Akko 1 shipwreck: the effect of cannon fire on the wooden hull

Abstract

The Akko 1 shipwreck was discovered inside the harbour of the old walled city of Akko (Acre, St. Jean d'Acre, Akka), Israel. The ship's hull was built mainly of oak, with closely-set framing timbers that created a solid side. The shipwreck was apparently a result of the naval bombardment of the town in 1840.Reduced scale experiments of simulating the firing of cannonballs at a ship's side were conducted by Rafael (Advanced Defense Systems Ltd., Israel). The experimental set-up included a laboratory gun firing at wooden targets representing the side of a ship, and a monitoring high-speed camera system, measuring the entrance and exit velocities of projectiles. Scaling up the results of the tests showed that a 12-pdr cannonball could easily have penetrated the hull. The lower the impact velocity of the cannonball, the greater the damage caused to the ship's side, with a larger amount of splinters being generated. The minimum penetration velocity was about 150 m/s.