The classification societies of the world have special notations for different types of vessel, and these appear as a string of letters on some line of the publicity material. It is always possible to find out what these mean but for ease of reference here are some of them. Where necessary these descriptions are modified to make them easier to understand, but the actual classification society documents should be consulted for formal wording. Only a selection of notations are included here, a judgement being made as to which ones are most relevant.

The ABS notations which apply specifically to offshore vessels, or which appear to do so, are limited to vessels of less than 90 metres in length. Now that there are offshore support vessels of more than 90 metres in length one wonders what they will do.

 

Maltese Cross A1

This indicates a vessel surveyed by ABS during construction with a hull conforming to ABS requirements

DPS-0

The notation indicates that the vessel is fitted with a system of thrusters, positioning instruments and controls, with a centralised manual control and a means of automatically maintaining the heading. This means joystick control.

DPS-1

The notation indicates that the vessel is fitted with a system of thrusters, positioning instruments and controls, with an automatic means of maintaining station and heading, and with a centralised manual control. This means that the vessel is fitted with a means of identifying the position of the ship on the earth, and keeping it in that position, and in addition is provided with a joystick control. The means of maintaining station is often a fanbeam or similar system.

DPS-2

The notation indicates that the vessel is fitted with a system of thrusters, positioning instruments and controls, with an automatic means of maintaining station and heading, and with a centralised manual control. This means that the vessel is fitted with a means of identifying the position of the ship on the earth, and keeping it in that position, and in addition is provided with a joystick control. The position will be maintained after a single fault except the loss of a compartment or compartments. The means of maintaining station is often a fanbeam and a GPS system and that all the software is duplicated from the desks downwards.

DPS-3

To avoid complete boredom it is sufficient to say that this notation takes in all the above with the additional capability that in the event of the loss of a single compartment the system will still be operational. This of course means that there will be two engine rooms, two propulsion systems divided into separate compartments and software and desks in separate compartments. So even if these is a desk on the bridge from which the ship is usually controlled, there will be another desk in an adjacent compartment from which the ship could be operated.

HAB and HAB+

A notation assigned to vessels which comply with the ABS minimum criteria for crew accommodation in relation to vibration, noise, climate and lighting as defined by the relevant ABS Guidance. Of course the + means that the ship complies with even more stringent requirements.

HELIDK and HELIDK(SFR)

This of course means that the vessels if fitted with a helideck conforming to ABS requirements. However, the SFR addition means that the vessel is provided with the means of storage of fuel and the means of refuelling aircraft.

Ice Class A0 to A5

The ice class notations indicate the thickness of the ice in which the ship can work. The designations are related to the areas in which the vessel can work. In addition the A0 designation relates to first year ice and there also exist B0, C0 and D0 also indicating areas for work. Ice class A2 to A5 are designated as icebreakers. For further Ice Class notations the relevant ABs documentation should be consulted.

NBL

This is a notation assigned to vessels having a bridge layout complying with ABS requirements in “Guidance for Navigation Bridge Design…” also NBLES and NIBS.

RCM

This notation plus a secondary acronym in brackets means that there is a “reliability centred maintenance system” for the area shown in the brackets.

Fire Fighting Vessel

This designation goes from Class 1 to Class 3.

Class 1 equipment must include 2 monitors capable of delivering 1200 m3 per hour each.

Class 2 equipment includes either three monitors delivering 2400 m3 each or four monitors delivering 180-0 m3 each, plus foam generators.

Class 3  fire fighting vessels must be provided with four monitord each delivering 2400 m3 per hour plus foam monitors.

Offshore Sup-port Vessel

The description in the text of the notation is that of a standard off shore vessel, accommodation forward, open deck aft. There are additional designations in brackets:

AH. An offshore support vessel designed for anchor-handling activities

WS. An offshore support vessel designed for well stimulation.

Safety Standby Service

The designation for standby vessels followed by a letter and number in brackets for the number of people who can be recovered to the vessel.

GR A (N) Group A is a number of survivors greater than 300.

GR B (N) Group B is for a number of survivors between 20 and 300 – including 300.

GR C (N) Group C for a number less than 20.

Towing Vessel

Indicates a vessel to be used primarily for towing services with the additional notation BP (xx) for bollard pull and QR for quick release of the winch or tow hook.

HAB (WB) and HAB+(WB)

An offshore support vessel less than 90 metres in length conforming to the ABS Guide for Crew Habitability on Workboats and HAB+ to the more stringent requirements with respect to crew accommodation, whole body vibration and indoor climate.

RB

A notation which indicates that a vessel has been surveyed so as to allow it to actively work beyond its normal 25 year life.

 

 

 
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