A marine rigger is a person who works with a ship's rigging, the system of ropes, cables, and accompanying equipment such as winches and pulleys that a ship carries. Riggers on a ship use the rigging to move heavy loads, such as when cargo is being loaded or unloaded at port, and in the case of a sailing vessel they also use it to adjust the ship's sails to control course and speed while at sea. They are also responsible for inspecting and maintaining the ship's rigging to keep it in working order.
The term marine rigger is used to distinguish riggers working on ships from workers who use cables, pulleys, and similar equipment in other contexts, such as construction sites or theaters. In this context “marine” simply means a job related to the sea and does not refer to the United States Marine Corps or other military organizations that use the term, though such organizations may also have personnel called riggers; in the U.S. Marine Corps, for instance, “rigger” commonly refers to a person who prepares and maintains parachutes and other equipment for air drops. Most present-day marine riggers discussed here are civilians working in the commercial shipping industry.
During most of nautical history, the primary purpose of a marine rigger was to operate the ship's sails. While today the term “rigging” is frequently used outside of a maritime context and generally refers primarily to ropes, cables, pulleys, and other related equipment, historically the term also encompassed the ship's sails and masts, and the modern use of the term “rigger” to describe someone who uses specialized equipment to move heavy objects comes from this. This aspect of rigging has faded in importance with the replacement of sails with engines in modern cargo and military vessels, but it is still essential on modern sailing vessels and sailboats, such as those used for recreational trips.
For a sail-powered ship to change course or speed or to maintain these when wind conditions change, the ship's rigging is used by the ship's rigger to adjust the sails and hold them in their new position to keep the ship under control. Today motorized equipment such as winches are often used by marine riggers to assist in this task, though for most of sailing history riggers did not have such devices and had to position the sails through sheer muscle power. During severe weather conditions, the work of a maritime rigger can mean the difference between a ship's survival and its destruction, because in high winds and rough seas failure to adjust the sails appropriately for these conditions can cause the entire ship to capsize.
The primary job of a marine rigger on a modern commercial or military vessel is using the rigging to assist in the movement of heavy loads, such as the cargo the ship carries. The riggers set up a system of ropes or cables, along with other equipment such as winches, pulleys, and cranes, that they attach to the objects to be moved. This is not a simple process, as it requires understanding the cargo being moved, the rigging's capabilities, and techniques for suspending and moving objects that can weigh many tons, and errors in planning or execution can result in potentially deadly accidents.