Liferafts and HRUs: service intervals, extensions and approved stations

The basic rule: 12 months at an approved station

SOLAS regulation III/20.8 requires every inflatable liferaft to be serviced at an approved service station at intervals of no more than 12 months. The same applies to inflatable lifejackets and marine evacuation systems. The flag may extend this to 17 months, but only where servicing within 12 months is impracticable, so it is an exception for a specific ship and situation, not a routine option. Get any extension in writing from the flag or its recognised organisation.

Hydrostatic release units (HRUs) of the serviceable type follow the same rule under III/20.9: serviced at least every 12 months at a competent station, with the same possible extension to 17 months.

Two ways the interval can be longer

Following the survey window. MSC/Circ.955 lets flags that apply the harmonised survey system allow liferaft servicing to follow the survey window, which can mean up to 18 months between services. Not every flag uses this, and some ask for the recognised organisation to be told. Check your flag’s notice before relying on it.

Extended-service-interval (ESI) liferafts. Under SOLAS III/20.8.3 and MSC.1/Circ.1328, a flag may accept specific liferaft models for an extended interval:

• servicing at least every 30 months during the raft’s first 10 years;
• an inspection on board every year, for humidity and gas leaks, by staff certified by the maker, with a log kept with the certificate;
• acceptance is per flag and per product. The Dutch administration, for example, has accepted Viking’s S30 since 2006 and in 2020 extended that acceptance to rafts up to 15 years old.

What the service station must do

Resolution A.761(18), as amended by MSC.55(66) and MSC.388(94), sets the conditions for approved liferaft service stations:

• servicing in an enclosed workshop, by staff certificated by the liferaft maker, working to the maker’s service manual;
• the station accredited by the maker and approved by the flag. Bureau Veritas requires the maker’s authorisation for each make and model the station services;
• the owner or a representative may attend the service where practicable;
• service records kept for at least five years.

Test or item	When	Basis
Working pressure test	Every service	Res. A.761(18)
Gas inflation test	Every 5 years	Res. A.761(18)
Necessary additional pressure (NAP) and floor seam tests	Every service once the raft is more than 10 years old	Res. A.761(18) as amended
Davit-launched raft overload test (10 %)	Every second service	Res. A.761(18) as amended
Pack items with an expiry date (flares, water, rations, batteries)	Replaced if they would expire before the next service	Res. MSC.388(94)

A.761(18) words the floor seam test slightly differently in its text (“after” the tenth year) and in its table (“at” ten years). The release hook of a davit-launched raft falls under MSC.402(96): an annual examination and an overhaul with a load test at least every five years.

Disposable HRUs

The LSA Code requires the hydrostatic release to work at a depth of 4 m or less and the weak link to break at 2.2 kN ± 0.4 kN. Disposable HRUs carry their expiry date; how long they last depends on the maker. The widely used Hammar H20 lasts 24 months from the month it is installed (30 months for its RX type). In March 2025 the maker warned about refurbished H20 units sold as new, so buy from authorised dealers and check the unit before fitting.

What PSC and class keep finding

• Service overdue.
• Painters tied to the cradle or connected the wrong way, so the weak link cannot do its job.
• HRUs without a visible expiry date, or past it.
• Rafts installed incorrectly in their cradle.

On ships classed by ClassNK, port State control found 3, 4 and 7 detainable liferaft deficiencies in 2022, 2023 and 2024, mainly overdue service, wrong installation and HRU painters not connected; ABS and IMCA report the painter and expiry-date problems too. In the Tokyo MoU’s 2024 report, life-saving appliances made up 13.2 % of all deficiencies, with no separate figure for liferafts.

Checklist for the ship

1. Keep a list of every raft and HRU with its last service date and next due date, and get any extension from the flag in writing.
2. Use a station that is approved by the flag and holds the maker’s authorisation for that model.
3. Know which tests the raft’s age requires, and attend the service where you can.
4. When the raft comes back, check the certificate, the “date last serviced” on the canister and the expiry dates of the pack items.
5. Check the HRU: expiry date marked and valid, painter connected through the weak link and not to the cradle, a genuine unit.
6. For ESI rafts, book the annual on-board inspection and keep its log with the certificate.
7. Record the weekly and monthly inspections.

How we help

We collect the rafts, have them serviced at an approved station and bring them back with their certificates, replace HRUs before they expire and keep the due dates in your customer portal. Where the ship cannot wait, we arrange an exchange raft. See Liferafts and hydrostatic release units.