Support from the Sea: Replenishment, sea-lift, amphibious or logistic support ship – why it really matters to Army - Part 1

In addition to reaffirming the acquisition of two new replenishment vessels by the early 2020s, the 2016 Defence White Paper had a surprising inclusion – “a third high-capacity replenishment ship or an additional logistics support ship similar to HMAS Choules in the late 2020s”. Less of a surprise was the programing of the replacement of HMAS Choules, as “the benefits of this type of vessel in extending the reach of the ADF and enhancing our capacity to deploy larger and better-equipped forces”, are well known in the ADF but have now been codified by Government. More on Choules in Part 2. 

Views on the role of replenishment ships in supporting the joint force must be nested within the context of Navy’s growth in surface combatants. Replenishment ships are a force multiplier. They increase operational effectiveness of frigates, destroyers, patrol vessels and amphibious ships. Replenishment ships extend both the range and endurance of the maritime task group. Not only do these replenishment platforms align to Government’s direction for greater regional engagement and maritime operations at greater distances from Australia, but they also provide options for niche contributions to coalition operations such as those undertaken by HMAS Success and Westralia during the First Gulf War.

The 2016 Integrated Investment Program (IIP) states that the role of the potential third replenishment vessel is to “provide an assured [replenishment] capability to continuously generate one operationally available replenishment ship”. While the door has been left open for an additional logistic support vessel, perhaps similar to HMAS Choules, if it was a choice between greater support to the whole fleet and increased sea lift it would appear prudent, or arguably essential, for additional replenishment-at-sea capabilities.

Project SEA 1654 Phase 3 will deliver two Spanish designed Auxiliary Oiler Replenishment (AOR) ships similar to Cantabria by the early 2020s to replace the current fleet of one AOR, HMAS Success and one AO HMAS Sirius.[1] Navy has a good understanding of Cantabria’s capabilities, as she conducted a year-long deployment to Australia in 2013 while HMAS Success was in an extended maintenance period.

So what does the Cantabira deliver?

Assuming minimal changes are made to the Spanish design, a single new AOR will  deliver 47% more aviation fuel (1530 m3), 65% more ammunition (255 tons) and 56% more general stores (470 tons) than HMAS Success– a significant  improvement for the fleet.[2] Interestingly, based on the publically available information, she will carry 27% less diesel (7080 tons) and 20% less water (200 tons), presumably this meets Navy’s need or modest changes are envisaged to improve the Australian design. The new AOR will also have capacity for two MRH90 sized helicopters, doubling the existing capacity of Success. HMAS Sirius had no helicopter capability.

To support the land force ashore, if a deep-water port is available and the sea state permits, Cantabria can crane stores ashore or into a landing craft from an amphibious ship.  Helicopter resupply could also be conducted. Large volumes of fuel can be pumped ashore using Army’s bulk fuel distribution system[3]. The primary benefits to land forces from an assured AOR fleet are: a Navy capable of greater reach and endurance with one, possibly two surface action groups supporting a campaign; enhanced support to the Canberra Class Amphibious Ships; and greater logistic support for time sensitive operations such as HADR missions.

It would therefore appear to be an obvious choice to order a third Cantabria from the running production line before the conclusion of the current project. This would deliver many advantages, including common training, common systems with other Navantia designed ships in the fleet, and provides the assured replenishment-at-sea capability Navy needs and Government demanded.

These are significant improvements, but do little to improve the ADF’s sea-lift capabilities. More on this next week in Part 2!

[1] Auxiliary oiler and Replenishment (AOR) and Auxiliary Oiler (AO) are two classes of replenishment ship. While both classes provide underway replenishment of fuel, the AOR has a greater capacity for dry stores and ammunition.

[2] Note- all calculations are based upon diesel density of 885kg/m3 and aviation fuel density of 810kg/m3.

[3] Towed flexible barge system requires 5-7 20’ TEU containers. This is a significant portion of the container stowage space on the AOR