The thickness of the ozone layerâthat is, the total amount of ozone in a column overheadâvaries by a large factor worldwide, being in general smaller near the equator and larger towards the poles. It also varies with season, being in general thicker during the spring and thinner during the autumn.
Report Abuse. How ever many you have-is your fleet of ships. The US Merchant Marines currently have 465 ships in their fleet. The US Navy has a fleet of 286 ships. A fleet is the total number of ships. It can be the total number of a nation, or can be a fleet of ships operating under the same ownership.
Of the 50-60 ships typically assigned to Seventh Fleet, 18 operate from U.S. facilities in Japan and Guam. These forward-deployed units represent the heart of Seventh Fleet. The 18 permanently forward-deployed ships of the US 7th Fleet are the centerpieces of American forward presence in Asia.