NavalToday reports the Launch of the sixth and last Offshore Patrol Vessel of the Oaxaca Class, the ARM (Armada Republica Mexicana) Hidalgo, for the Mexican Navy. These ships were designed and built by and for the Mexican Navy, but they would look quite at home painted white with USCG stripes and WMEC hulll numbers. Statistically they are very close to Coast Guard 270s.

• ___________________Oaxaca Class_______________WMEC 270
• Displacement (full load)  1,680 tons_________________1829 tons
• Length                    282.2 feet (86.0 m)_______________270 feet (82 m)
• Beam:                      34.4 feet (10.5 m)_______________38 feet (12 m)
• Draft                         11.8 feet (3.6 m)________________14.5 feet (4.4 m)
• Speed:                      20+ knots_____________________19.5 knots

The occasion prompted me to take a look at the Mexican Navy. While the Mexican Navy does have six former USN frigates, most of their missions are closer to what we do in the USCG, and most of their ships are offshore patrol vessels. They have 21 ships (soon to be 22 with Hidalgo) in five classes that look an awful lot like WMECs. These ships have evolved over time, with each class an incremental improvement over the previous ships. Only the oldest of these, the Uribe class ships were built in Spain by Navantia, the remaining 17 were built in Mexican Navy shipyards in Tampico and Salina Cruz with the first of the Mexican built ships being commissioned in 1991.

• Uribe-class – 5 ships, 988 tons full load (fl), commissioned 1982-83
• Holzinger-class – 4 ships, 1,290 tons fl, 1991-94
• Sierraclass – 3 ships, 1,340 tons fl, 1999
• Durango-class – 4 ships, 1,340 tons fl, 2000-2001
• Oaxaca-class – 5+1 ships, 1,680 tons fl, 2003-2016

Photo: Uribe class OPV ARM Jose  Aueta (P-122)

The Uribe class were very similar in size and concept to the 210s, with a similar configuration of the foc’sle and flight deck on the O-1 deck. They did include a hangar, were 10 feet longer (67 m overall), and had more than twice the horsepower at 13,320 allowing a maximum speed of 21 knots. Its main gun was a single 40mm/7

The Holzinger or Aquila class were the first class built in Mexico. They stretched the design 24 feet to 244 feet (74.4 m), provided two main machinery spaces vice one, and retaining the same horsepower, achieved 22 knots. Originally they were to have had a 57mm, but because of stability consideration a twin 40mm/60 was used instead.

Sierra Class OPVs of the Mexican Navy

The Sierra, Mendz, or Holzinger 2000 class retained essentially the same dimensions as the preceding class, but introduced a number changes. The hull aft was extended upward to create a flush main deck at what had been the O-1 deck. A stern ramp was incorporated in the transom for launching a “chase boat.” The superstructure was given a more “stealthy” form with the RHIBs placed in enclosed pockets.  A Vosper fin stabilization system was also provided, and a 57 mm main gun was included. A max speed of 18 knots is claimed, but it is likely to be more than 22.

ARM Durango, Mexican Navy, 8 October 2008, photo by Apodemia.

The four ships of the Durango class were originally intended as units of the preceding Sierra class but the design was modified and is now considered a separate class although statistically they appear little different.

The Oaxaca are a bit larger. They seem to have decided that the “stealthy” superstructure is not worth doing. The 57 mm gun of the preceding class has been replaced by a 76 mm gun, but it is not the newest type so this may have been a case of the guns being available on favorable terms rather than a reflection of dissatisfaction with the 57 mm. There is also a auto-cannon aft (variously reported as 25 or 30 mm) and two remote weapon stations with .50 cal. Like US WMECs the range is substantial at 8,500 nautical miles. They have a crew of 77 and accommodations for 39 special forces and/or marines.

Given that the USCG is now responsible for maintenance of all US 76 mm guns and also operates the 57mm, the Mexican Navy’s choice of weapons suggests this may be an area of potential cooperation.

Auk class minesweeper now used as an Offshore Patrol Vessel by the Mexican Navy

Unfortunately not all of Mexico’s OPVs are relatively modern. They still have ten Auk  class 1,250 ton (fl), 221 foot, WWII vintage, steel hulled minesweepers that continue to function as patrol vessels. The ships are referred to as the Valle class in Mexican service. They are the same class as USCGC Tanager (WTR-885) that served as a CG Reserve training ship 1964 to 1972. They will certainly need to be replaced soon. Obviously their building program is not complete.

I find it interesting that Mexico with an EEZ of 3,144,295 km^2,, with less than a third of the EEZ of the US (11,351,000 km²) has a fleet of OPVs that approaches that of the USCG.