Vertical replenishment
{{Short description|Supply of vessels by helicopter}}
File:US Navy 0245911-N-72-028 A SH-60F Sea Hawk helicopter VERTREP.jpg]]
Vertical replenishment, or VERTREP, is a method of supply of seaborne vessels by helicopter. The United States Department of Defense defines VERTREP as:
...the transfer of cargo between ships using helicopters. VERTREP is often used to supplement connected replenishment. Weapons loads, generally limited to 1,800 kg (4,000 pounds), are transferred from the supply ship to the flight deck of the amphibious ship. The decided advantage of a VERTREP is that it can effect replenishment without ship-to-ship connection.[http://www.fas.org/man/dod-101/navy/docs/6_3_1.pdf OPNAVINST 8000.16 Volume II] United States Department of Defense, 01 September 1999, Chapter 6, Page 6-3-3
History
The United States Sixth Fleet had developed VERTREP routines in 1962 with SH-3 Sea King helicopters operating from {{USS| Mississinewa|AO-144|6}} and {{USS|Altair|AKS-32|6}}.Polmar, Norman, "Historic Aircraft: The King of the Sea," Naval History, February 2012, p. 13. Each ship carried one SH-3. At that time, there was some anticipation that nuclear-powered ships might reduce the need for alongside refueling. Altair performed the first night VERTREP to an aircraft carrier in 1965.{{Harvard citation no brackets|Nickodemus|1967|p=115}}
Modern United States Navy VERTREP procedures were initiated from {{USS|Sacramento|AOE-1|6}} in November 1964.{{Harvard citation no brackets|Pursley|1966|p=183}} Sacramento embarked two CH-46 Sea Knight helicopters to enable simultaneous transfer of ammunition by helicopter while petroleum fuels were pumped through conventional alongside-hose connections. Ammunition could be delivered to other ships up to 100 miles from Sacramento. Receiving ships have greater freedom of maneuver during VERTREP than conventional alongside transfers; and time loss is minimal in comparison to maneuvering alongside and rigging transfer lines. One Cold War VERTREP was accomplished while the receiving United States destroyer maintained contact with a Soviet submarine.
Transfer methods
File:USNavy - MH-60S Sea Hawk helicopter on the flight deck during a vertical replenishment in the Pacific Ocean-April2025.jpg helicopter on the flight deck of the USS Nimitz during a vertical replenishment in the Pacific Ocean, April 7, 2025.]]
File:VMM-364 Marines - vertical replenishment training - MV-22B Osprey - landing on USS Lewis B Puller in the Red Sea - May 2023.jpg Marines conducting vertical replenishment training exercise with MV-22B Osprey landing on the USS Lewis B. Puller in the Red Sea, May 23, 2023.]]
VERTREP helicopters are equipped with a cargo hook from which may be suspended either special ordnance slings or conventional cargo nets for less sensitive loads. A normal load is two to four pallets, depending on weight. The load is placed in position on the deck of the receiving ship by lowering the helicopter slowly from a high hover, and the load can be released manually by a helicopter crewman positioned to watch the load.{{Harvard citation no brackets|Pursley|1966|p=185}}
In October 2020, the U.S. Navy demonstrated an ability to resupply its ballistic missile submarine USS Henry M. Jackson at sea using a drone, a C-17 Globemaster, an MH-60R Sea Hawk and a MV-22B Osprey.[https://news.usni.org/2020/11/18/video-ballistic-missile-submarine-tests-aerial-resupply-with-air-force-c-17-drone#more-81535.VIDEO: Ballistic Missile Submarine Tests Aerial Resupply With Air Force C-17, Drone]
Rate of transfer
Ships without large flight decks or support equipment like forklifts are often unable to break down palleted loads and transfer them off of the receiving deck as rapidly as the helicopter can deliver another load.{{Harvard citation no brackets|Pursley|1966|p=184}} VERTREP supply ships carrying more than one helicopter can simultaneously make deliveries to several ships of a task group. Food can be handled somewhat faster than munitions because of the reduced safety considerations.
Limitations
Lift capabilities of helicopters are reduced by adverse wind conditions or high temperature or humidity. Pre-loading of pallets is necessary for rapid transfer, and requires advance knowledge of weather conditions and special care to secure light items which may otherwise be blown out of containers. While popular in use, VERTREP is considered relatively dangerous (as compared to other replenishment methods) as it involves danger to the loading personnel due to the helicopter and the load, and in turn, potential risks to the helicopter due to Foreign Object Damage (FOD).[http://www.tpub.com/gunners/50.htm Replenishment Methods] (from the 'tpub.com' website. Accessed 2008-04-25.)
See also
Notes
{{Reflist}}
References
- {{cite journal|first=Gordon K., CAPT USN|date=April 1967|title=Comment and Discussion: Vertical Replenishment and the UH-46A|publisher=United States Naval Institute Proceedings|author=Nickodemus}}
- {{cite journal|first=Charles R., LT USNR|date=November 1966|title=Vertical Replenishment and the UH-46A|publisher=United States Naval Institute Proceedings|author=Pursley}}
External links
{{Commons category inline|Vertical replenishment}}