http://dwarffortresswiki.net/index.php/Stupid_dwarf_trick#Journey_to_the_Center_of_the_Earth

The D.S. Callchannels is equipped with a bridge, treasury, living quarters, and food and drink stores. It has a Billon coated hull and four turbines hooked up to two generators to power through the dense magma. Controls to seal the entrances and launch the ship are inside so adventurous dwarves can launch when ready.

The ship is located above the magma pipe in the NW corner of the map. The lever just inside the ship closes the floodgate entrance and the hatch on top. The lever in the tip of the drill breaks the supports holding the ship to the crane. The switch at the top of the crane raises the bridges to the ship, this is not necessary to launch the ship.

Copy descent folder to ~/data/save/