16th/17th century chain shot

[fernando]

Originally Posted by M ELEY

...huge balls with a very short bar between them just big enough for one hand ...

According to (translating) Memories for an Artillery Officer in Campaign, the palanqueta (barshot) bar should have 10 1/2 inches. This is a very interesting work on artillery, put up in 1778, and was digitized by the New York Public Library, now available through Google, but its (portuguese) text was not translated.
BOOK
it contains the description of the inumerous types of shot (PAGE 96). Unfortunately it doesn't detail the shot bar cross section, but the term (perno = unthreaded bolt) takes us to consider that the bar is cylindrical.
Browsing the term palanqueta (barshot) one finds that this type of device was vastly used by the Portuguese. I have read about a few coast fortifications stocking these things by the hundred ... but no pictures yet