Too tired last night, but today I can post a full array of pics with captions by way of explanation. Why are we interested in this Howitzer? Probably the unusual shape has a lot to do with that. Up close, this seacoast artillery piece exudes the feeling of power. It's fairly long for a howitzer at 114" and no lightweight either at 14,290 Lbs. Simply put, it has Presence.
Enjoy the pics; the surprises are placed randomly in the bunch.
T&M
The breech is what we are studying, as well as smaller details which don't appear on the official drawing from US Archives and displayed in
The Big Guns, Seacoast, Siege and Naval Guns of the Civil War by Olmstead, Stark and Tucker.
In this view, you can tell that the breech is a section of a sphere. The ratchet rack is a casting, probably wrought iron, as it did not "ring" when lightly tapped by a plastic hammer as cast iron will do. Another educated guess is that there is a cylidrical projection from the breech that fits into a closely toleranced recess in the rack to share the load placed on the rack when a lifting handspike is used to pry up on the rack to depress the gun. To elevate the tube you pry up a little, remove the support pawl and then release the preponderance weight slowly as the pawl is re-engaged into the ratchet recess.
A close-up of the ratchet rack, an important part of the elevation and depression gear. Note that only two bolts attach this important assembly to the breech.
Here I hold the long blade of the try square to the breech's spherical surface. There is a small wedge under the end furthest from me. When Mike put the camera down he came over and measured the gap under my end at 12". The blade contacted the breech surface at about 6" with the wedge near 0". This way you get two gap readings, slightly unequal, find the sum and divide by two. This drop-off dimension will be computed later to find the spherical radius of the breech. We backed this technique up with a shape duplicator application and then pencil transfer to paper.
More to post shortly..............
Here is the first discovery that we made. In all of our trips which have criss-crossed the United States to study seacoast artillery, we have never seen a sight like this one. There is not one hole in the breech or the reinforce to indicate a position for a rear sight or a holder for a rear sight as there would have been with a pendulum-hausse type rear sight. There is no hole or incised line to be used to hold a front sight either. After tippy-toe inspection to avoid climbing on the cannon or cannon pedestal, we are about 95% sure that this very unique sight is a front and rear combination sight. The length and narrowness of the groove (3.287 X .187") indicate a method of sight alignment. Elevation is another thing entirely, but the designer thought of that too! The groove bottom is angled, based on the sight's top surface. We expected it to be angled upward as you go toward the front, but SURPRIZE, it's not. No it is much more sophisticated than that. It is angled downward so that a number of degrees of automatic elevation are calculated to bring the howitzer to bear on a ship at the howitzer's Point Blank range, the range at which you get a hit from 0 to X number of yards with the same sight setting. Our SWAG for this 'X' number is 300 yards based on trajectories of similar guns. At distances beyond that, field expedient sights (shaved match sticks, filed pennies, etc.) can be fashioned using that slot for alignment only.
A complex shape, filed from a casting and smoothed with abrasives. This is pure craftsmanship, gentlemen.
Cyrus Alger & Company on the right trunnion face.
1844, the date of casting on the left trunnion face.
More after lunch.......
