Underway replenishment
First developed in the early 20th century, it was used extensively by the United States Navy as a logistics support technique in the Pacific theatre of World War II, permitting U.S. carrier task forces to remain at sea indefinitely.
The Royal Navy had an unparalleled global logistics network of coaling stations and the world's largest collier fleet.
This had two disadvantages: the infrastructure was vulnerable to disruption or attack, and its use introduced a predictable pattern to naval operations that an enemy could exploit.
[1] Lieutenant Robert Lowry was the first to suggest the use of large-scale underway replenishment techniques in an 1883 paper to the Royal United Services Institute.
He argued that a successful system would provide a minimum rate of 20 tons per hour while the ships maintain a speed of five knots.
According to a report from The Times, a French collier had been able to provision two warships with 200 tons of coal at a speed of six knots using a Temperley transporter in 1898.
Lacking a similar collier fleet and network of coaling stations, and embarking on a large naval expansion,[3] the Navy began conducting experiments in 1899 with a system devised by Spencer Miller and the Lidgerwood Manufacturing Company of New York.
The Thames Ironworks and Shipbuilding Company also patented its "Express equipment", which delivered supplies to the broadside of the ship, instead of from the aft.
With the transition to oil as the main fuel for ships at sea, underway replenishment became practicable since liquid could be continuously pumped posing fewer problems than the transfer of solids.
The trial found that a transfer rate of 115 tons per hour could be achieved with the vessels traveling at speeds up to 12 knots in fine weather.
The trial found that the oiler's replenishment mechanism had a tendency to break due to the high pumping pressures required.
[12] Astern refuelling was again employed, this time utilizing a hose which ran on wooden rollers suspended in stirrups from a jackstay.
[11] Despite proving the concept viable, the C-in-C Home Fleet reported that "the use of tanker vessels for oiling destroyers at sea was unlikely to be of service and that further trials were unnecessary".
[12] As a result, the Royal Navy preferred to continue to use fuelling alongside in harbour, rather than at sea until World War II.
[11] In 1916, Chester Nimitz, executive officer and chief engineer of the United States Navy oiler USS Maumee, designed and jerry-rigged a riding-abeam refueling system while the ship was stationed in Cuba, with the assistance of G. B. Davis, Matt Higgins and Lieutenant F. M. Perkins.
This was used extensively as a logistics support technique in the Pacific theatre of World War II, permitting U.S. carrier task forces to remain at sea indefinitely.
[15] Since it allowed extended range and striking capability to naval task forces the technique was classified so that enemy nations could not duplicate it.
They required both submarines to be stationary on the surface, took a long time to transfer stores, and needed to be in radio contact with the replenished boat, making them easy targets.
The alongside connected replenishment (CONREP) is a standard method of transferring liquids such as fuel and fresh water, along with ammunition and break bulk goods.
[19] For this reason, experienced and qualified helmsmen are required during the replenishment, and the crew on the bridge must give their undivided attention to the ship's course and speed.
Because of the risks involved crews practice emergency breakaway procedures, where the ships will separate in less-than-optimal situations.
However, the maximum load and transfer speeds are both limited by the capacity of the helicopter, and fuel and other bulk liquids cannot be effectively supplied via VERTREP.
