The 15-year Philippine Navy development plan, published on several newspapers discussed on the Timawa.net forum here, is noteworthy in that it highlights the navy’s recognition of the need for an Underway Replenishment (UNREP) capability. The list included a requirement for “three Logistics Support/Replenishment Ship (LSS)”.
UNREP is a process by which ships take on food, fuel, and other stores, while they are at sea. This eliminates the need to return to port for re-supply thus allowing the vessels to stay on-station longer, and reducing the non-productive transit time to and from the desired area of operations. Given the relatively small size of the Philippine Fleet, this capability will allow the AFP to make the most of limited resources.
The following is a video of how the US Navy performs both UNREP and VERTREP (Vertical Replenishment involving helicopters).
Both the BRP Gregorio del Pilar, and the BRP Ramon A Alcaraz are UNREP capable. The photograph below clearly shows the UNREP receptacle on the former. Theoretically the PN’s lone Cyclone class ship, the BRP Mariano Alvarez (PS-38), should have a similar capability since its sisterships in the USN are replenished while underway. The capability is there, so all that is required for in-house capability will be the supply ships. Before these arrive, the PN could, presumably, incorporate UNREP training in its exercises with its allies.
This topic is also discussed on Timawa.net here.