[kronckew]

Originally Posted by celtan

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see my post no. 24, the writer of that blurb on fort hayes was incorrect in implying cannon round iron shot was made in the tower. they probably made lead balls for cannister and for shrapnel shells, but iron cannon balls, not possible. not enough height for them to cool & solidify before hitting the water, which was to cushion the fall, NOT to solidify the shot. possibly they made round cannon shot there, but if so it was by moulding.

note that the ref. to the baltimore tower specifically mentions the production of iron cannon shot there was by use of moulds.

note the reference link to other world wide shot towers near the top of that page, all of which more correctly only refer to lead shot.

additionally:

In 1783, William Watts of Bristol took out a patent for a process "for making small shot perfectly globular in form and without dimples, notches and imperfections which other shot hereto manufactured usually have on their surface". By pouring lead into a sieve, and letting it cool as it falls, the lead forms into a perfect sphere before falling into a water tank at the bottom.

however, pig iron was frequently used as ballast in wooden ships as you noted, and would have been in whatever convenient sized chunks it was originally cast into. it was stored in the lowest part of the ship to ensure the stability of the vessel by countering any heavy weights (like cannon) above the centre of gravity as well as the lateral pressure of the sails which might have blown it over. (the english 'mary rose' is a good example of what happens when you get it wrong). the captain might on occasion shift the ballast around to 'trim' the vessel to gain an extra knot speed or two, or to improve the stability. cannon balls were of course stowed at the lowest part of the ship and were thus part of the overall ballast.

one of the jobs we had aboard ship, which was there from time immemorial, was to ensure that anything brought on board was stored stably, ballast, fuel, water, food, machinery parts, people, cargo, etc. all have to be stored so as to keep the ship not only level fore and aft, and from one side to the other, but vertically to ensure the stability of the vessel. as a marine engineer, i was trained in not only designing ships, but calculating their stability and how to test that stability. for any who are interested, here is the 'simplified stability testing for small passenger vessels' as an example. the unsimplified version is of course more complex Linky to PDF

as a coast guard marine inspector in new orleans, i actually supervised and approved these kind of tests...