Spate of fires results in new yacht toy and tender guidelines

The Maritime & Coastguard Agency (MCA) has released new guidance on the handling and storage of small electric-powered craft and their lithium-ion batteries following a spate of yacht fires last summer.

Yacht industry groups estimate 16 total losses due to fires between August 2021 and August 2022, with around half of the fires still having no established cause. Although, a number of agencies have pointed to faulty or inadequately stored lithium-ion batteries as a suspected cause.

Small electrically powered craft (such as jet skis, tenders, sea scooters and e-foils) are becoming increasingly popular on board, but poor practice surrounding fire prevention, storage and suppression has meant that lithium-ion fires currently pose a far greater risk compared to their petroleum counterparts. 

Lithium-ion battery fires are often self-sufficient and continue to burn without access to additional oxygen. This renders firefighting systems that rely on oxygen deprivation less effective. They may also continue to generate high amounts of heat following fire-extinction and are at risk of re-ignition, with a larger electric tender requiring approximately 10,000 litres of water for a battery fire to be fully suppressed.

The new guidelines recommend that yacht crew monitor batteries for signs of damage. This includes, in order of severity, a blue or clear fluid leak; hissing, whistling, or popping; a sweet chemical smell; black “smoke” (nanoparticles of heavy metals); white vapour. Consulting the manufacturer's user manual is always recommended, as signs of overheating may vary on a case-by-case basis, but appropriate firefighting measures must be taken if any of these symptoms manifest.

The MCA also advises that crew store spare or removed batteries with a rating above 100Wh in a dedicated cabinet or locker, constructed according to a recognised international standard; the integration of temperature into the ships alarms and control system where practical; and dedicated spaces for battery charging activities, always at least one metre away from the MCA’s outlined boundaries.

Damaged batteries should "under no circumstances" be charged, and any charging should be ceased immediately if damage occurs during charging. MCA recommends that crew store it “with extreme caution” and unload it at the first available opportunity for disposal or repair.

There is no exception for vehicles based on battery size (unless the battery is removed from the vehicle), so even small vehicles with a battery capacity of less than 100Wh would still have to comply with these requirements.

The MCA claim that the guidance is not intended to restrict the use and charging of personal items on board, such as mobile phones and laptop computers. However, even in these cases, crew should be aware of the risk posed and should avoid storing them in such a way that the "aggregate capacity of [the] batteries is greater than 500Wh".

While the recent spate of fires has raised great concern, the MCA is confident that the new guidance will result in an increased understanding of lithium-ion battery fire risk among yacht crew, designers, and owners, leading to better practice and fire safety. Off-gas detectors are also being considered as a developing technology that may aid with early-stage lithium-ion fire detection in future.

The guidance by the MCA was published following a consultation period between November and February 2023 with class societies, shipyards, insurers and surveyors. The full guidelines can be found here.