In one of those instances, a Lincolnville woman died from injuries she received when she was struck by a boat while swimming after sunset.
A state game warden offers some practical safety tips for boaters and swimmers alike.
"Boaters need to remember operating under the influence, whether alcoholic beverages or drugs, is against the law. It must be stressed there's been no official determination on what caused either of these recent boat/swimmer accidents," Sgt. Alan Gillis said.
"We don't have any speed limits per se, but we do have laws which govern how you operate your watercraft," he said.
Gillis said that prudent speed is dictated by the weather and water conditions, as well as the experienced eye of the game warden.
"If you're operating on a bright sunny day and the water is flat calm and there's no traffic around, that would be a day to put some speed on your boat and enjoy your ride," he said.
However, on the other hand, boaters should ease up on the throttle when in rough waters, Gillis said, "because you just can't see what's in front of you."
Rivers and harbors often have a no wake zone, he said.
Lakes, however, also have restricted high-speed zones so any time a watercraft is within 200 feet of the shoreline, the operator must operate at headway speed, which Gillis defined as "just fast enough to be able to steer your boat."
Gillis said there are steps swimmers can take to improve their visibility.
"A really good idea would be to take somebody with you that's in a kayak or a boat to ride along beside you, so you don't have a bad experience," he said.
While the Maine Warden Service does not keep statistics on boat/swimmer accidents, a department spokesman agreed such accidents are rare.
Gillis said it boils down to personal responsibility. Boaters and swimmers alike are responsible for their own personal safety.