Maintenance and modification standards for fishing vessels
Source: gov.uk (2025-06-16)

Codes of Practice detail the regular maintenance requirements of safety equipment and systems to a high standard, as is required to maintain fishing certificates.

Fishing vessel codes of practice emphasise the importance of regular maintenance of a high standard - particularly of safety equipment and systems. For vessels below 24 metres in length, this requirement forms part of the annual self-certification needed to maintain the Fishing Certificate.

The MCA inspects vessels of 15 to 24 metres overall length. Vessels over 24 metres have safety equipment and systems checked annually and are also subject to more detailed statutory intermediate surveys. If safety equipment is not properly maintained, vessels may be detained, and the owners prosecuted.

The MCA also provides guidance on specific problems, such as:

premature failure of copper pipes in engine cooling water systems (https://www.gov.uk/government/publications/mgn-190-fv-failure-of-copper-pipe-in-engine-cooling-water-systems)

avoiding flooding by using suitable grades of stainless steel for pipe work (https://www.gov.uk/government/publications/mgn165-amendment-1-f-fishing-vessels-risk-of-flooding)

bilge systems and additional/alternative equipment to help prevent flooding (https://www.gov.uk/government/publications/min-631-mf-bilge-pumping-systems)

testing of emergency sources of electrical power (https://www.gov.uk/government/publications/mgn-52-testing-emergency-sources-of-electrical-power)

maintenance of electrical equipment (https://www.gov.uk/government/publications/mgn-132-electrical-equipment-maintenance-and-incidents)

MGN 331 Amendment 1 (M+F) provides guidance on the legal obligations on shipowners and employers that apply to fitting, maintenance and use of work equipment (https://www.gov.uk/government/publications/mgn-331-mf-amendment-1-provision-and-use-of-work-equipment-regulations-2006)

maintenance of portable fire extinguishers (https://www.gov.uk/government/publications/mgn-276-maintenance-of-portable-fire-extinguishers)

fire detection and alarm systems on fishing vessels (https://www.gov.uk/government/publications/mgn-291-fire-detection-and-alarm-systems-on-fvs)

A free online Safety Folder (https://www.safetyfolder.co.uk/) service has been developed by industry, which can assist you with planning your maintenance. As well as this, it can also help to conduct and record risk assessments, help you to comply with ILO 188 regulation, keep track of crew training and certification and provides reminders of equipment certification and servicing.

Preventing flooding

The condition of seawater pipework within a fishing vessel is an important factor in preventing flooding in a vessel.

Stainless steel seawater pipework can reduce pipework corrosion, but some grades of stainless steel are not suitable for marine use. For example, austenitic stainless steels (304/304L and 316/316L) may be at risk of chloride stress corrosion cracking when used with seawater or polluted water, possibly leading to fracture. One solution is to increase the nickel content (eg alloy 330, 904L) or to use a duplex or ferritic stainless steel, eg 329, 2205, 439, 26Cr 1 Mo.

MGN 165 (F) Fishing vessels: the risk of flooding (https://www.gov.uk/government/publications/mgn165-amendment-1-f-fishing-vessels-risk-of-flooding) provides guidance on bilge systems, during construction and operation, to help reduce the number of vessels and lives lost as a result of flooding. This Notice also recommends owners and skippers to consider using additional or alternative equipment, such as salvage pumps, propeller shaft-mounted pumps and secondary bilge alarms, to reduce the risk of catastrophic flooding.

Operational standards for fishing vessels

Read the relevant Code of Practice for the different length categories of fishing vessels.

Fishing vessel codes of practice and regulations provide guidance on best practice in areas such as:

construction, watertight and weathertight integrity and water freeing arrangements

maintaining your stability

machinery and electrics, including propulsion, steering, pipework and emergency arrangements

fire protection, including fire precautions and the deployment and use of fire-protection equipment

protection of personnel, including risk assessments, accident prevention and securing of equipment

life-saving equipment

emergency procedures, including inspections and drills in relation to emergency procedures (https://www.gov.uk/government/publications/mgn-570-f-fishing-vessels-emergency-drills)

prevention of man overboard (https://www.gov.uk/government/publications/mgn-571-f-fishing-vessels-prevention-of-man-overboard)

You must ensure that all onboard equipment is of serviceable condition and regularly maintained. Equipment and maintenance schedules are inspected during statutory surveys of vessels over 15 metres in length. The MCA will check these areas in smaller fishing vessels during normal inspections.

Vessel modification

Fishing vessels are required to ensure that, prior to modifications being carried out on their vessel, they seek MCA approval to ensure that safety of the vessel is not affected. This approval should be sought regardless of whether these modifications are being undertaken with or without funding from the Marine Management Organisation or Devolved Administrations.

By approaching MCA prior to applying for funding, owners can ensure they:
- Incorporate any amendments to the proposed modifications that MCA may require into the application; and
- Obtain MCA approval to proceed with the modification
Therefore, if work commences without MCA approval, the owner is at risk of his certificate being suspended whilst the MCA conducts an inspection or survey of the vessel. The MCA may require amendments to the intended modifications or potentially the vessels to be reinstated to its original condition. This work may not be covered by additional funding.

For this reason it is particularly important that owners approach the MCA prior to submitting an application for funding to minimise the risk of the vessel being suspended fishing and from having to undertake additional work to address the vessels safety.

Further details can be found in Marine Information Note 593 (F): Vessel Modifications – Pre Approval by MCA. (https://www.gov.uk/government/publications/min-593-f-vessel-modifications-pre-approval-by-mca)