Vertical replenishment

US Navy 0245911-N-72-028 A SH-60F Sea Hawk helicopter VERTREP

Bell-Boeing CMV-22B Osprey lands aboard USS Nimitz (CVN-68) in the Pacific Ocean, 25 February 2021 (210225-N-JX182-1011)

Defense.gov News Photo 060424-N-9723W-074

Vertical replenishment (VERTREP) is a method of supply chain management used by naval forces to transfer cargo from one ship to another while at sea, using helicopters. This technique is crucial for maintaining the operational readiness of naval vessels over extended periods, especially when they are deployed far from their home ports and cannot easily resupply by docking. VERTREP allows for the rapid transfer of supplies, including ammunition, food, spare parts, and other essential items, ensuring that the fleet remains operational and effective.

Overview

The primary advantage of vertical replenishment is its ability to quickly transfer cargo without the need for the ships to connect physically. This is particularly useful in rough sea conditions where traditional alongside replenishment methods, known as Underway Replenishment (UNREP), might be too dangerous. VERTREP operations can be conducted while the ships are moving, which minimizes the disruption to the naval task force's maneuverability and mission.

Procedure

During a VERTREP operation, cargo is typically slung under the helicopter using a cargo hook and long line. The helicopter then flies from the supply ship to the receiving ship, where the cargo is carefully lowered onto a designated area on the deck. Precision flying is required, as the helicopter must contend with the movement of both the supply and receiving ships, as well as any adverse weather conditions. The crews on both ships and the helicopter work closely together, coordinating their efforts to ensure the safe and efficient transfer of supplies.

Equipment

The helicopters used for VERTREP missions are specially equipped for the task, featuring robust cargo hooks, winches, and often, automatic flight control systems to aid in the precise handling of loads. Examples of helicopters commonly used for VERTREP include the Sikorsky CH-53 Sea Stallion, Sikorsky MH-60 Seahawk, and the Boeing CH-47 Chinook. These aircraft are chosen for their lift capacity, reliability, and ability to operate in a wide range of conditions.

Safety and Training

Safety is a paramount concern during VERTREP operations. Rigorous training is conducted regularly to ensure that all personnel involved are proficient in their roles and aware of the procedures to mitigate risks. This includes emergency procedures in the event of a cargo drop, helicopter malfunction, or sudden changes in weather conditions.

Strategic Importance

VERTREP plays a vital role in modern naval strategy, allowing fleets to remain at sea for longer durations without the need for port visits. This capability enhances the strategic mobility and sustainability of naval forces, enabling them to project power and maintain a presence in key areas of the world's oceans.

Challenges

Despite its advantages, VERTREP poses several challenges. Weather conditions, such as high winds and rough seas, can significantly impact the operation's safety and success. Additionally, the limited cargo capacity of helicopters compared to ship-to-ship transfers means that VERTREP is often used in conjunction with other resupply methods to meet the logistical needs of a naval task force.