The thing on the left is a:
Bombardons: A number of ideas were considered for breakwaters. The first of these involved the use of compressed air. Perforated pipes were to be laid on the sea bottom around the area to be protected and compressed pumped through it. The result was a calm area within which ships were able to discharge at the piers. Although the principle was quite sound, the trials proved that the pipes would be moved in any heavy swell and that an enormous amount of power was required (at least 1.5 million horse-power for an area half that required).
Robert Lochner, who was in charge of this project, thought about what the were trying to achieve and realised that waves were in fact only surface deep and, therefore, only a shallow barrier was required. From experiments in his garden pond with a lilo, Lochner and his team went on to produce a floating, steel hollow cruciform “tube” which would form a suitable breakwater (code name Bombardon - to suggest a link with anti-aircraft defences)
http://www.hksw.org/despatches_107_1_a.htm