Ballast

Heavy material placed low in a vessel to improve its stability.

Weight

150 t

Armor

0 MJ

Toughness

1 MJ

Density

1,200 kg/m³ · sinks

Cost

free

Size

1 × 1 × 1 cells

Armor is taken off every blast that reaches the block; toughness is the damage it takes before it is destroyed. Water is 1,025 kg/m³: denser blocks sink, lighter ones keep the ship afloat. Complexity is the part's share of a ship's 65,535-triangle limit.