Section 2 Classification

201. Classification

Units built and surveyed for the classification in accordance with the Rules or in accordance with requirements deemed to be equivalent to the Rules by the Society will be assigned a class and reg- istered in the Register of Ships.

202. Class notations

The class will be distinguished by the class notations and the class notations assigned to the units 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, "Mobile Offshore Drilling Unit"

shall be assigned as a ship type notation and the following special feature notations shall be as- signed according to the type of unit.

(1) Self-elevating

(2) Column-stabilized

(3) Ship Type

(4) Barge Type

203. Maintenance of classification

1. Units 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 approved scantlings or arrangements of hull, machinery or equipment are to be submitted for approval by the Society before the work is com- menced 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 the Rules.

2. Submission of plan 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) Hull and hull equipments

(a)

Transverse section showing scantlings

(b) Longitudinal section showing scantlings

(c)

Deck construction plan(including details of well and helicopter deck)

(d) Framing

(e)

(f)

Shell expansion Final stability data

(g) Methods and locations for non-destructive testing

(h) Construction plan of watertight bulkheads and deep tanks indicating the highest position of tank and positions of tops of overflow pipes

(i)

(j)

Construction of leg, bottom mats, leg tanks and load transmitting parts of jacking sys-

tem, etc.

Construction of columns, lower hull, footings

(k) Construction of superstructures and deckhouses

(l)

Details of arrangement and closing devices of watertight doors and hatchways, etc.

(m) Seatings of boilers, main engines, thrust blocks, plummer blocks, dynamos and other im- portant auxiliary machinery

(n) Construction of machinery casings

(o) Construction of cargo handling appliances and its foundation

(p) Pumping arrangements

(q) Steering gear

(r)

(s)

(t)

Construction of fire protection Means of escape

Temporary mooring arrangements and towing arrangements

(u) Welding details and procedures

(v) Details of corrosion control arrangements

(w) Documents in respect of maintenance, corrosion control and inspection

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

(B) Machinery

(a)

For self-elevating unit, construction plan and operating diagram of jacking systems

(b) General arrangement of machinery spaces, boilers and pressure vessels, main and auxil- iary engines, shaftings, and auxiliary machinery and pipings, etc. specified in Pt 5, Ch

1 of Rules for the Classification of Steel Ships.

(c) 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.

(d) Fire extinguishing arrangements and inert gas system

(e)

(2) At the

Other plans and/or documents considered necessary by the Society

Classification Survey during Construction, the following plans and documents are to be

submitted to the Society for reference.

(A) Specifications

(B) General arrangement

(C) Summary of distributions of fixed and variable weights

(D) Plan indicating design loadings for all decks

(E) Preliminary stability data

(F) Structural analysis and calculation for relevant loading conditions

(G) Resultant forces and moments from wind, waves, current, mooring and other environmental loadings taken into account in the structural analysis

(H) Calculations for significant operational loads from derrick and other equipment

(I) For self-elevating unit, calculations substantiating adequacy of structure to transmit forces be- tween legs and hull through the jacking systems

(J) Evaluation of the unit's stability to resist overturning while bearing on the sea bed

(K) Lines or offsets

(L) Capacity plans and sounding tables of tanks

(M) Plans showing arrangement of watertight compartments, openings, their closing appliances, etc., necessary for calculation of stability

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

Submitted calculations are to dynamic response calculations required calculations.

be suitably referenced. Results from relevant model tests or may be submitted as alternatives or as substantiation for the

3. Presence of Surveyor

(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 Pt 4 of Rules for the Classification of Steel Ships are carried out.

(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, anchoring and mooring equipment, cargo handling appliances, fire detection systems, 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 each part of drilling derricks and sub-structures including supporting structures of drilling derricks is completed and drilling derricks and sub-structures are installed on board.

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

(N) When the sea trials are carried out.

(O) 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) For units not provided with propelling machinery

(a) When the tests specified in Ch 5, 209. are carried out. However, the presence of the surveyors at respective tests of apparatuses used for the systems specified in Ch 5, 104. may be modified in accordance with the usage of the apparatuses.

(b) When generators, prime movers for generators and essential auxiliaries are installed on board.

(c)

(B) For

(a)

When sea trials are carried out.

units provided with propelling machinery

When the tests specified in Ch 5, 209. are carried out.

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

(c)

Main parts of machinery

(i) When the tests prescribed in Pt 5 and

Ships according to the respective kind

6 of Rules for the Classification of Steel

of machinery are carried out.

(ii) When machining of the main parts is finished and, if necessary, at the proper stage

during machining.

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

(iv)When shop trials are carried out on main engines and generators.

(d) When main engines, generators and essential auxiliaries are installed on board.

(e) When performance tests/onboard

tests are carried out on measurement instruments, re-

mote control devices of closing appliances, remote control devices for machinery and

(f)

gears, automatic control devices,

ments, piping, etc.

When sea trials are carried out.

steering gear, jacking system, fire extinguishing equip-

(3) For column-stabilized units, when the draught scales are fitted.

(4) For units requiring the mooring system specified in Ch 4, Sec 2, 205. when that system is installed on the unit.

(5) For units with a dynamic positioning system, when components of the dynamic positioning sys- tem are installed on the units 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 the Rules.

5. Sea trials and stability experiments

(1) At the Classification Survey during Construction, the following tests of unit are to be carried out during the sea trial in addition to the

corresponding to the type relevant test items of sea

trials specified in Pt 1, Ch 1, 308. of the Rules for the Classification of Steel Ships.

(A) For self-elevating units, 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 calculation specified in Ch 6, 103.

(B) For column-stabilized units, a function test of the ballast system

(C) For units with the dynamic positioning system, performance tests of the dynamic positioning system.

(2) Stability experiments

(A) At the Classification Survey during Construction, stability experiments are to be carried out upon completion of the unit. In addition, a stability information booklet prepared on the ba- sis of the particulars of stability determined by the results of stability experiments is to be approved by the Society and provided on board.

(B) The stability experiments of an individual unit may be dispensed with, provided that reliable stability data can be obtained from the stability experiments of a similar unit and approval is given by the Society. However, the stability experiments for a column-stabilized unit are to be carried out even though the stability data is available from a similar unit.

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 unit and the actual scantlings, etc. of the main parts of the unit are to be measured as necessary.

2. Submission of plans and documents

At the Classification Survey after Construction, plans and documents as may be required for the Classification Survey during Construction are to be submitted. If plans and documents cannot be obtained, facilities are to be given for the Surveyor to take the necessary information from the unit.

3. Sea trials and stability experiments

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 ex- periments may be dispensed with provided that sufficient information based on previous tests is available and neither alteration nor repair affecting sea trials and stability experiments has been

made after such previous tests.

quired where deemed necessary similar unit.

The stability experiments for a column-stabilized unit may be re- by the Society even though the stability data is available from a