Vessel Lenght Classes and Definition of Vessel Length Overall

Vessel lenght classes
Vessel lenght classes

A vessel’s length class determines the equipment necessary to comply with federal and state laws.

Class Aless than 16 feet length overall
Class I16 to less than 26 feet length overall
Class II26 to less than 40 feet length overall
Class III40 to 65 feet length overall
Small Research Vessel (SRV)greater than 65 feet length overall but less than 300 gross tons

Length is measured from the tip of the bow in a straight line to the stern. This does not include outboard motors, brackets, rudders, bow attachments, or swim platforms and ladders that are not a molded part of the hull.

Definition of vessel length overall

For the purpose of maritime legislation the technical information to be presented by the owners and or builders varies considerably according to the needs of administrations. The terms Length Overall (LOA), Registered Length, Length Between Perpendiculars (LBP) and Length1 are all different. There are also differences in the way length, breadth and depth are measured depending upon the material of construction. Furthermore, the terms GT, GRT and NT are no less confusing when two sister-fishing vessels can have different tonnage measurements.

Notwithstanding the apparent anomalies, the differences are usually associated with the provisions of International Conventions that are incorporated in the national laws and regulations of a Party to the Convention.

Conventions that apply in one way or another to fishing vessels are:

  • Safety of Life at Sea (SOLAS).
  • The International Collision Regulations.
  • The International Convention on the Tonnage Measurement of Sips 19694.
  • The Agreement to Promote Compliance with Conservation Measures by Fishing.
  • Vessels on the High Seas (Compliance Agreement).

The Compliance Agreement uses the same definition of length as The Tonnage Convention (in force) and the basic provisions require reporting on vessels of 24m in length and over 24m. That figure, however, can be reduced under certain conditions for the application of the Agreement. The GFCM is a case in point and if the Agreement comes into force, the lower limit for the Mediterranean would be 15m (or between 17 and 18m in length overall).

With regard to national legislation, the requirements for the licensing and or registration of a fishing vessel vary greatly. Some countries register on the basis of length, some by GT and others by NT. But all have to acknowledge LOA with regard to the International Collision Regulations, therefore, apart from normal shipbuilding practice, an administration is duty bound to record the overall length of a vessel.

It is also the practice to measure open boats, such as lifeboats, by cubic capacity with the inside measurements of the hull taken for the purpose of the formula.

Where no International Conventions apply for the safety of fishing vessels and their construction, national legislation often relies on the Cubic. FAO has long promoted the use of the Cubic Number and it is the reference point used in the design of small fishing vessels and transport vessels associated with fisheries. In such cases, it is essential to know the LOA.

Most international agreements are directed towards the industrial fleets with scant reference to the greater proportion of vessels that constitute the world fleet. Even the Collision Regulations have limitations. On the other hand, the Standard Specifications for the Marking and Identification of Fishing Vessels, endorsed by eighteenth session of COFI7 simplified the question of application by using the length overall as the reference point.

The length overall is the usual criterion with regard to small vessels, whether decked or undecked. In these cases the LOA8 and installed power will certainly be the minimum required by administrations and may even suit the needs for the estimation of fishing effort provided that the craft fall into identifiable categories (pirogues for example). In addition, it would be acceptable for any researcher to apply an agreed multiplier to the length should it be required to estimate the cubical capacity of the hull (as if it had a deck).

An FAO consultant who is an expert in the field, John Fitzpatrick, has proposed the following definition of “length overall” (LOA) :

Length overall is defined as the distance measured in metres in a straight line on a line parallel to the design waterline between the foremost point of the bow and the aftermost point of the starn. For the purpose of this definition :

a) The bow is taken to include the watertight hull structure, the forecastle, stem and forward bulkward, if fitted, but not to include bowsprits and safety rail.

b) The stern is taken to include the watertight hull structure, transom, poop, trawl ramp and bulwark, but does not include safety rails, bumkins, propulsion machinery, rudders and steering gear, and divers’ladders and platforms.

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