BRP General Mariano Alvarez (PS-38)

The ship's operational capabilities were designed to meet the unique requirements of its Special Warfare missions. Operationally, the ship is capable of accelerating from stop to 35 knots (65 km/h) in under three minutes, then move from full ahead to 15 knots (28 km/h) astern in 60 seconds. In high-speed, hard-over turns, the ship barely heeled as the automatic stabilizers engaged.

Originally armed with two Mk38 25 mm chain guns fore and aft, several pintle mounts for attaching .50 caliber machine guns or Mk 19 grenade launchers, and a position for launching Stinger shoulder-fired SAMs (although this was removed when the ship was transferred to the Philippine Navy and is currently unavailable), the ship, along with others of her class still in the US Navy, were upgraded early on by replacing the after Mk.38 mount with the new Mk.96 platform. The Mk.96 combines both a M242 Bushmaster 25 mm chain gun and a 40 mm automatic grenade launcher on a single stabilized platform. The Mk.96 features an electro-optical fire control system with 27x zoom, infrared and low-light modes, a laser rangefinder, and an array of environmental sensors, which feed data into the ballistics computer to produce an accurate firing solution even while maneuvering at high speed. The computer can also interface with Stinger SAMs (which are currently unavailable).[8] The US Navy was positive about the performance of the Mk.96 and briefly considered up-gunning the 25 mm Bushmaster cannon to a 30 mm or even 35 mm cannon, but due to the high price this never came to pass.

The Sperry Vision 2100M combat system employs the navigational radars and the Sperry Voyage Management System integrated navigation and control system as a combat data suite. The radar intercept equipment was developed for use on helicopters. Has a Sperry Marine automated Integrated Bridge System (IBS).Each Mk 52 decoy rocket launcher carries 12 ready-service rounds, and 15 more rockets per launcher are carried in adjacent lockers. Ammunition supply includes 2,000 rounds 25-mm, 2,000 rounds .50 cal, 2,000 rounds 7.62-mm, and 1,000 40-mm grenades.[8][9][10]

Navigation systems include Global Positioning System and Loran receivers. Radio gear includes LST-5C SATCOM/line-of-sight UHF transceiver, A5 Spectra VHF radio, ICM120 Marine Band radio, and RF 5000 HF, VRC-92A VHF, and VRC-83(V)2 VHF/UHF transceivers. AN/SAT-2A infrared signaling systems are fitted, and the Marconi Vistar stabilized FLIR sensor with integral low-light-level television camera is mounted on the mast. Have IFF transponder but no interrogation capability, although it may be added later. The sonar transducer is retracted within the hull at speeds above 14 kn.[8][9][10]

The hull was constructed using BS-4360 Grade 43A steel, the superstructure was constructed using 5086 aluminum alloy. Main propulsion is generated by four Paxman Valenta 16CM-16RP200M diesels, developing 3,350 bhp, driving 12.8 cm six-blade highly skewed, variable pitch and rake, NI-AL bronze MIL-B24480A, alloy 1 amendment 3 (nickel-aluminum-bronze alloy) propellers, with pitch ratio of 1.465 at 0.7 radius and designed by USN NSWCCD (Code 544 drawing number P-5237B). Four Reintjes WVS-2232 reduction gearbox, with a reduction ratio: 2.025:1. Fuel capacity is 47,772 liters (12,620 gallons). Oil capacity is 568 liters (150 gallons). Total air conditioning plants production, 83.33 kW. They can refuel at sea, using astern fueling rigs. Fully operational at Sea State 3 with cruising speed of 25 knots (46 km/h; 29 mph), with 50% fuel capacity. Ship can survive up to Sea State 5. Maximum ship endurance at 10 days. Electricity supplied by two Caterpillar Model 3306 DIT Series B, rating 150 kW @ 1,800 rpm. Reverse osmosis desalinators, having a 1,514 liters (400 gallons) capacity per day. Fresh water capacity is 4,701 liters (1,242 gallons).[8][10] Equipped with Vosper fin stabilization system and a stern wedge to improve trim at high speeds.[9] Kevlar armor is fitted to the command space.[8]

Refitted by Bollinger Machine Shop and Shipyard prior to delivery[2] and received a stern ramp modification upgrade known as the Combat Craft Retrieval System (CCRS) which had the ship's stern extended by nine feet to accommodate a deck ramp - which extends down to below the water line, for a 20 feet Rigid Hull Inflatable Boat (RHIB).[9]