So friends moving on to our next topic which is intact stability criteria. Now what is intact stability criteria? Intact stability criteria from the name itself you can get an idea it is the stability criteria when the vessel is in intact condition that is the watertight condition. So when the ship is in the intact condition, what would be the stability criteria which is required for the vessel is given under your intact stability criteria. Where will you find the information about the intact stability criteria of your vessel is under the international intact stability.
Code 2008. This was adopted by the IMO on 4th December 2008 under resolution MSC 267 85. Under 85th session of the IMO this code was adopted. Now the Intact Stability Code, what is the purpose of these codes? Usually remember that for all the codes the basic purpose of these codes are to protect what? To protect the ship, the cargo, the persons on board and the environment.
Basically safety of the cargo, safety of the ship. Safety of persons on board and safety of the environment is what all codes are related to. So what is the purpose? We are discussing about intact stability code. So the stability criteria is the purpose over here.
So this presents mandatory and recommendatory stability criteria and other measures for what? For ensuring safe operation of ships to minimize the risk to such ships, to the persons on board and to the environment. So we have covered all the factors.
your ship, persons on board and the environment. Let's see what this code has under it. So, intact stability code 2008 is divided into introduction and part A and also part B.
Introduction and part A will give you the mandatory criteria. All the mandatory criteria for the stability are presented under introduction and part A of the intact stability code 2008. Whereas, all the recommendations and other guidelines are presented you presently. presented to you under the part B of this code.
This is basic introduction to the Intact Stability Code 2008. We will be discussing about the Intact Stability Criteria for various vessels under the next slide. So the International Code for Intact Stability 2008 came into force on 1st July 2010. Now it applies to various types of ships and other marine vehicles of 24 meters in length and above or unless otherwise stated. First and foremost is the cargo ship. Number 2, cargo ships carrying timber deck cargoes.
Number 3, passenger vessels. Number 4, fishing vessels. Number 5, special purpose ships.
Number 6, offshore supply vessels. Number 7, mobile offshore drilling units. Number 8, pontoons.
Now pontoons are nothing but pontoons are which are non self-propelled vehicles. So those are pontoons. Number 9, cargo ships carrying containers and container ships.
So these are the ships for which the intact stability criteria are present under the International Code for Intact Stability Criteria. We'll be looking into further details. So moving on to our next question which is what What does the International Code for Intact Stability 2008 include? Now remember that the International Code for Intact Stability includes fundamental principles such as first and foremost thing what we will be looking into is the capsizing of your vessel. So general precautions against capsizing.
Now when will your vessel capsize? Your vessel will capsize due to a negative GM or the rightening lever which is negative or the negative rightening lever which is known as capsizing lever or the capsizing moment which is occurring. Hence, Next what we have, we have a criteria regarding metacentric height, your GM and your right wing lever GZ.
So these criteria would be presented to you under your intact stability criteria for general precautions against capsizing. Next is weather criterion which is the severe wind and rolling criteria. Then effect of free surfaces and icing and also the water tight integrity of your ship is taken into account. Now the international code for intact stability.
2008 also addresses related operational aspects like information for master including your stability and operating booklets and operational procedures in heavy weather. So this all things are given to you under your intact stability code which is IS code 2008. So let's finally discuss the intact stability criteria for all cargo vessels or specifically for general cargo. tankers and passenger ships. Now for general cargo and passenger ships you can find the intact stability criteria under the international code for intact stability criteria 2008 whereas In the vessels, the criteria, the intact stability criteria is given under MARPOL.
Under regulation 27 of the MARPOL, you can find this. So, let's begin. The first and foremost point is the initial GM of the vessel. The requirement for the initial GM. GM for general cargo, passenger ships as well as tanker is considered when the vessel is in upright condition and the angle of heel is 0 degrees.
Additionally for tanker vessels free surface correction would be applied. This initial GM GM shall not be less than 0.15 meters in length. So the requirement for initial GM this length shall not be less than 0.15 meters in length. It can be 0.15 meter or greater than 0.15 meter. So initial GM for general cargo vessels, tanker vessels and passenger ships shall be not less than 0.15 meters.
Next is the righting lever GZ shall be at least 0.20 meter for angle of heel greater than 0.15 meter. or equal to 30 degrees. So what do you understand from this point is that the rightening lever, this is the rightening lever GZ, the length of this rightening lever GZ shall be at least 0.20 meters. So this length shall be at least 0.20 meters in length for angle of heel greater than 30 degrees or equal to 30 degrees. So what do you understand from this is at 30 degrees.
angle of heel your GZ the length of the GZ would be at least 0.20 meters in length okay it can be greater but the requirement states it shall be at least 0.20 meters in length okay so that is about your lightning lever GZ then the maximum GZ should occur at angle of heel greater than 30 degrees but in any of the cases not less than 25 degrees your maximum GZ what is your maximum GZ this this is the maximum GZ, the tangent, wherever it cuts, this is the maximum GZ. Okay. So, the maximum GZ shall occur at an angle greater than 30 degrees.
Okay. Always greater than 30 degrees is the requirement. But in any of the cases, it shall not be less than 25 degrees.
Okay. So, this is the requirement for the maximum GZ. of the vessel. Then the requirement for area under the GZ curve. Now before moving on to this let me also clarify one more thing.
The initial GM of your vessel from the graph in order to understand from the graph. If the initial gm is from 57.3 degree you draw a vertical. So the requirement states the gm shall not be less than 0.15.
So 0.15 we know. So this is the point of 0.15 meters. So the initial gm shall be always greater than 0.15 meter. So we can have a look from here itself how we want our initial gm to be.
And accordingly we will make the vessels stable. The area under the GZ curve now the area under the GZ curve shall not be less than 0.055 meter radian for an angle of heel up to 30 degrees. So up to 30 degrees as you can see from the figure over here this area shall not be less than 0.055 meter radian.
So it can be 0.055 meter radian or greater than 0.055 meter radian but in any of the cases not less than 0.055 meter radian is the requirement. Then comes the area under the GZ curve shall not be less than 0.09 meter radian for an angle of heel up to 40 degrees. So up to 40 degrees or up to the angle of down flooding or the angle of flooding.
Angle of down flooding or angle of flooding is nothing but it is the angle at which your deck edge immerses. So if the angle of down flooding is lesser than 40 degrees then the area up to the angle of down flooding. This area, this total area shall not be less than 0.09 meter radian. Okay, is the requirement. Next is the area under the GZ curve shall not be less than 0.03 meter radian for an angle of heel between 30 degrees and 40 degrees or between 30 degrees and the angle of down flooding.
So this area, if you are taking the area between 30 degrees and angle of down flooding, it would be this area. In case the angle of down flooding is less than 40 degrees then we take angle of down flooding on this. So this is the requirement for general cargo, tanker and passenger ships. The intact stability criteria for general cargo, tanker and passenger ships is as follows. So next let's begin with the intact stability criteria for container ships greater than 100 meters in length or for other vessels with the same length and those vessels having a larger flare or equivalent water plane area.
So for those vessels also the same intact stability criteria will apply. So for those things we'll most certainly... initial gm of the vessel shall be not to be less than 0.15 meter. Now this 0.15 meter is what is given under the International code for intact stability 2008. In some of the notes as well as other websites I have seen that the intact stability criteria for container vessels, the initial gm is given as 0.20 m not to be less than 0.20 m. But I could not find the exact source or the MSC resolutions or the IMO resolutions where I rely my notes on.
So I could not find it where it is given as 0.20 m. What I found under the intact stability code 2008 was that for vessels having a complete superstructure and those vessels with 70 meters in length and above the initial gm not to be less than shall not be less than 0.15 meter is the requirement so we will be going with this for the intact stability criteria for container ships as we have the proof about the information that we have so currently i am going with this itself then the lightning lever gz so initial gm this is the initial gm shall not be less than 0.15 meter okay Then the lightning lever GZ shall be at least 0.033 meter for angle of heel greater than or equal to 30 degrees. So your initial lightning, the lightning lever GZ shall be at least 0.033 meters for angle of heel greater than or equal to 30 degrees. For greater than or equal to 30 degrees, your lightning lever shall be 0.033 meters in length. Then the...
the maximum GZ should be at least 0.042 meters in length. So the maximum GZ which is occurring the length requirement is for maximum GZ at whatever angle of field it occurs the length shall be at least 0.042 meters. Now also have a look at the SI units when you will be looking at the units under the code it is given 0.042 divided by C meter. C is nothing but the form factor.
Kindly have a look at the further image in order to understand how we get this form factor. This form factor is based upon the dimensions of your vessel. Every vessel is different in construction hence you have a form factor which we will be dividing in order to get the exact intact stability of that vessel. Then the area under the GZ curve shall be not less than 0.009 meter radian for angle of heel up to 30 degrees for continuous. to 30 degrees the area under the GZ curve shall not be less than 0.009 meter radian shall not be the area under the GZ curve shall not be less than 0.016 meter radian up to 40 degrees okay or the angle of down flooding the area under the GZ curve not less than 0.006 meter radian between 30 degree and 40 degree so between 30 degree and 40 degree the area area shall not be less than 0.006 meter radian or the area between 30 degree and the angle of down flooding.
30 degree and angle of down flooding I am saying because in case the angle of down flooding is less than 40 degrees then what you take is up to the angle of down flooding. Between 30 degrees and the angle of down flooding the area has to be not less than 0.006 meter radian. Then you have the area under the GZ curve shall not be less than 0.029 meter radiant up to your angle of down flooding.
When you, if this is the angle of down flooding, up to the angle of down flooding, the total area shall not be less than 0.029 meter radiant. Okay. So this is another requirement for your container ships.
Then I have told you about C. C is the form factor. So kindly have a look at.
at the next slide for better understanding of the form factor. Moving on to the intact stability criteria for ships carrying timber deck cargoes. Now for ships carrying timber deck cargoes at all times during the voyage the metacentric height that is the GM of your vessel shall not be less than 0.1 meters in length.
So the metacentric height at all times during the voyage cannot be, shall not be less than 0.1 meters. Okay. We also take into account the fact. factors such as the absorption and the icing. Absorption means during the voyage the timber cargo absorbs some water.
When it is loaded on the deck, this cargo has the property of absorbing the water. So it absorbs water. So due to that absorption the weight increases on the deck.
Hence some change in GM will occur. So taking into account absorption and then the icing factor. Icing factor is also same as absorption.
see what will occur. Ice formation will occur on the timber cargo. Hence the icing as well as absorption factor taking into account both these factors at all the conditions during the voyage your GM shall not be less than 0.1 meters is what is required under the intact stability criteria for ships carrying timber deck cargoes. Then comes the maximum rightening lever GZ shall be at least 0.25 meters in length.
maximum GZ, the length of the maximum GZ has to be at least 0.25 meters. It can be greater than 0.25 meters, but in any of the cases not less than 0.25 meter is the requirement. Then comes the area under the GZ curve.
When we talk about the area under the GZ curve shall not be less than 0.08 meter radian up to angle of heel of 40 degrees or the angle of flooding if the angle of flooding is less than 40 degrees. So, this is the requirement. Then what is your angle of flooding?
Your angle of flooding is nothing but it is the angle at which the non-watertight opening of your ship, if it is present on the hull or on the superstructure of the ship, if that opening goes underwater, the angle at which it goes underwater is your angle of flooding. That means water ingress will start occurring at this angle because non-watertight opening has gone underwater. So, hence it is termed as angle of flooding. angle of flooding. So if your angle of flooding is less than 40 degrees under that condition the area under the GZ curve shall not be less than 0.08 meter radian up to the angle of flooding.
Next is under the action of steady wind what would be the limiting angle of heel. So under the action of steady wind the limiting angle of heel for ships carrying timber deck cargo is 16 degrees. So note this point 16 degrees is the limiting angle of heel.
limiting angle of heel under action of steady wind. So this is the intact stability criteria for ships carrying timber deck cargoes. So next we have the intact stability criteria for cargo ships carrying grain in bulk. They shall comply with the requirements of the International Code for Safe Carriage of Grains. This was adopted under resolution MSC.
23, 59. So this is the resolution under which this code was adopted. You will find the intact stability criteria for cargo ships carrying grains in bulk under this code. Okay. So throughout the voyage, what are the requirements that the ship has to meet?
The intact stability requirements are as follows. So first and foremost is the initial metacentric height, the GM zero of your vessel, the GM zero shall not be less than shall be not less than 0.30 meter. So your initial metacentric height GM0 has to be at least 0.30 meter or it can be greater but in any of the cases shall not be less than 0.30 meter is the requirement.
So this is your initial metacentric height. Second is the angle of heel due to shift of grain shall not be greater than 12 degree. The angle of heel due to shift of grain shall not be greater than 12 degree. So 12 degree is max. Shall not exceed 12 degree or angle at which the deck edge immerses.
The angle at which the deck edge immerses is the angle you can get it through your curve of statical stability. So this is the initial metacentric height. or the GZ curve. So that is from where you can get the angle at which the deck edge immerses.
So if that angle is less than 12 degrees then you will be considering that angle in accordance with this point. The next point is the residual area between the heeling arm curve and the rightening arm curve. The residual area between the heeling arm curve and the rightening arm curve shall not be less than 0.075 meter radial up to 40 degrees angle of heel or upto the angle of flooding whichever is less. So this is the angle the lightening arm curve and this would be the heeling arm curve. So this area shall not be less than 0.075 meter radian upto 40 degrees of angle of heel or the angle of flooding whichever is less.
So this is the intact stability criteria for cargo ships carrying grain in bulk.