Unique US Navy Shot Gauge

[cannonmn]

This shot gauge, built at the Washington Navy Yard in 1843, was designed for the inspection of 12-inch Navy round shot to be used in any of the three 12-inch wrought-iron guns the Navy had ordered. The Navy had no other 12-inch guns at the time, and would probably have made only one shot gauge in that size, which is why I termed it "unique." One of the three guns, named "Peacemaker" exploded in 1844, killing a number of spectators.

The round shot loaded into the "Peacemaker" prior to the explosion undoubtedly passed through this very shot gauge when it was inspected after receipt from the founder. Two of the Ericsson-designed 12-inch wrought iron guns survive, one at the US Naval Academy and one at the Washington Navy Yard.



The story of the explosion is here:

http://www.military.com/NewContent/0,13190,NH_0905_Cruise-P1,00.html

A larger image of the colored engraving of the event:



A few more photos of the gauge are at link below.

 http://s17.photobucket.com/albums/b62/cannonmn/miscforumsetc/forums41/?action=view&current=f1e9ce61.pbw

For scale, a small tape measure was included in the photos, with 12 inches of tape exposed.

[RocklockI]

it would be interesting to check its roundness and actual size when measured with cmm like 300 pt average . see if they used 'the rule' on windage .....

was that the one were sec stanton or some big pants got killed ?

[GGaskill]

Yes, there were lots of high ranking casualties but, contrary to the above linked report, Ericsson was somehow assigned most of the blame.  Hard to understand how people believed that.

"Ericsson stayed away, his relationship with the captain having soured in part over Stockton's insistence on mounting the Peacemaker, which Ericsson considered unproven."--The gun exploded on its third shot; apparently it had never been test fired.

[cannonmn]

see if they used 'the rule' on windage .....

In the additional photos, look at the second line of markings on the gauge.

"12.11.80" 

I intepret that to mean it is for 12-inch projectiles, which are actually 11.80 inches in diameter.

Do you think that's a correct interpretation?

I do have a good 12-inch digital caliper and will do some checking later.

It'd be interesting if the gauge was oversized, wouldn't it?  That's shed a whole new light on the explosion!

[cannonmn]

Average diameter now is 11.817, so inspecting many shot seems to have ground some metal off the ring.  The diameter taken along a line extended from the long axis of the handle is several thos. over that average, which is what I expected since the greatest "grinding" action would occur on the inside ring surface opposite the handle.

[RocklockI]

i wonder how many balls they used for only three cannons ?  size vs. wear compared to where the peacemaker blew up .

[cannonmn]

i wonder how many balls they used for only three cannons ?

I read that one of the guns had fired over 180 rounds in testing; not sure how many the Peacemaker actually fired total before it blew.

However the wear on the shot gauge relates to how many 12-inch shot, total, were ordered by the Navy, because the gauge was only used for inspecting shot when received from the contractor, as far as I know.  Navy contract records for that period would have to be checked to see how many 12-inch shot were ordered, but I would expect to see some fairly round number like 300 (100 per gun.) or maybe 500.

[RocklockI]

i'm wondering , when the peacemaker blew up vs. ball production/wear on the gage .

maybe they got the first perfect early one's .....but as the gauge wore onward on inspecting the 300-500 it could have let a bit larger ball than normal .

and i suspect they wanted a big bang for the vistor's on board . IIRC you thought the gage was over size to the windage rule ...?

i geuss there is no way to tell if the Peacemaker got an eary perfect ball or a slighly over sized one that passed through the worn gage .

was there ever any explanations to why it blew up .....if they did use a bit extra powder , combined with an over size ball .......

[Soot]

It is sad to think that the technology existed during the Civil War, yet they never even knew that they could make giant soap bubbles.

[cannonmn]

combined with an over size ball .....

I haven't found any evidence the shot was oversized.  The powder was loaded into cartridge bags before it ever went aboard the ship so I doubt any charge error occurred.  The story linked to described the cause of the accident.

[KABAR2]

I know there exists a fragment from one of the more famous cannon failures from later,

but does anything of the Peacemaker exist? if it did could a bore measurement be made in relation

to existing 12" shot and ball gauge?

[cannonmn]

If any pieces of that gun exist they are very small metal samples sent out to laboratories to analyze after the accident.  You would not be able to determine anything about the gun's bore diameter from them even if you found any.

[Victor3]

Average diameter now is 11.817, so inspecting many shot seems to have ground some metal off the ring.  The diameter taken along a line extended from the long axis of the handle is several thos. over that average, which is what I expected since the greatest "grinding" action would occur on the inside ring surface opposite the handle.

 This is assuming that the tool was exactly 11.8" dia when new. Dropping/banging it around could also have made it larger and/or out of round.

 Where I work, if a ring gage is dropped it must be recalibrated (unless nobody sees you drop it).

[KABAR2]

It would be interesting to find a copy of the report and findings made on the peacemaker,

"Stockton, in full dress uniform, welcomed the guests as they were piped aboard his ship.
Ericsson stayed away, his relationship with the captain having soured in part over Stockton's
insistence on mounting the Peacemaker, which Ericsson considered unproven."

This sounds like the gun was not properly proofed, it may be that Stockton's ego played a part
in the disaster, he wanted the ship done and ready to show off, this may have been a political move
also, it would not have been the first time a military man had his eyes on higher office.

[cannonmn]

It would be interesting to find a copy of the report and findings made on the peacemaker,

That won't be hard to do, the main report was done by the Franklin Institute but a lot of other people were involved, Navy, Army, etc.

[cannonmn]

about a half-minute of googling:

http://books.google.com/books?id=osSG7ceTGekC&lpg=PA295&ots=IxOlunbhls&dq=peacemaker%20princeton%20explosion%20report&pg=PA295

I have the book mentioned in note 33, which contains the FI report.  I have to run now but will look for it later.