Tag Archives: river monitor

Goodbye RIVRONs, hello MESF

The Navy announced recently they have “officially changed the name and mission of the Coastal Riverine squadrons to reflect their role amid a new era of great power competition; they are now known as the Maritime Expeditionary Security Force.”

The prerequisite moto video, tying the new units to the old Brown Water PBR gang of Southeast Asia (although the SWCC guys of SBT22 will most likely dispute ownership of this lineage, as they carried the dim candle of the small boat shop at Rodman for decades):

“As we maintain a connection to our legacy we must honor those warriors that come before us and learn from their heroism,” said RADM Joseph DiGuardo, commander NECC, “we must continuously evolve to meet the needs of the Navy and the Nation for Great Power Competition, crisis, and conflict. The change to Maritime Expeditionary Security Force clearly articulates the mission of our sailors to reinforce lethality in the blue water and dominate in the littorals.”

The MESF now consists of two groups; one in San Diego and one in Virginia Beach. The force includes two expeditionary security detachments in Guam and Bahrain, seven Maritime Expeditionary Security Squadrons, and 31 Maritime Expeditionary Security Companies.

The original three Coastal Riverine squadrons of the Navy Expeditionary Combat Command (RIVRON 1, 2, and 3) were all formed in 2006-07, modeled after the Marines Small Craft Company (SCCO) of 2D MAR Div– then the only specialized small boat company in the Marines– which had been disbanded the year prior although that forgotten unit of Devil Dogs in tiny boats had been bloodied and proved their mandate in the marshes and reservoirs around Haditha, fighting the kind of war that was familiar to Vietnam. Their Riverine Assault Craft, zodiacs, and Raider boats were handed over to the Navy, although Big Blue soon bought lots of new go-fasts.

Marines from Small Craft Company tether their Riverine Assult Crafts together during a break in training. Marines from Small Craft Company, 2nd Marine Division, Camp Lejeune, North Carolina, demonstrated their capabilities to Paraguayan Marines in the Joint Training Exercise Unitas. The exercise was conducted in Asuncion, Paraguay. USMC Photo by LCPL Tyler J. Mielke. 29/09/1999

“People think it’s money or manpower problems, but no one knows for sure why they’re getting rid of us,” said Marine Gunnery Sgt. Brian Vinciguerra, who had spent 14 years with the SCCO, on the occasion of the unit’s disbandment in Feb. 2005. “The capabilities we provided to the Marine Corps, Special Forces, and Navy SEALS in Iraq are too big to be gone for long. We’re leaving an avenue of approach open for the enemy now,” he said. “I think Small Craft Company will be back in a few years when people realize what we brought to the fight.”

Now, after a similar 14-year run, the Navy’s trio of RIVRONs have a name change, and, notably, are moving to more 80+ foot platforms such as the MKVI. Not a lot of “river” about that.

Oh well, at least SBT22 and NAVSCIATTS are still around, keeping that lamp tended for the next time.

Take a break to celebrate the Brown Water Navy today

Nothing says “get some” like a twin M2

Remember, today is National Vietnam War Veterans Day:



With that being said, dig this far out training film covering the “Small Boat Navy” as it was called in the 1960s, which consisted that wide range of Vietnam-era shallow watercraft such as the PBR, RPC, PGM, PTF, et. al


For your reference: (Drawn from Boats of the United States Navy, NAVSHIPS 250-452, 1967)


Warship Wednesday Nov. 25, 2015: The enduring monitor of the Amazon

Here at LSOZI, we are going to take off every Wednesday for a look at the old steam/diesel navies of the 1859-1946 time period and will profile a different ship each week. These ships have a life, a tale all of their own, which sometimes takes them to the strangest places. – Christopher Eger

Warship Wednesday Nov. 25, 2015: The enduring monitor of the Amazon

Note the sat dish

Note the sat dish and Jet Ranger

Here we see, stationed deep in the Mato Grosso region of the Amazon Rainforest around Morro da Marinha, near Fort Coimbra, is the unique inland river monitor Parnaíba (U17).

Laid down in 1936 on the Isle of Snakes at the Brazilian Naval Yard (Arsenal de Marinha do Rio de Janeiro) as part of the Brazilian Navy’s modernization program on the eve of WWII, Parnaíba is a traditional name for that fleet with no less than four predecessors carrying it back well into the 19th Century.

Parnaíba was an important vessel, with President Getulio Vargas himself attending the keel laying.

Pre-1960, note the 6" forward mount. That's a big gun for a 180-foot riverboat

Pre-1960, note the 6″ forward mount. That’s a big gun for a 180-foot riverboat. She also has a very British tripod mast and fire-control tower.

She was built with English assistance, her power plant included 2 Thornycroft triple expansion boilers while her armament consisted of a single 6″/50 (15.2 cm) BL, a pair of Royal Ordnance QF 25-pounder (3.45″/13cal) howitzers and, for defense against small boats, a pair of 47mm (3pdr) Hotchkiss singles. Some 180-feet long, Parnaíba could float in 5-feet of freshwater. To protect her topside she was given 38mm of armor on deck and around her bridge while a 3 inch belt protected the engine room, waterline and machinery spaces.

Commissioned 4 March 1938, Parnaíba proceeded inland to join the Flotilha de Mato Grosso as the fleet flag.

Peaceful riverine service ended in late 1942 when she was rushed to the coast upon Brazil’s entry into World War II.

Her armament updated with four single 20/70 Mk 4 Oerlikons and some depth charge racks, Parnaíba was used extensively for coastal patrol, then as the guard ship at Salvador-Bahia, and escorted at least five coastal convoys on the lookout for German U-boats and surface raiders which, gratefully, she never encountered. Her hull was thought too shallow to catch a torpedo, she was considered strong enough to fight it out in a surface action if push came to shove.

On 29 Nov 1943, Parnaíba greeted the fresh new battleship USS Iowa on a brief visit to Bahia just days after that leviathan dropped President Roosevelt off at Oran, Algeria. The next day she escorted Iowa back out after a night of festivities.

Parnaiba U17-02

The rest of her wartime experience were even more quiet though she did sortie out ready for action and to search for survivors when the Brazilian cruiser Bahia was lost in July 1945. Thought sunk at first by a rogue German U-Boat but later confirmed Bahia was destroyed in a freak accident by her own depth charges.

Landing her depth charges and sailing back up river in October of that year, Parnaíba has maintained her place in the Amazon area ever since.


In 1960, she was overhauled and a U.S. 3” /50 Mk 22 and two 40 mm/60 cal Mk 3 Bofors replaced her dated 25-Pounders and 6-incher though her Oerlikons were saved as they were still useful and her Hotchkiss popguns kept for saluting.


A subsequent series of overhauls between 1996-99 saw her six decades-old engineering suite removed (and put on museum display), replaced by a more modern set of GM twin diesels. Racal Decca and Furuno 3600 radars were fitted as were more modern 40/70 Bofors in the old positions. A helicopter platform was also added for a light Jet Ranger or A350-sized whirlybird.

She also carries multiple 7.62 and 12.7mm machine gun mounts as well as 81mm mortars to drop it like its hot in a region that sees a good bit of smuggling and the occasional excitement.



Note the 20mm over the fantail, right out of the Battle of Midway. Also note that Brazilian LSOs wear the same color float coats and everything as in the USN

Her current fodder of 76mm and 40mm rounds. Her crew still drills with both and her WWII-era Mk 22, other than on some ships of the Thai and Philippine navies, is the last in functional use on a warship

Her current fodder of 76mm, 40mm and 20mm rounds. Her crew still drills with her WWII-era Mk 22, and other than on some ships of the Thai and Philippine navies, is the last in functional use on a warship

Ahh, don't these belong as hood ornaments for WWII submarines?

Ahh, don’t these belong as hood ornaments for WWII submarines? How many thousands of man hours have been put into polishing that bright work over the past half century?

A 40mm will still make mincemeat of a low-flying plane or helicopter as well as ruin a small boat (or ashore guerrilla hangout)

A 40mm will still make mincemeat of a low-flying plane or helicopter as well as ruin a small boat (or ashore guerrilla hangout). Note the old school Hotchkiss in the far left of the picture.

If past history is any indicator of future events, odds are Parnaíba will be in service another several decades and she is regarded as the oldest commissioned naval ship still in active fleet use and not in museum status.


Celebrating her 75th year in service in 2013

Celebrating her 75th year in service in 2013

Brazilian Navy river monitor u17 Brazilian Navy monitor Parnaíba (U17) still in service

Below is a 2015 VERTREP operation where you get a pretty good view of the old girl

Most of these images in the post are courtesy the excellent Brazilian warship site, Naval Brazil and Defesa Aérea & Naval which have more information about this interesting vessel.


620 tons – Standard
720 tons – full load
Length: 55 m (180.4 ft.) oa
Beam: 10.1 m (33.1 ft.)
Draught: 1.6 m (5.2 ft.)
Two VTE engines, two 3-drum Thornycroft boilers, 70 tons fuel oil (As built)
Two 650shp GM 8V92 diesel engines, 90 tons diesel
Two propellers
Speed: 12 knots (22 km/h)
Range: 1,350 mi (1,170 nmi; 2,170 km) (2500 km) 10 knots (19 km/h)
Complement: 60-90
(As built)
1x 6″/50 (15.2 cm) BL,
2x 1 QF 25-pounder (3.45″/13cal) howitzers
2x 1 47mm (3pdr) Hotchkiss
1x 6″/50 (15.2 cm) BL,
2x 1 QF 25-pounder (3.45″/13cal) howitzers
2x 1 47mm (3pdr) Hotchkiss
4x 1 20mm/70 Oerlikons
Depth charges
1x 3″/50 Mk.22
2x 1 47mm (3pdr) Hotchkiss
2x 1 40/60 Mk 3
6x 1 20mm/70 Oerlikon
1x 3″/50 Mk.22
2x 1 47mm (3pdr) Hotchkiss
2x 1 40/70 M48
2x 1 20mm/70 Oerlikon
2 × 81mm mortar
Various machine guns

Aviation facilities: Helipad for IH-6B Bell Jet Ranger III or H-12 Squirrel (after 1996)

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