Crate

Description
Crates are dropped by the boss of the Undersea Lairs and will contain a random Upgrade. There are 3 categories of upgrades:
 * General Upgrades
 * Torpedo Upgrades
 * Turret Modifiers

Crates must be hit 3 times to open: 2 times to destroy the chains and 1 time to destroy the wood. Higher damages done per hit will not destroy it faster.