Hull Survey Definitions, Terms & Terminology

Updated: Nov 29, 2020

Terminology for Marine Surveyors and other Maritime Professionals & Seafarers

Reference Material & Definitions incorporated, as applicable, in Marine Appraisals & Marine Survey Reports, prepared by Karatzas Marine Advisors & Co.

Abaft: A point beyond the midpoint of a ship’s length, towards the rear or stern.

ABS (American Bureau of Shipping): a vessel classification agency that also assigns international loadlines.

ABS Load Line Certification: An International load line certificated vessel that meets the requirements of the International Maritime Organization’s International Convention on Load Lines.

Abrasion: The removal of material by mechanical, i.e. rubbing or frictional, means.

Abrasion Test: A laboratory test to evaluate drilling-grade weighting material for potential abrasiveness. The test measures weight loss of a specially shaped, stainless-steel mixer blade after 20 minutes at 11,000 rpm running in a laboratory-prepared mud sample. Abrasiveness is quantified by the rate of weight loss, reported in units of mg/min. Mineral hardness, particle size and shape are the main parameters that affect abrasiveness of weighting materials. Some crystalline forms of hematite grind to a higher percentage of large particles than do other forms and are therefore more abrasive. Hematites are harder than barites, grind courser and are more abrasive. Thus, a hematite that is proposed as a weighting material for mud is typically a candidate for abrasion testing.

Access Holes: Holes cut in ship’s structure to permit entering or leaving various compartments.

Active Corrosion: Gradual chemical or electrochemical attack on a metal producing loose scale, by atmosphere, moisture or other agents.

Admeasure: To measure, calculate, and certify; for the purpose of registration, certain dimensions of a vessel as well as its gross and net tons.

Affreightment, Contract Of, (COA): An agreement by an ocean carrier to provide cargo space on a vessel at a specified time and for a specified price to accommodate an exporter or importer.

Aft: Movement toward the stern (back end) of a ship.

After Rake: The part of the stern which overhangs the keel.

AHP (Above Head of Passes): used with mileage designations on the Mississippi River, the Head of Passes being mile zero.

AIWW: Atlantic Intracoastal Waterway.

All Fast: he time during which the Vessel is completely moored, which includes gangway down and secured (for all Vessels other than Inland Barges), at the Cargo Transfer Point.

All Hands: The entire crew.

All In: The total price to move cargo from origin to destination, inclusive of all charges.

All Standing: To bring to a sudden stop.

Alleyway: A vessel’s internal passageway or corridor.

Allowable Corrosion or Wastage Limit: The acceptable thickness diminution of structural elements.

Aloft: Above the upper deck (above).

Alongside: A phrase referring to the side of a ship. Goods delivered “alongside” are to be placed on the dock or barge within reach of the transport ship’s tackle so that they can be loaded.

Alteration: Change that does not affect the basic character or structure of the ship to which it is applied.This is typically a limited change to the ship's structure, equipment or functions, such as change of components, change of local structure, change of draught or change of class notations not affecting ship's purpose/type.

AMVER: Automated Mutual-Assistance Vessel Rescue System

Anchor Watch: The detail on deck at night, when at anchor, to safeguard the vessel (not necessarily at the anchor; a general watch).

Anchor Handling Tug Support Vessels (AHTS): Specialist vessels designed for towing and/or anchor handling. Predominantly employed in the movement of rigs and platforms, and for the handling and laying of their anchors. Anchor Handling Tug Supply (AHTS) vessels combine the role of supply vessels and anchor handling tugs. They are the backbone of offshore operations and constitute the largest proportion of offshore vessels. Not only do they deliver supplies such as deck cargo, water, fuel, dry bulk and mud to oil rigs and platforms, they are specially designed to provide anchor handling services, towage duties and in some cases also serve as an Emergency Towing Rescue and Recovery Vessel (ETRRV). Some modern AHTS vessels are also equipped for fire fighting, rescue operations and oil recovery to enable them to have a more multi-role capability.

Anode: The positively charged metal surface and the corroding part of an electrochemical corrosion cell at which the oxidation or loss of electrons occurs. Sacrificial anode or impressed current anode. Also, Sacrificial Anode.

Antifouling: Paint for use on underwater areas on hulls. Antifouling contains agents who prevent the adhesion and growth of organisms on the hull.

API-MPMS: The American Petroleum Institute Manual of Petroleum Measurement Standards, as such may be amended and/or updated from time to time.

Arkansas River Lock and Dam 1 (Located in Tichnor, AR at mile 10 on the Arkansas River): This is a single chamber lock that is 600 ft. by 110 ft. in dimension (also called Norrell Lock).

Asdem Pumping Performance Formula: The formula maintained by Asdem and used to assess underperformance by a tanker’s pumps during discharge of cargo. The formula can be found on Asdem’s website at:

Astern: Behind a vessel; or, move in a reverse direction.

Atlantic: A grain export region that includes export elevators in Brunswick, GA, Albany, NY, and Chesapeake, VA.

ATDNSHINC: Any Time Day or Night Sundays & Holidays Included.

ATUTC: Actual Times Used to Count

Athwartship: Transverse or across a vessel from side to side or a direction across the width of a vessel.

Automated Identification System (AIS): An electronic instrument placed on regulated powered vessels to automatically provide their identity, location and other navigational data to a central receiving base to facilitate navigational control and safety.

Auxiliary Lock: The smaller chamber of a double lock that transfer vessels from one water level to another water level. The advantage of this two-lock facility is that both chambers can be working at the same time, and more importantly while one chamber is closed for repairs, the other chamber can handle the traffic. See Main Chamber Lock.

Avast: An order to stop or cease hauling (stop action at once).

Avoirdupois weight (n): the series of units of weight based on the pound of 16 ounces and the ounce of 16 drams

Awash: Level with the water (water ready to, or slightly covering decks).

AWWL: Always Within Institute Warranties Limits (insurance purpose).

Backhaul: To haul a shipment back over part of a route it has traveled.

Bacterial Corrosion or Microbially Influenced Corrosion (MIC) is corrosion which is induced or accelerated by the presence of micro organisms.

Ballast: Any substance, other than cargo, which is usually placed in the inner compartment of a vessel to produce a desired draft or trim.

Bareboat Charter (Demise Charter): A form of vessel rental in which the charterer assumes total responsibility for the vessel and its operations, as if the vessel was owned by the charterer.

Barge: A large, flat-bottomed, rigged or unrigged, craft of full body and heavy construction, specially adapted for the transportation of bulk freight such as grain, ethanol, fertilizer, coal, lumber, oil etc. from a port to shallow-draft waterways. Barges have no locomotion and are pushed by towboats. A single, standard barge can hold 1,500 tons of cargo or as much as either 15 (jumbo hopper) railroad car or 58 large grain hopper semi-trailers or 60 truckloads. A barge load of grain, as a unit of measure is 52,500 bushel . A jumbo covered hopper barge is the type of barge most frequently used for moving grain on the rivers. A barge is 200 feet long, 35 feet wide and has a draft of 9 feet. Barges carry dry bulk (grain, coal, lumber, gravel, etc.) and liquid bulk (petroleum, vegetable oils, molasses, etc.).

Barge, Inland: A USCG- or American Bureau of Shipping-inspected and approved tank barge that is restricted to operations in the inland waterways of the US.

Barge, Jumbo Covered Hopper: Type of barge most frequently used for moving grain on the rivers. Older barges held 52,500 bushels, but some newer barges have larger capacities.

Ocean Barge or Ocean-Going Barge: A USCG- or American Bureau of Shipping-inspected and approved tank barge that has an ABS Load Line Certification and is certified to operate in offshore waters.

Barges Unloaded: The number of barges of grain unloaded in the area between Baton Rouge New Orleans, LA.

Barrel (and BBL): 42 US Gallons measured at 60 degrees Fahrenheit (60°F).

Base Rate / Freight Rate: A tariff term referring to ocean rate less accessorial charges, or simply the base tariff rate.

Beam: The breadth of a vessel.

BENDS: Both Ends (Load & Discharge Ports)

BEP: Best Environmental Practice.

Bentonite: A material composed of clay minerals, predominantly montmorillonite with minor amounts of other smectite group minerals, commonly used in drilling mud. Bentonite swells considerably when exposed to water, making it ideal for protecting formations from invasion by drilling fluids. Montmorillonite forms when basic rocks such as volcanic ash in marine basins are altered.

BIMCO: Baltic & International Maritime Council

Blasting or Shot-Blasting: The cleaning of a metal surface by a stream of abrasive particles.

Blister: A raised area, often dome shaped, resulting from loss of adhesion between a coating or deposit and the substrate.

BNWAS: Bridge Navigational Watch Alarm System

Bollard Pull: The static pulling force of a tugboat measured in pounds/tons.

Bone in her teeth: A colloquial phra