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.
An individual nation's fleet and the people that crew it are referred to as its merchant navy or merchant marine. Merchant shipping is the lifeblood of the world economy, carrying 90% of international trade with 102,194 commercial ships worldwide. On rivers and canals, barges are often used to carry bulk cargo.