Formulas

Question 1

3 methods for calculating squat?

Answer 1

10% of the draught
0.3m for every knot of speed
V(2) knots/100

Question 2

LDL?

Answer 2

Draught + squat + safety (2m) - HOT

Question 3

Percentage Springs?

Answer 3

HOT - (MHWN - MLWN)/(MHWS-MLWS) - (MHWN - MLWN)

Question 4

Calculating tidal stream?

Answer 4

Percentage springs x known stream

Question 5

Safety swing circle?

Answer 5

Total length of shackle + ships length + safety (200x)

Question 6

Minimum expected depth?

Answer 6

(Charted depth + HOT) - (draught + squat)

Question 7

Anchor drag circle?

Answer 7

Length of cable veered + Ships length + error allowance (50x)

Question 8

Shackle required for anchorage (depth in meters)?

Answer 8

1&1/2 x square root of depth in m

Question 9

Shackles required for anchorage (depth in fathoms)?

Answer 9

2&1/2 x square root of depth in m

Question 10

Block coefficient?

Answer 10

volume of displacement/ length x breadth x draught

Question 11

100% onset depth

Answer 11

Velocity (knots) x 0.17 (3) root of displacement in tonnes

Question 12

Visible Horizon

Answer 12

2.1 x square root of HOE (m)

Question 13

Raw SOA

Answer 13

raw distance/passage time

Question 14

Revised SOA

Answer 14

passage time - zero PIM

Question 15

Passage time

Answer 15

Last line to first line time - pilotage time

Question 16

Time in hand

Answer 16

total time - (distance/intended speed)