- Your gateway to the Maritime Knowledge!
- ask@funnel2tunnel.com

#### Calculate the maximum quantity that can be loaded into the account the ship’s deadweight, the load line zones she will pass through, the weights on board, draft limitations etc. This process is called the Deadweight Calculation

#### Distribute this cargo into the holds so as to have the maximum number of filled holds but also considering the vessel’s required draft, trim, stresses etc.

#### Divide the cargo weight by the stowage factor to obtain the cargo volume/depth of cargo in each hold

#### From the heeling moment diagrams in the grain loading booklet, find out the volumetric heeling moments for each hold

#### Multiply the volumetric heeling moments by the appropriate factor to compensate for the vertical shift of G

#### Divide the corrected Volumetric Heeling Moments by stowage factor to obtain Weight heeling moments

#### Add up all the heeling moments for each hold to calculate Total heeling moments

#### Compare the Total Heeling Moments with the Allowable Heeling Moments obtained from the Grain Stability Booklet

#### If the calculated Total Heeling Moments are lesser than Allowable Heeling Moments. Proceed with the loading else re – distribute the cargo and re-work the calculation

#### The ship should have a valid Document of Authorization

#### The ship should have an approved Grain Stability Booklet/Grain Loading Manual

#### Document of authorization shall be issued to a ship which is permitted to be loaded in accordance with the regulations of the Grain Code and is authorized to carry grain in bulk

#### It shall be incorporated in the Grain Stability Booklet/Grain Loading Manual.

#### A ship can’t load grain without DoA unless Master demonstrates to the satisfaction of the Administration that the ship is under loaded condition complies to the regulation of the Code.

#### Grain loading manual or Grain Stability Booklet are Class Approved information booklets which gives the ship’s officer various information with respect to Grain Loading onboard

#### Following are the contents of Grain Loading Booklet —

#### Ship’s particulars, lightship displacement & KG values

#### Table giving values Free Surface Correction

#### Capacities and Centre of Gravity of Hold Compartments

#### KN Curves and angle of flooding tables, where less than 40 degrees, at all degrees of heel

#### Curves or tables of hydrostatic properties suitable for the range of operating drafts

#### Cross curves of stability at 12 and 40 degrees

#### Curves/tables of volume/vertical centre of volumetric and assumed heeling moments for every compartment, including the effects of the temporary fittings.

#### Tables/curves of maximum permissible heeling for varying displacements

#### Details of scantlings or any temporary fittings

#### Loading instructions in the form of notes

#### A worked example for Master.

#### Typical service, loaded departure and arrival conditions

As you can see above the meaning of various factors taken into account while drawing the stability curve.

Let us start drawing the Stating Stability Curve (also called the Righting Arm Curve). This curve is drawn using the Cross Curves (also called KN Curves) given in the Stability Booklet.

Step 1: The corrected righting arm (corrected GZ) at any given angle (say θ), is obtained from following equation

Here;

GZ = Value of GZ obtained from Cross Curve tables

KGa = Value of KG assumed in the Cross Curves

KGo = KG +GGo

KG= KG value obtained for loading condition under consideration

GGo = Loss of GM due to free surface

θ =Angle of inclination

An example calculation from a vessel’s grain stability booklet is given below for you to understand-

Read more on grain loading here.

## 9 Comments

How much difference in the loadicator draft and observed draft acceptable, if all the parameter filled correctly in the loadicator at the arrival port??

Can u explain how to match observed draft and loadicator draft??

Hi there!

Loadicator helps you in order to get an idea that for a certain loading condition what should be your drafts. Simply speaking, for a certain load distribution the loadicator gives you an idea as to what your approximate drafts would be.

Since, the loadicator is an approved instrument it can be well trusted in order to consider the output values to be fairly accurate.

Hence, the question of matching the observed draft with the loadicator draft is not correct. What you should focus on is that if in case your observed draft is varying from the calculated drafts (obtained from the loadicator), you should try to find out the reason for this difference. This could be either of the two – actual loading/discharging operation being carried out is different from what was planned OR actual ballasting/deballasting operation is being carried out differently from what was planned.

Hope it clears!!!

Thanks understood

Thanks for your topic, but can you pls list down which document we should have on board for grain carriage?

The following documents shall be carried on board for carriage of grain:

1. Document of Authorization for carriage of grain

2. Grain loading booklet and/or Grain stability manual

Is it necessary to add constant every time on loadicator? If constant not updated correctly then it will show in correct draft???

The value of constant needs to be updated every time you obtain the value of the constant. This is usually done after determining the constant’s value during the Initial Draft Survey at the loading port.

Usually constant value will not differ much UNLESS the draft survey was performed incorrectly. So, although the drafts will differ from the actual but IT WILL BE NOT MUCH.