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.
A simple thing you can do is just slow ships down and add some tug boats for better manoeuvring - but that all has cost implications.. There are currently 163 ships on the world's seas with a capacity over 10,000 TEU - but 120 more are on order, including Maersk's fleet of 20 Triple Es.