself - someone needs to oversee the big picture. Use your imagination and think of how to use all of your available helpers. Where possible, ensure that everyone including the victim see you are organized and confident.
Here is a short article that focuses on the ICS Roles.
In most private boating parties, everyone knows each other's skills and what equipment they bring. Rick always has the best first aid kit (but I am catching up thanks to Rick). Ron has every piece of rescue gear ever invented. Pat is a very solid paddler and well versed in rescues. Dave is the electronics guru and probably has a cell phone and GPS device. I am an excellent rock hopper and can quickly scramble to any position necessary. I am also light and useful for vertical work if necessary. You catch the drift, we each have specialties and we know what they are. When paddling with new boaters, do a quick equipment check at shuttle time. This can save a great deal of time in an emergency. When an incident takes place, each of us can make a quick assessment and spring into action without a great deal of communication. This is great in a pin situation where you may not have the luxury of time. Although we lack a formal structure, we still work as a team and support each other.
Professionals versus Recreational Boaters
Professional rescue squads always opt for the formal ICS structure and for very good reasons. Besides safety, they really have major liability and insurance issues to contend with. If a firefighter enters the water without properly recognized training and injures themselves, their insurance claim is denied. Most rescue squads have a very wide range of skill levels and unfortunately, most do not gett the time to practice their skills. The formal ICS structure serves them quite well.
As boaters, we are exceptionally comfortable in whitewater and practice our skills quite frequently. We often paddle with similarly skilled boaters so we can mix and match duties as needed. We often paddle with the same group of people and know there abilities. We for the most part simply tackle roles that need to be dealt with - often without asking. This enables us to act very quickly and complete most rescues before the situation degrades. On the other hand, really big rescues often require teamwork from multiple paddling parties and raft guides. These larger efforts often involve some type of leadership structure to avoid interfering with each other. As rescuers, you really need to be comfortable with both approaches.