5.1 General requirements
5.1.1 Bulwarks or guard-rails are to be provided at the boundaries of exposed freeboard and superstructure decks and first tier deckhouses. Bulwarks or guard-rails are to be not less than 1,0 m in height measured above sheathing, and are to be constructed as required by 5,2. Consideration will be given to cases where this height would interfere with the normal operation of the ship.
5.1.2 The freeing arrangements in bulwarks are to be in accordance with 5.3.
5.1.3 The opening below the lowest course of guard-rails is not to exceed 230 mm. The other courses are to be spaced not more than 380 mm apart. In the case of ships with rounded gunwales, the guard-rail supports are to be placed on the flat of the deck.
ks sb
RULES ANDREGULATIONS FOR THECLASSIFICATION OFSHIPS, July 2000
Superstructures, Deckhouses and Bulwarks
Part 3, Chapter 8
Sections 2 to 5
LLOYD’SREGISTER OFSHIPPING
4
Item Percentage increase
Fronts, sides, aft ends, unsheathed
deck plating 20
Decks sheathed in accordance
with 2.3.2 10
Deck sheathed with wood, and on which the plating is fixed to the wood sheathing at the centre of each
beam space Nil
Stiffeners and beams 70
Scantlings of small isolated houses Nil
5.1.4 Satisfactory means, in the form of guard-rails, life- lines, handrails, gangways, underdeck passageways or other equivalent arrangements, are to be provided for the protection of the crew in getting to and from their quarters, the machinery space and all other parts used in the necessary work of the ship in accordance with Table 8.5.1.
5.1.5 Chains are only permitted in short lengths in way of access openings.
5.1.6 Where gangways on a trunk are provided by
means of a stringer plate fitted outboard of the trunk side bulk- heads (port and starboard), each gangway is to be a solid plate, effectively stayed and supported, with a clear walkway at least 450 mm wide, at or near the top of the coaming, with guard rails complying with 5.1.3 and hatch cover securing appliances accessible from the gangway.
5.1.7 Where permitted by the National Authority, gang- ways or walkways may be omitted on ships engaged on protected or extended protected water service. However, life- lines are to be provided on tankers and flush deck ships, or where the cargo hatch coamings are less than 600 mm high.
5.1.8 For a Type ‘A’ ship with freeboards assigned greater than, or equal to, Type ‘B’, a life-line may be provided in lieu of a walkway.
5.2 Bulwark construction
5.2.1 Plate bulwarks are to be stiffened by a strong rail section and supported by stays from the deck. The spacing of these stays forward of 0,07L from the forward perpendicular is to be not more than 1,2 m on Type ‘A’, Type ‘B-60’ and Type ‘B-100’ ships (as defined in Ch 11,1.1), and not more than 1,83 m on other Types. Elsewhere, bulwark stays are to be not more then 1,83 m apart. Where bulwarks are cut to form a gangway or other opening, stays of increased strength are to be fitted at the ends of the openings. Bulwarks are to be adequately strengthened in way of eyeplates for cargo gear, and in way of mooring pipes the plating is to be doubled or increased in thickness and adequately stiffened.
5.2.2 Bulwarks should not be cut for gangway or other openings near the breaks of superstructures, and are also to be arranged to ensure their freedom from main structural stresses. See shell plating in appropriate Chapters.
5.2.3 The section modulus, Z, at the bottom of the bulwark stay is to be not less than:
Z = (33,0 + 0,44L) h2s cm3
where
h = height of bulwark from the top of the deck plating to the top of the rail, in metres
s = spacing of the stays, in metres, in accordance
with 5.2.1
L = length of ship, in metres (as defined in Ch 1,6.1),
but to be not greater than 100 m.
5.2.4 In the calculation of the section modulus, only the material connected to the deck is to be included. The bulb or flange of the stay may be taken into account where connected to the deck, and where, at the ends of the ship, the bulwark plating is connected to the sheerstrake, a width of plating not exceeding 600 mm may also be included. The free edge of the stay is to be stiffened.
5.2.5 Bulwark stays are to be supported by, or to be in line with, suitable underdeck stiffening, which is to be connected by double continuous fillet welds in way of the bulwark stay connection.
5.2.6 It should be noted that the above requirements do not allow for any loading from deck cargoes.
5.3 Freeing arrangements
5.3.1 The requirements of 5.3.2 to 5.3.11 apply to ships of Type ‘B’. Additional requirements applicable to ships of Type ‘A’, Type ‘B-100’ and Type ‘B-60’ are indicated in 5.3.15 to 5.3.17. The ship Types are as defined in Ch 11,1.1.
5.3.2 Where bulwarks on the weather portions of free- board or superstructure decks form wells, ample provision is to be made for rapidly freeing the decks of large quantities of water by means of freeing ports, and also for draining them.
5.3.3 The minimum freeing area on each side of the ship, for each well on the freeboard deck or raised quarterdeck, where the sheer in the well is not less than the standard sheer required by the International Convention on Load Lines,1966, is to be derived from the following formulae:
(a) where the length, l, of the bulwark in the well is 20 m or
less:
area required = 0,7 + 0,035l m2
(b) where the length,l , exceeds 20 m:
area required = 0,07l m2
l need not be taken greater than 0,7LL, where LLis the length of the ship as defined in Ch 1,6.1.
5.3.4 If the average height of the bulwark exceeds 1,2 m or is less than 0,9 m, the freeing area is to be increased or decreased, respectively, by 0,004 m2per metre of length of
well for each 0,1 m increase or decrease in height respectively.
5.3.5 The minimum freeing area for each well on a first tier superstructure is to be half the area calculated from 5.3.3.
5.3.6 Two-thirds of the freeing port area required is to be provided in the half of the well nearest to the lowest point of the sheer curve.
5.3.7 When the deck has little or no sheer, the freeing area is to be spread along the length of the well.
5.3.8 In ships with no sheer the freeing area as calculated from 5.3.3 is to be increased by 50 per cent. Where the sheer is less than the standard, the percentage is to be obtained by linear interpolation.
Superstructures, Deckhouses and Bulwarks
Part 3, Chapter 8
5.3.11 Where a ship fitted with bulwarks has a continuous trunk, or hatch side coamings that are continuous, or substan- tially continuous, the minimum freeing area is to be not less than 20 per cent of the total bulwark area where the width of trunk or hatchway is 0,4B or less, and not less than 10 per cent of the total bulwark area when the width of the trunk or hatch is 0,75B or greater. The freeing area required for an intermediate width of trunk or hatch is to be obtained by linear interpolation.
5.3.9 Where the length of the well is less than 10 m, or where a deckhouse occupies most of the length, the freeing port area will be specially considered but in general need not exceed 10 per cent of the bulwark area.
5.3.10 Where it is not practical to provide sufficient free- ing port area in the bulwark, particularly in small ships, credit can be given for bollard and fairlead openings where these extend to the deck.
RULES ANDREGULATIONS FOR THECLASSIFICATION OFSHIPS, July 2000
Superstructures, Deckhouses and Bulwarks
Part 3, Chapter 8
Section 5
LLOYD’SREGISTER OFSHIPPING
6
Table 8.5.1 Protection of crew
Location in ship (On exposed freeboard deck or
raised quarter deck)
1. Between poop and bridge
or
Between poop and deckhouse containing living accommodation or navigating equipment or both
2. Between poop and forecastle (if there is no bridge) or
Between bridge and forecastle or
Between a deckhouse containing living accommodation, or navigating equipment or both,
and forecastle or
In the case of a flush deck vessel, between crew accommodation and the forward and after ends of the ship
Assigned Summer Freeboard, in mm Acceptable arrangements according to type of freeboard assigned Type A Type (B-100) Type (B-60) Type (B & B +) < 3000 a b a b a b c(1) > 3000 a b a b a b c(1) & (2) < 3000 a b c(1) a b c(1) & (2) a b c(1) & (2) > 3000 a b c(1) d(1) a b c(1) & (2) d(1) & (2) a b c(1), (2) & (4) d(1), (2) & (3) a b c(1), (2) & (4) d(1), (2) & (3) Acceptable arrangements:
Acceptable arrangements referred to in the Table are defined as follows:
a A well-lighted and ventilated underdeck passage (clear opening 0,8 m wide, 2 m high) as close as practicable to the freeboard deck, connecting and providing access to the locations in question.
b On or near the centreline of a ship a permanent and efficiently constructed gangway fitted at the level of the superstructure deck, providing a continuous platform at least 0,6 m in width and a non-slip surface, with guard rails extending on each side throughout its length. Guard- rails are to be at least 1 m high with courses as required in 5.1, and supported by stanchions spaced not more than 1,5 m; a foot-stop is to be provided.
c A permanent passageway at least 0,6 m in width fitted at deck level consisting of two rows of guard-rails with stanchions spaced not more than 3 m. The number of courses of rails and their spacing to be as required by 5.1. On Type B ships, hatchway coamings not less than 0,6 m in height may be regarded as forming one side of the passageway, provided that between the hatchways two rows of guard-rails are fitted.
d A 10 mm minimum diameter wire rope life-line supported by stanchions about 10 m apart, or a single handrail or wire rope attached to hatch coamings, continued and adequately supported between hatchways.
Alternative transverse locations for 'c' and 'd':
(1) At or near centreline of ships; or
fitted on hatchways at or near centreline of ship (2) Fitted on each side of the ship
(3) Fitted on one side, provision being made for fitting on either side (4) Fitted on one side only
NOTES
1. In all cases where wire ropes are fitted, adequate devices are to be provided to ensure their tautness. 2. In all cases a proper step arrangement is to be provided in way of obstructions such as pipe lines, etc. 3. Where stanchions are fitted, every third stanchion is to be supported by a bracket or stay.
5.3.12 Where the trunk referred to in 5.3.11 or its equivalent is included in the calculation of freeboard, open rails are to be fitted for at least 50 per cent of the length of the exposed part of the weather deck. Alternatively, if a continuous bulwark is fitted, the minimum freeing area is to be at least 33 per cent of the bulwark area. The freeing area is to be placed in the lower part of the bulwark.
5.3.13 Where a deckhouse has a breadth less than 80 per cent of the beam of the ship, or the width of the side passageways exceed 1,5 m, the arrangement is considered as one well. Where a deckhouse has a breadth equal to or more than 80 per cent of the beam of the ship, or the width of the side passageways does not exceed 1,5 m, or when a screen bulkhead is fitted across the full breadth of the ship, this arrangement is considered as two wells, before and abaft the deckhouse.
5.3.14 Adequate provision is to be made for freeing water from superstructures which are open at either or both ends and from all other decks within open or partially open spaces in which water may be shipped and contained.
5.3.15 Suitable provision is also to be made for the rapid freeing of water from recesses formed by superstructures, deckhouses and deck cargo arrangements, etc., in which water may be shipped and trapped. Deck gear, particularly on fishing vessels, is not to be stowed in such a manner as to obstruct unduly the flow of water to freeing ports.
5.3.16 The lower edges of freeing ports are to be as near to the deck as practicable, and should not be more than 100 mm above the deck.
5.3.17 Where freeing ports are more than 230 mm high, vertical bars spaced 230 mm apart may be accepted as an alternative to a horizontal rail to limit the height of the freeing port.
5.3.18 Where shutters are fitted, the pins or bearings are to be of a non-corrodible material, with ample clearance to prevent jamming. The hinges are to be within the upper third of the port.
5.3.19 Ships of Type ‘A’ and Type ‘B-100’ are to have open rails for at least half the length of the exposed part of the weather deck. Alternatively, if a continuous bulwark is fitted, the minimum freeing area is to be at least 33 per cent of the total area of the bulwark. The freeing area is to be placed in the lower part of the bulwark.
5.3.20 Where superstructures are connected by trunks, open rails are to be fitted for the whole length of the exposed part of the freeboard deck.
5.3.21 Ships of Type ‘B-60’ are to have a minimum freeing area of at least 25 per cent of the total area of the bulwark. The freeing area is to be placed in the lower part of the bulwark.
5.4 Free flow area
5.4.1 The effectiveness of the freeing port area in bulwarks of vessels not fitted with a continuous deck obstruction, depends on the free flow across the deck.
5.4.2 The free flow area is the net total longitudinal area of the transverse passageways or gaps between hatchways and superstructures or deckhouses, due account being made for any obstructions such as equipment or other fittings. The height of passageways or gaps used in the calculation of the area is the height of the bulwark.
5.4.3 The provision of freeing area in bulwarks should be related to the net free flow area as follows:
(a) If the free flow area is equal to, or greater than the freeing port area calculated from 5.3.11 when the hatchway coamings are continuous, then the minimum freeing area calculated from 5.3.3 is sufficient.
(b) If the free flow area is less than the freeing port area calculated from 5.3.3, then the minimum freeing area is to be that calculated from 5.3.11.
(c) If the free flow area is less than the freeing port area derived from (a) but greater than that derived form (b), the minimum freeing area, F, in the bulwark is to be obtained from the following formula:
F = F1+ F2– fp m2
where:
fp = total net area of passages and gaps between hatchways, superstructures and deckhouses (the free flow area)
F1 = minimum area from 5.3.3
F2 = minimum area from 5.3.11.
5.5 Special requirements for tugs and offshore supply ships
5.5.1 In tugs and offshore supply ships where there is a recess at the after end of the forecastle for the towing winch, the freeing port area in way of the recess is to be calculated as follows:
B = breadth of ship b = breadth of recess L = length of well
l = mean length of recess
a = freeing area for well length L Freeing port area in way of recess:
A = a
Reduction due to breadth of recess:
A1 = A
Reduce A1by 25 per cent for winch area:
A2 = 0,75 A1
= required freeing port area each side in way of the recess
Where the winch is enclosed in a non-weathertight compart- ment freeing ports are not required but adequate drainage by means of scuppers is to be provided.
b B l L
Superstructures, Deckhouses and Bulwarks
Part 3, Chapter 8
■
Section 1
General
1.1 Application
1.1.1 The requirements of this Chapter are to be taken in conjunction with the Chapters of Parts 3 and 4 applicable to the particular ship type.
1.2 Symbols
1.2.1 The following symbols and definitions are applicable to this Chapter:
k = higher tensile steel factor, see Ch 2,1.2
l = overall length, of the stiffening member, in metres
le = effective length, in metres, of the stiffening member,
measured between span points, see Ch 3,3.3
s = spacing, of stiffeners, in mm
B = moulded breadth of ship, in metres, see Ch 1,6.1
L = length of ship, in metres, see Ch 1,6.1
Z = section modulus of the stiffening member, in cm3, see Ch 3,3.2.
1.2.2 Other symbols are defined in the appropriate Section.