Draft Sib Sailing

  • View

  • Download

Embed Size (px)

Text of Draft Sib Sailing








DATE: xx/xx/200X


CONTENTS General Particulars Diagram to show Draught mark locations Datum Reference Information Unit Conversion Table Arrangement of Tanks Sample Tank Capacity Table Notes to the Master General instructions Tank usage and free surface moments Masters shipboard procedures Precautions against capsize Notes on use of KN Curves Angles of down flooding General Stability Requirements Sample form for calculating Loading Condition Explanation and notes on completing Sample Stability Form Freeboard Loadline Marks Loading Conditions Hydrostatic Properties Cross Curve Stability Plot Appendix I Appendix II Inclining Experiment Results Minor Modifications


GENERAL PARTICULARS Ships Name Official Number Port of Registry Owners name and address Classification Society Builder Yard Number Date of keel laying Dimensions Length overall (LOA) Length between perpendiculars (LBP) Max Beam Depth Assigned Freeboard Max Summer loaded draught Max Displacement at Summer Load Draught Gross Tonnage m m m m m m T ----------------------------------



AP X(m)

LBP (m) Y(m)


Aft Draught Mark

Fwd Draught Mark

DATUM REFERENCE INFORMATION Longitudinal datum Transverse datum Vertical datum Aft Perpendicular Fwd Perpendicular Aft Draught Marks = = = = = = amidships centreline base line ? metres aft amidships ? metres fwd amidships X metres aft amidships Y metres fwd amidships

Fwd Draught Marks =


UNIT CONVERSION TABLE MULTIPLY BY 0.039370 0.39370 3.2808 2.2046 0.00098421 0.98421 2.4999 8.2017 187.98 TO CONVERT FROM mm cm m KG KG Tonnes (1000 KG) Tonnes per cm Tonnes metres units (MCTC) Metre Radians TO OBTAIN TO OBTAIN inches inches feet lbs Tons (2240 lbs) Tons (2240 lbs) Tons per inch Ton feet units (MCTI) Foot Deg TO CONVERT FROM 25.4 2.54 0.3048 0.45359 1016.0 1.016 0.40002 0.12193 0.0053198 MULTIPLY BY

Relationships between Weight and Volume 10mm cubed = 1 cubic cm 1 cubic cm of fresh water (S.G. = 1.0) = 1 gram 1000 cubic cm of fresh water (S.G. 1 = 1.0) = 1 kg (1000grams) 1 cubic meter of fresh water (S.G. 1 = 1.0) = 1 tonnes (1000kg) 1 cubic meter of salt water (S.G. 1 = 1.025) = 1.025 tonnes (1025kg) 1 Tonne of salt water (S.G. 1 = 1.025) = 0.975 cubic metres 1 cubic metre 1 cubic foot = 35.316 cubic feet = 0.0283 cubic metres



2 1


4 3

1. Fuel Oil Tank Stb 2. Fuel Oil Tank Port 3. Fresh Water Tank Stb 4. Fresh Water Tank Port 5. Grey Water Tank


SAMPLE TANK CAPACITY TABLE Tank Name Contents Capacity Max Sounding Depth (m) 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 XX FW/FO etc YY % Full 100 90 80 70 60 50 40 30 20 10 Mass (MT) 5.2 4.5 3.8 3.2 2.2 1.5 1.09 0.85 0.56 0.23 VCG (m) X X X X X X X X X X LCG (m) Y Y Y Y Y Y Y Y Y Y FSC (m) Z Z Z Z Z Z Z Z Z Z


NOTES TO THE MASTER 1. General Instructions A stamped, approved copy of this booklet must be kept on board the vessel at all times. It must also be complete, legible and readily available for use. If this booklet is lost or becomes unusable a replacement copy of the approved booklet must be obtained immediately. MCA operating Restrictions (if any). Min liquids to be carried in arrival condition (if any). The loading conditions shown in this booklet represent typical service conditions. It is emphasised that a separate calculation is necessary for all differing conditions of loading. Masters Shipboard procedures are to be followed at all times. 2. Tank Usage and Free Surface Moments Provided a tank is completely filled with liquid no movement of the liquid is possible and the effect on the ships stability is pr ecisely the same as if the tank contained solid material. Immediately a quantity of liquid is withdrawn from the tank the situation changes completely and the stability of the ship is adversely affected by what is known as the free surface effect. This adverse effect on the stability is referred to as a loss in GM or as a virtual rise in VCG and is calculated as follows: Free Surface Mmt (Tonnes m ) Vessel Displacement (Tonnes )


Loss of GM =

When preparing loading conditions, it is to be noted that free surface effects must be allowed for the maximum number of tanks which are slack or shortly to become slack in that given loading condition. This will mean that, for departure conditions all main fuel tanks as well as fresh water tanks are considered to be slack. The number of slack tanks should be kept to a minimum. Where port and starboard tanks are cross coupled, such connection should be closed at sea to minimise the reduction in stability. Where ballast tanks are used they should be pressed full or empty as far as possible. Dirty water in the bilges must be kept to a minimum. 3. Masters ship board procedures Internal sliding WT doors, may be left open, but should be closed when risk of hull damage and flooding increases eg, in fog, in shallow rocky waters, in congested shipping lanes, when entering and leaving port and at any other time the master considers appropriate. Sliding WT doors should be checked daily to ensure that nothing has been placed in way of the door or where it might fall into the opening and prevent the door from closing.8

4. Precautions against capsize Before a voyage commences care should be taken to ensure large items of equipment and stores are properly stowed to minimise the possibility of both longitudinal and transverse shifting under the effect of acceleration caused by pitching and rolling, or in the event of a knockdown to 90 degrees. All external hull doors and flush hatches (list them) are to be closed and secured. In adverse weather conditions and where there is the possibility of encountering a severe gust, squall or large breaking wave, all exposed doors, hatches, skylights, vents, etc. should be closed and securely fastened to prevent the ingress of water. Storm boards etc. should be erected and fitted. The number of slack tanks should be kept to a minimum. Where port and starboard tanks are cross coupled, such connection should be closed at sea to minimise the reduction in stability. Compliance with the stability criteria indicated in the booklet does not ensure immunity against capsizing regardless of the circumstances or absolve the Master from his responsibilities. Masters should therefore exercise prudence and good seamanship having regard to the season of the year, experience of the crew, weather forecasts and navigational zone, and should take appropriate action as to the speed, course and sail setting warranted by the prevailing conditions. The amount of sail carried is at the discretion of the Master and his decision will have to take into account many factors. In assessing the risks of downflooding, the Master should be guided by Figures 1 and 2 below.


Notes on use of KN Curves KN curves for displacements of X to Y tonnes are presented for angles of heel at intervals between 0 and Z degrees. To obtain righting arm (GZ) curves at a given displacement, the following equation should be used: GZ = KN KG sin This enables the value of GZ to be calculated at each of the heel angles presented, and subsequently plotted as in the loading conditions presented herein.






Angles of down flooding This is the angle of heel at which progressive down flooding of the vessel will occur due to the immersion of an opening. Description Area of Opening (m2) A B C ANGLES OF IMMERSION (degs) 100% Consumable 10% Consumable 42 40 46 40 30 29

Saloon X Crew Y Gallery Z


Critical Flooding is deemed to occur when the lower edges of openings have an aggregates area in m2, greater than; Vessel Displacement (Tonnes ) 1500

Downflooding =

The master should note that the presence of the vent and skylights significantly reduces the ability of the vessel to withstand down flooding and with these opening securely closed the safety of the vessel is enhanced considerably. Figure 1 shows the maximum recommended steady heel angle to prevent downflooding in gusts. Operation of the vessel at a greater heel angle would result in downflooding if it were to encounter the strongest possible gust in the prevailing turbulent airstream, which could exert a heeling moment equal to twice that of the mean wind. Figure 2 shows the maximum recommended steady heel angle to prevent downflooding in squalls. Operation of the vessel at a greater heel angle would result in downflooding if it were to encounter the heeling effects of a squall arising from a storm or frontal system which may result in a heeling moment many times greater than that of the mean wind. For this reason the Master should have regard to the maximum steady heel angle curves presented for a range of squall speeds. By using the readings from his inclinometer and anemometer a master is able to determine the degree of risk of capsize in gusts or squalls which may occur in the prevailing weather system. He may then decide to shorten sail together with other actions he considers necessary.] Additional care should be taken when sailing with the wind from astern, as in the event of the vessel broaching or a gust striking the vessel on the beam, the heeling effects of the wind may be increased to a dangerous level when the preceding heel angle was small.


Maximum Steady Heel Angle to Prevent Downflooding in Gusts

GUSTING CONDITIONS When sailing in a steady wind the vessel heels to the angle at which the heeling arm curve intersects the GZ curve. When struck by a gust the heel angle will increase to the intersection of the gust hee