2 Equipment Number Calculation

2.1 Requirements

2.1.1

Anchors and chains are to be in accordance with Table 1 and the quantity, mass and sizes of these are to be determined by the equipment number (EN), given by:

where:

h : Effective height, in m, from the summer load waterline to the top of the uppermost house, to be obtained in accordance with the following formula:

h = h_FB + Σh_n

When calculating h, sheer and trim are to be disregarded. For the lowest tier h is to be measured at centreline from the upper deck or from a notional deck line where there is local discontinuity in the upper deck, as shown in Figure 1.

h_FB : Freeboard amidships from the summer load waterline to the upper deck, in m.

h_n : Height, in m, at the centreline of superstructure or of deckhouse tier ‘n’ having a breadth greater than B/4. Where a house having a breadth greater than B/4 is above a house with a breadth of B/4 or less, the upper house is to be included and the lower ignored.

A : Side projected area, in m², of the parts of the hull, superstructures and houses above the summer load waterline which are within the length L and also have a breadth greater than B/4.

Fixed screens or bulwarks 1.5 m or more in height are to be regarded as parts of houses when determining h and A. In particular, the hatched area shown in Figure 2 is to be included.

The height of hatch coamings and that of any deck cargo, such as containers, may be disregarded when determining h and A.

2.1.2

For ships with EN greater than 16000, the determination of the equipment will be considered by the Society on a case-by-case basis.

Figure 1: Measurement of heights

Figure 2 Profile areas of screens and bulwarks

Table 1 : Equipment - Bower anchors and chain cables

Equipment Number		Stockless bower anchors		Chain cable stud link bower chain
Greater than	Equal to or less than	Number of anchors ⁽¹⁾	Mass per anchor, in kg	Length, in m	Diameter, in mm
Greater than	Equal to or less than	Number of anchors ⁽¹⁾	Mass per anchor, in kg	Length, in m	Normal strength steel (Grade 1)	High strength steel (Grade 2)	Extra high strength steel (Grade3)
150	175	2	480	275	22	19	*
175	205	2	570	302.5	24	20.5	*
205	240	2	660	302.5	26	22	20.5
240	280	2	780	330	28	24	22
280	320	2	900	357.5	30	26	24
320	360	2	1020	357.5	32	28	24
360	400	2	1140	385	34	30	26
400	450	2	1290	385	36	32	28
450	500	2	1440	412.5	38	34	30
500	550	2	1590	412.5	40	34	30
550	600	2	1740	440	42	36	32
600	660	2	1920	440	44	38	34
660	720	2	2100	440	46	40	36
720	780	2	2280	467.5	48	42	36
780	840	2	2460	467.5	50	44	38
840	910	2	2640	467.5	52	46	40
910	980	2	2850	495	54	48	42
980	1060	2	3060	495	56	50	44
1060	1140	2	3300	495	58	50	46
1140	1220	2	3540	522.5	60	52	46
1220	1300	2	3780	522.5	62	54	48
1300	1390	2	4050	522.5	64	56	50
1390	1480	2	4320	550	66	58	50
1480	1570	2	4590	550	68	60	52
1570	1670	2	4890	550	70	62	54
1670	1790	2	5250	577.5	73	64	56
1790	1930	2	5610	577.5	76	66	58
1930	2080	2	6000	577.5	78	68	60
2080	2230	2	6450	605	81	70	62
2230	2380	2	6900	605	84	73	64
2380	2530	2	7350	605	87	76	66
2530	2700	2	7800	632.5	90	78	68
2700	2870	2	8300	632.5	92	81	70
2870	3040	2	8700	632.5	95	84	73
3040	3210	2	9300	660	97	84	76
3210	3400	2	9900	660	100	87	78
3400	3600	2	10500	660	102	90	78
3600	3800	2	11100	687.5	105	92	81
3800	4000	2	11700	687.5	107	95	84
4000	4200	2	12300	687.5	111	97	87
4200	4400	2	12900	715	114	100	87
4400	4600	2	13500	715	117	102	90
4600	4800	2	14100	715	120	105	92
4800	5000	2	14700	742.5	122	107	95
5000	5200	2	15400	742.5	124	111	97
5200	5500	2	16100	742.5	127	111	97
5500	5800	2	16900	742.5	130	114	100
5800	6100	2	17800	742.5	132	117	102
6100	6500	2	18800	742.5	*	120	107
6500	6900	2	20000	770	*	124	111
6900	7400	2	21500	770	*	127	114
7400	7900	2	23000	770	*	132	117
7900	8400	2	24500	770	*	137	122
8400	8900	2	26000	770	*	142	127
8900	9400	2	27500	770	*	147	132
9400	10000	2	29000	770	*	152	132
10000	10700	2	31000	770	*	*	137
10700	11500	2	33000	770	*	*	142
11500	12400	2	35500	770	*	*	147
12400	13400	2	38500	770	*	*	152
13400	14600	2	42000	770	*	*	157
14600	16000	2	46000	770	*	*	162
⁽¹⁾ Spare anchors are not included in the number of required anchors. Note 1: ’*’ chain grade not to be used at this diameter.