Modified parameters of the ships - they are much larger and appropriately more expensive.

Their parameters are:

Small tanker: 10 000 000 liters of oil
Large tanker: 22 000 000 liters of oil

Small cargo ship: 6000 tons of cargo
Large cargo ship: 15000 tons of cargo

Small ferry: 500 passengers
Large ferry: 800 passengers
Hovercraft: 160 passengers