This includes a general responsibility for the ship's stability and special care for cargoes that are dangerous, hazardous or harmful.

Even under the best of conditions, a ship is balanced precariously upon the water and is subject to a number of forces, such as wind, swells, and storms, which could capsize it.

The cargo officer uses tools like ballasting and load balancing to optimize the ship's performance for the expected type of environment.

At sea, the mate on watch has three fundamental duties: navigate the ship, safely avoid traffic, and respond to any emergencies that may arise.

A ship's draught, trim, speed and under-keel clearance all affect its turning radius and stopping distance.

Shiphandling is key when the need arises to rescue a man overboard, to anchor, or to moor the ship.

The officer directs the helmsman to keep to track, accounting for effects of winds, tides, currents and estimated speed.

The officer uses supplemental information from nautical publications, such as Sailing Directions, tide tables, Notices to Mariners, and radio navigational warnings to keep the ship clear of danger in transit.

Safety demands the mate be able to quickly solve steering control problems and to calibrate the system for optimum performance.

Since magnetic and gyrocompasses show the course to steer, the officer must be able to determine and correct for compass errors.

Weather's profound effect on ships requires the officer be able to interpret and apply meteorological information from all available sources.

Finally, human errors such as inaccurate speed inputs and confusion between true and relative vectors add to the limitations of the radar/ARPA suite.

Responsibilities include performing damage assessment and control, understanding the procedures for rescuing persons from the sea, assisting ships in distress, and responding to any emergency which may arise in port.

The officer must understand distress signals and know the IMO Merchant Ship Search and Rescue Manual.

Then, the candidate must attend approximately 13 weeks of classes or complete the assessments from NMC Policy Letter 04-02[3] and pass a series of examinations given by the United States Coast Guard.

A master of 1,600 ton vessels can, under certain circumstances, begin the application process for an unlimited third mate's license.

These critics assert that the newer requirements will eventually lead to a shortage of qualified mariners, especially in places like the United States.