Class Type is a code indicating the size and function of the ship. Each nation tends to have a slightly different interpretation of what the commonly used (as least in the West) codes stand for. A simplified classification criteria have been applied the same way to ships of all nations. The more conventional letter designations are given in parenthesis.

• Carrier indicates aircraft carriers (CV, CVL. CVN, CVA, CVH) which vary in size from 12,000 tons up to over 90,000 displacement tons.
• "B" is Battleship (BB), displacing over 20,000 tons of water and capable of independent operation although these are often the primary ship of a task force. This class of ships is likely to finally disappear in the next decade or so, about a century after they were first conceived and built.
• Cruiser is a Cruiser class ship (CA, CG, CL) of 5,000 to 20,000 tons displacement. Most are between 6,000 and 12,000 tons. Basically, these are smaller battleships with less of everything except speed. Cruisers also tend to specialize in something like anti-submarine, anti-air or surface combat. Cruisers sometimes operate with one or more other cruisers or destroyers in a small task force. Also included here is the Russian battlecruiser Kirov, which is a little heavier.
• Destroyer are destroyers (DD, DDG, FF, FFG), or 2,000 to 5,000 tons.
• Escort are escort and patrol ships (DE, PH, PT, etc.), under 2,000 tons and typically found in coastal waters.
• SSBN are ballistic missile boats.
• SSN are nuclear and SS non-nuclear attack submarines, types (SS, SSG, SSN, SSGN).

Not included are ships under 100 tons (including minesweepers and minelayers, which are sometimes larger). These are little more than sea going police cars. What anti-submarine gear some of them have is largely ineffective against modern subs. Some also have lightweight surface-to-air missiles. Russia and China have the largest number of these small boats, several hundred in fact. Some boats in this class have anti-ship missiles. These are included in the Escort category.

Class Name is the name of the lead ship of a group of generally identical ships.

# - is the number in that class as of 2001.

Combat Values - are numerical evaluations of the ship's combat capabilities against surface ship, capabilities (SURF), submarine (SUB) and air (AIR) targets. These values take into account the quality and quantity of onboard weapons, equipment and crew as well as past performance. The most critical factor is the quality of crew training and leadership.

Prot - is the protection value of that ship against attacks from enemy weapons. For submarines this includes the difficulty other ships and subs have in detecting it. This is a function of sub quietness, diving depth, displacement, hull arrangement and countermeasures. For surface ships, these values suggest the number of major weapon hits the ship would have to receive before it was no longer capable of combat.

Long - is the ship's length in meters. This, and weight (below) pretty much defines how large the ship is.

Wght (weight) - is the ship's full-load displacement in thousands of tons. For submarines it is surface displacement. The term displacement refers to the weight of water the ship displaces when it is floating on the surface. I know it sounds complicated, but it is the common term used. If you want to deal with the navy, learn to speak their language.

Speed - is top speed in kilometers per hour. Rarely used except in emergencies. Also rarely achieved except when the engines and hull are in top shape. These conditions decline the longer a ship is at sea and/or in action. At that point, top speed declines 10 or 20 percent. Efficient cruising speed tends to be one half to two-thirds of top speed.

Range - is the un-refueled range in thousands of kilometers, at cruise speed of between 20 and 30 kilometers an hour. This is quite slow for wartime activities, and task forces normally cruise at 50 kilometers an hour or even faster. This can reduce RANGE by up to 50 percent. Nuclear ships the range is shown as 200,000 kilometers. In many cases it can be up to five times this before the nuclear reactors fuel must be replaced. The range given is what most nuclear boats would have at the beginning of a war. Note that the navy has their own units of distance (nautical mile, equals 1.8 kilometers) and speed (knot, equal to one nautical mile per hour). Most landlubbers (and some sailors) use kilometers. So will we.

EW - is the effectiveness of the ship's electronics in general and its electronic-warfare capabilities in particular. The higher the number, the better.

Guns - is the number of gun systems the ship mounts. Multibarrel Gatling types (used against cruise missiles) count as one gun. Almost all guns are under 128 mm and are used primarily for air defense.

Aircraft - is the number of helicopters and fixed wing aircraft on board. Smaller ships only carry helicopters.

SAM - is surface-to-air missile launchers carried. This is sometimes misleading, as most launchers have magazines and the launcher is capable of firing a dozen or more missiles in one engagement.

SSM - is surface-to-surface missile launchers. These are usually one shot affairs.

TT - is the number of tubes for launching torpedoes (TT) Modern submarines have four to ten torpedo tubes on board, with twice as many on surface ships armed with torpedoes. Many Russian ships still use depth charge throwers, a remarkably ineffective weapon against nuclear subs, although still of some use against Russia's own large fleet of non-nuclear subs. Figure that one out.

End Build - is the year in which the last ship of that class was built. This indicates how up-to-date that class is. This is very true with Russian, and non-Western, ships, as Western navies tend to upgrade their ships every ten years or so. The Russians simply build a new class in most cases. Dates later than 2001 usually indicate that the class is still being built.