seawaymax

{{Use dmy dates|date=May 2021}}

{{short description|Largest ships that can pass through the St. Lawrence Seaway}}

{{Infobox ship begin}} {{Infobox ship characteristics | Hide header = | Header caption = | Ship type = | Ship tonnage = {{DWT|28,500}} | Ship displacement = | Ship length = {{convert|740|ft|abbr=on|1}} | Ship beam = {{convert|78|ft|abbr=on|1}} | Ship height = {{convert|116.5|ft|abbr=on|1}} | Ship draught = | Ship draft = {{convert|26.51|ft|abbr=on|1}} | Ship depth = | Ship decks = | Ship deck clearance = | Ship ramps = | Ship ice class = | Ship sail plan = | Ship power = | Ship propulsion = | Ship speed = | Ship capacity = | Ship crew = | Ship notes = }}

File:Ship_measurements_comparison.svg of Seawaymax with some other ship sizes in isometric view.]]

A Seawaymax vessel is one of the maximum size that can fit through the canal locks of the St. Lawrence Seaway, linking the inland Great Lakes of North America with the Atlantic Ocean.{{cite web |access-date=2023-03-13 |year=2022 |title=Seaway Handbook |url=https://greatlakes-seaway.com/en/commercial-shipping/seaway-handbook/ }}

File:CSL Laurentien (IMO 7423108) on St Clair River Michigan.jpg

Seawaymax vessels are {{convert|225.55|m|ft}} in length, {{convert|23.80|m|ft}} wide, and have a draft of {{convert|8.08|m|ft|1}} and a height above the waterline of {{convert|35.5|m|ft|1}}. A number of lake freighters larger than this size cruise the Great Lakes and cannot pass through to the Atlantic Ocean. The size of the locks limits the size of the ships which can pass and so limits the size of the cargoes they can carry. The record tonnage for one vessel on the Seaway is 28,502 tons of iron ore while the record through the larger locks of the Great Lakes Waterway is 72,351 tons. Most new lake vessels, however, are constructed to the Seawaymax limit to enhance versatility by allowing the possibility of off-Lakes use.{{fact|date=May 2021}}