![]() |
|
![]() |
#1 |
Member
Join Date: Sep 2008
Location: PR, USA
Posts: 679
|
![]()
This procedure was originated by the inmortal Leonardo DaVinci. The result was a predictable perfectly spherical form.
Best M [QUOTE=M ELEY] Still another possibility is that this is a cannon ball made using the 'shot tower' method. I've included two sites explaining this innovative method of making cannon shot, and although one confesses that the balls produced were perfectly round, I beg to differ. . www.waymarking.com/waymarks/WM5CD3_Fort_Hayes_Shot_Tower_Columbus_OH /QUOTE] |
![]() |
![]() |
![]() |
#2 |
Member
Join Date: Sep 2008
Location: PR, USA
Posts: 679
|
![]()
Guys, I remember seeing as a child some large ovoid metal shapes lying around in Galicia's ports. I believed initially that they were old cannon balls. I was eventually told by a local sailor that in old times, these were used in sailing boats for balance, "to keep the keel down, and the sail up". Somehow, these ovoid metal bodies were either attached under the boat, or in the lowest internal part of the ship. IIRC, they might have been placed near the keelboard housing.
My two "pesetas". Best M |
![]() |
![]() |
![]() |
#3 | ||
Member
Join Date: Mar 2006
Location: Room 101, Glos. UK
Posts: 4,250
|
![]() Quote:
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 ![]() as a coast guard marine inspector in new orleans, i actually supervised and approved these kind of tests... Last edited by kronckew; 12th September 2010 at 07:58 AM. |
||
![]() |
![]() |
![]() |
#4 |
Member
Join Date: Dec 2004
Location: NC, U.S.A.
Posts: 2,196
|
![]()
No, no, wait! What if the tower was...
Just kidding. I'm one to admit when I'm wrong. Lead shot was made, but I've heard of lead cannon balls in times of desparation. Perhaps with it's low cooling point, they could have been made as such? In any case, our ovoid subject here was not a shot tower ball. Ballast I suppose seems possible, but I would think that there were much better uses for iron, even pig iron. (early blacksmiths even fashioned tomahawk heads from it). After all, the majority of ballast in the past had been stones, right? Could this ovoid mass of iron have been used for anything else? A reserve of iron for cannon balls during seiges? As a giant paperweight! ![]() |
![]() |
![]() |
![]() |
#5 | |
Member
Join Date: Sep 2008
Location: PR, USA
Posts: 679
|
![]()
Well, we know that vimanas, and UFOs have been reported in several holy books, including the Bible. Works of art in medieval time often depict these drawn in the skies.
It well might be this is a projectile was to be used in a giant slingshot or trebuchet machine, against these pesky visitors? : ) Quote:
|
|
![]() |
![]() |
![]() |
#6 |
Member
Join Date: Dec 2004
Location: NC, U.S.A.
Posts: 2,196
|
![]()
I know this is a shell, but I'm wondering if this could fit the bill of a double shot for short range?? I've never heard of double shell, but apparently one did exist, so??? It is the right shape. The argument that an ovoid projectile was impractical seems moot judging from this existing projectile.
www.aeragon.com/o/am/index.html |
![]() |
![]() |
![]() |
#7 |
(deceased)
Join Date: Dec 2004
Location: Portugal
Posts: 9,694
|
![]()
Hi Mark,
Point noted, thanks. ... and link saved intyo my favorits ![]() |
![]() |
![]() |
![]() |
#8 | |
Member
Join Date: Sep 2008
Location: PR, USA
Posts: 679
|
![]()
Thank you very much for the explanation. Live to learn!
: ) Quote:
|
|
![]() |
![]() |
![]() |
|
|