Vent angle / Blackbeard on PBS

[Pinhead]

Hello,  When I look at drawings of cannon I notice the vent on some are 90 degrees to the bore and some are angled back.  What determines this and is there a modern standard that is used today?        Also there is a show, called Secrets Of The Dead, on PBS about salvaging Blackbeard's ship.  Here,  it's on Wednesday, April 22  at 7 PM central time,  check your local listings.  I don't know how cannony it will be but whar thars pirates thars cannon.                          Thanks, Michael

[cannonmn]

Yes all kinds of angles have been used, covering at least a 90-degree sector, if you include bore-coaxial vents such as in the Whitworth breechloaders.

I haven't read a lot on vent angles specifically but I know one influence on it was how the cannon was to be ignited.  Another may have been barrel strength estimates, since a steeply angled vent would decrease hoop strength of the barrel at the vent's location, just a tiny bit less than a 90-degree vent.

Your question is a good one and I've never seen any articles that covered it in much detail.  When you get enough information, please write an article on it.

[Cat Whisperer]

We've discussed that here - about a year ago?

IIRC - two issues were strength and lighting the thing/where the fuse gets blown to.

This would be a good one for FEA (finite element analysis) to show the effects of stress at various locations (forward-aft) and angles.  Also the strength of a secondary fuse hole that is drilled almost through.