Navy 15 inch Dahlgren gun model

[cannonmn]

We've just begun to study this piece so we don't know a great deal about it other than what we can see and measure.

Weight:  50 lbs.
Materials:  Cast iron barrel, possibly wrought iron or steel carriage
Estimate of scaling factor:  1/10


Barrel:
Bore diameter:  1.5 in.
Bore length:  15.5 inches, muzzle face to rear of hemispherical ? chamber
Barrel length overall 18.0 in.
Trunnion dia:  1.25 in.
Muzzle dia:  2.5 in.
Breech dia:  4.8 in.
Length over trunnions:  5.9 in.
Cascabel diameter:  1.2 in.

Carriage:
Carriage width, extreme, at rear:  6.4 in.
Carriage body width:  5.25 in
Carriage length less wheels:  9.62 in.
Axle length:  7.62 in.

Comments:  This may be a US Navy scale model, however it is devoid of any markings except small "match marks" put on by craftsmen to indicate where one part joins another.  Most official Navy models we've seen bear markings similar to the full-scale pieces they represent.  The workmanship and precision with which this piece was executed are typical of surviving US Navy official models we've seen in the USNA Museum collection. 

Design features:  The model is different from any full-sized US Navy 15-inch gun in that the model has two vents and two associated sets of percussion lock "ears."  As far as we know, no US Navy 15-inch muzzle-loading gun was equipped with two sets of vent "ears" and two vents.  This could mean the item was built to show a proposed design that was never built in the form of a full-sized weapon.

The bore diameter of the model scales exactly to the 15-inch bores of full-sized weapons.   The bore length of the model is slightly longer than the 1/10 the length of the "regulation" 1862 pattern USN 15-inch gun (total bore length from drawing is 146 inches.)

Condition;  The model may have had a percussion lock hammer at one time, which is now missing.  The toggle bar is missing from the top of the elevating screw.

Information requested:  We would greatly appreciate any documentation regarding the use of scale models of cannons in the US Army or Navy.

click on thumbnail for larger image

[Ex 49'er]

That there is a neat looking model. Good luck in your search for info. Thank you for sharing.

[cannonmn]

I was going through the book one at a time and probably should have started with Olmstead, Stark, Tucker's THE BIG GUNS.  Better late than never, anyway.  Pages 91-94 are devoted to Dahlgren XV-inch guns.  The authors took great pains to dig out all the drawings for the various models.  Until I read those pages I thought there had been only two Navy XV-inch gun models during the 19th C., but in fact there were many.  The last one matches the model almost exactly.  For instance, when I had been trying to compare the model to the 1862 drawing for a 15-inch gun, it was way off in muzzle diameter, the drawing calling for a 21-inch muzzle diameter, and the model's (scale) muzzle diameter was 10 x 2.5 inches= 25 inches.  The book solves that, as well as explaining the dual lock-lugs and vents, in the caption to the figure including the drawing on pp. 93:

 

The final XV-inch pattern of 1870 on which nos. 109-120 were produced at Fort Pitt foundry in 1871 and 72....The muzzle diameter increased by four inches.  Two vents with lock lugs and an elongated hemispheroid chamber replaced the single vent and nearly ogival chamber of the prior pattern.

So the small model is undoubtedly the "pattern of 1870."

[cannonmn]

The following views depict scenes on board USS Passaic:

Photo #: NH 58734

USS Passaic (1862-1899)

Line engraving published in "Harper's Weekly", 1862, depicting the interior of the ship's gun turret.
Passaic was armed with two large Dahlgren smooth-bore guns: one XI-inch and one XV-inch.
Note round shot in the foreground, that at right in a hoisting sling, and turning direction marking on the gun carriage.


http://www.history.navy.mil/photos/images/h58000/h58734.jpg

[JeffG]

I am just re-reading "A Quest For Glory", Dahlgren's biography...at one time Dahlgren had miniatures of the (11 inch)cannon made up for Abraham Lincoln's sons. Make sure that's not what you are dealing with.  The Bureau of Ordnance workers supposedly made them as gifts for Lincoln's sons. If I am not mistaken the dual vent holes was the trademark of the IX inch guns.

[cannonmn]

Thanks, I have the book and never quite finished it, will have to look.  There are some other Dahlgren models here so I'll have to check them out. 

As far as this one goes, the scaling is perfect for 15-inch pattern of 1870, on a scale of 1/10.  Generally scale cannon models are made using even numbered scaling factors, popular scales we have include 1/10, 1/8, and 1/6, but I'm sure others were used.

I think this one would be a bit inconvenient for kids, it weighs 50 lbs. and would crush a foot if dropped, if they could pick it up.