Roll on, roll off..

RO/RO Ferries.

This is the type of shipping that brings in the buck's. Right across the globe, where ever a ferry is needed the 'roll on -roll off system is employed. 

Over the years there have been many accidents and disaster in relation to ships leaving or entering ports with their doors open, before actually docking or leaving. Water has entered and ships have capsized with sometimes great loss of life. Greed seems to be the main factor in many of these cases, despite international agreements on safety.

Originally the 'roll on- off concept was for ships that carried trains and later adapted for truckers. This is probably the best system to date and will continue until some other shipping design replaces what we have today.

Icebreakers.

The Ice breaking ship was and is very much associated with Russia, but many other nations have them too. the U.S.A, Canada, Japan and the U.K. To be enabled to break ice and allow shipping to access ports in winter is quite a feat and an essential. 

Many of the largest ships built by the Russians were used for exploration and spying of one kind or another. To have access to both poles was a breakthrough in engineering. 

These type of ships will probably remain being built and improved in their capabilities for the years to come. Man has leaned much about the polar regions on the planet, but there is still so much more.