Officer James is cruising on a straight course, constantly accelerating at 7m/sec/sec, while in route.....?

Officer James is cruising on a straight course, constantly accelerating at 7m/sec/sec, while in route to test-fire blank rounds on the ship’s newly installed short range gun that has a muzzle velocity of only 100m/sec. On signal, simulating an helicopter attack, somebody shouted “Enemy at 12 o’clock” and the gunner instantly fired a few rounds successively at the imaginary helicopter straight ahead of their course and at some elevation. A few seconds, thereafter, the blank projectile shells dropped like rain on the gunner on deck. Officer James noted the velocity of the ship at the instant of firing to be 10m/sec, but the gun’s angle of elevation was not recorded. Could anyone help solve for this angle, as he will note not to use it again with live ammo.