Unit-ship:Catapult Ship

__NOWYSIWYG__

Description
The catapult at the deck of the ship is smaller than its counterpart on land due to a lack of space. The ocean waves make it very imprecise, but it does fire clay jugs of burning oil, which leave dangerous little oil slicks behind at sea.


 * During sea battles, the Catapult Ships deploy to the .
 *  Catapult Ships fill a battlefield space. __NOWYSIWYG__

Construction times
$$Construction \ time \ = \left \lceil Base \ time \times 0.95 ^ {n - n_0} \right \rceil$$
 * where :
 * Construction time : The calculated time (in seconds) needed to construct the specific ship on the nth Shipyard's level.
 * Base time : The time (in senonds) needed to construct the specific ship on the Shipyard's first level that the specific ship can be constructed [ for this ship 50 minutes = 3,000 seconds ].
 * n : The nth Shipyard's level.
 * n0 : The Shipyard's first level where the specific ship can be constructed [ for this ship is the  Level ].

1 - 10 = 11 - 20 = 21 - 30 = 31 - 38 =