Final answer:
The safest initial practice if you run aground in shallow water is a careful attempt to reverse off the shallow area. Heeding safety signs and understanding the priority of removing a drowning person from water before administering CPR are also critical safety practices.
Step-by-step explanation:
The safest practice to try first if you run aground in shallow water is to assess your surrounding for safety and then attempt to reverse off the shallow area slowly. If this does not work, lightening the boat by removing heavy gear may shift the weight distribution and help dislodge the boat. It is essential to remain calm and avoid panicking. Remember, your top priority should be to protect yourself and any passengers from injury before considering the condition of the vessel.
You should always heed signs such as "no diving" to prevent nervous system injuries due to shallow water. If someone is drowning, the first step should be to remove the person from the water as CPR is ineffective in the water. Lastly, if you're crossing a salt-marsh or in a canoe, knowing your environment and operating safely within it is imperative for safety.