Crossing the T
Crossing the T is a tactic that dates back to the use of primitive naval cannons. Sailing ships were long and comparatively thin(to reduce total mass and create less resistance to wind, the primary driving force of a warship before the invention of steam power), so there was very little space to fit forward batteries in on a ship of the line. The logical choice, therefore, was to line up the ship's primary firepower on the long, multi-tiered sides(hence the term 'broadside').
Crossing the T refers to such a ship moving ahead of and roughly perpendicular to an enemy ship's path, allowing it to engage with it's full broadside firepower while simultaneously forcing the enemy to engage with the handful of forward batteries they possess. While the target profile is harder to hit, the sheer volume of fire guarantees damage. This tactic was used up until the end of World War II, where the use of long range aircraft that could attack without exposing their carrier to harm(indeed, they needn't even be in sight of the enemy) made this tactic less useful. Later, the invention of long range missles and advances in aircraft technology sealed this tactic's fate forever; it has never been used since then.
See Also
--Commander Taveco 13:15, 21 December 2007 (EST)