Final answer:
When two vessels cross paths, the general rule is that they should alter their courses, usually to starboard, to prevent collision. They may also adjust their speed as necessary to ensure safe passage.
Step-by-step explanation:
When two vessels cross paths, the actions they should take are governed by maritime rules known as 'The International Regulations for Preventing Collisions at Sea' (COLREGs). These rules specify the behavior of vessels to avoid collisions. Typically, the rule of thumb is that both vessels should alter their course to starboard (which is the right side when one is facing forward) in order to pass on the port side (which is the left side) of each other. They may also need to adjust their speed to ensure a safe passage. It is not advisable to maintain current courses and speeds because that could lead to a collision. Increasing speed is generally not recommended as it may reduce the time available to react to any close-quarters situation. So, the most appropriate general action when vessels cross paths is to alter their courses to avoid a collision, and if necessary, adjust speed.