Section 8 Anchor windlass design and testing

8.1.1 A windlass, capstan or winch used for handling anchors, suitable for the size of chain cable required by Vol 1, Pt 3, Ch 5, 5 Anchor cable and complying with the following criteria is to be fitted. Where Owners require equipment significantly in excess of Rule requirements, it is their responsibility to specify increased windlass power.

8.1.2 The design, construction and testing of windlasses are to conform with a relevant National or International Standard or code of practice acceptable to LR. To be considered acceptable, the standard, or code of practice, is to specify criteria for evaluation of stresses, performance and testing.

8.1.3 Operation and maintenance procedures for the anchor windlass are to be incorporated in the vessel operations manual.

8.3.1 Materials used in the construction of torque-transmitting and load-bearing parts of windlasses are to comply with LR's Rules for the Manufacture, Testing and Certification of Materials, July 2022 or an appropriate National or International Standard acceptable to LR, provided that the Standard gives reasonable equivalence to the requirements of LR. The proposed materials are to be indicated in the construction plans and are to be approved in connection with the design. All such materials are to be certified by the material manufacturers and are to be traceable to the manufacturers’ certificates.

8.3.2 Weld joint designs are to be shown in the submitted construction plans and are to be appraised in association with the approval of the windlass design in accordance with an appropriate National or International Standard acceptable to LR. .

8.3.3 Welding procedures, welding consumables and welders are to comply with the LR Rules for the Manufacture, Testing and Certification of Materials, July 2022 or an appropriate National or International Standard acceptable to LR.

8.3.4 The degree of non-destructive examination of welds and post-weld heat treatment, if any, are to be specified and submitted for consideration.

8.4.1 In addition to the requirements of the National or International Standard or code of practice acceptable to LR (see Vol 1, Pt 3, Ch 5, 8.1 General 8.1.2) the following performance requirements are to be complied with:

1. Holding Loads: Calculations are to be made to show that, in the holding condition (single anchor, brake fully applied and chain cable lifter declutched) and under a load equal to 80 per cent of the specified minimum breaking strength of the chain cable, the maximum stress in each load bearing component will not exceed the maximum permissible yield. For installations fitted with a chain cable stopper, 45 per cent of the specified minimum breaking strength of the chain cable may instead be used for the calculation.
2. Inertia Loads: The design of the drive train, including prime mover, reduction gears, bearings, clutches, shafts, cable lifter and bolting is to consider the dynamic effects of sudden stopping and starting of the prime mover or chain cable, so as to limit inertial load.
3. Continuous Duty Pull: The windlass is to have sufficient power to exert a continuous duty pull , Z_cont1, over a period of 30 minutes corresponding to the grade and diameter, d_c, of the chain cables as follows:
   1. for specified design anchorage depths up to 82,5 m when using ordinary stockless anchors: :

      Chain cable grade	Zcont1 (N)
      U1	37,5d c 2
      U2	42,5d c 2
      U3	47,5d c 2

   2. for specified design anchorage depths greater than 82,5 m a continuous duty pull Z_cont2 is:
      
      where

      dc	=	is the chain diameter, in mm
      Da	=	is the specified design anchorage depth, in metres

   The anchor masses are assumed to be the masses as given in Table 5.6.1 Equipment - Kedge anchors and wires, towlines and mooring lines. The value of Z_cont is based on the hoisting of one anchor at a time, and assumes that the effects of buoyancy and hawse pipe efficiency (assumed to be 70 per cent) have been accounted for. In general, stresses in each torque-transmitting component are not to exceed 40 per cent of yield strength (or 0,2 per cent proof stress) of the material under these loading conditions.

4. Overload Capability: The windlass prime mover is to be able to provide, for a period of at least two minutes, the necessary temporary overload capacity for breaking out the anchor. This temporary overload capacity is to be a pull equal to the greater of:

   1. short term pull:

      1,5 times the continuous duty pull as defined in Vol 1, Pt 3, Ch 5, 8.4 Windlass design 8.4.1.(c), or

   2. anchor breakout pull:

      
      where:

      Lc	=	is the total length of chain cable on board, in metres, as given by Table 5.4.1 Equipment - HHP Bower anchors and chain cables
      W	=	is the mass of bower anchor(kg) as given in Table 5.4.1 Equipment - HHP Bower anchors and chain cables.

   Note The speed in this period may be lower than normal.
5. Hoisting Speed: The mean speed of the chain cable during hoisting of the anchor and cable is to be 0,15 m/s.
6. Brake Capacity: The capacity of the windlass brake is to be sufficient to stop the anchor and chain cable when paying out the chain cable in a controlled manner. Where a chain cable stopper is not fitted, the brake is to produce a torque capable of withstanding a pull equal to 80 per cent of the specified minimum breaking strength of the chain cable without any permanent deformation of strength members and without brake slip. Where a chain cable stopper is fitted, 45 per cent of the breaking strength may instead be applied. The following simplified formula is to be used to calculate the required brake capacity:

   K _b d _c ² (44 − 0,08d _c) N

   where K _b is given in Table 5.8.1 Values of K_b .

8.4.2 As an alternative to conducting the engineering analyses required by Vol 1, Pt 3, Ch 5, 8.4 Windlass design 8.4.1, approval of the windlass mechanical design can be based on a type test, in which case the testing procedure is to be submitted for consideration.

8.4.3 Calculations for torque transmitting components are to be based on 1500 hours of operation with a nominal load spectrum factor of K_m = 1,0. Alternatively unlimited hours with a nominal load spectrum factor of K_m = 0,8 can be applied.

8.4.4 The following criteria are to be used for gearing design:

1. Torque is to be based on the performance criteria specified in Vol 1, Pt 3, Ch 5, 8.4 Windlass design 8.4.1.

2. The use of an equivalent torque, T_eq, for dynamic strength calculations is acceptable but the derivation is to be submitted to LR for consideration.

3. The application factor for dynamic strength calculation, K_A, is to be 1,15.

4. Calculations are to be based on 1500 hours of operation.

5. The static torque is to be 1,5 x T_n where T_n is the nominal torque.

6. The minimum factors of safety for load capacity of spur and helical gears, as derived using ISO 6336 or a relevant National or International standard acceptable to LR, are to be 1,5 for bending stress and 0,6 for contact stress.

Gears intended to transmit power greater than 100 kW are to be certified by LR, and the gears are to meet the requirements of Vol 2, Pt 3, Ch 1 Gearing.

8.5.1 Hand-operated windlasses are only acceptable if the effort required at the handle does not exceed 150N for raising one anchor at a speed of not less than 2 m/min and making about thirty turns of the handle per minute.

8.5.2 Windlasses suitable for operation by hand as well as by external power are to be so constructed that the power drive cannot activate the hand drive.

8.5.3 Where a chain stopper is fitted, the windlass braking system is only to ensure safe stopping when paying out the anchor and chain. It is the Master's responsibility to ensure that the chain stopper is in use when riding at anchor. At clearly visible locations on the bridge and adjacent to the windlass control position, the following notice is to be displayed:

“The brake is rated to permit controlled descent of the anchor and chain only. The chain stopper is to be used at all times whilst riding at anchor“

8.6.1 Hydraulic systems, where employed for driving windlasses, are to comply with the requirements of Vol 2, Pt 7, Ch 5, 11 Hydraulic power actuating systems.

8.7.1 Electric motors are to meet the requirements of Vol 2, Pt 9, Ch 3, 6 Rotating machines – general requirements and motors. Motors exposed to weather are to have enclosures suitable for their location, see also Vol 2, Pt 9, Ch 1, 2.2 Design, construction and location 2.2.10.

8.7.2 Motor branch circuits are to be protected in accordance with the applicable Rules, and cable sizing is to be in accordance with the requirements of the Vol 2, Pt 9, Ch 3, 8 Electric cables, optical fibre cables and busbar trunking systems (busways).

8.8.1 All control devices are to be capable of being controlled from readily accessible positions and protected against unintentional operation.

8.8.2 The maximum travel of the levers is not to exceed 600 mm if movable in one direction only, or 300 mm to either side from a central position if movable in both directions.

8.8.3 Wherever practical, the lever is to move in the direction of the intended movement. If this cannot be achieved, it is to move towards the right when hauling and towards the left when paying out.

8.8.4 For lever-operated brakes, the brake is to engage when the lever is pulled and disengage when the lever is pushed. The physical effort on the brake for the operator is not to exceed 160 N.

8.8.5 For pedal-operated brakes, the maximum travel is not to exceed 250 mm and the physical effort for the operator is not to exceed 320 N.

8.8.6 The handwheel or crankhandle is to actuate the brake when turned clockwise and release it when turned counterclockwise. The physical effort for the operator is not to exceed 250 N for speed regulation and 500 N at any moment.

8.8.7 When not provided with automatic sequential control, separate push-buttons are to be provided for each direction of operation.

8.8.8 The push-buttons are to actuate the machinery when depressed and stop and effectively brake the machinery when released.

8.8.9 The above mentioned individual push-buttons may be replaced by two ‘start’ and ‘stop’ push-buttons.

8.8.10 Control systems for windlasses are to comply with the requirements of Vol 2, Pt 9, Ch 8, 5 Programmable electronic systems (PES).

8.8.11 Windlass motors are to be protected against overload, overspeed and overpressure, using appropriate safety techniques suitable for the intended installation.

8.9.1 Where applicable, moving parts of windlass machinery are to be provided with suitable railings and/or guards to prevent injury to personnel.

8.9.2 Protection is to be provided for preventing persons from coming into contact with surfaces having temperatures over 50°C.

8.9.3 Steel surfaces not protected by lubricant are to be protected by a coating, in accordance with the requirements of a relevant National or International Standard acceptable to LR.

8.9.4 For arrangements of power transmission systems and relief requirements, see Vol 2, Pt 7, Ch 5, 11.1 General 11.1.2.

8.9.5 Electrical cables installed in exposed locations on open deck are to be provided with effective mechanical protection.

8.9.6 Means are to be provided to contain potential debris resulting from severe damage of the prime mover due to over-speed in the event of uncontrolled rendering of the cable, particularly when an axial piston type hydraulic motor forms the prime mover.

8.9.7 An arrangement to release the anchor and chain in the event of windlass power failure is to be provided. Windlasses are to be fitted with couplings which are capable of disengaging between the cable lifter and the drive shaft. Hydraulically or electrically operated couplings are to be capable of being disengaged manually.

8.9.8 The design of the windlass is to be such that the following requirements or equivalent arrangements will minimise the probability of the chain locker or forecastle being flooded in bad weather:

1. a weathertight connection can be made between the windlass bedplate, or its equivalent, and the upper end of the chain pipe by means of a cover or seal, and
2. access to the chain pipe is adequate to permit the fitting of a cover or seal, of sufficient strength and proper design, over the chain pipe while the ship is at sea.

8.10.1 Windlasses are to be inspected during fabrication at the manufacturers’ facilities by a Surveyor for conformance with the approved plans. Acceptance tests, as specified in the specified Standard (see Vol 1, Pt 3, Ch 5, 8.1 General 8.1.2), are to be witnessed by the Surveyor and include the following tests, as a minimum:

1. No-load test. The windlass is to be run without load at nominal speed in each direction for a total of 30 minutes. If the windlass is provided with a gear change, an additional run in each direction for 5 minutes at each gear change is required.
2. Load test. The windlass is to be tested to verify that the continuous duty pull, overload capacity and hoisting speed as specified in Vol 1, Pt 3, Ch 5, 8.4 Windlass design 8.4.1 can be achieved.

   Where the manufacturer’s works does not have adequate facilities, these tests, including the adjustment of the overload protection, can be carried out on board ship. In these cases, functional testing in the manufacturer’s works is to be performed under no-load conditions.

3. Brake capacity test. The holding power of the brake is to be verified through testing if not verified by calculation.

8.10.2 Windlass performance characteristics specified in Vol 1, Pt 3, Ch 5, 8.10 Shop inspection and testing 8.10.1 are based on the following assumptions:

1. one cable lifter only is connected to the drive shaft;

2. continuous duty and short term pulls are measured at the cable lifter;

3. hawse pipe efficiency assumed to be 70 per cent.

8.11.1 Each windlass is to be tested under working conditions after installation on board to demonstrate satisfactory operation. Each unit is to be independently tested for braking, clutch functioning, lowering and hoisting of the chain cable and anchor, proper riding of the chain over the cable lifter, proper transit of the chain through the hawse pipe and the chain pipe, and effecting proper stowage of the chain and the anchor. It is to be confirmed that anchors properly seat in the stored position and that chain stoppers function as designed, if fitted. The braking capacity is to be tested by intermittently paying out and holding the chain cable by means of the application of the brake.

8.11.2 The mean hoisting speed, as specified in Vol 1, Pt 3, Ch 5, 8.4 Windlass design 8.4.1.(e) is to be measured and verified. For testing purposes, the speed is to be measured over two shots of chain cable and initially with at least three shots of chain (82.5 m or 45 fathoms in length) and the anchor submerged and hanging free.

8.11.3 Load testing is to be carried out if this was not previously completed as required by Vol 1, Pt 3, Ch 5, 8.10 Shop inspection and testing 8.10.1.(b).

8.11.4 Where the depth of water in the trial area is inadequate, suitable equivalent simulating conditions will be considered as an alternative.

8.12.1 The windlass is to be permanently marked with the following information:

1. The size designation of the windlass (e.g. 100/3/45, where 100 is the nominal diameter of the chain cable in mm, 3 is the numeral in the chain cable steel grade U3, and 45 refers to the holding load expressed as a percentage of the chain cable breaking load).
2. Maximum anchorage depth, in metres.

8.13.1 The windlass is to be efficiently bedded and secured to the deck. The thickness of the deck in way of the windlass is to be increased, and the supporting structure for the anchor windlass should be examined for the brake holding loads specified by Vol 1, Pt 3, Ch 5, 8.4 Windlass design. The allowable stresses specified in Table 5.5.1 Allowable stresses in windlass and chain stopper supporting structure are to be used to derive the net scantlings of the supporting structure. The capability of the supporting structure to withstand buckling is also to be assessed. The structural design integrity of the bedplate is the responsibility of the Builder and windlass manufacturer.

8.14.1 Windlasses located on the exposed deck over the forward 0,25L_R of the Rule length, of naval ships of sea-going service of length 80 m or more, where the height of the exposed deck in way of the item is less than 0,1L_R or 22 m above the design draught, whichever is the lesser, are to comply with the following requirements. Where mooring winches are integral with the anchor windlass, they are to be considered as part of the windlass.

where

Px	=	force acting normal to the shaft axis, in kN
Py	=	force acting parallel to the shaft axis, either inboard or outboard whichever gives the greater force in bolt group i, in kN
h	=	shaft height above the windlass mounting, in cm
xi, yi	=	x and y coordinates of bolt group i from the centroid of all N bolt groups, positive in the direction opposite to that of the applied force, in cm
Ai	=	cross-sectional area of all bolts in group i, in cm2
Ix	=	for N bolt groups, in cm4
Iy	=	for N bolt groups, in cm4
Rsi	=	static reaction at bolt group i, due to weight of windlass, in kN.

8.14.6 Tensile axial stresses in the individual bolts in each bolt group i are to be calculated. The horizontal forces Fxi and Fyi are normally to be reacted by shear chocks. Where ‘fitted’ bolts are designed to support these shear forces in one or both directions, the von Mises equivalent stresses in the individual bolts are to be calculated, and compared to the stress under proof load. Where pourable resins are incorporated in the holding down arrangements, due account is to be taken in the calculations.

8.14.7 The safety factor against bolt proof strength is to be not less than 2,0.

8.14.8 Bolts are to be of lSO 898/1 material Grade 8.8, 10.9 or 12.9 or equivalent and are to be pretensioned by controlled means to 70 to 90 per cent of their yield stress. Pretensioning is to be in accordance with the manufacturer’s instructions and, in general, pretensioning by bolt torqueing up to bolt size M30 may be used. Beyond this, pretensioning is to be carried out by an hydraulic tensioning device and the elongation of the bolts measured to determine pre-load. Where resin chocks are proposed, plans and calculations are to be submitted for consideration.

The allowable stresses specified in Pt 3, Ch 13, 8.12 Structural requirements associated with anchoring 8.12.2 are to be used to derive the net scantlings of the supporting structure. The capability of the supporting structure to withstand buckling is also to be assessed.

8.14.10 The axial tensile and compressive forces in Vol 1, Pt 3, Ch 5, 8.14 Structural requirements for windlasses on exposed fore decks 8.14.4 and the lateral forces in Vol 1, Pt 3, Ch 5, 8.14 Structural requirements for windlasses on exposed fore decks 8.14.5 are also to be considered in the design of the supporting structure.