Full Text
REGD. No. D. L.-33004/99
EXTRAORDINARY
PART II—Section 3—Sub-section (i)
PUBLISHED BY AUTHORITY
NEW DELHI, TUESDAY, MAY 28, 2024/JYAISHTHA 7, 1946
3256 GI/2024 (1)
CG-DL-E-13062024-254679
CHAPTER 1
PRELIMINARY
1. Short title and commencement.— (1) These rules may be called the Inland Vessels (Design and Construction) Rules, 2024.
(2) Save as otherwise provided in these rules, they shall come into force on the date of their publication in the Official Gazette.
2. Application.— Unless otherwise specified, these rules shall apply to inland vessels which are required to be registered under the Inland Vessels Act, 2021 (24 of 2021) or to inland vessels operating in the inland waters of India.
3. Definitions.— (1) In these rules, unless the context otherwise requires,—
(a) “Act” means the Inland Vessels Act, 2021 (24 of 2021);
(b) “cargo vessel” means any mechanically propelled inland vessel which is not a passenger vessel;
(c) “classification society” means a recognised organisation within the meaning of clause (20) of section 3 of the Act which is a member of the International Association of Classification Societies;
(d) “deck vessel” means a vessel with a continuous watertight deck extending from stem to stern;
(e) “existing vessel” or “existing inland vessel” means any inland vessel which is not a new inland vessel as defined in clause (n);
(f) “freeboard” means the distance measured downwards vertically from the lowest point of the upper edge of the open deck to the waterline or, for an open boat, the distance measured downwards vertically from the lowest point of the upper strake to the waterline;
(g) “freeboard deck” means the uppermost complete deck exposed to weather and sea, which has permanent means of closing all openings in its exposed part, and below which all openings in the sides of the vessel are fitted with permanent means of watertight closing.
Explanation.— For the purpose of this clause, it is clarified that in an inland vessel with a discontinuous freeboard deck, the lowest line connecting the exposed part of the deck and the continuity of that line parallel to the upper part of the deck shall be taken as the freeboard.
(h) “gross tonnage” means the gross tonnage of a vessel calculated in accordance with the International Convention on Tonnage Measurement of Ships, 1969;
(i) “high speed vessel” means a vessel capable of attaining a speed of more than 21 nautical miles per hour in relation to the water area;
(j) “length” or “L” means the maximum length of the hull in meters;
(k) “length of waterline” or “LWL” means the length of the hull in meters measured at the maximum draught;
(l) “load line” shall have the same meaning as in clause (p) of section 3 of the Act;
(m) “major conversion or alteration” means—
(i) a change of more than ten per cent in the gross tonnage of the vessel; or
(ii) a change in the type of the vessel; or
(iii) a change in the propulsion system or the type of main engine or fuel,
as the case may be;
(n) “new inland vessel” means any inland vessel the keel of which is laid or which is at a similar stage of construction on or after the date of coming into force of these rules;
(o) “open vessel” or “open boat” means an inland vessel which—
(i) is not fitted with a watertight open deck in its length; or
(ii) is fitted with a watertight open deck in its length; or
(iii) is fitted with a watertight open deck throughout its length, but the deck does not meet the minimum requirement for freeboard, freeboard;
(p) “residual freeboard” means the available vertical clearance in the event of the vessel tilting, at the lowest point of the submerged part of the hull between the level of the water and the upper surface of the deck or, if there is no deck, at the lowest point of the upper surface of the side of the fixed vessel;
(q) “Schedule” means the Schedule annexed to these rules;
(r) “standards for design and construction of inland vessels” means the standards and design specified in the Schedule annexed to these rules;
(s) “twin vessel” means a vessel constructed with similar designs;
(2) Words and expressions used in these rules and not defined but defined in the Act shall have the same meanings as assigned to them in the Act.
CHAPTER 2
CLASSIFICATION AND COMPLIANCE
4. Classification of inland vessels.— For the purposes of these rules, inland vessels shall be classified as per the following categories, namely:—
(1) Category 'A' vessels which are deck vessels of any type and operating in Zone 1, namely:—
(a) other vessels than houseboats, whose length is more than twenty-four meters and houseboats, whose length is more than thirty meters;
(b) vessels carrying more than fifty passengers;
(c) all vessels equipped for towing other vessels, whose bollard pull capacity is more than ten tons;
(d) vessels designed and constructed for carrying petroleum products, chemicals or liquefied gases in bulk as cargo;
(e) vessels carrying dangerous goods; and
(f) vessels of three hundred gross tonnage and above.
(2) Category 'A' vessels shall be designed, constructed and surveyed in accordance with the standards and design specified in the Schedule and shall be designed and constructed under the survey of a classification society:
Provided that the survey by the classification society shall be in addition to the survey conducted by the surveyor appointed under section 10 of the Act.
(3) Category 'B' vessels are those which do not fall under Category 'A' vessels or Category 'C' vessels, and whose design, construction and maintenance shall be carried out in accordance with the standards and design specified in the Schedule under the survey of a classification society or the designated authority.
(4) Category 'C' vessels are those whose length is less than 10 meters, and whose design, construction and maintenance shall be carried out in accordance with the standards and design specified in the Schedule or under the survey of the designated authority.
(5) Open vessels operating in Zone 1 and Zone 2:
Provided that due regard shall be given to the operating restrictions imposed by the local authorities by the Master.
5. Extent of compliance.— (1) All existing inland vessels shall comply with the existing requirements before the coming into force of these rules:
Provided that existing inland vessels undergoing major conversion or alteration shall comply with the requirements specified in these rules to the extent deemed appropriate and practicable by the designated authority, and in the case of propulsion system or type of main engine or fuel, these rules shall apply only to such equipment and system.
(2) Notwithstanding anything contained in sub-rule (1), existing inland vessels shall comply with the requirements of stability information and freeboard calculation as provided in rules 13 and 15 within two years from the date of coming into force of these rules.
(3) Subject to sub-rule (1), the owner or operator and master of a new vessel shall ensure that its construction, maintenance and operation are in accordance with the requirements of these rules and that it is suitable for its intended service.
(4) No survey certificate shall be issued to any new inland vessel under the Act, unless such vessel complies with the standards of design and construction requirements specified in the Schedule.
6. Material.— (1) All materials used for the construction of Category 'A' and Category 'B' vessels shall be in accordance with the requirements and testing standards specified in the Schedule.
(2) Materials used for the construction of Category 'C' vessels shall be in accordance with the standards deemed appropriate by the designated authority.
7. Equipment standards and guidance.— The type of equipment and machinery required to be carried on board shall be in accordance with the standards of the Bureau of Indian Standards or the International Standards Organisation.
CHAPTER 3
SHIP CONSTRUCTION, FITTINGS AND EQUIPMENT
8. General applicability.— (1) The requirements of this Chapter include minimum requirements related to structure, strength, freeboard, subdivision and stability, machinery, bilge system and electrical installations.
(2) This Chapter specifies the minimum requirements which vessels shall comply with in accordance with the standards and design specified in the Schedule.
9. Design, strength and structural arrangement.— (1) The structural strength of mechanically propelled inland vessels shall be suitable for the intended service and operating area, and Category 'A' vessels shall comply with the structural requirements, standards and design specified in the Schedule.
(2) The structural strength and scantlings of Category 'C' vessels made of fiber reinforced plastic and wooden material shall be subject to the requirements of a classification society acceptable to the designated authority.
(3) The general structural arrangement, scantlings and construction of the hull shall be in accordance with the following criteria, namely:—
(a) nature and characteristics of the materials used, their application and method of combination;
(b) type of vessel, its dimensions, its internal arrangement and permissible maximum operating draught; and
(c) the forces to which it is subjected and any specific distribution of load on board, including navigation.
(4) The structural strength of the vessel shall be in accordance with the assigned maximum permissible draught, in accordance with the adjusted freeboard of the vessel.
10. Watertight subdivision and general arrangement.— (1) Watertight bulkheads, terminating at the freeboard deck or where there is no such deck, up to the upper strake, shall be installed in the following condition, namely:—
(a) The collision bulkhead shall be installed at a distance of between 0.04 L and 0.1 LWL measured from the forward perpendicular of the vessel and, if the bulkhead is fitted aft of the limits specified above, it shall be demonstrated by calculation that
the vessel shall remain buoyant with a residual freeboard of at least 100 mm in the event of flooding in the space forward of the collision bulkhead;
(b) The aft freeboard bulkhead shall be installed at a distance of between 1.4 m and 0.04 L + 2 m measured from the aft perpendicular of the intersection of the hull with the maximum draught line and, if the bulkhead is fitted forward of the limits specified above, it shall be demonstrated by calculation that the vessel shall remain buoyant with a residual freeboard of at least 100 mm in the event of flooding in the space aft of the aft freeboard bulkhead.
(2) Accommodation spaces or installations, stabilization and steering equipment necessary for vessel safety or operation shall not be located forward of the collision bulkhead or aft of the aft freeboard bulkhead, as the case may be.
(3) Accommodation spaces, engine rooms, boiler rooms and working spaces forming part thereof shall be separated from cargo holds by watertight transverse bulkheads extending to the freeboard deck.
(4) Accommodation spaces, engine rooms, boiler rooms and holds shall be separated and directly accessible from the deck.
(5) If such an arrangement is not provided, an emergency exit leading directly to the open deck shall be provided, in addition to the normal means of access.
(6) There shall be no doors in the bulkheads mentioned in sub-rule (1) for the separation of the areas specified in sub-rule (3), namely:—
(a) The number of pipes passing through the collision bulkhead shall be as few as possible and shall be fitted with suitable valves operable from above the freeboard deck and the valve chest shall be secured to the bulkhead within the fore end of the vessel:
Provided that the designated authority may permit the fitting of suitable valves on the aft part of the collision bulkhead if such valves are readily accessible and the spaces where they are located are not cargo spaces;
(b) Doors in the aft freeboard bulkhead and in the forepeak, especially for shafts, shaft
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451 THE GAZETTE OF INDIA : EXTRAORDINARY [PART II—SEC. 3(i)]
CHAPTER 4
VIBRATION AND ALIGNMENT
4.1 SCOPE
4.1.1 The requirements of this Chapter apply to main propulsion systems of 200 [kW] and above and to auxiliary machinery systems for essential services with a power of 200 [kW] and above.
4.1.2 Unless otherwise advised, it is the responsibility of the main contractor to ensure that the information required by this Chapter is prepared and submitted in cooperation with the engine manufacturers.
4.2 BASIC SYSTEM REQUIREMENTS
4.2.1 Systems shall be free from excessive torsional, axial and lateral vibration, and shall be aligned in accordance with the relevant manufacturer's tolerances.
4.2.2 Where subsequent changes are made to a dynamic system, which have been approved, revised calculations shall be submitted for consideration.
4.3 FLEXIBLE MOUNTING
4.3.1 Where machinery is installed on flexible mountings, linear vibration (steady state and transient) shall not exceed the tolerances of the machinery manufacturers or the flexible mountings.
4.3.2 Such vibration shall not impose excessive loads on the machinery components within the misaligned system.
4.4 TORSIONAL VIBRATION
4.4.1 Calculations of dynamic systems, including all their branches, for diesel engines, turbines, motors, generators, flexible couplings, gearings, shafting and propellers, where applicable, including torsional torque and stress analysis, with related diagrams, shall be submitted for approval.
4.4.2 For turbines over the full speed range, or from all intended combinations of diesel engine installations with more than one engine, and/or details of power distribution with power take-off systems, shall be submitted.
4.4.3 Any special speed requirements for long periods in service shall be indicated, e.g., controllable pitch propeller, idle speed, etc., and limits of operation per minute.
4.4.4 Calculations and/or measurements made on diesel engine installations with transmission items sensitive to torsional torque, e.g., gearings, flexible couplings, or generator rotors and their drives, taking into account the effects of engine malfunction normally experienced in service, such as cylinders not firing.
4.4.5 Restricted speed limits shall be applied in speed ranges where continuous operation is considered to cause excessive stress. Where excessive torsional torque is considered for specific machinery components, similar restrictions shall be applied, or other safety measures may be required.
4.4.6 Where calculations indicate the possibility of excessive torsional vibration within the limits of operating speeds, torsional vibration measurements may be required to be taken from the machinery installation for the purpose of determining the need for restricted speed limits, using appropriate recognized techniques.
4.5 AXIAL VIBRATION
4.5.1 For all main propulsion shafting systems, the shipbuilder shall ensure that the amplitude of axial vibration is satisfactory over the full speed range, as far as practicable. Where appropriate, the use of vibration dampers or phasing of propellers and engines, etc., may reduce the amplitude.
4.5.2 Unless previous experience of similar installations shows it to be unnecessary, calculations of the shafting system shall be carried out. These
452 THE GAZETTE OF INDIA : EXTRAORDINARY [PART II—SEC. 3(i)]
calculations shall include the effects of the thrust block seating and adjacent hull structure participating in the vibration. The results of these calculations, or evidence of previous experience, shall be submitted for consideration.
4.5.3 Where calculations indicate the possibility of excessive axial vibration amplitudes within the limits of operating speeds, axial vibration measurements may be required to be taken from the shafting system for the purpose of determining the need for restricted speed limits, using appropriate recognized techniques.
4.6 LATERAL VIBRATION
4.6.1 For all main propulsion shafting systems, the shipbuilder shall ensure that the amplitude of lateral, or bending, vibration is satisfactory over the full speed range.
4.6.2 Unless previous experience of similar installations shows it to be unnecessary, calculations of the lateral, or bending, vibration characteristics of the shafting system shall be carried out. These calculations, taking into account dynamic bearing stiffness, are to cover all critical speeds producing significant amplitudes within the speed range, and also indicate relative deflections and bending moments over the full shafting system.
4.6.3 The results of these calculations, or evidence of previous experience, shall be submitted for consideration.
4.6.4 Where calculations indicate the possibility of excessive lateral vibration amplitudes within the limits of operating speeds, lateral vibration measurements may be required to be taken from the shafting system for the purpose of determining the need for restricted speed limits, using appropriate recognized techniques.
4.7 SHAFT ALIGNMENT
4.7.1 For main propulsion installations, the shafting shall be aligned to give acceptable bearing reactions and bending moments over all conditions of vessel loading and operation. The shipbuilder shall position bearings appropriately and construct bearing seats to minimize the effects of movements under all operating conditions.
4.7.2 For geared installations, where two or more pinions are driving a final reduction wheel, calculations shall be submitted to verify that the shaft alignment is such that acceptable bearing reactions are maintained under all operating conditions.
4.7.3 Verification of shaft alignment shall be by measurement.
CHAPTER 5
BOILERS AND PRESSURE VESSELS
CONTENTS
SECTION
1 GENERAL
SECTION 1
GENERAL
1.1 SCOPE
1.1.1 The requirements of this Chapter apply to seamless and fusion welded pressure vessels for the following uses, and to their mountings and fittings:
(a) Fire tube boilers;
(b) Exhaust gas heated boilers;
[PART II—SEC. 3(i)] THE GAZETTE OF INDIA : EXTRAORDINARY 453
(c) Economizers, superheaters, reheaters and steam receivers associated with (a) and (b);
(d) Steam heated steam generators;
(e) Other pressure vessels not included in (a) to (d).
1.1.2 Arrangements or details of boilers, pressure vessels and equipment which can be shown to comply with other recognized standards may be considered, provided they are not less effective.
1.2 DESIGN PRESSURE
1.2.1 The design pressure is the maximum permissible working pressure and shall not be less than the highest set pressure of any safety valve.
1.2.2 Calculations for the scantlings of pressurized parts are based on the design pressure, where pressure differences are adjusted taking into account the most severe operating conditions.
1.2.3 It is desirable that the normal pressure range in which the boiler or pressure vessel operates is between the design pressure and such a lower pressure at which a safety valve is set to lift, so as to prevent unnecessary lifting of safety valves.
1.3 METAL TEMPERATURE
1.3.1 The metal temperature, T, used for evaluating the permissible stress shall be taken as the actual metal temperature expected under operating conditions for the relevant pressurized part, which shall be stated by the manufacturer when the plans of the pressurized parts are submitted for consideration.
1.3.2 For boilers, the design metal temperature shall not be taken less than the following values, unless such is justified by accurate calculation of temperature drop and in no case shall it be less than 250 degrees Celsius:
(a) For steam heated steam generators, double evaporation boilers, steam receivers and pressure parts of gas heated pressure vessels which are not heated by hot gases and are adequately protected by insulation, the metal temperature, T, shall be taken as the maximum temperature of the internal fluid;
(b) For pressure parts heated by hot gases, T shall not be taken less than 25 degrees Celsius above the maximum temperature of the internal fluid;
(c) For combustion chambers of the wet-back type used in horizontal wet-back boilers, T shall not be taken less than 50 degrees Celsius above the maximum temperature of the internal fluid;
(d) For furnaces, fireboxes, rear-tube plates of dry-back boilers and pressure parts subject to similar rates of heat transfer, T shall not be taken less than 90 degrees Celsius above the maximum temperature of the internal fluid;
(e) For boiler, superheater, reheater and economizer tubes, the design temperature shall be taken as follows: For boiler tubes, the design temperature shall be mainly saturated steam temperature plus 25 degrees Celsius for tubes subject to convection heat or mainly radiant heat plus 50 degrees Celsius;
Superheater and reheater tubes, the design temperature shall not be taken less than the estimated steam temperature of the part under consideration, which shall also include 35 degrees Celsius for tubes mainly subject to convection heat. Mainly radiant heat,
454 THE GAZETTE OF INDIA : EXTRAORDINARY [PART II—SEC. 3(i)]
the design temperature for tubes subject to radiant heat shall not be taken less than the estimated steam temperature of the part under consideration, which shall also include 50 degrees Celsius, but the estimated actual metal temperature shall be stated when the plans are submitted;
Economizer tubes, the design temperature shall not be less than 35 degrees Celsius above the maximum temperature of the internal fluid.
1.3.3 Generally, any part of boiler drums or headers not protected by tubes, and exposed to radiation in contact with fire or hot gases, shall be protected by suitable refractory material or other approved means.
1.3.4 Drums and headers with a thickness greater than 30 [mm] in contact with hot gases with an estimated temperature greater than 650 degrees Celsius shall not be allowed, unless they are efficiently cooled by closely arranged tubes.
1.4 PLANS AND DETAILS
1.4.1 Where applicable, the following plans shall be submitted in triplicate for approval for boilers and pressure vessels:
(a) General arrangement with valve and fitting arrangement;
(b) Sectional assembly;
(c) Seating arrangement;
(d) Steam, water drum and header details;
(e) Water wall details;
(f) Steam and superheater tubing, with tube support arrangement;
(g) Economizer details;
(h) Casing arrangement;
(i) Reheat section;
(j) (Fuel oil burning arrangement;)
(k) Forced draft system;
(l) Boiler mountings including steam stop valve, safety valve and their relieving capacity, feed water connection, blow-off arrangement, water gauge, test cock, etc.
1.4.2 In the plans, where applicable, the following details shall be included:
(a) Scantlings;
(b) Materials;
(c) Weld details;
(d) Design pressure and temperature;
(e) Heating surface areas of boilers and superheaters;
(f) Estimated pressure drop through superheater;
(g) Estimated evaporation rate;
(h) Proposed setting pressure of safety valves on steam drum and superheater;
(i) Pressure vessel class;
(j) Details of heat treatment and testing of welds;
(k) Calculation of thickness, when necessary; and
(l) Test pressure.
1.5 CLASSIFICATION OF PRESSURE VESSELS
1.5.1 For Rule purposes, boilers and pressure vessels are classified as shown in Table 1.5.1.
1.5.2 Pressure vessels manufactured according to the requirements of Class 2 or Class 3, if manufactured according to the requirements of a higher class, shall be approved with scantlings suitable for that class.
[PART II—SEC. 3(i)] THE GAZETTE OF INDIA : EXTRAORDINARY 455
TABLE 1.5.1 : GRADING OF PRESSURE VESSELS
Boiler | Steam-heated Generators | Other Pressure Boilers
Class 1 | p > 3.5 | Di > (15/p - 1) * 1000 | P > 50 or t > 38
Class 2 | p ≤ 3.5 | Di < (15/p - 1) * 1000 | P ≤ 50 or Di > (20/p - 1) * 1000 and 16 < t ≤ 38 or material temperature >
permissible axial loads and buckling strength are to be calculated in accordance with Chapter 3, Section 6. In calculating sectional properties the width of attached plating is not to be taken in excess of 40 times the plate thickness. Also see Chapter 8, Section 5.1.1.
Section 4
Design Loads
4.1 Watertight bulkhead loads
4.1.1 The design pressure 'p', for ordinary watertight bulkheads is given by:
p = 10 h [kN/m2]
where,
h = the vertical distance [m] from the loadpoint to the uppermost continuous deck.
4.1.2 For bulkheads bounding cargo spaces intended to carry dry bulk cargoes, the design pressure 'p' is to be taken as the higher of that given in 4.1.1 and the pressure due to bulk cargo as given below:
p = 12.5 C hc [kN/m2]
where,
C = Sin2 Tan2(45 - /2)+Cos2
= angle made by the panel under consideration with the horizontal plane [deg.]
= angle of repose of cargo [deg.] not to be taken greater than the following
20 for light bulk cargo (e.g. coal, grain)
25 for bulk cement cargo
35 for heavy bulk cargo (e.g. ore)
hc = vertical distance [m], from the loadpoint to the mean horizontal plane corresponding to actual volume of cargo being considered
= density of cargo [t/m3].
For vessels designed to carry heavy bulk cargoes which are also required to carry lighter cargoes, the pressure 'p' based on maximum mass of cargo to be carried in the hold and filled up to the top of hatch coaming would also require to be considered.
4.2 Tank bulkhead loads
4.2.1The design pressure 'p' for tank bulkheads are normally to be taken as the greater of
p = 12.5 hs [kN/m2]
= 6.7 hp [kN/m2]
= 10 (hs + 1) [kN/m2]
where,
hp = vertical distance [m] from the loadpoint to the top of the air pipe.
hs = vertical distance [m] from the loadpoint to the top of the tank or hatchway.
For very large tanks which may be partially filled, sloshing pressures may have to be considered.
4.2.2 The pressure 'p' on girder web panels in cargo tanks or ballast tanks is not to be taken as less than 20 [kN/m2].
4.3 Wash bulkheads loads
4.3.1 The design pressure 'p' for wash bulk-heads may be taken as 50% of that for boundary bulkhead in the same location.
Section 5
Plating and Stiffeners
5.1 Bulkhead plating
5.1.1 The thickness 't' of the bulkhead plating is not to be less than the minimum thickness given in 5.1.2 nor less than
t = 15.8s * sqrt(p/) * 10^-3 + tc [mm]
where,
p = applicable design pressure as given in Section 4.
= as per Table 5.1.1 for longitudinal bulkheads.
= 160/k for transverse tank bulkheads and collision bulkhead;
= 220/k for ordinary transverse watertight bulkheads.
= 190/k for transverse dry bulk cargo bulkheads
5.1.2 The minimum thickness requirement of the bulkhead plating is given by
t = (4.0 + 0.01L) + tc [mm]
5.1.3 The plate thickness of corrugated bulkheads is not to be less than that required according to 5.1.1 and 5.1.2. The spacing 's' to be used in the calculation of the plating thickness is to be taken as the greater of 'b' or 'c' where 'b' and 'c' are indicated in Figure 5.1.3.
For built up corrugation bulkheads, where the thickness of the flange and web are different, the thickness of the wider plating is also not to be less than :
Table 5.1.1 : '' values for longitudinal bulkhead plating
Region | Framing system | At neutral axis | At strength deck or at bottom | Between neutral axis and strength deck or bottom
0.4L amidships | Vertical | 140/k | (175-130 fs)/k max. 120/k | To be obtained by linear interpolation
Longitudinal | 160/k | (185-105 fs)/k max. 120/k | To be obtained by linear interpolation
Within 0.1L from ends | 160/k | 160/k | 160/k |
Elsewhere | to be obtained by linear interpolation between allowable values at regions specified above.
t = sqrt(s^2 * p^2 / (2 * ^2) - (ta - tc)^2) + tc [mm]
where,
ta = thickness of adjacent plating [mm] not to be taken greater than t.
5.1.4 The longitudinal bulkhead plating within 0.1D from bottom or strength deck is also to comply with the requirements of buckling strength given in Chapter 3, Section 6.
5.1.5 In way of stern tubes, doubling plate of same thickness as the corresponding strake is to be fitted, or the strake thickness is to be increased by at least 60 per cent.
5.2 Longitudinals
5.2.1 The section modulus of continuous longitudinal stiffeners and corrugations is not to be less than:
Z = s * p * l^2 / (m * ) + Zc [cm3]
where,
p = applicable design pressure given in Section 4.
m = 12
= (215 - 145 fs)/k, max. 160/k [N/mm2] at deck/bottom level within 0.4L amidships
= 160/k at neutral axis within 0.4L amidships
= 160/k for longitudinals within 0.1L from ends.
For longitudinals between the regions specified above may be obtained by linear interpolation.
5.2.2 The thickness of the web and flange is not to be less than the minimum plating thickness requirements stipulated in 5.1.2.
5.2.3 The rule section modulus of a corrugated bulkhead element is to be obtained according to 5.2.1 taking 's' as shown in Figure 5.1.3.
5.2.4 The actual section modulus of a corrugated bulkhead element may be obtained in accordance with the following:
Z_actual = t * d * (b + c/3) / 2000 [cm3]
where, t,d,b and c [mm], are as shown in Figure 5.1.3.
5.3 Vertical and transverse stiffeners on tank bulkheads, collision bulkheads, dry bulk cargo bulkheads and wash bulkheads
5.3.1 The section modulus of bulkhead stiffeners is not to be less than:
Z = s * p * l^2 / (m * ) + Zc [cm3]
where,
p = applicable design pressure [kN/m2] given in Section 4.
m = 10 for transverse stiffeners and vertical stiffeners which may be considered fixed at both ends
= 7.5 for vertical stiffeners simply supported at one or both ends
= 10 for horizontal corrugation fixed at ends
= 13 for fixed upper end of vertical corrugation
= 20 for non-fixed upper end of vertical corrugation
= 10 for lower end of vertical corrugation
= 160/k for tank bulkhead and collision bulkhead
= 210/k for dry bulk cargo bulkheads.
5.3.2 The thickness of web and flange is to be as required in 5.1.2.
5.3.3 Actual section modulus of corrugations is to be obtained as per 5.2.4.
5.3.4 Brackets are normally to be fitted at the ends of non-continuous stiffeners. Where stiffeners are sniped at the ends, the thickness of the plating supported by the stiffeners is not to be less than:
t = 0.0395 [(l - 0.0005s) s.p.k] + tc [mm]
5.4 Vertical and transverse stiffeners on ordinary watertight bulkheads
5.4.1 The section modulus of bulkhead stiffeners is not be less than
Z = s * p * l^2 / (m * )
where,
p = applicable design pressure given in Section 4.
m = 16 for stiffeners fixed at both ends
= 12 for stiffeners fixed at one end (lower end in case of vertical stiffeners) and simply supported at the other end.
= 8 for stiffeners simply supported at both ends.
= 220/k
5.4.2 The thickness of web and flange is to be as required in 5.1.2. For sniped ends, the thickness of bulkhead plating is to be as per 5.3.4.
5.4.3 Actual section modulus of corrugations is to be obtained as per 5.2.4.
Section 6
Girders
6.1 General
6.1.1 Bulkhead stringers and deep transverses are to be arranged in line with other primary supporting structure to the adjoining deck, side shell and bottom so as to facilitate the formation of continuous ring structures. Otherwise equivalent scarphing arrangement is to be provided.
6.1.2 The section modulus requirement 'Z' of simple girders is not to be less than:
Z = b * p * S * l^3 / (m * ) + Zc [cm3]
where,
m = 12 for continuous longitudinal girders with end attachments in accordance with Chapter 3, Section 5.
= 10 for other girders with end attachments in accordance with Chapter 3, Section 5.
= (190 - 45fS), max 160/k [N/mm2], for continuous longitudinal girders within 0.4L amidships.
= 160/k [N/mm2] for continuous longitudinal girders within 0.1L from ends and for vertical or transverse girders on tank and collision bulkheads.
= 210/k for vertical and transverse girders, in general.
For continuous longitudinal girders between the regions specified above, '' may be obtained by linear interpolation.
6.1.3 The depth of the girders should not be less than 2.5 times the depth of the cutout (if any) for the passage of continuous stiffeners. The net cross sectional area 'A' of the girder web at ends is not to be less than
A = CkSbp + 0.01 dw tc [cm2]
where,
C = 0.060 for tank and collision bulkheads
C = 0.045 for other watertight bulkheads
dw = depth of web [mm].
However, for lower end of vertical girders value of C to be taken as 0.08 and 0.06 respectively.
6.1.4 Tripping brackets are to be fitted in accordance with the requirements given in Chapter 3, Section 4.
Chapter 10
Superstructures, Deckhouses and Bulwarks
Contents
Section
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