Suezmaxis anaval architectureterm for the largest ship measurements capable of transiting theSuez Canal, and is almost exclusively used in reference totankers. Since the canal has nolocks, the only serious limiting factors aredraft(maximum depth below waterline), and height due to theSuez Canal Bridge. The current channel depth of the canal allows for a maximum of 20.1m (66ft) of draft,[1]meaning a few fully ladensupertankersare too deep to fit through, and either have to unload part of their cargo to other ships ("transhipment") or to a pipeline terminal before passing through, or alternatively avoid the Suez Canal and travel aroundCape Agulhasinstead. The canal has been deepened in 2009 from 18 to 20 m (60 to 66ft).The typicaldeadweightof a Suezmax ship is about 240,000 tons and typically has a beam (width) of 50m (164.0ft). Also of note is the maximum head room"air draft"limitation of 68m (223.1ft), resulting from the 70m (230ft) height above water of the Suez Canal Bridge.Suez Canal Authorityproduces tables of width and acceptable draft, which are subject to change.[2]Currently the wetted surface cross sectional area of the ship is limited by 945 m2, which means 20.1m (66ft) of draught for ships with the beam no wider than 50.0m (164.0ft) or 12.2m (40ft) of draught for ships with maximum allowed beam of 77.5 m (254ft 3 in).Similar terms ofPanamax,MalaccamaxandSeawaymaxare used for the largest ships capable of fitting through thePanama Canal, theStrait of MalaccaandSaint Lawrence Seaway, respectively.Aframaxtankers are those with a capacity of 80,000metric tonsdeadweight(DWT) to 120,000DWT. The term "capesize" refers tobulk carriersof size unable to traverse the Suez Canal and needing to go around theCape of Good Hopebut the recent deepening of the canal permits most ships of this class to traverse the canal. Future plans of deepening draft to 70ft may lead to redefining of Suezmax specification as has happened in the case of Panamax specification consequent to plans to upgrade thePanama Canal.

PanamaxandNew Panamaxare popular terms for the size limits for ships traveling through thePanama Canal. Formally, the limits and requirements are published by thePanama Canal Authority (ACP)titled "Vessel Requirements".[1]These requirements also describe topics like exceptional dry seasonal limits, propulsion, communications and detailed ships design.The allowable size is limited by the width and length of the availablelockchambers, by the depth of the water in the canal and by the height of theBridge of the Americas. Ships that do not fall within the Panamax-sizes are calledPost Panamax. The limits have influenced those constructing cargo ships, giving clear parameters for ships destined to traverse thePanama Canal."Panamax" has been in effect since the opening of the canal in 1914. In 2009 the Canal management published the "New Panamax",[2]that will be in effect when thethird lane of locks, larger than the current two, are operational from 2014.The increasing prevalence of vessels of the maximum size is a problem for the canal as a Panamax ship is a tight fit that requires precise control of the vessel in the locks, possibly resulting in longer lock time, and requiring that these ships transit in daylight. Because the largest ships traveling in opposite directions cannot pass safely within theGaillard Cut, the canal effectively operates an alternating one-way system for these ships.

An Aframax ship is anoil tankersmaller than 120,000 metric tonnes and with a breadth above 32.31 m.[1]The term is based on theAverage Freight Rate Assessmenttanker rate system. Aframax class tankers are largely used in the basins of theBlack Sea, theNorth Sea, theCaribbean Sea, theChina Seaand theMediterranean. Non-OPECexporting countries may require the use of tankers because the harbors and canals through which these countries export their oil are too small to accommodatevery-large crude carriers and ultra-large crude carriers.