Pards, All,
What you have in the pic is a Lyle Gun/Cannon, it was specifically designed and used for shore-to-ship rescue of foundered boats and seacraft. It fired a long line to the ship that was then pulled onboard then returned with a stronger pulling line to get the boat off the shoals, rocks, etc. The line was also used to pull in lifeboats.
For pics and details go to
www.cannonsuperstore.com/lyle_cannons.htmThey claim prices for this item run up to the $9,000 level, perhaps higher for known cannons with a history.
Just an added note, if my memory recalls correctly, in the early days of Navy Arms catalogs you could buy one complete with rope line and a 2" hawser/pulling rope in a boxed set, the rope was all coiled up nice and tight.
Blair's comment about the 45-70 blank gun follows the same pathway as Navy Arms also sold a cased version of that as well, some are still around and are seen every so often at bigger gun shows, I saw one at the annual show in Des Moines, Iowa a few years back and the case was worn on the edges but the gun was in fine shape, the seller claimed it had been on a yacht on the east coast.
Best regards and good rescuing!
'Ol Gabe
P.S. Can't prove it, but I recall seeing concert videos years ago where they used several of these for the cannon fire in the 1812 Overture when played on the 4th. The Lyle guns were better they claimed due to the higher firing angle, the report carried farther over the orchestra.