Section 2 Classification

201. Classification

Offshore Support Vessels built and surveyed for the classification in accordance with this Guidance or in accordance with requirements deemed to be equivalent to this Guidance by the Society will be assigned a class and registered in the Register of Ships.

202.

1.

2.

Class notations

The class will be distinguished by the class notations and the class notations assigned to the Offshore Support Vessels classed with the Society are to be in accordance with the requirements specified in Pt 1, Ch 1, 201. of Rules for the Classification of Steel Ships. However, Offshore Support Vessel shall be assigned as a ship type notation and the Special Feature Notation shall be assigned as followings.

(1) Special Feature Notation may be assigned as the following according to the specialized func- tional service of the Offshore Support Vessel.

(A) for supply service : Supply

(B) for anchor handling service : AH

(C) for towing service : Tow

(D) for heavy lift service : HL

(E) for wind turbine installation, maintenance and repair service : WTIMR

(F) for fire fighting service :

(a) FFS1, FFS2 or FFS3 according to the minimum requirement of table 8.1

(b) Satisfy the requirements for FFS1 at the same time, satisfying the requirements for Offshore Support Vessel (FFS2) or Offshore Support Vessel (FFS3) also , the Class nota- tion Offshore Support Vessel - FFS1 FFS2, or Offshore Support Vessel - FFS1 FFS3

may be assigned.

(c) Vessels not in full compliance with this Ch 8 or not specifically built for the service in- tended to be covered by this Ch 8, but equipped with some fire fighting capability in ac- cordance with this Ch 8 may be assigned Special Feature Notation FF.

(G) for oil spill recovery service : Oil Spill Recovery

(H) for other services : Special Feature Notation considered appropriate by the Society

The combination of Special Feature Notation may be assigned corresponding to the specialized functional services of the Offshore Support Vessel. For example, an Offshore Support Vessel for anchor handling service and towing service may be assigned the class notation "Offshore Support Vessel - AH, Tow".

3. Offshore Support Vessels built with strengthened for carrying heavy cargoes specified in accordance with Ch 3, 202. may be assigned the relevant Special Feature Notation HDC(P, Locations) or HLC(Ř, Tanks) additionally.

(1) For example, an Offshore Support ing service, strengthened for heavy class notation

Vessel for anchor handling service, supply service and tow- deck cargo of 30 kN/m2 at main deck may be assigned the

Offshore Support Vessel - Supply AH Tow HDC(30 kN/m2, main deck).

(2) For example, an Offshore Support Vessel for anchor handling service, supply service and tow-

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Ch 2 Classification and Survey Ch 2

ing service, strengthened for heavy liquid cargo of specific gravity 2.5 in number 3 and 5 cargo tanks may be assigned the class notation

Offshore Support Vessel - Supply AH Tow HLC(2.5 SG, Tank Nos. 3 and 5).

203. Maintenance of classification

1. Offshore Support Vessels classed with the Society are to be subjected to the surveys to maintain the classification and are to be maintained in good condition in accordance with the requirements specified in this Chapter.

2. Plans and particulars of any proposed alterations to the scantlings or arrangements of hull, machi- nery or equipment that are approved by the Society are to be submitted for approval to the Society before the work is commenced and such alterations are to be surveyed by the Surveyor of the Society.

204.

Classification survey during construction

1. General

At the Classification Survey during Construction, the hull, machinery and equipment are to be ex- amined in detail in order to ascertain that they meet the relevant requirements of this Guidance.

2. Submission of plans and documents

(1) At the Classification Survey during Construction, the following plans and documents are to be submitted to the Society for approval before the work is commenced.

(A) relating to Hull Structure

(a) Midship section

(b) Construction profile

(c)

Shell expansion

(d) Watertight and oiltight bulkheads

(e)

(f)

Deck plans

Stem, sternframe and rudder

(g) Single bottoms and double bottoms

(h) Superstructure end bulkheads

(i)

Fore and aft bodies

(j) Pillars and deck girders

(k) Shaft tunnels

(l) Foundations and the relevant structure plan of boilers, main engines, thrust and plummer blocks, generators, and other heavy weight auxilary machinery.

(m) Machinery casings

(n) Deckhouses

(o) Masts, derrick posts and derrick booms and the relevant structure plans

(p) Final stability data

(q) Loading manual

(r)

Where self elevating unit is installed, connection of all leg, bottom mats or spud can,

structural plan of leg tanks, leg jack or other elevating unit and structure and control plan of jacking system etc.

(s) Other plans and/or documents considered necessary by the Society

(B) relating to Machinery

(a) Plans and data relevant to machinery installation specified in

Rules for the Classification of Steel Ships.

Pt 5, Ch 1, Sec 2 of

(b) Electrical installations specified in Pt 6, Ch 1 of Rules for the Classification of Steel Ships, and automatic and remote control system specified in Pt 6, Ch 2 of Rules for the Classification of Steel Ships.

(c)

Fire extinguishing arrangements and inert gas system

(d) Where dynamic positioning system is installed, structural plan, arrangement and control plan of dynamic positioning system

(e) Other plans and/or documents considered necessary by the Society

(2) At the Classification Survey during Construction, the following plans and documents are to be submitted to the Society for reference.

(A) General arrangement

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Ch 2 Classification and Survey Ch 2

(B) Specification

(C) Calculation sheets for midship section modulus

(D) Where special cargoes are to be loaded on ships, the plans showing their distribution and loading arrangements.

(E) Calculation sheets for masts, derrick booms, boat davits, and similar structures requiring strength.

(F) Preliminary stability data.

(K) Where dynamic positioning system is installed, calculation sheet of dynamic positioning sys- tem, test procedures (test items, test procedures and criteria etc. for periodical survey)

(L) Where self elevating unit is installed, calculations substantiating adequacy of structure to transmit forces between legs and hull through the jacking systems, and calculations for ca-

pacity of resisting overturning moment.

(M) Other plans and/or documents considered necessary by the Society

(3) Hydrostatic curves, capacity plans, records of sea trials and various test reports are to be sub- mitted before the delivery of the ship.

3. Presence of surveyors

(1) At the Classification Survey during Construction, the presence of the Surveyor is required at the following stages of the work in relation to hull and equipment.

(A) When the tests of the materials specified in Pt 2, Ch 1 of Rules for the Classification

of Steel Ships and the equipment specified in

Steel Ships are carried out.

Pt 4 of Rules for the Classification of

(B) When the tests of welding specified in Pt 2, Ch 2 of Rules for the Classification of Steel Ships are carried out.

(C) When designated by the Society during shop work or sub-assembly.

(D) When each block is assembled and erected.

(E) When each part of the hull is completed.

(F) When structural tests, leak test, hose tests and non-destructive tests are carried out.

(G) When performance tests are carried out on closing appliances of openings, remote control devices, steering gears, anchoring and mooring equipment, cargo handling appliances, fire de- tection and fire extinguishing systems, piping, etc.

(H) When each part of the fire protection construction is completed.

(I) When measurement of principal dimensions, hull deflection, etc. are carried out.

(J) When a loading instrument is installed on board.

(K) When the load line mark is marked.

(L) When the onboard tests and stability experiments are carried out.

(M) When deemed necessary by the Society.

(2) At the Classification Survey during Construction, the presence of the Surveyor is required at the following stages of the work in relation to machinery.

(A) When the tests of materials of main parts of machinery specified in Pt 2 of Rules for the Classification of Steel Ships are carried out.

(B) Main parts of machinery

(a) When the tests specified in either Pt 5 or Pt 6 of Rules for the Classification of Steel Ships according to the kind of machinery are carried out.

(b)

(c)

(d)

When the materials are assembled for construction of the parts and the parts are as-

sembled for installation on board.

When machining of the main parts is finished and, if necessary, at appropriate stages during machining.

In the case of welded construction, before welding is commenced and when it is completed.

(e) When the shop trials are carried out.

(C) When main parts of machinery are installed on board.

(D) When performance tests/onboard tests are carried out on measurement instruments, remote control devices of closing appliances, remote control devices for machinery and gears, auto- matic control devices, steering gear, mooring equipment, fire extinguishing equipments, pip- ing, etc.

(E) When deemed necessary by the Society.

(3) When performance tests are carried out on the installations for the specialized functional service of the Offshore Support Vessel.

(4) For Offshore Support Vessels with a dynamic positioning system, when components of the dy-

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Ch 2 Classification and Survey Ch 2

namic positioning system are installed on the Offshore Support Vessels and tests are carried out in accordance with the testing procedure.

4. Tests

At the Classification Survey during Construction, hydrostatic tests, leak tests, hose tests and per- formance tests, etc are to be carried out in accordance with the relevant requirements of this Guidance.

5. Sea trials and stability experiments

(1) For Classification Survey during Construction, the following tests are to be carried out if appli- cable in addition to the sea trials specified in Pt 1, Ch 1, 308. of Rules for the Classification of Steel Ships.

(A) For self-elevating Offshore Support Vessels, elevating and lowering tests of legs and decks and function tests of their safety devices; and where legs are not provided with bottom mats,

pre-loading tests on each leg to a load as near as possible to that of the strength cal-

culation for the leg.

(B) For Offshore Support Vessels with a dynamic positioning system, a function test of the dy- namic positioning system.

(2) Stability experiments

At the Classification Survey after Construction, stability experiments are to be carried out in ac- cordance with the requirements specified in Pt 1, Ch 1, 307. of Rules for the Classification of Steel Ships.

205. Classification survey after construction

1. General

At the Classification Survey after Construction, the examination of the hull, machinery and equip- ment are carried out as required for the Special Survey corresponding to the age, kind and purpose

of the Offshore Support Vessels and the actual scantlings, etc. of

Support Vessels are to be measured as necessary.

2. Submission of plans and documents

the main parts of Offshore

At the Classification Survey after Construction, plans and documents Classification Survey during Construction are to be submitted. If plans

as may be required for and documents cannot be

the ob-

tained, facilities are to be given for the Surveyor to take the necessary information from

Offshore Support Vessel.

3. Sea trials tests and stability experiments

the

At the Classification Survey after Construction, sea trials and stability experiments are to be carried out in accordance with the requirements specified in 204. 5. However, sea trials and stability experi- ments may be dispensed with provided that sufficient information based on previous tests is avail- able and neither alteration nor repair affecting sea trials and stability experiments has been made af- ter such previous tests.

206. Classification Survey of ships classed by other Societies

When a ship holding class with any Society which is subject to verification of compliance with QSCS(Quality System Certification Scheme) of IACS is intended for classification, plans and docu- ments to be submitted and survey items, etc. are to be in accordance with the Pt 1, Ch 1, 403. of Guidance relating to the Rules for the Classification of Steel Ships.