Section 1A. Except as provided in section one, whoever, not being a pilot or public officer, boards a boat or vessel without the permission of the owner or person in charge thereof shall be punished by a fine of not more than fifty dollars.

This section shall not apply to a person who boards a rafted-up boat or vessel to reach a boat or vessel which he is authorized to board, or to reach a wharf, dock or float, or who boards a boat or vessel which has been abandoned, or who boards a boat or vessel to save life or prevent personal injury or property damage.