Doc No: FM0484
Version: 1
Refer to Underkeel Clearance (UKC) (SP0413) and Squat Effect on Draft (SP0118) for further information.
* File a copy of this form in binder: Navigating Officer #3 for a minimum period of 3 years
NOTE: Page 1 of this form shall be completed for each section of the passage where the anticipated static underkeel
clearance has been judged to be less than 3.5 metres. It should also be completed if deemed necessary by the master.
Page 2 (Table 5.) of this form shall be prepared in anticipation of various drafts and speeds and shall be available on the
bridge at all times. This need not be re-calculated for every voyage.
Calculation of Deepest Draft & Under Keel Clearance
Vessel: Eta Date/Time LT
Port:
1. Anticipated Controlling / Minimum Depth Metres Remark
Depth of channel Location: 9.000
Correction Tide 1.000
Weather
Other
Anticipated controlling depth: (after corrections) 10.000
2. Calculated Maximum Draft Metres 3. Transit Speed Calculation
Vessel's maximum draft (static) 5.530 Planned Speed over ground 2.0 Kts
Correction List / Roll / Trim / Swell Effect of tide (+/-) 1.0 Kts
Water density: 1.020 Effect of current (+/-) Kts
Estimated Squat effect (Table 5) Effective Speed through water 3.00 Kts
This speed is to be taken into account to
Calculated Maximum Draft: (after corrections) 6.550
derive squat
4. Dynamic Underkeel Clearance Calculation Metres Remarks
Anticipated controlling / minumum depth: (after corrections) 10.000
Calculated Maximum Draft (after corrections) 6.550
Dynamic Underkeel Clearance 3.450
Approved
Date: Officer: by Master: Capt. Gunnar Rosengren
Time: Signature: Signature:
SALLIE KNUTSEN
Effect Of Squat in Confined Waters on Vessel’s Draft (in metres)
Draft in metres (Enter range of draft and corresponding Cb suitable to your vessel)
Draft
9.00 9.50 10.00 10.50 11.00 11.50 12.00 12.50 13.00 13.50 14.00 14.50 15.00 15.50 16.00
Cb
0.774 0.779 0.783 0.787 0.791 0.795 0.799 0.803 0.807 0.811 0.815 0.818 0.822 0.825 0.828
1.00
0.015 0.016 0.016 0.016 0.016 0.016 0.016 0.016 0.016 0.016 0.016 0.016 0.016 0.016 0.01656
3.00
0.139 0.14 0.141 0.142 0.142 0.143 0.144 0.145 0.145 0.146 0.147 0.147 0.148 0.148 0.14906
Vessel’s Speed through water in Knots ( V )
5.00
0.387 0.389 0.391 0.393 0.395 0.397 0.4 0.402 0.404 0.405 0.407 0.409 0.411 0.412 0.41405
6.00
0.557 0.561 0.563 0.566 0.569 0.572 0.575 0.578 0.581 0.584 0.587 0.589 0.592 0.594 0.59623
7.00
0.759 0.763 0.767 0.771 0.775 0.779 0.783 0.787 0.791 0.795 0.798 0.802 0.805 0.808 0.81154
8.00
0.991 0.996 1.002 1.007 1.012 1.017 1.023 1.028 1.033 1.038 1.043 1.047 1.052 1.056 1.05997
9.00
1.254 1.261 1.268 1.275 1.281 1.288 1.294 1.301 1.307 1.314 1.32 1.325 1.331 1.336 1.34152
10.00
1.549 1.557 1.565 1.574 1.582 1.59 1.598 1.606 1.614 1.622 1.629 1.636 1.643 1.65 1.6562
11.00
1.874 1.884 1.894 1.904 1.914 1.924 1.934 1.943 1.953 1.962 1.971 1.98 1.988 1.996 2.004
12.00
2.23 2.242 2.254 2.266 2.278 2.289 2.301 2.313 2.324 2.335 2.346 2.356 2.366 2.376 2.38493
12.50
2.42 2.433 2.445 2.459 2.472 2.484 2.497 2.509 2.522 2.534 2.546 2.557 2.568 2.578 2.58781
13.00
2.617 2.631 2.645 2.659 2.673 2.687 2.701 2.714 2.728 2.741 2.753 2.766 2.777 2.788 2.79898
Above squat is calculated using the formula: V 2 x Cb / 50.
V is Speed through the water Squat effect in open waters is normally considered to be half of that
for confined waters. (ie V 2 x Cb / 100)
Cb is vessel’s Block coefficient at draft Refer to Squat Effect on Draft (GL0261) for further information.
Date: Officer: 2/O F. Betco Jr. Master: Capt. Gunnar Rosengren
Signature: Signature:
FM0484
