UNDERWAY REPLENISHMENT

Underway Replenishment

Underway Replenishment

Introduction

Underway replenishment is a broad term applied to all methods of transferring fuel, munitions, supplies, and personnel from one ship to another while the vessels are underway. Two general methods of UNREP are used - connected (CONREP) and vertical (VERTREP). They may be used singly or at the same time. In connected replenishment, two or more ships steam side-by-side and the hoses and lines used to transfer fuel, ammunition, supplies, and personnel connect the ships. Prior to underway replenishment, coaling stations were the only way to refuel ships far from home. This however had two disadvantages: the competition between the colonial powers for suitable sites astride the world's trade routes, and the introduction of a predictable pattern to a nation's naval operations.

There are several factors in favor of replenishment with the ships alongside each other instead of astern. First, by replenishing alongside, the oiler or other auxiliary ship, can service two ships at once, with multiple replenishment stations to each ship (Withington, 2010). Second, by replenishing alongside rather than astern, the whole formation of ships can maintain greater speed (up to 16 knots instead of the 7-8 knot maximum for astern refueling). Third, by replenishing alongside, both fuel and dry cargo can be transferred, instead of being limited to fuel only. Astern fueling does have a place in the replenishment plan, but it is generally limited to a tanker in convoy refueling the convoy escorts.

Discussion & Analyses

Following some early development starting at about 1900 for transferring coal, the technique of underway replenishment was perfected by the United States Navy in the late 1930s, beginning with the supply ship and receiver ship coming along side each other at full stop in good sea states, but this was found impractical and methods were developed while ships were underway (Kreisher, 2008). And these methods developed were used extensively as a logistics support technique in the Pacific theatre of World War II. Since it allowed extended range and striking capability to naval task forces the technique was classified so that enemy nations could not duplicate it (Lewis, 2010). Presently, most underway replenishments for the United States Navy are handled by the Military Sealift Command. It is now used by most, if not all, blue-water navies.

If they are going to be combat-effective, warships must be able to remain at sea for weeks at a time with fuel, provisions, parts, and ammunition. The U.S. Navy is highly proficient at underway replenishment (underway replenishment) techniques that use special cargo-handling gear to make transfers from one ship to another while the two are steaming abreast or, in some cases, astern (Withington, 2010). Vertical replenishment (VERTREP) is a form of underway replenishment in which cargo-carrying helicopters are used to transfer goods from one ship to another. MSC ships (such as T-AOs and T-AEs) carry out much of the underway replenishment capability of the Navy today, but fast combat-support ships (AOEs) are the largest and most powerful of the Navy's non-combatant seagoing ...