With no car lanes, no stop signs and no one directing traffic on the water, safety among boaters is critically important. And most boat operators are polite. A customary wave is exchanged between two helmsmen when they are in a constricted area.

But in recent years and especially this summer, there appears to be a change in this custom. Some helmsmen are driving their boats unsafely, their heads pointed straight ahead, ignoring others around them.

It is not only customary but mandatory that when two boats approach or pass each other, the operators visually acknowledge each other, usually with a wave of the hand, sometimes a nod of the head. This mutual salute is expected and routine among all operators of different types of water craft.

On big ships and occasionally between ferryboats, there will be the toot of a horn, either once or twice, as they pass. Sometimes there is bridge-to-bridge communication on the marine radio.

These simple acknowledgements give a boater reassurance that he has been seen by the other boater.

But when one boater doesn’t acknowledge the other, trouble can crop up in a hurry, especially in a tight space.

Failure to acknowledge is not just bad manners, it is dangerous.

Coast Guard petty officer Jason Chapa with station Menemsha, said it is important for all mariners to be educated on the water. “Take a boating safety course,” he advised.

That’s good advice for all who plan to spend time out on the water next summer.