Anchors

3.2.1.1 Ships are to be provided with approved anchors, the number and mass of which are to comply with the requirements of Table 3.1.3.

3.2.1.2 It is recommended that ships operating in areas with the presence of cur-rents are provided with a permanent stream anchor. Application of the stream an-chor is decided by the Purcharser. When applied the stream anan-chor is to comply with the requirements of Table 3.1.3 and is to be ready to be used.

3.2.1.3 The requirements for materials, manufacture and tests of anchors are specified in Chapter 19, Part IX – Materials and Welding.

3.2.2 Number of Anchors

3.2.2.1 Two bow anchors, selected according to Table 3.1.3, are to be connected to chain cables and ready for use.

3.2.2.2 Upon PRS agreement, instead of two the ship may be equipped with one bow anchor provided that its mass is increased by 25%. The anchor chain should be adequate for the increased mass anchor.

3.2.3 Mass of Anchors

3.2.3.1 The mass of an individual bow anchor may vary by 2% from the value required in Table 3.1.3, provided that the total mass of all bow anchors is not less than that required for these anchors.

3.2.3.2 Where high holding power anchors are used, the mass of each of them may be equal to 75% of the anchor mass required by Table 3.1.3.

3.2.3.3 The mass of the head of a stockless anchor, including pins and fittings, is to be not less than 60% of the total mass of the anchor.

3.2.3.4 In the case of stocked anchors application, the mass of the stock is to be 20% of the total mass of the anchor, including the anchor shackle.

3.2.4 High Holding Power Anchors (HHP Anchors)

3.2.4.1 The anchor may be considered as a high holding power anchor (HHP anchor), provided that satisfactory comparative tests of previously approved ordi-nary stockless anchor are carried out at sea according to the requirements of 3.2.4.2 and 3.2.4.3.

3.2.4.2 The tests are to be carried out at sea on various types of bottom and are to be applied to anchors the weight of which is, as far as possible, representative of the full range of HHP anchors sizes proposed.

For a definite group of the range, the two anchors selected for testing (approved ordinary stockless anchor and HHP anchor) are to be approximately of the same weight and are to be tested in association with the size of chain cable appropriate to this weight. The tested anchor is to have a holding power at least twice that of an ordinary stockless anchor of the same weight.

The length of cable with each anchor is to be such that the pull on the shank re-mains practically horizontal. For this purpose, a scope of 10 is considered normal, but a scope of not less than 6 may be accepted. Three tests are to be carried out for each anchor and nature of bed. The pull is to be measured by dynamometer. The stability of the anchor and ease at breaking out should be noted where possible.

Measurements of pull based on RPM/bollard pull curve of tug may be accepted instead of dynamometer readings. Tests are normally to be carried out from tug but alternatively shore based tests may be accepted. For the tests, previously approved HHP anchors may be used instead of ordinary stockless anchors.

3.2.4.3 For approval of HHP anchors of the whole range of weight, tests are to be carried out on at least two sizes of anchors and the weight of the maximum size to be approved is not to exceed 10 times the weight of large size tested.

3.2.5 Super High Holding Power (SHHP) Anchors

3.2.5.1 The anchor may be considered as super high holding power anchor (SHHP anchor), provided that comparative tests of previously approved ordinary stockless anchor are carried out in accordance with the requirements of 3.2.5.4, 3.2.5.5 and 3.2.5.6.

3.2.5.2 SHHP anchor is to have a holding power of at least four times that of an ordinary stockless anchor or at least two times that of HHP anchor, of the same mass.

3.2.5.3 When super high holding power anchors of the proven holding power are used as bow anchors, the mass of each such anchor may be reduced to not less than 50% of the mass required for ordinary stockless anchors specified in Table 3.1.3.

3.2.5.4 The tests, required in 3.2.5.1, are to be carried out at sea on three types of bottom: soft mud or silt, sand or gravel and hard clay or similar compounded mate-rial. The tests are to be applied to anchors of mass which is, as far as possible, rep-resentative of the full range of sizes proposed.

For a definite group within the range, the two anchors selected for testing, i.e.

ordinary stockless and SHHP anchor are to be approximately of the same mass and are to be tested in association with the size of chain required for the anchor mass and anchor type. Where an ordinary stockless anchor is not available, a previously approved HHP anchor may be used in its place. The length of the cable with each anchor is to be such that the pull on the shank remains practically horizontal. For this purpose a scope of 10 is considered sufficient. Three tests are to be taken for each anchor and each type of bottom. The pull is to be measured by dynamometer.

The stability of the anchor and ease of breaking out should be noted where possi-ble. Tests are to be carried out from a tug but alternatively shore based tests may be accepted.

Measurements of pull, based on the RPM/bollard pull curve of tug, may be ac-cepted as an alternative to dynamometer.

Comparative tests with a previously approved SHHP anchor may be also ac-cepted as a basis for approval.

3.2.5.5 If approval is sought for a range of SHHP anchor sizes, then at least three anchor sizes are to be tested, indicative of the bottom, middle and top of the mass range.

3.2.5.6 The holding power test load is not to exceed the proof load of the anchor.

3.3 Anchor Chains and Anchor Wire Ropes