stability and trim sheets

MCA Stability Information Booklet Large Yacht Unit STABILITY INFORMATION BOOKLET my " " M WATER LINE G K Z N DATE: MCA Stability Information Booklet Large Yacht Unit 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 Angles of down flooding Notes on Free Surface Moments Notes on use of KN Curves General Stability Requirements Sample form for calculating Loading Condition Explanation and notes on completing Sample Stability Form Max KG limiting criteria (not compulsory) Freeboard Loadline Marks Loading Conditions Hydrostatic Properties Cross Curve Stability Plot Appendix I Inclining Experiment Results Appendix II Compartment Definition (NOT REQUIRED IN SIB!) Appendix III Damage Stability (NOT REQUIRED IN SIB!) MCA Stability Information Booklet Large Yacht Unit MCA Stability Information Booklet Large Yacht Unit General Particulars Ship’s Name Official Number Port of Registry Owner’s name and address Classification Society Builder Yard Number Date of keel laying Dimensions Length overall (LOA) m Length between perpendiculars (LBP) m Max Beam m Depth m Assigned Freeboard m Max Summer loaded draught m Max Displacement at Summer Load Draught T Gross Tonnage MCA Stability Information Booklet Large Yacht Unit Diagram to show Draught mark locations LBP (m) X(m) AP Aft Draught Mark Y(m) FP Fwd Draught Mark Datum Reference Information Longitudinal datum = amidships Transverse datum = centreline Vertical datum = base line Aft Perpendicular = ? metres aft amidships Fwd Perpendicular = ? metres fwd amidships Aft Draught Marks = X metres aft amidships Fwd Draught Marks = Y metres fwd amidships MCA Stability Information Booklet Large Yacht Unit 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 = cubic cm cubic cm of fresh water (S.G = 1.0) = gram 1000 cubic cm of fresh water (S.G = 1.0) = kg (1000grams) cubic meter of fresh water (S.G = 1.0) = tonnes (1000kg) cubic meter of salt water (S.G = 1.025) = 1.025 tonnes (1025kg) Tonne of salt water (S.G = 1.025) = 0.975 cubic metres cubic metre cubic foot = 35.316 cubic feet = 0.0283 cubic metres MCA Stability Information Booklet Large Yacht Unit Arrangement of Tanks AP FP 6 8 Fuel Oil Tank Stb Fuel Oil Tank Port Fresh Water Tank Stb Fresh Water Tank Port Grey Water Tank Aft Ballast Tank Stb Aft Ballast Tank Port Lub Oil Tank MCA Stability Information Booklet Large Yacht Unit Sample Tank Capacity Table Tank Name Contents Capacity Max Sounding Depth (m) 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 MCA Stability Information Booklet Large Yacht Unit Notes to the Master 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 Master’s Shipboard procedures are to be followed at all times 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 ship’s stability is precisely 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: EQ.1 Loss of GM = Free Surface Mmt (Tonnes m ) Vessel Displacement (Tonnes ) 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 bilge’s must be kept to a minimum MCA Stability Information Booklet Large Yacht Unit Precautions against capsize Before a voyage commences care should be taken to ensure large items of equipment and stores are properly stowed All external hull doors and flush hatches (list them) are to be closed and secured If poor weather is likely to encountered during the passage additionally storm boards and shutters should be 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 does not ensure immunity against capsize or absolve the Master from his responsibilities Masters should therefore exercise prudence and good seamanship having regard to the season of year, weather forecast and the navigational zone 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 10 MCA Stability Information Booklet Large Yacht Unit Notes on use of KN Curves KN curves for displacements of X to Y tonnes are presented for angles of heel at intervals between and Z degrees To obtain righting arm (GZ) curves at a given displacement, the following equation should be used: EQ.2 GZ = KN − KG sin θ 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 M θ G K WATER LINE Z N 11 MCA Stability Information Booklet Large Yacht Unit 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 Saloon X Crew Y Gallery Z Area of Opening (m2) A B C ANGLES OF IMMERSION (degs) 100% Consumable 10% Consumable 42 46 30 40 40 29 12 MCA Stability Information Booklet Large Yacht Unit General Stability Requirements It is import ant to ensure that in any sailing condition the stability of the vessel complies with the following minimum criteria of section 11.2 of the Code of Practice for Large Commercial Sailing and Motor Vessels C A B GZ (m) D E 0o 10o 20o 30o 40o 50o 60o 70o Angle of heel (degs) A B C D E Area under the curve up to 30o is to be not less than 0.055 metre-radians Area under the curve up to 40o, or the angle of down flooding (which ever is less) is to be not less than 0.090 metre-radians Area under the curve between 30o and 40o or the angle of down flooding (which ever is less), is to be not less than 0.030 metre-radians Maximum GZ is to occur at angles of heel preferably exceeding 30o but not less than 25o and the GZ value must be at least 0.20 metres at an angle of heel equal to or greater than 30o Initial GM is to be not less than 0.15 metres The curves of righting levers (also known as GZ curve), for each condition of loading should be obtained at the trim shown in the condition by interpolation between the appropriate sets of trimmed cross curves (KN curves) Areas under the curve may be calculated by a suitable numerical method Alternatively the values of GZ righting arm levers may be plotted against heel angles on graph paper and the number of squares under the curve may be manually counted 13 MCA Stability Information Booklet Large Yacht Unit Sample form for calculating Loading Condition TABLE ITEM Passengers and effects Crew and Effects Provisions and stores Deck A Provisions and stores Deck B Provisions and stores Deck C Provisions and stores Deck D Jet Skis etc Tender TANKS Fuel Oil Tank Stb Fuel Oil Tank Port Fresh Water Tank Stb Fresh Water Tank Port Grey Water Tank Aft Ballast Tank Stb Aft Ballast Tank Port Lub Oil Tank Load % CAPACITY MT Load % A B C D E F G H Total Dead Weight Lightship Weight Displacement (MT) WT MT WT MT I LCG m aft amidships LCG m L Mmt VCG m -BL m –MT V Mmt m-MT aft amidships L Mmt VCG m –MT J K L m -BL FSM m-MT FSM V Mmt m-MT M - m-MT Note: Lightship weight includes x, y and z items TABLE Stability Calculation Fwd Draught METRES Aft Draught METRES Trim METRES Displacement MT VCG METRES KMT METRES GMT (solid) METRES FSC METRES GMT (fluid) METRES 14 MCA Stability Information Booklet Large Yacht Unit TABLE Trim Calculations LCF Draught (above base line) LCG (fwd/aft of amidships) LCF (fwd/aft of amidships) LCB (fwd/aft of amidships) Trim lever MCTC Trim LBP Fwd Draught Aft Draught METRES METRES METRES METRES METRES MT m/cm METRES METRES METRES METRES Explanation and notes on completing Sample Stability Form Table • • • • • • • • • • • • • Calculating the Displacement and Centres of gravity Fill in the weights in column (WT) Fill in the longitudinal and vertical centres of gravity in columns (LCG) and 6(VCG) respectively Multiply the weight of each item by its centre to get the longitudinal and vertical moments and enter moments in column (L Mmt) and Column (V Mmt) Record all the tank loads and enter the % into column (load %) From the tank capacity plan enter the tank weights into column (WT), LCG’s into column 4, VCG’s into column and FSC into column Multiply the weight of each tank by its centre to get the longitudinal and vertical moments and enter moments in column (L Mmt) and Column (V Mmt) Sum up columns 3,5 and and enter total in Dead Weight row Add Dead Weight mass to Light Ship mass and enter new total in Total Displacement row column Add Dead Weight LCG Mmt to Light Ship LCG Mmt and enter new total in Total Displacement row column Divide Total Displacement row column by Total Displacement row column to calculate overall estimate of LCG location for loading condition Enter calculation into Total Displacement row column Add Dead Weight VCG Mmt to Light Ship VCG Mmt and enter new total in Total Displacement row column Divide Total Displacement row column by Total Displacement row column to calculate overall estimate of VCG location for loading condition Enter calculation into Total Displacement row column Sum up column (FSC) and enter total into Total Displacement row column 15 MCA Stability Information Booklet Table • • • • • • • • • • Calculating the Stability Transfer the value of the overall VCG from table and enter it in table Record fwd and aft draught estimates in table Subtract fwd draught from aft draught (noting if trim is stern down or bow down), and enter trim value in table Using the trim estimate and the displacement value calculated in Table determine hydrostatics values of KMT, LCB, MCTC, LCF and LCF draught, and enter in table Subtract the overall VCG value in table from KMT to obtain GMT solid, enter in table Subtract the overall FSC value from table from GMT solid to obtain GMT fluid, enter in table Table • • Large Yacht Unit Calculating actual trim To obtain the trim lever take the difference between LCB and LCG, enter in table To obtain an estimate of the actual trim multiply the displacement by the trim lever and divide that sum by the MCTC This provides the trim in cm units If the LCG is fwd of the LCB the vessel is trimmed bow down, and conversely if the LCG is aft of the LCB the vessel is trimmed stern down The aft draught may be found by dividing the LCF value by the X (m) value shown on the ‘Diagram to show Draught mark locations’ and multiplying that value by the trim, and adding or subtracting that value to or from the LCF draught value depending on the direction of trim If the vessel is trimmed stern down, then add, otherwise subtract The fwd draught may be found by dividing the LCF value by the Y (m) value shown on the ‘Diagram to show Draught mark locations’ and multiplying that value by the trim, and adding or subtracting that value to or from the LCF draught value depending on the direction of trim If the vessel is trimmed stern down, then add, otherwise subtract Using the newly calculated values for fwd and aft draughts calculate the revised estimate of the trim Compare this revised trim value to the original estimate of trim in table Iterate to convergence 16 MCA Stability Information Booklet Large Yacht Unit Max KG limiting criteria (not compulsory) Table or Graph as appropiate Freeboard Load line Mark In accordance with the load line regulation the following Plimsoll mark is to be attached to the vessel Top of Deck at side Assigned summer freeboard 25mm 25mm Summer Draft 300mm USK 450mm underside of keel Note: Loadline approving classification societies initial to be inserted on Plimsoll mark Loading Conditions Stability Form and stability criteria code assessment to be presented in the following conditions; • • • • Lightship Departure (100% consumables) Half Load (50% consumables) (OPTIONAL CONDITION) Arrival (10% consumables) 17 MCA Stability Information Booklet Large Yacht Unit Hydrostatics Tabular output showing Displacement, Draught, LCG, VCB, KMT, KML, TPC and MCTC across the range of operational draughts and trims Suggested at Trims of –0.5m, -0.25m, 0m, 0.25m & 0.5m NOTE: Water Density =1.025 T/m3 K is to underside of keel at amidships Draught is to underside of keel at amidships Cross Curve Stability Plot Tabular Output showing KN curve values across the range of operational displacements and trims Suggested at Trims of –0.5m, -0.25m, 0m, 0.25m & 0.5m NOTE: Water Density =1.025 T/m3 VCG = zero m 18 [...]... (FSC) and enter total into Total Displacement row column 8 15 MCA Stability Information Booklet Table 2 • • • • • • • • • • Calculating the Stability Transfer the value of the overall VCG from table 1 and enter it in table 2 Record fwd and aft draught estimates in table 2 Subtract fwd draught from aft draught (noting if trim is stern down or bow down), and enter trim value in table Using the trim estimate... Explanation and notes on completing Sample Stability Form Table 1 • • • • • • • • • • • • • Calculating the Displacement and Centres of gravity Fill in the weights in column 3 (WT) Fill in the longitudinal and vertical centres of gravity in columns 4 (LCG) and 6(VCG) respectively Multiply the weight of each item by its centre to get the longitudinal and vertical moments and enter moments in column 5 (L Mmt) and. .. obtain the trim lever take the difference between LCB and LCG, enter in table To obtain an estimate of the actual trim multiply the displacement by the trim lever and divide that sum by the MCTC This provides the trim in cm units If the LCG is fwd of the LCB the vessel is trimmed bow down, and conversely if the LCG is aft of the LCB the vessel is trimmed stern down The aft draught may be found by dividing... locations’ and multiplying that value by the trim, and adding or subtracting that value to or from the LCF draught value depending on the direction of trim If the vessel is trimmed stern down, then add, otherwise subtract The fwd draught may be found by dividing the LCF value by the Y (m) value shown on the ‘Diagram to show Draught mark locations’ and multiplying that value by the trim, and adding... Record all the tank loads and enter the % into column 2 (load %) From the tank capacity plan enter the tank weights into column 3 (WT), LCG’s into column 4, VCG’s into column 6 and FSC into column 8 Multiply the weight of each tank by its centre to get the longitudinal and vertical moments and enter moments in column 5 (L Mmt) and Column 7 (V Mmt) Sum up columns 3,5 and 7 and enter total in Dead Weight... includes x, y and z items TABLE 2 Stability Calculation Fwd Draught METRES Aft Draught METRES Trim METRES Displacement MT VCG METRES KMT METRES GMT (solid) METRES FSC METRES GMT (fluid) METRES 14 MCA Stability Information Booklet Large Yacht Unit TABLE 3 Trim Calculations LCF Draught (above base line) LCG (fwd/aft of amidships) LCF (fwd/aft of amidships) LCB (fwd/aft of amidships) Trim lever MCTC Trim LBP... to or from the LCF draught value depending on the direction of trim If the vessel is trimmed stern down, then add, otherwise subtract Using the newly calculated values for fwd and aft draughts calculate the revised estimate of the trim Compare this revised trim value to the original estimate of trim in table 2 Iterate to convergence 16 MCA Stability Information Booklet Large Yacht Unit Max KG limiting... MCTC across the range of operational draughts and trims Suggested at Trims of –0.5m, -0.25m, 0m, 0.25m & 0.5m NOTE: Water Density =1.025 T/m3 K is to underside of keel at amidships Draught is to underside of keel at amidships Cross Curve Stability Plot Tabular Output showing KN curve values across the range of operational displacements and trims Suggested at Trims of –0.5m, -0.25m, 0m, 0.25m & 0.5m NOTE:... manually counted 13 MCA Stability Information Booklet Large Yacht Unit Sample form for calculating Loading Condition TABLE 1 ITEM Passengers and effects Crew and Effects Provisions and stores Deck A Provisions and stores Deck B Provisions and stores Deck C Provisions and stores Deck D Jet Skis etc Tender TANKS 1 2 3 4 5 6 7 8 Fuel Oil Tank Stb Fuel Oil Tank Port Fresh Water Tank Stb Fresh Water Tank Port... mark Loading Conditions Stability Form and stability criteria code assessment to be presented in the following conditions; • • • • Lightship Departure (100% consumables) Half Load (50% consumables) (OPTIONAL CONDITION) Arrival (10% consumables) 17 MCA Stability Information Booklet Large Yacht Unit Hydrostatics Tabular output showing Displacement, Draught, LCG, VCB, KMT, KML, TPC and MCTC across the range