Heavy Demolition Ship

The Heavy Demolition Ship is a military vessel in Age of Empires II, packed with explosives that blows up enemy ships, Docks, land units caught in shallows and anything too close the shore. It has better armor (although still very little) and a much stronger and larger explosion than its predecessor. It can sink a Galleon or groups of them in a single hit. They may be referred to as the Petard of the sea due to it being a suicide unit.

The Heavy Demolition Ship is an upgrade to the Demolition Ship, and is available in the Imperial Age. Only the Aztecs, Incas, Indians, Italians Japanese, Koreans, Magyars and Slavs do not have this unit available to them.

Tactics
Heavy Demolition Ships are very good against other ships, especially Fire Ships and fully loaded transports. Heavy Demolition Ships explode when killed, dealing blast damage to any nearby units. However, they do not cause friendly fire damage, so any nearby allied units will not be damaged.

Like its predecessor the Demolition Ship, its tactics resemble those of a cruise missile. The Heavy Demolition Ship and its predecessor are the fastest units in the game (especially with Dry Dock), much faster than most naval units making it very capable of chasing down enemies. It can cause great damage when it hits and will destroy most ships in one shot, but since it's a suicide unit it may not be worth the resource cost. It all depends on the exact situation. Since demolition ships are available for nearly all civilizations, civilizations with poor naval technology may improvise by using demolition ships to even the odds. Heavy Demolition ships are useful against the Galley and its upgrades if the demolition ships manage to approach to them, is excellent against Fire Ships, and devastating against Transport Ships; however, they fare poorly against the heavily armed and armoured Korean Turtle Ship but in sufficient numbers they can be very cost effective against the Turtle Ships, Longboats are a severe threat to the demolition ships.

Heavy Demolition Ships can also be an excellent tool for dealing with the enemy shoreline infrastructure as they can take down rapidly enemy Docks without having to compromise other naval vessels intended to survive that can support demolition ships by distance.

Civilization Bonuses

 * Persians: Heavy Demolition Ships are created 10%/15%/20% faster in Feudal/ Castle / Imperial age.
 * Celtish herdables cannot be stolen within a Heavy Demolition Ship's Line of Sight.
 * Chinese: Technologies that benefits Heavy Demolition Ships are 10%/15%/20% cheaper in Feudal/Castle/Imperial age. Demolition Ships have +50% hp.
 * Vikings: Heavy Demolition Ships cost -20%.

Changes in The Forgotten expansion

 * Demolition Ships +10 HP.
 * Vikings: Demolition Ships cost 10%/15%/20% less in Feudal/Castle/Imperial age.

History
"Demolition ships eventually were made larger and filled them with explosives of greater power, especially gunpowder. This heavy demolition ship resulted in greater explosions and a greater chance of damaging or destroying one or more enemy ships. It could be devastating against a large target or many enemy ships caught traveling close together."