12-Pounder Dahlgren Rifled Howitzer and 6-Pounder Model 1841 at Portsmouth, Virginia

Jul 7

Dahglren Rifled 12-Pounder Boat Howitzer at the Portsmouth Naval Shipyard Museum in Portsmouth, Virginia

Outside of the Portsmouth Naval Shipyard Museum in Portsmouth, Virginia are as Dahlgren Rifled 12-Pounder Boat Howitzer and a 6-Pounder Field Gun, Model 1841.

This was my first close look at one of Admiral Dahlgren’s boat howitzers, and I may have more questions than answers. I regret that I did not measure the bore - according to Warren Ripley it should be 3.4 inches - though it is plugged with an object labeled 2.5 inches. The tube is marked with a US Navy Anchor and “Rifled 12-Pounder Boat Howitzer, 1863, J.A.D., Dahlgren, US NY Washington 876 Pounds 47 Pre”. (I have learned since my initial post that “47 Pre” stands for 47 pounds preponderance - indicating the force with which the breech pushes down when the tube is balanced upon the mounting point.) The carriage looks original to me. I noted the mounting points for both the hammer and the front and rear sights.

The US Army 6-Pounder Field Gun was cast in 1847 by Ames. The registry number is 352 and the weight was 884 pounds as cast. (One commenter on the Facebook version of this post suggested a connection with this piece to the “Grimes Battery”, but another commenter reached out to the curator of the museum who explained that there is no recorded connection. The Grimes battery was armed with a 10-Pounder Parrott Rifle and two “12-Pounder boat guns” at the Battle of Antietam.)

Also, a number of older cannons surround the neighboring building. Most are light iron ship’s cannons from the late 18th and early 19th century. The most striking of these cannons is a Spanish 18-Pounder cast at Seville in 1801.

Video posted by Youtube Channel Historic Forrest: 1850’s Dahlgren Boat Howitzer Firing and Barrel Shift Exercise