A refit is the single most complicated period for IHM compliance. Contractors work across every system, materials are added and removed, and documentation from multiple parties needs to be collected before they leave the yard. Under the Hong Kong Convention, Part I must reflect the vessel’s current state — which means any refit that changes a material listed in Annex I of the Convention creates an obligation to update the IHM.

This briefing covers what that obligation looks like in practice.

The core obligation

The Hong Kong Convention requires that Part I of the IHM be maintained throughout the vessel’s operational life. When a material listed in Annex I is added, removed, or changed, the IHM must be updated accordingly. A refit that replaces insulation, refrigeration equipment, pipework, or electrical systems may involve multiple Annex I materials across multiple contractors.

The obligation arises from the work itself — not from a subsequent survey. By the time your class society conducts a renewal survey, the changes should already be recorded.

Material Declarations and Statements of Compliance

The primary mechanism for documenting material changes is the Material Declaration (MD) — a document from the supplier or manufacturer confirming what controlled substances, if any, are present in the supplied product.

When a material is confirmed to contain no Annex I substances, the supplier provides a Statement of Compliance (SDoC) instead.

These documents form the evidence base for Part I updates. The IMO guidelines for IHM implementation (MEPC.269(68)) set out the format and content requirements for both documents. When you update Part I after a refit, the corresponding MDs and SDoCs are the supporting records that a surveyor will ask to see.

Which contractors owe you documentation

At the planning stage of a refit, the question to ask for each work package is: does this work involve any materials that could contain Annex I substances? Contractors whose scope may require MD or SDoC documentation include:

Insulation contractors — pipe lagging, machinery spaces, and accommodation insulation. Asbestos is an Annex I substance (Table A).
Paint and coatings contractors — anti-fouling coatings. Organotin-based compounds (TBT) are in Annex I (Table A).
Refrigeration contractors — refrigerant gases. Ozone-depleting substances are in Annex I (Table A).
Electrical systems contractors — transformers, capacitors, and older ballasts. Polychlorinated biphenyls (PCBs) are in Annex I (Table A).
Equipment suppliers — any new equipment installed should be accompanied by confirmation of its hazardous material status.

This does not mean every contractor needs to supply extensive documentation. A contractor replacing stainless steel pipework needs a SDoC confirming no hazardous material content — which is typically straightforward. The obligation is proportionate to what is actually being installed.

Building the documentation chain

The practical challenge in a refit is collecting documentation systematically before contractors leave the yard.

A process that works in practice:

At specification stage — include an MD/SDoC requirement in the work scope for each contractor whose work could involve Annex I materials
At material delivery — request MD or SDoC from each supplier as part of the delivery documentation, before work begins
At completion of each work package — confirm that documentation has been received before signing off
Post-refit — consolidate the documentation, update Part I for any changed entries, and file the MD/SDoC records alongside the change log

Chasing documentation after the yard period ends is significantly harder. Contractors move on, records are difficult to obtain, and there is no obvious prompt to resolve the gap until a survey reveals it.

When documentation is unavailable

Not every contractor or supplier will have ready-made MD or SDoC documentation. For new equipment from established manufacturers, this documentation is usually available on request. For older materials, or smaller contractors, it may require more effort.

Options when documentation is not immediately available:

Request information from the original manufacturer directly, using the product name and batch or lot number
For materials where an MD cannot be obtained, arrange for sampling and laboratory analysis to determine hazardous material content
Document the gap in the change record, including what steps were taken to obtain confirmation

The IMO guidelines for IHM implementation (MEPC.269(68)) describe the approach for circumstances where supplier documentation cannot be obtained.

After the refit

Once work is complete and documentation is collected:

Update Part I for any entries that have changed — removing materials that were replaced, adding new ones containing Annex I substances, and updating quantities and locations as required
Add a change record entry for the refit period, referencing the supporting MD/SDoC documentation
File the MD/SDoC documents in a location accessible to a surveyor

The IHM is not updated at the survey — it is updated when the change happens. The survey verifies that the updates were made correctly and are supported by documentation.

For the full picture of what an IHM requires and how to keep it current, see the complete IHM for superyachts guide. For the documentation side specifically, see managing MD and SDoC paperwork.

MANTIS manages IHM change records, stores MD/SDoC documentation against each change entry, and tracks survey intervals. Start free beta →