Not only is it illegal in many states, but it makes a fall overboard more likely. If you need to change position in the boat, hold on to both sides and keep your weight low. Standing in a small boat to start the engine or land a fish makes a fall overboard likely. Toss the person a life saving device even if he or she can swim. Use whatever device is nearest.
Time is essential.
If underway, slow the boat, keeping the person in view. Other persons on board should act as lookouts and point at the person in the water. At night, direct the best possible light source on the victim. Try to approach the person from downwind or into waves. Consider existing conditions such as water temperature, physical condition and ability of the victim.