Q.What is the difference between convention and code ?

A convention is an agreed set of rules related to a particular matter. For example 

• Safety of life at Sea convention (SOLAS) for safety related matters at sea.
• MARPOL for matters related to Marine pollution

More often than not, the need of a convention is triggered by a major incident. 

For example the need to have SOLAS convention was triggered after sinking of Titanic. Similarly the need to have MARPOL convention was triggered by number of pollution incidents.

Sometimes the need of a new convention is also felt after a major research study. For example, research on ballast water found that ballast water is a reason of concern and requires attention to the way we manage ship's ballast. That led to the "Ballast water convention".

For whatever reason, when a need for a new convention is felt, IMO after a long study and processes drafts the convention.

This draft is discussed and adopted by the relevant committee of the IMO. The adopted convention is ratified once the pre set conditions (number of states and minimum tonnage) are met.

Now let us come to the point. Where does code fit in all this ?

To understand that, put yourself in the center stage. You have been given the work to draft a convention. 

Let us say you have to draft SOLAS convention. And you are now drafting Chapter III of SOLAS convention, which is

Life saving appliances and arrangement

Let us say in this chapter you are drafting the requirements for Lifejackets. And you wrote this,

Brilliant !!! But there is something missing. Which lifejacket are we talking about here ? Will the inflatable type life jacket do ? What do we mean by "Infant Lifejacket ? So many questions. And here are the answers to the specifications of the required life jacket.

And the standards required for Lifejacket goes on for another 3 pages in the LSA code.

And we are not talking about including only these 4 pages in SOLAS chapter III. This is only the description for Lifebuoy. We have many more life saving equipments and description of those will also be required.

Not only that. We have a SOLAS chapter for fire fighting equipments also and the description of those would also be required.

So if we do not put all these requirements of required standards into a different book called "Code", we will face two issues

• The size of the draft of convention would increase 10 fold, and
• The conventions will not be clear to the reader

Imagine if we have all these codes (that are part of SOLAS) incorporated inside the SOLAS

• FSS Code
• LSA Code
• ISM Code
• ISPS Code
• Intact stability code

It would be difficult. So instead what we can do is

• Provide all these informations as a "code" and
• wherever required, mention the code reference in the convention 

This is exactly what IMO does with all its conventions. Want to see how the SOLAS requirement of Life Jacket is drafted ? Here it is

So one line and a different book for standards called "Code" does the trick.

So a Code to a convention is part of the convention. It provides the international standards required for the elements mentioned in that particular chapter of the convention.