FIGURE I-9

Tug power estimate required to hold 80-MDWT fully loaded tanker

Sig. Wave H

Wind Speed

Tanker Resistance

Tug Resist.

Minimum Bollard

Est. Loss of Efficiency

Required Bollard

Estimated Tug BHP

Wind

Wave

Total

meters

kn

tons

tons

tons

tons

tons

%

tons

HP

4

30

11

20

31

3

34

20

40

3000

5

35

14

31

45

4

49

22

60

4500

6

40

19

45

64

5

69

24

85

6400

7

45

24

76

100

7

107

26

135

10100

10

50

30

79

109

9

118

28

150

11300

Note: Loss of efficiency is estimate to show effect of motions on effective tug power.

FIGURE I-10

Tug power estimate required to hold 140-MDWT fully loaded tanker.

Sig. Wave H

Wind Speed

Tanker Resistance

Tug Resist.

Minimum Bollard

Est. Loss of Efficiency

Required Bollard

Estimated Tug BHP

Wind

Wave

Total

meters

kn

tons

tons

tons

tons

tons

%

tons

HP

4

30

14

22

36

3

39

20

46

3500

5

35

19

36

55

4

59

22

71

5400

6

40

24

54

78

5

83

24

103

7700

7

45

31

95

126

7

133

26

167

12500

10

50

38

121

159

9

168

28

215

16100

Note: Loss of efficiency is estimate to show effect of motions on effective tug power.



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