Familiarizacion Con Buques Tanque

7/27/2019 Familiarizacion Con Buques Tanque.

1/33

ShipMeasurement

DeterminingOBQ/ROB Quantity

LevelMeasurements

TemperatureMeasurement

Vessel ExperienceFactor VEF

Sampling CargoTanks

BUREAU VERITAS DEL PERU S.A. - CAPACITACIN

Ship measurements(Mediciones marinas)

Tanker familiarization(Familiarizacion con Buque Tanque)


2/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Conventional tanker : Skin-tank ships incorporating twinlongitudinal bulkheads.

P C S

Segregated

bal last tanks

Cargo

tanks

Crude Oil Carriers

Ship - Tanker familiarization


3/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Double-Skin ships : Have segregated ballast tanks surroundingthe cargo tanks.

P C S

Crude Oil Carriers

Ship - Tanker familiarization


4/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Forward perpendicular ( FP ) : This is represented by a line which is perpendicular to the intersection of the designed load water-line with the forward side of the stem.

After perpendicular ( AP ) : This is represented by a line which is perpendicular to the intersection of theafter edge of the rudder-post with the designed load water-line.

Length between perpendiculars ( LBP ) : This is the horizontal distance between the forward and theafter perpendiculars.

Length overall ( LOA ) : This is the length measured from the extreme point forward to the extreme point aft.

A.P. F.P.Mid ship

ForeAft

Lbp

Loa

Definitions

Ship - Ship measurement


5/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Trim : This is the difference between the draughts forwardand aft.If the draught forward is greater than the draught aft it iscalled trim by head, or bow.If the draught aft is greater, it is called trim by the stern.

HeadStemstern

Trim by stern

Fore draughtAft draught

DefinitionsShip - Ship measurements


6/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Moulded Breadth ( B ) : This is the maximum breadth of the ship measured inside the inner shell, andusually occurs amidships. Moulded base line : This represents the lowest extremity of the moulded surface of the ship. At the

point where this line cuts the midships section a horizontal line is drawn, and it is this line which actsas the datum, or base line for all hydrostatic calculations.

Moulded Depth ( D ) : This is the vertical distance of the ship measured inside the inner shell, andusually occurs amidships.

Moulded Draught : This is the draft measured to any water-line, either forward or aft, using the moulded base line as a datum.

Mouldeddraught M

o u l d e d

d e p t

h

Moulded breadth S.W.L.

Ship - Ship measurementsDefinitions


7/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Heel ( List ) : This is the amount of inclination of the ship in thetransverse direction, and is usually measured in degrees.

S.W.L.

Starboarddraught

Portdraught0

Clinometer

Vessel is listed to the port s ide

Definitions

Ship - Ship measurements


8/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Line serves port cargo tanks. Line serves Starboard cargo tanks. Line serves centre cargo tanks.

Segregated ballast line.

Top line

Bottom line

Pumproomraiser Drop

line

Piping arrangementShip - Ship measurements


9/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Liquid Metering : Ship tanks to be filled with a convenient liquid (e.g. water) throughan accurately calibrated reference meter, and ullage compared with recorded volumethroughout the operation. (normal accuracy +/- 0.05 % )

Advantage : Produce a very accurate set of ship tank calibrations. Disadvantages:

Time consuming therefore expensive. List and trim corrections cannot be calculated from the basic data. Problems with constantly changing trim and list when the ship is afloat.

Internal measurement : Ship tanks to be entered and a large number of internaldimensions of width, length and height measured, together with the size and position of all internal displacements. (normal accuracy +/- 0.25 % )

Advantages : Reasonably accurate. Less time consuming than metering. List and trim corrections can be calculated from the basic data.

Disadvantages: Difficulty in measuring foremost tanks ( 1 wing ) as they are tapering

towards the bottom and the forward end.

Ship Tanks Calibration



10/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Shipyard : The calibration tables are based on the plans and drawings fromwhich the ship was fabricated. (Themost common calibration method usedfor Crude oil carrier )

Advantage:

Supplied with the ship. Disadvantages :

Actual location of deadwoodis not determined. Theobstructions volumes areadded together and averageout the total displacementover the entire tank depth.

The exact position of the bulkheads not measured.

Bulkhead and hull distortionnot accounted for.

Variation in total heights notdetected.

Actual deadwood displacement

Assumed deadwood displacement

Tank Cross -section

Ship Tanks Calibration



11/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Bottom sediment : Non-hydrocarbon solids present in a tank as a separate layer at the bottom (non free flowing material e.g. sand, rust particles) .

Sludge : Hydrocarbon waxes present in a tank and may contain water/oil emulsions andsediment.

On board quantity ( OBQ ) : All the oil, water, sludge and sediment in the cargo tank s andassociated lines and pumps on a ship before loading a cargo commences.

Remaining on board (ROB ) : All the oil, water, sludge and sediment in the cargo tank s andassociated lines and pumps on a ship after discharging a cargo.

Slops : Material collected after such operations as stripping, tank washing or dirty ballast

separation. It may include oil, water, sediment and emulsions. Clingage : Oil residues which adhere to the surface of tank walls and structures on

Completion of discharge.

Definitions



12/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Your safety is your own responsibility. Wear the required safety protective clothing. Obey all terminal safety/ Vessel rules.

Ensure all pressure in the tank has been released beforegauging/ sampling. Ensure all Loading and vapor movements has ceased

before gauging / sampling . Stand to the upwind side of the gauge hatch while

gauging or sampling

Safety precautions



13/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Ship measurements

Determining OBQ and ROB


14/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


All ballast and bunker tanksto checked.

All vessel lines, pumps must

be drained. Overboard discharge valve

and sea valves must be closedand sealed.

Obtain slop information ( If exist ).

All cargo tanks to be checked. Measure the OBQ from the

Aft position of the tank (if possible).

Before Loading

Ship - Ship measurements API - Chapter 17 Section 2


15/33

Ship

Measurement


LevelMeasurements



Sampling CargoTanks


Measured quantity is liquid .

If S =< ( L - U ) X F

Apply wedge formula S' = [(U - DF)X F] + S Wedge formula

Note : The formula assumes that the

liquid is free flowing. It only applies for zero list. Units used must be consistent.

Trim factor ( F ) =T

Lbp

S' X B2

2 X FVolume =

U

T

Lbp

U : Aft bulk distanceS : SoundingL : Tank lengthB : Tank breadthD : Tank depth

S LS'

D

Fore

Determining OBQ/ROB Quantity



16/33

Ship

Measurement


LevelMeasurements



Sampling CargoTanks


Fore

MeasuredUllage

Trim correctedullage

U

T

Lbp

Level measurement

Trim correction

If the ullage hatch is located

In the middle of the tank No Trim correction

In the aft of the tank

Trim correction = (+) In the fore of the tank

Trim correction = (-)



U = Aft bulk distanceT = TrimLbp = Length between perpendicular

Measured quantity is liquid, But wedge not applicable .


17/33

Ship

Measurement


LevelMeasurements



Sampling CargoTanks


Measure the sounding ( S ). Check the sounding from more

than one location ( if possible ). Measured sounding assumed to be

uniform all over the tank. Enter the calibration table and get

the volume corresponds to this

sounding with trim =0.

Fore

S

Measured quantity is Non-liquid.




18/33

Ship

Measurement


LevelMeasurements



Sampling CargoTanks


Measuring Slop tank

Measure Oil level and theoil/water interface level inthe slop tank(s), preferablyusing a UTI.

Measure the temperature of the oily layer.

Obtain the density, correctthe oil volume .

Fore

Oil Ullage Oil/water interface

(X) Temp Oil Layer

Free Water




19/33

Ship

Measurement


LevelMeasurements



Sampling CargoTanks


Level measurement(Mediciones de Tanques)

Ship measurements

U l l a

g e


20/33

Ship

Measurement


LevelMeasurements



Sampling CargoTanks


Before measuring the ullage : Get the official measuring point

from calibration table. Get the ship's draughts; i.e.. trim

and list. Make sure that lines are drained

into cargo tanks. Check the measuring equipments.

Level measurement using Steel tape:

Only applicable for open-systemships.

Check the bob and the steel tapecompatibility

Check the ullage. It is better to get the cut on the tape. If there is swell take more than one

ullage and get the average.

U l l a g e

Level measurement



21/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Level measurement usingSonic tape :

Applicable for closed-system ships.

If used for open-systemships UTI must beearthed.

Make sure that HC instated in calibrationtable, or attachedcertificate.

Check the ullage. If there is swell take

more than one ullageand get the average.

Level measurement



22/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Fore

MeasuredUllage


U

T

Lbp

Level measurementLevel measurement

Trim correctionIf the ullage hatch is located :

In the middle of the tank

No Trim correction In the aft of the tank

Trim correction = (+) In the fore of the tank

Trim correction = (-)

U = Aft bulk distanceT = TrimLbp = Length between perpendicular



23/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Fore

MeasuredUllage


U

T

Lbp

Level measurementLevel measurement



24/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Temperature measurement



25/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Thermometer must be checked against certified thermometer before use.

Three levels temperature to be measured at 1/6, 1/2 and 5/6

of the oil depth for each cargo tank. If there is cargo stratification in the tank more temperature

measurement is preferred.

Average Temperature = TemperatureNo of temperatures

Temperature measurement

Ship - Ship measurements API Chapter 7


26/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Temperature Profile for a cargo tank.

75 80 85 90 95 100 105 110

Temp oF

0

5

10

15

20

25

S o u n

d i n g

This exercise was carried out on a vessel at Dis-port for wing tank loadedwith AHC.40 temperatures measurements were used to plot this curve.

Temperature measurementShip - Ship measurements


27/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Vessel experience factor : Is a compilation of the history of theTCV vessel measurements, adjusted for OBQ or ROB,compared with the TCV shore measurements. Separate VEFsshould be developed for both the load and discharge operations.

Information used to calculate a VEF should be based onDOCUMENTS that follow accepted industry standards and

practices, such as inspection company reports.

Ship Vessel experience factor API Chapter 17 Section 1 Appendix C


28/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Do not use weight or mass, but use Cubic meters or barrels for all voyages . Use compatible ASTM tables for Ship / Shore figures. Excluded the following voyages :

All voyages prior to any modification which affected the vessel's cargocapacity.

All voyages where shore measurements were not available or basedsolely on shipboard measurement.

Part cargo. Ship to ship transfer.

List the available data in chronological order. Calculate individual LVR for each voyage. Calculate an average TCV ratio. Delete any voyage whose LVR does not lie within +/- 0.0003 of the average

TCV ratio. Add all remaining vessel TCVs together and all remaining Shore TCVs. Calculate the load VEF


Calculation procedure


29/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Voy No CargoGrade Loadport Date ShipTCV ShipOBQ ShipTRV ShoreTCV VCF Tbl. V.L.R. QU.

39 A L C Yanbu 06.04.96 952356 1260 951096 949546 6 1.00163 Y

38 Sarir M.Elhar 04.02.96 1045143 873 1044270 1042321 6 A 1.00187 Y

36 A L C S.Kerir 01.01.96 923396 1469 921927 919485 6 A 1.00266 Y

32 Forozan S.Kerir 02.10.95 1004501 1808 1002693 1002500 6 A 1.00019 Y

30 Es Sider Es Sider 30.07.95 948024 562 947462 944433 6 A 1.00321 Y

28 I R H S.Kerir 22.06.95 945724 262 945462 940235 6 A 1.00556 N

27 A L C S.Kerir 07.06.95 905373 546 904827 903694 6 A 1.00125 Y

25 Zeit Bay S.Kerir 05.04.95 1010790 333 1010457 1009126 6 A 1.00132 Y

24 AM/ALC S.Kerir 04.03.95 1007911 1101 1006810 1004147 6 A 1.00265 Y

23 IRL/IRH S.Kerir 01.02.95 986310 187 986123 984130 6 A 1.00203 Y

21 G S M S.Kerir 07.12.94 961199 348 960851 957782 6 A 1.0032 Y

20 A M C R.Tanura 11.11.94 991069 668 990401 987395 6 1.00304 Y

TOTAL 11672379 11644794

Average TCV ratio 1.00237Upper Limit =1.00537Lower Limit = 0.99937

Vessel Experience Factor =1072691710704559 = 1.0021


Calculation procedure


30/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Sampling



31/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


Draw a sample from each cargo tank. Draw a free water samples (if possible). Ship composite sample must be prepared in the laboratory. Individual samples must be blended in proportion to the

tank volume each sample represents.

Manual Sampling

Ship SamplingAPI Chapter 8 Section 1


32/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks


The sampler is located at thecustody transfer point.

The cargo received/delivered isdivided to parcels, each parcel

passes through a ship'smanifold. If one of the two unitused is O/O/S, about half thecargo is sampled.

This portable samplers usually

pneumatically operated. Flow is measured by the mean

of differential pressure actingupon the annubar.

Ship-board in-line Sampler

Ship Sampling API Chapter 8 Section 2


33/33

ShipMeasurement


LevelMeasurements



Sampling CargoTanks

Ship-board samplers

Ship Sampling API Chapter 8 Section 2

Documents

Familiarizacion Con Buques Tanque