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.
With 10 aircraft carrier groups, dozens of destroyers, 22 cruisers (nearest rival Russia has five) and a large modern submarine force, the US Navy rules the seas. This blue-water branch of the US military is run by more than 320,000 people and is also the owner of the largest warships in the world.