Equipment, Steering and Appendages

Transcription

1 RULES FOR CLASSIFICATION OF High Speed, Light Craft and Naval Surface Craft PART 3 CHAPTER 5 STRUCTURES, EQUIPMENT Equipment, Steering and Appendages JANUARY 2005 This chapter has been amended since the main revision (January 2005), most recently in July 20. See Changes on page 3. The content of this service document is the subject of intellectual property rights reserved by Det Norske Veritas AS (DNV). The user accepts that it is prohibited by anyone else but DNV and/or its licensees to offer and/or perform classification, certification and/or verification services, including the issuance of certificates and/or declarations of conformity, wholly or partly, on the basis of and/or pursuant to this document whether free of charge or chargeable, without DNV's prior written consent. DNV is not responsible for the consequences arising from any use of this document by others.

2 FOREWORD DET NORSKE VERITAS (DNV) is an autonomous and independent foundation with the objectives of safeguarding life, property and the environment, at sea and onshore. DNV undertakes classification, certification, and other verification and consultancy services relating to quality of ships, offshore units and installations, and onshore industries worldwide, and carries out research in relation to these functions. The Rules lay down technical and procedural requirements related to obtaining and retaining a Class Certificate. It is used as a contractual document and includes both requirements and acceptance criteria. The electronic pdf version of this document found through is the officially binding version Det Norske Veritas AS January 2005 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 Rules for High Speed, Light Craft and Naval Surface Craft, January 2005 Pt.3 Ch.5 Changes Page 3 CHANGES General The present edition of the Rules includes additions and amendments decided by the Board as of November 2004, and supersedes the January 996 edition of the same chapter. The Rule changes come into force on July Text affected by the main rule changes is highlighted in red colour in the electronic pdf version. However, where the changes involve a whole chapter, section or sub-section, only the title may be in red colour. This chapter is valid until superseded by a revised chapter. Amendments July 20 General The restricted use legal clause found in Pt. Ch. Sec.4 has been added also on the front page. In addition, the layout has been changed to one column in order to improve electronic readability. Main changes General The machinery related requirements for steering gear have been moved to a new chapter, Pt.4 Ch.4 Steering Gear, and Sec. Hull Appendages and Sec.2 Steering Arrangement have been revised accordingly. Corrections and Clarifications In addition to the above stated rule requirements, a number of corrections and clarifications have been made in the existing rule text.

4 Rules for High Speed, Light Craft and Naval Surface Craft, January 2005 Amended July 20, see page 3 Pt.3 Ch.5 Contents Page 4 CONTENTS Sec. Hull Appendages... 6 A. General... 6 A 00 Introduction... 6 A 200 Definitions... 6 A 300 Documentation... 6 B. Materials and Workmanship... 7 B 00 Certificates... 7 B 200 Material combinations... 7 B 300 Welded constructions... 7 B 400 Cast constructions... 7 B 500 GRP/sandwich constructions... 7 C. Arrangement of Appendages... 7 C 00 Functional requirements... 7 C 200 Protection and accessability... 8 D. Design Loads and Supporting Structure... 8 D 00 Design loads... 8 D 200 Foundations and strengthening... 8 D 300 Connections... 8 E. Rudders... 9 E 00 Arrangement and details... 9 E 200 Design loads... 9 E 300 Dimensioning of rudders... 9 E 400 Dimensioning of rudder stocks... E 500 Rudder bearings... 3 F. Rudder Posts... 4 F 00 Design loads and acceptable stress levels... 4 G. Shaft Brackets... 4 G 00 Design loads and acceptable stress levels... 4 G 200 Twin brackets... 4 G 300 Single arm brackets... 4 H. Foils... 5 H 00 Documentation... 5 I. Waterjets... 5 I 00 Design principles... 5 I 200 Duct design... 5 I 300 Design loads... 5 I 400 Allowable stresses... 6 I 500 Bolt connections... 6 Sec. 2 Steering Arrangement... 7 A. General... 7 A 00 Introduction... 7 Sec. 3 Anchoring and Mooring Equipment... 8 A. General... 8 A 00 Introduction... 8 A 200 Documentation... 8 A 300 Towing... 8 A 400 Berthing... 9 B. Structural Arrangement for Anchoring Equipment... 9 B 00 General... 9 C. Equipment Specification C 00 Equipment number C 200 Equipment tables D. Anchors... 2 D 00 General... 2 D 200 Materials D 300 Anchor shackle... 22

5 Amended July 20, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2005 Pt.3 Ch.5 Contents Page 5 D 400 Testing D 500 Additional requirements for H.H.P. anchors and S.H.H.P. anchors D 600 Identification E. Anchor Chain Cables E 00 General E 200 Materials E 300 Heat treatment and material testing E 400 Breaking test E 500 Proof test E 600 Tolerances E 700 Identification E 800 Repair of defects F. Windlass and Chain Stoppers F 00 General design F 200 Materials F 300 Testing G. Wire Ropes... 3 G 00 General... 3 G 200 Materials... 3 G 300 Testing of steel wire ropes... 3 G 400 Testing of natural fibre ropes G 500 Mooring winches... 33

6 Rules for High Speed, Light Craft and Naval Surface Craft, January 2005 Amended July 20, see page 3 Pt.3 Ch.5 Sec. Page 6 SECTION HULL APPENDAGES A. General A 00 Introduction 0 The requirements in this section apply to hull appendages necessary for satisfactory performing of the following functions: propulsion steering dynamic lift. Such appendages are: rudders rudder posts shaft brackets foils. Further, the requirements will include structural strength of hull foundations of above items, and appended propulsion units such as waterjets. Requirements for steering arrangement are given in Sec.2. Requirements for steering gear, hydraulic cylinders, rotating parts, propellers and impellers with shafting bearings for such are given in Part 4. Requirements for side thrusters and other appliances intended for manoeuvring or positioning purposes are given in Pt. 4. A 200 Definitions 20 Some terms used in this part are defined as follows: Redundancy is the ability of a component or system to maintain or restore its function when one failure has occurred. Redundancy can be achieved for instance by installation of more units or alternative means for performing a function. Operational conditions: Operation within sea state/speed restrictions for which the strength of the craft has been approved. Dynamic lift: Support of craft other than hydrostatic support. A 300 Documentation 30 The following plans shall be submitted for approval: rudder including details of bearings, shaft, pintles and rudder lock arrangement rudder stock including details for couplings, bolts and keys rudder carrier water jet components transmitting thrust and steering forces to hull including details for bolts etc. water jet shaft/tunnel details shaft brackets foils hull foundations supporting appendages and steering gear. The plans shall give full details of scantlings and arrangement as well as data necessary for verifying scantling calculations. Material specifications and particulars about any heat treatment are also required. 302 For important components of welded construction full details of the joint, welding procedure, filler metal and any heat treatment after welding shall be specified on the plans. 303 Plans of the following items shall be submitted for information: general arrangement. 304 Strength calculations shall be submitted for information upon request.

7 Amended July 20, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2005 Pt.3 Ch.5 Sec. Page 7 B. Materials and Workmanship B 00 Certificates 0 «Det Norske Veritas certificates» will be required for: structural parts connecting bolts for rudder flange shafts/pintles rudder stock. For bolts connecting thrusters and water jets to the hull, see Pt.4 Ch.5 Sec.3. B 200 Material combinations 20 When the appendage, or parts connected to it, is made from other material than the hull, such that a risk for galvanic corrosion arises, an approved coating system and/or approved cathodic protection will be required. Fatigue resistance in sea water may have to be documented upon request. B 300 Welded constructions 30 Welds shall be full penetration welds only. Necessary preheating shall be applied for parts of substantial thickness, according to approved procedure % non destructive testing shall be carried out on following welds: connection appendage/hull connections between separate parts of the appendage (e.g. shaft boss/bracket arm) important hull welds connection welds for ears for hydraulic cylinders and important link members weld in way of shaft boss. 303 All welds to be ground flush and corners rounded well off. B 400 Cast constructions 40 Casts for heavily loaded parts are subject to requirements as for propeller blades (see Pt.2) with respect to certification and testing. 402 Surface finish shall be closely examined, also after removal of lifting ears etc. B 500 GRP/sandwich constructions 50 Only approved raw materials shall be used. Lamination plan and procedure to be approved before production starts. 502 Any overlamination of metal parts shall take place after thorough grinding of metal surfaces and according to approved procedure. C. Arrangement of Appendages C 00 Functional requirements 0 Within operational conditions, propulsion, steering and dynamic lift (if applicable) shall not be unduly impaired by the craft s motions and accelerations. 02 The arrangement shall be such that acceptable manoeuvrability is provided even beyond the operational restrictions with respect to maximum wave height and speed for the craft. 03 Longitudinal and transverse locations of appendages, and forces transmitted by appendages to the craft s hull shall be such that acceptable manoeuvrability is maintained within the speed range. Steering of twin propulsion craft only by propulsion thrust variations may be accepted only if each of the propulsion units is arranged with full redundancy. Generally, rudder area should be sufficient to ensure that the craft can keep a steady course with only one engine running, and at slow speed. For requirements for steering capacity, power supply, rudder actuators, carriers and tillers, remote steering redundancy and monitoring, see Sec.2 and Pt.4 Ch.4 Sec.. 04 The arrangement shall be such that within the speed range, any sudden manoeuvre will not cause loss of control or lead to dangerous situations.

8 Rules for High Speed, Light Craft and Naval Surface Craft, January 2005 Amended July 20, see page 3 Pt.3 Ch.5 Sec. Page 8 C 200 Protection and accessability 20 Water intakes to tunnels (e.g. for water jet installations) shall be designed to give adequate protection against being clogged by debris, etc. Adequate protection does not require a grid to be fixed on the waterjet duct inlet. Any outside protruding links, hydraulic equipment or other important parts for the functions listed in A0 shall be adequately protected against mechanical damage. 202 Cathodic protection shall be arranged to the extent considered necessary. 203 Hollow constructions like rudders, welded shaft brackets etc. shall be hydraulically tested with an internal test pressure of p o = 0 T (kn/m 2 ), minimum 20 kn/m 2 where T is the fully loaded draft of the craft in meters. Means for draining shall be provided. After pressure test internal surfaces shall be covered by a corrosion resistant covering. 204 Items listed in 20 shall be accessible for inspection and immediate remedial action. For water jets, inspection hatches shall be arranged close to the impeller. 205 Housings for gear systems, water jet impellers etc. shall be bolted to the hull to facilitate removal for servicing. D. Design Loads and Supporting Structure D 00 Design loads 0 The following main principles shall be applied when design loads are established: progressive strength of components, so that hydrodynamic lift generating part is weakest link all relevant cases of asymmetrical loading during manoeuvring absence of ice. 02 Specific loading criteria are given under E to I for the different applications. 03 Design loads shall be submitted together with documentation for approval. D 200 Foundations and strengthening 20 Major load carrying members shall be supported by properly aligned members inside the shell plating (floors, additional intercoastal stiffeners). 202 It is essential that the supporting structure is carried well outside the area of the supported appendage, and is well tied up with the vessel s primary structure. 203 For appendages welded to the hull, major load carrying members may be required to be carried continuously through the shell plating to tie up with internal primary structure. 204 Shell plating in way of any appendage shall have a thickness not less than.5 x rule thickness for shell plating at that location. 205 Floors, bottom girders and other internal structures shall have welding/bonding requirements increased by 50%. D 300 Connections 30 Flanges and machined areas prepared for bolted connections shall be of substantial thickness, normally not less than 3 x rule thickness for shell plating at that location. The extent of substantial thickness flange plating shall be such that it is directly supported by internal structure (e.g. passing closest floor plating forward and aft of flange). 302 Machining of bolted area shall take place after all welding is completed in the area. 303 Bolts shall be pretensioned according to an accepted standard. 304 When chockfast or similar is used, specification of type and pretension of bolts shall be documented. 305 After mounting, it shall be ensured that all gaps and corners are filled with compound. Smooth waterflow shall be ensured, to avoid undesirable cavitation creating erosion of surface.

9 Amended July 20, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2005 Pt.3 Ch.5 Sec. Page 9 E. Rudders E 00 Arrangement and details 0 Suitable stopping arrangement shall be provided. This may be arranged as an integral part of rudder actuator (see Sec.2). 02 Suitable arrangement to prevent the rudder from lifting shall be provided. 03 If the rudder trunk is open to the sea, a seal or stuffing box shall be fitted above the deepest load waterline, to prevent water from entering the steering gear compartment and the lubricant from being washed away from the rudder carrier. An additional seal of approved type is required when the rudder carrier is below the deepest load waterline. 04 Before final mounting of rudder pintles, the contact between conical surfaces of pintles and their housings shall be checked by marking with Prussian blue or by similar method. When mounting the pintles, care shall be taken to ensure that packings will not obstruct the contact between mating surfaces. The pintle and its nut shall be so secured that they cannot move relatively to each other. Guidance note: The after body should be so shaped as to ensure a proper flow of water to the propeller, and so as to prevent uneven formation of eddies as far as possible. The strength of pressure impulses from propeller to hull will normally decrease with increasing clearances. However, even with large clearances to the propeller, a hull may be exposed to strong impulses if the propeller is subject to heavy cavitation. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- E 200 Design loads 20 The design rudder force is given by: F R = 0.05 (H 2 + 2A) V 2 R (kn) H = mean height in m of that part of the rudder which is situated abaft the centre line of the rudder stock A = total area of rudder in m 3 V R = maximum service speed in knots. If the maximum output of the propelling machinery exceeds the normal output which corresponds to the contracted speed by 5% or more, V R. shall be increased by the following percentage: Max engine output above normal (%) V R increase (%) For rudders which at no angle of helm work in the slipstream behind a propeller, the rudder force may be taken as 80% of that obtained from The scantlings of rudder, rudder stock, steering gear and bearings may be based on direct stress analysis. The design loads shall comply with the rudder force and rudder torque given in 20 and 402. Allowable stresses are indicated for the various members in E and F. Acceptable direct calculation methods are given in Classification Note on «Strength Analysis of Rudder Arrangements». E 300 Dimensioning of rudders 30 Rudders dealt with are double plate, spade type rudders with internal vertical and horizontal web plates. 302 Other rudder types will be subject to special consideration. 303 Suitable arrangement shall be provided to prevent accidental unshipping of the rudder. 304 All rudder bearings shall be accessible for measuring of wear without lifting or unshipping the rudder. 305 Stresses determined by direct calculations as indicated in 200 are normally not to exceed the following values: normal stress: σ = 0 f N/mm 2 in general shear stress: τ = 50 f N/mm 2.

10 Rules for High Speed, Light Craft and Naval Surface Craft, January 2005 Amended July 20, see page 3 Pt.3 Ch.5 Sec. Page The material factor f for plates and sections, forgings (including rolled round bars) and castings may be taken as: a σ f f = σ f = minimum upper yield stress in N/mm 2, not to be taken greater than 70% of the ultimate tensile strength. a = 0.75 for σ f > 240 N/mm 2 =.0 for σ f 240 N/mm Materials with minimum specified tensile strength lower than 400 N/mm 2 or higher than 900 N/mm 2 will normally not be accepted in rudder stock, axle or pintles, keys and bolts. 308 Great care shall be taken in highly stressed connections such as welds between rudder side plating and upper heavy part of rudder at stock coupling. 309 Welds between plates and heavy pieces (cast or very thick plating) shall be made as full penetration welds, preferably to cast or welded on ribs. Where back welding is impossible welding shall be performed against backing bar or equivalent. 30 Webs shall be connected to the side plates in accordance with Ch.2 and Ch.3. Slot-welding shall be limited as far as possible. Horizontal slots in side plating in areas with large bending stresses shall be completely filled by welding. Normally, slots of length 75 mm and a breadth of 2 t (where t = rudder plate thickness), with a distance of 25 mm between ends of slots, will be accepted. In areas where slots are required to be completely filled by welding, more narrow slots with inclined sides (minimum 5 to the vertical) and a minimum opening of 6 mm at bottom may be used. A continuous slot weld may, however, in such cases be more practical. 3 Rudder plating The thickness requirement of side, top and bottom plating is given by: t = k a s T 0.F R t f A 0 ( mm) k a = ( s/b) 2 maximum.0 for s/b = 0.4 minimum 0.72 for s/b =.0 s = the smaller of the distances between the horizontal or the vertical web plates in m b = the larger of the distances between the horizontal or the vertical web plates in m t 0 = 2 for ordinary ship quality steel = 0 for stainless steel T = fully loaded draft of the craft in meters. 32 Section modulus The following requirements normally apply to vertical web plates and side plating within 40% of the rudder length for the cross-section in question. 33 The section modulus requirement at any section is given by: A = area in m 2 of the rudder part below the cross-section in question h = vertical distance in m from the centroid of the rudder area A to the section in question. 34 Web plates The thickness of vertical and horizontal webs shall not be less than 70% of the thickness requirement given in The total web area requirement for the vertical webs is given by: P A W = ( cm 2 ) 5f P = ---- F H R = height in m of the rudder part below the cross section in question. h h Z 9. F R A h = ( cm 3 ) f A

11 Amended July 20, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2005 Pt.3 Ch.5 Sec. Page Shear stresses in web plates determined by direct stress calculations shall not exceed: τ = 50 f N/mm 2. E 400 Dimensioning of rudder stocks 40 Stresses determined by direct calculations as indicated in D200 are normally to give equivalent stress σ c not exceeding 0 f N/mm 2. The equivalent stress for axles in combined bending and torsion may be taken as: σ c = σ 2 + 3τ 2 N mm 2 σ = bending stress in N/mm 2 τ = torsional stress in N/mm 2. The requirements to diameters are applicable regardless of liner. 402 Rudder torque The design rudder torque on regular shape rudders shall be taken as: M TR = F R x e ( knm) F R = as given in 20 x e = longitudinal distance in m from the centreline of the rudder stock to the point of application of F R =0.33 l r x f, minimum 0. l r l r = length of the rudder in m measured through the centroid of the rudder area. See Fig. x f = longitudinal distance in m from the leading edge of the rudder to the centreline of the rudder stock, measured at a level through the centroid of the rudder area. See Fig.. The rudderstock shall be so dimensioned, that the maximum loads from the steering gear actuator(s), do not cause permanent deformation to the rudderstock. At the quadrant or tiller the diameter of the rudder stock d v shall not be less than: d v 43 M -- 3 TR = f ( mm) The diameter of the rudder stock below the upper bearing shall be gradually increased to the diameter d s at the neck bearing given in 403. Fig. Spade rudder 403 Rudder bending moment For regular trapezoidal rudders (see Fig.) the bending moment at the neck bearing shall be taken as: F R M B = [ 3 ( l u + l l ) l ( 2l + l ) + h b l u n ( 2l u + l l )] ( knm) h n, l a, l b, l u, l l = lengths in m as shown in Fig..

12 Rules for High Speed, Light Craft and Naval Surface Craft, January 2005 Amended July 20, see page 3 Pt.3 Ch.5 Sec. Page 2 At the neck bearing the diameter of the rudder stock d s shall not be less than: 4 M d s B 2 = + 3 M TR 404 Where the rudder stock has a tapered lower end (cone coupling) fitted into rudder and secured by nut and key, without hydraulic arrangement for mounting and dismounting, the taper length l t (see Fig.2) should in general not be less than the rudder stock diameter d s at the top of the rudder. The taper on diameter is normally to be: M TR f d s d t -- = l t 8 2 The dimensions at the slugging nut shall not be less than (see Fig.2): external thread diameter: d g = 0.65 d s height of nut: h n = 0.6 d g outer diameter of nut: d n =.2 d t or d n =.5 d g, whichever is the greater. The nut shall be sufficiently secured to the rudder stock. ( mm) Fig. 2 Cone coupling The keyway in the tapered connection shall be fitted as close to the nut as possible, and ample fillets shall be provided at the corners of the keyway. The shear area of the key shall not be less than: A S = 294M TR ( cm 2 ) d m f d m = diameter of rudder stock in mm at key. The abutting surface between key and rudder stock or between key and rudder, respectively, shall not be less than: 0.3 A S f m f m =f for the key, stock or coupling material, whichever is the smaller. 405 Where the rudder stock is connected to the rudder by horizontal flange coupling the following requirements shall be complied with:

13 Amended July 20, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2005 Pt.3 Ch.5 Sec. Page 3 at least 6 tight fitted coupling bolts shall be used the shear diameter of coupling bolts shall not be less than: d = d s fms ( mm) nef mb d s = Rule diameter of rudder stock at coupling flange in mm as given in 402 n = number of coupling bolts e = mean distance in mm from the centre of bolts to the centre of the bolt system f ms = material factor (f ) for rudder stock f mb = material factor (f ) for bolts nuts shall be securely fastened by split pins or other efficient means the mean distance from the centre of the coupling to the bolts shall not be less than 0.9 d s if the coupling is subjected to bending stresses, the mean distance from the centerline of the bolt to the longitudinal centerline of the coupling shall not be less than 0.6 d s further, bolt pre-stress in shear part of bolt shall normally be in the range of 60 f mb to 20 f mb. In the minimum section of the bolt, pre-stress shall not exceed 65 f mb the width of material outside the bolt holes shall not be less than 0.67 d s the thickness of coupling flanges shall not be less than the greater of: f t = 0.56 d ms s ( mm) n n = number of coupling bolts, not to be taken greater than 8 or t = 70 M B = bending moment in knm at coupling a = mean distance from centre of bolts to the longitudinal centre line of coupling (mm) β = factor to be taken from the following table: d s /a β β M B ( mm) a Ample fillet radius to be in accordance with recognized standards. 406 The connection between rudder stock and steering gear shall comply with relevant requirements in Pt.4 Ch.4 Sec. B200. E 500 Rudder bearings 50 Bearing materials for bushings shall be stainless steel, bronze, white metal, synthetic material or lignum vitae. Stainless steel or bronze bushings shall be used in an approved combination with steel or bronze liners on the axle, pintle or stock. The difference in hardness of bushing and liners shall not be less than 65 Brinell. 3% Cromium steel shall be avoided. Synthetic bearing materials shall be of an approved type. The Rockwell hardness shall not be less than 80 N/ mm 2 measured at 23 C and with 50% moisture. 502 The maximum surface pressure p m for the various bearing combinations shall be taken as: p m = kn/m 2 for steel against stainless steel or bronze p m = kn/m 2 for steel against white metal, oil lubricated p m = kn/m 2 for steel against synthetic materials, water lubricated p m = kn/m 2 for steel or bronze against lignum vitae. 503 The bearing surface area shall not be less than: P A B = ( mm 2 ) p m

14 Rules for High Speed, Light Craft and Naval Surface Craft, January 2005 Amended July 20, see page 3 Pt.3 Ch.5 Sec. Page 4 A B is defined as h b d sl h b d sl P = height of bearing surface = diameter in mm of rudder stock measured on the outside of liners = calculated reaction force in kn at the bearing in question. P at various bearings may be taken as given in the following (see Fig.): P U = M B (kn) at upper bearing l a P N = ( F R + P U ) (kn) at neck bearing. 504 The thickness of any bushings in rudder bearings shall not be less than: t v = 0.32 P ( mm) minimum= 8 mm in general = 22 mm for lignum vitae The bushing shall be effectively secured to the bearing. The width of bearing material outside bushing shall not be less than 25% of the rudder stock diameter. 505 The bearing clearance on diameter is normally not to be less than: 0.00d b +.0 (mm) when metal bearing material d b +.0 (mm) when synthetic bearing material d b = inner diameter in mm of bushing. Due attention should, however, be given to the manufacturer s recommended clearance. For pressure lubricated bearings the clearance will be specially considered. F. Rudder Posts F 00 Design loads and acceptable stress levels 0 Design rudder force as given in E200 shall be applied as design load. Calculation of section modulus shall be documented. When calculating normal and shear stresses for the rudder post cross section, acceptable stress levels are as for rudders (see E300). For slender rudder posts or rudder posts of unusual design, comprehensive calculation of structural strength will be required. G. Shaft Brackets G 00 Design loads and acceptable stress levels 0 The following load conditions shall be considered: most unfavourable sideforces in a turn at full speed maximum bending moments and forces arising at full power maximum bending moments and forces arising with one propeller blade tip outside 0.9 R missing. Acceptable stress levels are as for rudders (see E300). G 200 Twin brackets 20 Twin brackets shall have an angle between the legs of at least 50. Calculation of section modulus shall be documented. Minimum plate thickness to be at least.5 times rule requirement for shell plating. G 300 Single arm brackets 30 Calculation of section modulus shall be documented. Minimum plate thickness shall be at least 2 times rule requirement for shell plating. Calculation of stiffness may be required in order to establish dynamic properties of bracket/shaft system.

15 Amended July 20, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2005 Pt.3 Ch.5 Sec. Page 5 H. Foils H 00 Documentation 0 The following documentation shall be submitted for approval: arrangement drawing calculation of design loads calculation of stresses and deflections. Acceptance criteria will be considered in each case. I. Waterjets I 00 Design principles 0 The reaction forces from the waterjet nozzles need to be transmitted into the hull structure in a manner for which adequate strength and fatigue life of critical details can be ensured through careful design. For steerable jet units the reaction forces will typically arise from acceleration and manoeuvring actions (steering, reversing, crash-stop). For booster nozzles with no steering, reaction forces arise from acceleration only. Additionally, vibration forces from impeller pulses/cavitation, turbulent waterflow in duct and around stator vanes, and various other possible sources (shaft misalignment, shaft/impeller imbalance etc.) will be present. 02 The nozzle reaction forces are normally transmitted into the hull structure through the duct and into the aft ship structure. The jet duct and the details of this, such as flanges, bolted connections, discontinuities, buttwelds and attachments, require special attention with respect to fatigue. The transom structure need to be designed so as to follow the deflections of the duct without excessive stress concentrations occurring in critical welds. The deflections of the duct and aft ship shall be kept within the tolerances of the impeller shafting and bearings. 03 Design and workmanship of duct penetrations (shaft, inspection hatches, etc.), attachments and surrounding structure (stiffeners and frames) should be carried out with fatigue properties in mind. Some general principles are listed below: increase thickness of main members and minimise panel stiffening (thickness of duct is normally not to be less than.5 times the bottom plating thickness) continuous welding shear connections between stiffeners and frames soft toe brackets avoid sniping of girder- and stiffener flanges in critical areas avoid termination of stiffeners and girders on plate fields avoid scallops where general stress levels are low avoid starts and stops of welding in corners and ends of stiffeners/brackets to improve fatigue properties of welded connections, welds and weld toes may be ground. I 200 Duct design 20 The duct(s) at transom shall be positioned in such a way as to give sufficient distance between the duct transom flange and ship side and bottom, and in the case of adjacent jets, between transom flanges, in order to allow flexing of transom plating, when ducts deflect due to the forces imposed by manoeuvring actions. Critical welded connections in the transom plate (duct transom flange/plating) shall be designed with respect to fatigue. 202 Geometry and details of tunnel to be specified based on results from tank tests if experience from comparable installation is not available. Documentation of such tank tests shall be submitted for information upon request. I 300 Design loads 30 The following loading conditions are normally to be considered: crash stop maximum reversing load, from 0 knots maximum steering load waterjet unit weight accelerated as cantilever in pitching high cycle loads from impeller pulses, if available from the manufacturer. Design forces/moments and information regarding weights shall be specified by the manufacturer of the waterjet.

16 Rules for High Speed, Light Craft and Naval Surface Craft, January 2005 Amended July 20, see page 3 Pt.3 Ch.5 Sec. Page 6 I 400 Allowable stresses 40 For the crash stop load case, the maximum allowable stress for the duct and transom structure is as follows: normal stress: σ = 80 f N/mm 2 shear stress: τ = 00 f N/mm For the steering, reversing and cantilever bending, the maximum allowable stresses shall be based on fatigue life considerations. The number of cycles for each load case shall be based on the expected operational time during 20 years lifetime of the craft and should normally not be taken less than: 0 5 cycles for reversing loads 0 6 cycles for steering loads 0 7 cycles for pitching loads for craft operating under the widest service restrictions. Alternative cycles shall be specified. Guidance note: Classification Note 30.8 Strength Analysis of High Speed and Light Craft is based on the number of cycles related to 2 hours operation per day in average. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e For fatigue assessment of the duct, a fine mesh finite element analysis of the duct may be required undertaken and submitted for information upon request. The fatigue assessment may be based on the Miner-Palmgren rule for accumulated fatigue damage, and the ECCS "European recommendations for aluminium alloy structures fatigue design". I 500 Bolt connections 50 The number of bolts for standard flange connections is normally not to be less than: N b = t f + d w where: D b = the diameter to bolt centre d w = the diameter nut/washer t f = the thickness of the aluminium flange. For duct flanges of other material than aluminium, the bolt connection shall be considered in each case. 502 Insulating gaskets and washers (if fitted) shall be thin and have high modulus of elasticity. 503 Documentation regarding pretension, calculated bolt maximum forces/stresses, as well as dynamic forces/ stresses, shall be submitted for information upon request. π D b

17 Amended July 20, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2005 Pt.3 Ch.5 Sec.2 Page 7 SECTION 2 STEERING ARRANGEMENT A. General A 00 Introduction 0 Craft shall be provided with approved means for steering (directional control) of adequate strength and suitable design. The means of steering shall enable the craft s heading and direction of travel to be effectively controlled without undue physical effort at all speeds and conditions for which the craft has been certified. This shall be demonstrated at seatrial. 02 Steering may be achieved by means of air or water rudders, foils, flaps, steerable propellers or jets, yaw control ports or side thrusters, differential propulsive thrust, variable geometry of the craft or its lift system components, or by any combination of these devices. 03 Requirements for rudders, flaps and foils are given in Sec.. For requirement for steering gear operating the rudder or flaps, reference is made to Pt.4 Ch.4 Sec.. If steering is achieved by means of waterjet, reference is made to Sec. I and to Pt.4 Ch.5 Sec.2. If steering is achieved by thrusters, reference is made to Pt.4 Ch.5 Sec The basic principle is that craft shall be provided with at least two alternative means for steering. The second, the auxiliary, need not however, be designed for all operational speeds and conditions, but shall be capable of steering the craft at navigable speed. 05 A single failure in one of the steering systems shall not render the other one inoperative. 06 For single screw craft, steering arrangement based on a single rudder may be accepted.

18 Rules for High Speed, Light Craft and Naval Surface Craft, January 2005 Amended July 20, see page 3 Pt.3 Ch.5 Sec.3 Page 8 SECTION 3 ANCHORING AND MOORING EQUIPMENT A. General A 00 Introduction 0 The requirements in this Section apply to equipment and installation for anchoring and mooring. Text quoted from the International Code of Safety for High-Speed Craft (HSC Code) is printed in italics. 02 A primary assumption made in this chapter is that high speed craft will only need an anchor for emergency purposes. (HSC Code 6..) 03 The arrangements for anchoring, towing and berthing and the local craft structure, the design of the anchor, towing and berthing arrangements and the local craft structure should be such that risks to persons carrying out anchoring, towing or berthing procedures are kept to a minimum. (HSC Code 6..2) 04 All anchoring equipment, towing bitts, mooring bollards, fairleads, cleats and eyebolts should be so constructed and attached to the hull that in use up to design loads, the watertight integrity of the craft will not be impaired. Design loads and any directional limitations assumed should be listed in the craft operating manual. (HSC Code 6..3) A 200 Documentation 20 The following plans and particulars shall be submitted for approval: equipment number calculations equipment (list) including type of anchor, grade of anchor chain, type and breaking load of steel and fibre ropes anchor design if different from standard or previously approved anchor types. Material specification windlass design. Material specifications for cable lifters, shafts and couplings chain stopper design. Material specification towline fastening arrangement and details, stating towing force. 202 The following plans and particulars shall be submitted for information: arrangement of deck equipment. 203 «Det Norske Veritas certificates» will be required for the following items: anchor anchor chain cable/wire rope windlass wire ropes for mooring (works certificate from approved manufacturer will be accepted). 204 For instrumentation and automation, including computer based control and monitoring, see Pt.4 Ch.5 Sec.. A 300 Towing 30 Adequate arrangements should be provided to enable the craft to be towed in the worst intended conditions. Where towage shall be from more than one point a suitable bridle should be provided. (HSC Code 6.3.) 302 The towing arrangements should be such that any surfaces against which the towing cable may chafe (for example, fairleads), is of sufficient radius to prevent the cable being damaged when under load. (HSC Code 6.3.2) 303 The maximum permissible speed at which the craft may be towed should be included in the operating manual. (HSC Code 6.3.3) 304 The design towing force F T is given by: F T = 480 THP (N) THP= towing horsepower at 0 knots.

19 Amended July 20, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2005 Pt.3 Ch.5 Sec.3 Page Stresses for towing bollards are normally to give equivalent stress σ c not exceeding 60 f N/mm 2. The equivalent stress for bollards in combined bending and shear may be taken as: σ c = σ τ 2 ( N mm 2 ) σ = bending stress in N/mm 2 τ = shear stress in N/mm The towing arrangements and all bollards, eyebolts, fair leads and bitts should be so constructed and attached to the hull that in the event of their damage, the watertight integrity of the craft is not impaired. 307 Requirements to towlines are not a subject to classification. Lengths and breaking strength are, however, given in G00 to G500 as guidance. A 400 Berthing 40 Where necessary, suitable fairleads, bitts and mooring ropes should be provided. (HSC Code 6.4.) 402 Adequate storage space for mooring lines should be provided such that they are readily available and secured against the high relative wind speeds and accelerations which may be experienced. (HSC Code 6.4.2) B. Structural Arrangement for Anchoring Equipment B 00 General 0 High speed craft should be provided with at least one anchor with its associated cable or cable and warp and means of recovery. Every craft should be provided with adequate and safe means for releasing the anchor and its cable and warp. (HSC Code 6.2.) 02 Good engineering practice should be followed in the design of any enclosed space containing the anchor-recovery equipment to ensure that persons using the equipment are not put at risk. Particular care should be taken with the means of access to such spaces, the walkways, the illumination and protection from the cable and the recovery machinery. (HSC Code 6.2.2) 03 Adequate arrangements should be provided for two- way voice communication between the operating compartment and persons engaged in dropping, weighing or releasing the anchor. (HSC Code 6.2.3) 04 The anchoring arrangements should be such that any surfaces against which the cable may chafe (for example, hawse pipes and hull obstructions) are designed to prevent the cable from being damaged and fouled. Adequate arrrangements should be provided to secure the anchor under all operational conditions. (HSC Code 6.2.4) 05 The craft should be protected so as to minimize the possibility of the anchor and cable damaging the structure during normal operation. (HSC Code 6.2.5) 06 The anchors are normally to be housed in hawse pipes of suitable size and form to prevent movement of anchor and chain due to wave action. The arrangements shall provide an easy lead of the chain cable from the windlass to the anchors. Upon release of the brake, the anchor is immediately to start falling by its own weight. At the upper and lower ends of hawse pipes, there shall be chafing lips. The radius of curvature at the upper end should be such that at least 3 links of chain bear simultaneously on the rounded part. Alternatively, roller fairleads of suitable design may be fitted. Where hawse pipes are not fitted alternative arrangements will be specially considered. 07 The shell plating in way of the hawse pipes shall be increased in thickness and the framing reinforced as necessary to ensure a rigid fastening of the hawse pipes to the hull. 08 The chain locker shall have adequate capacity and a suitable form to provide a proper stowage of the chain cable, and an easy direct lead for the cable into the chain pipes, when the cable is fully stowed. Port and starboard cables shall have separate spaces. The chain locker boundaries and access openings shall be watertight. Provisions shall be made to minimize the probability of chain locker being flooded in bad weather. Adequate drainage facilities of the chain locker shall be adopted. Provisions shall be made for securing the inboard ends of chain to the structure. This attachment shall be able to withstand a force of not less than 5%, nor more than 30%, of the minimum breaking strength of the chain cable. The fastening of the chain to the craft shall be made in such a way that in case of emergency when anchor and chain have to be sacrificed, the chain can be readily made to slip from an accessible position outside the chain locker. 09 The windlass and chain stoppers shall be efficiently bedded to the deck. The deck plating in way of windlass and chain stopper shall be increased in thickness and supported by pillars carried down to rigid structures. 0 Ships with bulbous bow or other protruding hull parts shall be reinforced in areas exposed to anchor/chain.

20 Rules for High Speed, Light Craft and Naval Surface Craft, January 2005 Amended July 20, see page 3 Pt.3 Ch.5 Sec.3 Page 20 C 00 Equipment number 0 The equipment number is given by the formula: H a h i θ A C. Equipment Specification EN = Δ BH+ 0.A = effective height in m from the summer load waterline to the top of the uppermost deckhouse, to be measured as follows: H = a + Σ h i sin θ = distance in m from summer load waterline amidships to the upper deck at side = height in m on the centreline of each tier of houses having a breadth greater than B/4. For the lowest tier, h i shall be measured at centre line from the upper deck, or from a notional deck line where there is local discontinuity in the upper deck = angle of inclination aft of each front bulkhead = area in m 2 in profile view of the hull, superstructures and houses above the summer load waterline, which is within L of the craft. Houses of breadth less than B/4 shall be disregarded. In the calculation of Σ h i and A, sheer and trim shall be ignored. Windscreens or bulwarks and hatch coamings more than.5 m in height above deck at side shall be regarded as parts of superstructures and of houses when determining H and A. The total area of the mentioned items measured from the deck, shall be included. 02 For catamarans the cross-sectional area of the tunnel above the waterline may be deducted from BH in the formula. C 200 Equipment tables 20 The equipment is in general to be in accordance with the requirements given in Table C reduced as per Table C2 in accordance with service restriction notation. 202 The required equipment of anchors and cables is suitable only for use in reasonably sheltered conditions, or in emergencies. 203 If the anchoring equipment is intended to be used during operations in open sea, the equipment will be considered in each case. Table C Equipment table, general Equipment No Equipment letter a 0 l a 0 l 2 al al 2 bl bl 2 cl cl 2 dl dl 2 el el 2 fl fl 2 gl gl 2 hl hl 2 il il 2 Number Anchors Stud-link chain cables 3) Rope alternatives Diameter and steel grade Mass per anchor kg Total length NV HHP ) SHHP 2) K m mm NV K2 mm NV K3 mm Minimum breaking strength kn Mooring lines Steel or fibre ropes Minimum number and length m 2 x 40 2 x 40 3 x 40 3 x 40 3 x 50 3 x 50 3 x 55 3 x 55 3 x 55 3 x 55 3 x 60 3 x 60 3 x 60 3 x 60 3 x 60 3 x 60 4 x 60 4 x 60 4 x 60 4 x 60 Minimum breaking strength kn

21 Amended July 20, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2005 Pt.3 Ch.5 Sec.3 Page 2 Table C Equipment table, general (Continued) jl jl kl kl ll ll ml ml nl nl ol ol pl pl ql ql rl rl sl sl tl tl ul ul vl vl wl wl ) HHP = ordinary high holding power anchors. 2) SHHP = super high holding power anchors. 3) Chain cable may be substituted by wire or synthetic fibre rope, according to E x 70 4 x 70 4 x 70 4 x 70 4 x 70 4 x 70 4 x 70 4 x 70 4 x 70 4 x 70 4 x 80 4 x 80 4 x 80 4 x 80 4 x 85 4 x 85 4 x 85 4 x 85 4 x 90 4 x 90 4 x 90 4 x 90 4 x 90 5 x 90 5 x 95 5 x 95 5 x 95 5 x Table C2 Equipment reductions for service restriction notations (see Table C) Bower anchors Stud-link chain cables Class Mass notation Number change per Length Diameter anchor change R0, R, R2, R3 R0, R, R2, R3 2 2 Alternative No red. No red. 30% No red. Alternative 2 30% + 60% 50% + 60% No red. No red. No red. No red. R4 will be specially considered. D 00 General 0 Anchor types dealt with are: H.H.P. («High Holding Power») anchor S.H.H.P. («Super High Holding Power») anchor. D. Anchors 02 When two anchors are chosen, the mass of individual anchors may vary by ± 7% of the table value, provided that the total mass of anchors is not less than would have been required for anchors of equal mass. The mass of the head shall not be less than 60% of the table value. 03 For anchors approved as H.H.P. anchors, the letter r will follow the equipment letter entered in the Register of Ships. 04 For anchors approved as S.H.H.P. anchors, the letters rs will follow the equipment letter entered in the Register of Ships.