Some jurisdictions or statutory applications of the term 'ship', omit oar propelled boats from the definition, whereas others specifically include oar propelled boats.
As Justice Blackburn wrote in Ex parte Ferguson, where the issue was whether or not the vessel in question was a ship and therefore obligated to assist in a nearby fatal sinking of another vessel:
"Whether a ship is propelled by oars or not, it is still a ship, unless the words 'not propelled by oars' excludes all vessels which are ever propelled by oars. Most small vessels rig out something to propel them and it would be monstrous to say they are not ships."
In most jurisdictions, statutes specify what is meant by a 'ship' in the contexts of various statutes. Thus, the definitions differ widely even within the same state.
In the United States Code, Title 47:
"The term ship or vessel includes every description of watercraft or other artificial contrivance, except aircraft, used or capable of being used as a means of transportation on water, whether or not it is actually afloat."
But in Title 18 of the US Code:
"Ship means a vessel of any type whatsoever not permanently attached to the sea-bed, including dynamically supported craft, submersibles or any other floating craft, but does not include a war ship, a ship owned or operated by a government when being used as a naval auxiliary or for customs or police purposes, or a ship which has been withdrawn from navigation or laid up."
In Canada, a floating crane was determined to be a ship under the (Saint John Shipbuilding) but in The Gulf of Aladdin case, a simple barge with no independent means of propulsion was held to not be a ship.
In Croswell v Dabal, at issue was the Canada Shipping Act in a tort action involving two pleasure crafts or "speed-boat", both 30 feet long. Justice Logie of the Ontario Court:
"... there can be no question that each of the motor-boats in question was a 'ship' under the Canada Shipping Act 1906".
In another, considering the North American Free-Trade Agreement, determined that a ship was a "large sea-going vessel" (Canada v McNally
Rather than refer to "navigation", some legal usages refer to a vessel made to move either on the surface of or under the water.
A ship is distinct from the cargo it carries.