STABILITY AND WATERTIGHT INTEGRITY, CLOSING APPLIANCES

Transcription

1 RULES FOR CLASSIFICATION OF HIGH SPEED, LIGHT CRAFT AND NAVAL SURFACE CRAFT STRUCTURES, EQUIPMENT PART 3 CHAPTER 6 STABILITY AND WATERTIGHT INTEGRITY, CLOSING APPLIANCES JANUARY 2011 CONTENTS PAGE Sec. 1 General Requirements... 4 Veritasveien 1, NO-1322 Høvik, Norway Tel.: Fax:

2 CHANGES IN THE RULES General As of October 2010 all DNV service documents are primarily published electronically. In order to ensure a practical transition from the print scheme to the electronic scheme, all rule chapters having incorporated amendments and corrections more recent than the date of the latest printed issue, have been given the date January An overview of DNV service documents, their update status and historical amendments and corrections may be found through Main changes Since the previous edition (January 2003), this chapter has been amended, most recently in January All changes previously found in Pt.0 Ch.1 Sec.3 have been incorporated and a new date (January 2011) has been given as explained under General. In addition, the layout has been changed to one column in order to improve electronic readability. The electronic pdf version of this document found through is the officially binding version Det Norske Veritas Any comments may be sent by to rules@dnv.com For subscription orders or information about subscription terms, please use distribution@dnv.com Computer Typesetting (Adobe Frame Maker) by Det Norske Veritas If any person suffers loss or damage which is proved to have been caused by any negligent act or omission of Det Norske Veritas, then Det Norske Veritas shall pay compensation to such person for his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided that the maximum compensation shall never exceed USD 2 million. In this provision "Det Norske Veritas" shall mean the Foundation Det Norske Veritas as well as all its subsidiaries, directors, officers, employees, agents and any other acting on behalf of Det Norske Veritas.

3 Pt.3 Ch.6 Contents Page 3 CONTENTS Sec. 1 General Requirements... 4 A. General... 4 A 100 Application... 4 A 200 Documentation... 4 A 300 Inclining and stability information... 4 A 400 Marking and recording of the design waterline... 5 B. Requirements... 5 B 100 Intact buoyancy and stability... 5 B 200 External watertight integrity... 5 B 300 Internal watertight integrity... 5 C. Methods Related to the Intact Stability Investigation of Hydrofoil Boats... 5 C 100 General... 5 D. Ice Accretion Applicable to all Types of Craft... 5 D 100 General... 5 E. Access Openings... 5 E 100 Doors... 5 E 200 Sill heights... 6 F. Air Intakes and Ventilation Openings... 6 F 100 Arrangement... 6 G. Windows... 6 G 100 General... 6 G 200 Window thickness... 7 G 300 Direct glazing... 8 G 400 Deadlights... 8

4 Pt.3 Ch.6 Sec.1 Page 4 SECTION 1 GENERAL REQUIREMENTS A. General A 100 Application 101 The requirements of this chapter and of the 2000 HSC Code Ch.2 Part A 2.1 and apply to all high speed craft for the assignment of the main class. A 200 Documentation 201 The following documentation is to be submitted: Documentation for approval: preliminary stability manual based on estimated lightweight data inclining test/lightweight survey procedure inclining test/lightweight survey report final stability manual based on lightweight data from inclining test/lightweight survey. Documentation for information: General Arrangement body plan/lines plan/offset tables external watertight integrity plan/freeboard plan Guidance note: Details of documentation in 201 are given in Classification Note No "Stability Documentation - Ships" ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e For instrumentation and automation, including computer based control and monitoring, see Pt.4 Ch.9 Sec.1. A 300 Inclining and stability information 301 Loading conditions representative for the intended service are to be presented in the stability manual. 302 If no stability limit curves are presented, the presented loading conditions will be considered as limiting for the vessel s operation. 303 The loading conditions are to be within the limit curves and/or are to comply with the required stability criteria. 304 If a loading computer is installed for the purpose of determining the craft s trim and stability, and also ascertain and record that the craft is in compliance with the stability criteria of the relevant requirements, it is subject to approval (see Rules for Classification of Ships Pt.6 Ch.9). 305 Additionally, 2000 HSC Code 2.7 and 2.8 are to be followed. Guidance note: The inclining test/lightweight survey is to be performed in accordance with the approved procedure according to 200 and in the presence of the Society s representative. For the second and subsequent craft in a series, a lightweight survey may be accepted in lieu of an inclining test. This, however, shall not be generally permitted in cases where the lightweight exceeds 75% of the maximum displacement. If the lightweight survey reveals significant difference between lightweight data obtained from the inclining test of the first craft and the lightweight survey of the sister craft, an inclining test may be required for the latter. Alternatively, the difference is to be positioned at the most unfavourable position, when calculating the vertical centre of gravity. In cases where it is practically impossible to perform an inclining test due to structural limitation or similar, a lightweight survey may be accepted also for the first craft. In such a case, a detailed lightweight estimate is to be worked out before the survey and checked "as built" to the satisfaction of the surveyor. This shall be considered as basis for comparison with the result of the lightweight survey, and submitted together with the lightweight survey report, at the latest. A safety margin of 10% is to be added to the estimated VCG, and the value including margin is to be used when calculating the final VCG after the lightweight survey. Any difference in lightship weight between the estimate and the result from the lightweight survey, which can not be justified, is to be positioned at the most unfavourable position, when calculating the vertical centre of gravity. I.e., any increase to be placed at the uppermost deck, and any decrease to be placed at keel height.

5 Pt.3 Ch.6 Sec.1 Page 5 If the lightweight survey reveals significant difference (more than 2%) between lightship weight obtained from the lightweight estimate and the lightweight survey, then the validity of the estimate should be reconsidered. The approved lightweight data and definition, i.e. items included/not included in the lightweight are to be included in the stability manual. If lightweight alterations exceed 1% of the maximum displacement, the lightweight data is to be updated and submitted for approval. The stability manual is to be revised accordingly. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- A 400 Marking and recording of the design waterline 401 Marking and recording of the design waterline and the load line mark shall be in compliance with the 2000 HSC Code 2.9. B. Requirements B 100 Intact buoyancy and stability 101 All high speed craft shall comply with the intact stability requirements of the 2000 HSC Code 2.2.1, 2.3, 2.4 and 2.5. Intact stability criteria are given in Annex 7 for multihulls and in Annex 8 for monohulls. B 200 External watertight integrity 201 All external openings which may become submerged within the required range of stability are to have weathertight closing appliances. Small openings through which progressive flooding may not occur need not be so equipped. B 300 Internal watertight integrity 301 Requirements to internal watertight integrity are given in Pt.3 Ch.1 Sec.1 B and in the 2000 HSC Code C. Methods Related to the Intact Stability Investigation of Hydrofoil Boats C 100 General 101 Hydrofoil boats are to comply with the requirements outlined in the 2000 HSC Code Annex 6 D. Ice Accretion Applicable to all Types of Craft D 100 General 101 All types of crafts are to comply with the requirements outlined in the 2000 HSC Code Annex 5. E. Access Openings E 100 Doors 101 Weathertight doors are to be fitted in all access openings in: bulkheads at ends of superstructures bulkheads of deckhouses on freeboard deck protecting openings in the freeboard deck companionways on freeboard deck and superstructure deck bulkheads of deckhouses on superstructure deck protecting openings in the superstructure deck companionways and bulkheads of deckhouse upon another deckhouse on freeboard deck protecting openings in the freeboard deck. 102 The doors are to be permanently attached to the bulkhead and are to be so arranged that they can be operated from both sides of the bulkhead. Guidance note: Doors should generally open outwards to provide easy evacuation of passengers and crew and additional security against impact of the sea. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

6 Pt.3 Ch.6 Sec.1 Page Weathertight doors are to have the same strength as their surrounding structure and are to be of an approved type. Doors may be made of steel, aluminium or FRP. 104 Weathertight doors are to be fitted with gasket and a sufficient number of clamping devices. The gasket is to be located in a groove to be protected from mechanical abrasion. The number of clamping devices shall normally be in accordance with Table E1. Table E1 Number of clamping devices Position Long side > 1500 mm < 1500 mm > 700 mm Short side < 700 mm No The hinges are normally considered as efficient clamping devices if having circular holes. 105 For weathertight doors in companionways and deckhouses on superstructure deck in vessels with service restriction R3 and R4, reduced clamping may be considered. E 200 Sill heights 201 Doors in superstructures or companionways on freeboard deck, giving access to spaces below the freeboard deck shall have sill height not less than 380 mm. 202 Doors in superstructures on freeboard deck not giving access to spaces below the freeboard deck and not necessary for the operation of the vessel at sea are to have sill heights of not less than 100 mm. Doors in this position which are necessary for the operation of the vessel at sea are to have sill heights of not less than 380 mm. F. Air Intakes and Ventilation Openings F 100 Arrangement 101 The lower edge of air intakes and ventilation openings is to be located at a height, H V, above the waterline, in the displacement mode in the fully loaded condition, not less than given in Table F1. Table F1 Lower edge of air intake and ventilation openings Service restriction H V (m) R L; minimum 2.30 m R L; minimum 2.00 m R L; minimum 1.70 m R L; minimum 1.70 m R4, R5 and R6 will be specially considered. For openings which are not necessary for the operation of the vessel at sea, a reduced H V may be considered. In that cases permanently fitted closing devices is to be available. Openings which are necessary for the operation of the vessel at sea, are to be arranged with a coaming above the level of the deck where it is located. The height of this coaming is to be at least equal to the sill height for doors in corresponding positions as given in E Ventilation openings are to be fitted with screens preventing ingress of water spray and are preferably to be facing aft or athwartships. 103 Ventilation openings facing forward are to be fitted with a drainage system preventing water from entering the opening. 104 Direct air intakes for machinery are to have a protecting grate and a water trap system. G. Windows G 100 General 101 Windows in sides and ends of superstructures and deckhouses are in general to be of toughened safety glass and firmly mounted in stiff aluminium frames or equivalent. In superstructure sides the windows are normally to be placed inside outer point of side. 102 For craft with service restriction R4 rubber frames may be accepted, provided the cross section is designed as to increase the grip on the glass as the lateral pressure from outside is increased.

7 Pt.3 Ch.6 Sec.1 Page Wheelhouse front windows are to be made of toughened safety glass. For windows in other positions materials other than those specified in 201 may be accepted based on consideration in each case. 104 Window glass panes with heating wires are to be considered with regard to their reduced strength. 105 The cut-outs for windows are to have well-rounded corners. G 200 Window thickness 201 The thickness of window panes is in general not to be less than: b t w = β p (mm) K w b = small dimension of window opening in mm K W = 225 for toughened safety glass = 190 for polycarbonate p = lateral pressure according to Ch.1 Sec.2 β = factor taken from Fig.1, dependent on the aspect ratio of the window. Polycarbonate window panes are to overlap their frames with not less than 0.03 b mm. Fig. 1 Diagram for factor β for windows Laminated glass is to comply with the following requirements: t 1 + t ti t w (mm) i = number of glass layers t i = thickness of glass layer no. i (mm) t w = required thickness calculated according to 201. Each glass layer is to be of toughened safety glass. 202 The thickness of window panes may be reduced from that given by the formula in 201 if they are satisfactorily pressure tested as described in 204 and 205. The window thickness is in no case to be less than 5 mm. 203 The test pressure is not to be taken less than 4 times the design pressure p in Ch.1 Sec.2 for toughened safety glass, and 3.5 times the design pressure for polycarbonate. 204 During the testing the window is to be fitted in similar arrangement as to be installed onboard the craft. The testing may be considered satisfactory provided: no failure in window or attachment method no leakages occur. 205 Large glass doors or windows in the aft end of superstructures or deckhouses will be especially considered.

8 Pt.3 Ch.6 Sec.1 Page 8 G 300 Direct glazing 301 Window panes may be fastened to the supporting structure by adhesively bonded joints without any counter frame or mechanical fasteners. Adhesives used for bonded joints shall be type approved by DNV. However, the weight of the window pane is normally to be carried by at least two support blocks along the lower edge. 302 The resistance of the adhesive to UV-light, high and low temperatures, cleaning chemicals, etc. is to be documented. Alternatively, the adhesive joint can be protected against such effects. The long time behaviour of the adhesive with respect to retention of adhesive and cohesive strength and elasticity and the creep properties are to be documented. 303 The joint width is not to be less than: d bp w = (mm) 2000σ t d min =0.02 b (mm) b = length of shortest window side (mm) P w = wind suction load = ( V) 2 (kn/m 2 ) V = the speed in knots σ t = allowable tensile stress for the glue (MPa). Normally to be taken as the stress at 12.5% elongation. 304 The joint depth (thickness of glue) is to be not less than: t = k l 10 3 (mm) t = minimum 6 mm and not to be less than d/2 for d > 12 mm k = 1.5 for glass k = 8.0 for polycarbonate l = length of longest window side (mm). For rectangular windows with l/b > 2, mounted with the longest side in the horizontal direction, and with the lower edge mechanically secured against in-plane movement, l in the formula above is to be substituted by 2 b. 305 Adhesives for direct glazing shall comply with the following minimum requirements: minimum tensile strength: 0.70 MPa tensile stress: not less than 0.14 MPa at 12.5% elongation minimum fracture elongation: 50% cohesive fracture. Testing is to be carried out according to ISO The short and long term performance of the adhesion between adhesive and substrate material shall be documented. 306 Direct glazing shall be carried out in accordance with documented procedures covering the following: environmental conditions surface preparation glue application curing time or conditions inspection and testing. The procedures are to be in accordance with the adhesive manufacturers instructions and specifications. G 400 Deadlights 401 The number of deadlights in relation to the number of windows is at least to be as follows depending on the service restriction notations (R): Table G1 Minimum number of deadlights in relation to number of windows Location R0 R1 R2 R3 R4-R6 Below main deck 100% 100% 100% 100% 100% Superstructure front 1st tier 100% 100% See Superstructure side See Deckhouse front 2nd tier and above See Deckhouse side 2nd tier and above See

9 Pt.3 Ch.6 Sec.1 Page Below the freeboard deck deadlights are to be permanently mounted and are to have the same strength as the surrounding structure. 403 Deadlights above the freeboard deck, for which there is 100% requirement, are to have the same strength as the surrounding structure. 404 Areas for which there is not 100% requirement are to be provided with adequate means (e.g. canvas) for temporary replacement of a damaged window, protecting crew and passengers from sea spray and wind. 405 Deadlights are to be stowed in such a way as to provide quick mounting.