The River Monitor Parnaiba

In our post on the C-1A Trader yesterday we discussed the Brazilian Navy’s aircraft carrier Sao Paulo. Any navy with an operational aircraft carrier can usually be expected to have at least a decent blue water force. And Brazil does indeed have  a respectable surface fleet. But what we sometimes forget is that, because of the Amazon River, Brazil also has a robust riverine force, with quite a few ships designed specifically for operations on the Amazon.

One such ship is the river monitor Parnaiba. The distinguishing characteristics of a monitor are pretty much unchanged since the first monitor was built by John Ericsson. A low freeboard and broad beam, coupled with a shallow draft, provides a stable a platform for guns.

The Brazilian Navy not only performs the traditional naval functions, but also fulfills those roles that in the United States would fall to the Coast Guard.

The Parnaiba was laid down in 1936, and commissioned and placed in active service in 1938. As far as I know, that makes her the oldest warship in active service.*

Parnaiba underwent a major overhaul from 1998 to 1999 that saw her reciprocating steam plant replaced with diesel engines, and added the helicopter flight deck aft. She’s armed with a single 3”/50 gun forward, two 40mm/70 guns amidships, and two 20mm guns on the fantail. She also carries two 81mm mortars.

We’ve talked about the 3”/50 gun before. Here’s a clip showing the Parnaiba doing some gunnery practice with it.


Brazil’s navy seems to have a somewhat less pompous choice in music when departing or returning to port than our own. And I have no idea what’s going one with Mr. Tacticool with the rifle.


Brazil isn’t the only country to use monitors on rivers. The Austro-Hungarian Empire used large monitors on the Danube, and Romania actually operates several modern monitors such as the Mihail Kogălniceanu class.

*USS Constitution, and HMS Victory, while both still in commission, cannot be said to be on active service.

7 thoughts on “The River Monitor Parnaiba”

  1. 40MM Bofors. Why do I think that the first space-borne fighting ship will carry 40MM Bofors and Ma Deuce?

  2. I do appreciate the weapons package on this vessel. The only possible change I might make would be to change out the 20 mm’s (and not that I’ve got anything against the Oerlikon’s), and replace with old 20mm Vulcans. Just a thought.

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