Operation Jackstay

Another ship comes alongside and transfers equipment, food or fuel. The jackstay is a strong wire cable that connects the ship needing the supplies to the ship bringing the supplies.

The two ships come close together, around 50 metres between them. One ship uses a line thrower to fire a line over to the other ship. The jackstay line is stretched out between the two ships and a pulley is attached that can slide along the line. The pulley has ropes on either side that can pull it in both directions. The supplies are then attached to the pulley and pulled across to the other ship. They can carry an item weighing up to 200 kg!

Pictures above shown a jackstay is passing a ladder between HMNZS Canterbury and HMNZS Wellington. The Navy personnel have to keep the line tight by hand.

HMNZS Aotearoa, the Royal New Zealand Navy’s largest ship.

Replenishment at Sea is the main role of HMNZS Aotearoa, the Royal New Zealand Navy’s largest ship. As well as carrying supplies and equipment, the ship also resupplies other ships’ fuel. This means ships can refuel on the move without having to go into port. For this they also use a jackstay, and a fuel hose is sent down the line. The fuel hose is connected to the ship’s fuel tank and the liquid fuel transferred.

It took HMNZS Aotearoa eight and a half hours to transfer 3.35 million litres of ship and airplane fuel to USS Boxer, a US Navy ship, while in the Pacific Ocean in August 2024!

Aotearoa can even fill two ships fuel tanks at the same time!