Transverse bulkheads, while expensive, increase the likelihood of ship survival in the event of hull damage, by limiting flooding to the breached compartments they separate from undamaged ones. Longitudinal bulkheads have a similar purpose, but damaged stability effects must be taken into account to eliminate excessive heeling.
Perpendicular partitions, although costly, enhance the probability of a ship's survival in the event of hull damage, by restricting flooding to the damaged compartments they isolate from undamaged ones. Longitudinal partitions have a comparable function, but considerations regarding excessive tilting must be taken into account to eliminate undesirable effects.