(i) The way’ is free, and gives access to most parts of the world.
(ii) Small power is needed to drive a vessel, so that large vessels are practicable and economies can be achieved.
(iii) Transport by sea is relatively slow, so that passengers are easily lost to airlines when speed is important.
(iv) The possibility of determination of cargo is great because sea water is corrosive and also liable to affect the quality and flavour of cargoes.
(v) Because weight is not important, ships can be massive enough to be strong.
(vi) Buoyancy of the effective weight zero. Hence sea transport is very suitable for heavy goods.
(vii) Pilfering of cargoes is not uncommon, though ‘containerization’ is doing much to reduce this.
(viii) Ports are expensive and delays not uncommon.
Other Transportation Systems
Hovercraft. Hovercraft operates on a cushion of air which is pumped under the vehicle and kept in by a skirt of heavy material. They are particularly effective over water, where they enable much higher speeds to be achieved than by the conventional ship. There is no water resistance worth speaking of, and a cross-channel ferry is now operating from a base at Pegwell Bay near Dover, carrying vehicles and passengers at about 80 knots.
The hovercraft is particularly advantageous in estuaries where its ability to ignore sandbanks and shallow water means it can operate by more direct routes. The use of longer skirts, possibly up to 12 feet deep will improve the ability of these craft to negotiate the larger waves. A second use for hover skirts has been found in moving heavy loads over bridges which are not strong enough to carry the load. By fitting a temporary skirt to Lorries carrying heavy loads of this type the weight which is usually borne by the axle assembled, and enabling the load to cross without damage to the bridge.
Pipe lines are increasing in importance for the transportation of natural gas and oil field from the ports to inland depots. While the capital cost is great, the savings on motor-vehicle costs for comparable movements by road, quite apart from the social costs of congested highways, make this form of transport both economical and socially desirable.
Pipelines cannot however compete with tanker costs, especially giant tankers on long hauls. Pipelines are also being used for the transport of solids carried in slurry form.
Monorails are form of transport that offers quick passenger and goods services along overhead routes, created on concreted pillars along the highways. The carrying units are small but make up for this by frequency of service, and high speed.
Although not practicable for long routes they have advantages in solving local transport problems, especially the connection of airports with city centres.