English Royal Ordinance 1637

The always interesting English Civil War blog recently had a post on Royal Ordinance in 1637. (I read it back when it came out, but my ready to post queue is 2-3 weeks out so it took awhile for you to see my post.) Now I'll admit that if it had been a 1637 (or better yet 1627) list of French Royal Ordinance I'd have been more intrigued and I probably would have bumped this post up in my queue. But our campaign is set in 1624 France and none of our PCs really care what sort of cannon the foul smelling Le Rosbifs use on their barbaric little island.

However the link in the article took me to a very nerdy web site with several interesting technical articles about historic ordnance. Just glancing at a few the articles I found several interesting factoids.

Interesting Factoid #1: Cannon and their shot were cast so that the diameter of the gun was wider by a fixed ratio than the diameter of the shot used. This difference or gap was known as windage.

Interesting Factoid #2: The usual ratio for the weight of powder to the weight of the round shot used in a cannon varied both over time and according to how far away the target was that the gunner was trying to hit. In general there were standard ratios that varied as technology changed.

• ¹/₂  the weight of the ball around 1600;
• ¹/₃  the weight of the round shot was the standard British service charge from 1760 onwards. 

The greater weight of powder in the early period was due to powder of lesser quality and cannon cast with greater windage. Because of this even though more powder was used the ranges achieved would have been similar.

Interesting Factoid #3: Territorial Waters was defined by how far your coastal gun batteries could fire. One of the reasons put forward for the international agreement that territorial waters extend 3 nautical miles from the coast, is that 3 nm was the maximum range of shore battery guns in the 18th century. In the mid 20th century the distance for Territorial Waters was extended to 12 nm.

Here are the articles from which the various factoids were derived.

Cannonball Sizes 

This article has an analysis of both weight and diameter and a comparison to the nominal gun sizes of the day. It also has a nice explanation of windage and its affect on Early Modern gunnery.

Smooth Bore Cannon Ballistics

This article covers the ballistics of Early Modern smooth bore cannon. It includes information on  the weight ratio of powder to shot that was used in the cannons in the period and an interesting footnote on how artillery range affected maritime law.