August 23, 2011

Turret's Syndrome

I think I had a few too many paint fumes, but the turret is almost done.
Haupt explaining to Stevenson why he does not like XV-Inch guns on ironclads. The armored porthole covers
are visible in this shot.

From: Dictionary of American Fighting Ships, Volume III, 1968, Navy Department, Office of the Chief of Naval Operations, Naval History Division, Washington, DC

Armament for the Monitors

by Eugene B. Canfield

On March 9, 1862 Gustavis V. Fox, Assistant Secretary of the Navy and Lt. Henry A. Wise, Bureau of Ordnance, watched the encounter between Monitor and Merrimack from a small tugboat in Hampton Roads. Although MONITOR was left in possession of the battleground, neither contestant had been materially injured and it was apparent that something more powerful than Monitor's 11-inch Dahlgren shell guns [7] was required.

Coming ashore at Fort Monroe, Fox was attracted by an experimental 15-inch Rodman columbiad lying nearby. This obviously was the needed gun.Therefore, in April, Dahlgren completed a 15-inch design to fit the 20-foot interior of the new Ericsson ironclads. The first 15-inch guns weremounted alongside 11-inch shell guns since the 15-inch guns could not be produced quickly enough to provide two for each turret. The carriages were made of iron and the gun ports were so small that the 26.5-inch muzzles could not protrude. Consequently, a smoke-box was devised as shown in the illustration to protect the gun crew from the blast of the explosion.

Early testing was carried out in attacks on Fort McAllister, Ga. On January 27, 1863, Commander John Worden, of Monitor fame, and now captain of the new Montauk, fired twenty-six 15-inch projectiles at the fort from a range of 1,600 yards. "The firing from turret seemed slow and deliberate to those in engine room; the smoke from guns was forced rapidly into fireroom at each discharge, but was well diluted with air by the fans, and rapidly passed out through furnaces and smokepipe, causing no unusual discomfort."

Rear Admiral DuPont commented, "We have obtained valuable information in the success of the working of the XV-inch gun . . . My own previous impressions of these vessels . . . have been confirmed, viz., that whatever degree of impenetrability they might have, there was no corresponding quality of aggression or destructiveness as against forts, the slowness of fire giving full time for the gunners in the fort to take shelter in the bombproofs."

On February 28, Worden first proved the effectiveness of the 15-inch guns by destroying Confederate steamer Nashville lying aground under the protection of Fort McAllister. The range to the steamer was approximately 1,200 yards; only eight 15-inch shells and six 11-inch shells were required to set the wooden ship afire. Average time for firing the 15-inch gun was a little over 6 minutes with a minimum time of 3 minutes.

On other occasions and with other monitors, the average firing time might be as much as 10 minutes.Captain Drayton of Passaic reported that "pointing was done for both guns with the XI-inch, the port of the other being entirely closed by the concussion box." Furthermore, the smoke or concussion box was nearly knocked down, and the small projection on the cartridge would not enter the chamber so that priming powder had to be used to ignite the charge. Perhaps because of this, half of the 34 original guns had the teat chambers reamed out to parabolic form and the muzzle was turned down to 21 inches, the diameter of the 13-inch gun. [8]

Later, for the Canonicus class, the gun ports were enlarged to eliminate the smoke box and the 15-inch guns were redesigned with a 16-inch long muzzle. Canonicus and her sisters carried two 15-inch guns in their turrets.

Normally, the crew for firing the 15-inch gun consisted of 14 men, but often only eight men were preferred as being equally efficient with less crowding. Three type of projectile were provided, and the 440-pound solid shot could be fired with 60-pound charges at close quarters, although 50 pounds was the normal charge. Cored shot of 400 pounds was recommended for use against masonry. The 330-pound shell contained 13 pounds of powder and was ordinarily fired with a 35-pound charge. It contained three navy time fuses of 3 1/2, 5, and 7 seconds.Final justification for the 15-inch gun came on June 17, 1863 when Weehawken’s cored shot penetrated Atlanta’s 4-inch armor plating and broke the heavy iron casting at the top of the pilot house. Surrender occurred after only 15 minutes of fighting.In addition to the heavy smoothbores, a few of the monitors were equipped with the 8-inch 150-pdr. Parrott rifles. Of the Passaic class, Lehigh and Patapsco had them in place of the 11-inch shell guns, and finally the 11-inch of Passaic was replaced with a 150-pdr. rifle. The twin-turreted Onondaga also had a 150-pdr. Parrott alongside the 15-inch smoothbore in each turret. The extra range of the rifles was occasionally useful in reaching targets unattainable with the smoothbore.


  1. This is a fantastic model Sir. Is that General Herman Haupt?

  2. Yes, General Haupt is in charge of the RR. He was also quite an aficionado of ironclads. Seriously, he wrote many letters to the Navy suggesting better designs for the ironclad ships. He was not in favor of XV-inch guns on ironclads. He thought they were too liable to burst. He advocated smaller guns that could fire faster, with the same muzzle velocity.

    So it is fitting that I build an ironclad for my layout.

    Yeah, that's the ticket. Uh, huh. Yup.

  3. That's a tough call, General Haupt. I would tend to agree in the case of the ironclads since they had few guns, but only if the smaller guns were more accurate than larger calibers. Something to ponder, though.