RACLAN, MGN 681, and What Superyacht Crew Actually Need to Know About Lithium Battery Storage

"RACLAN" Is a Product Name, Not a Regulation

If you've heard "RACLAN" mentioned around thermal runaway and superyacht fire risk, it's worth being precise about what it is. RACLAN is a commercial brand — made by the German manufacturer Fisacon — covering a range of lithium-ion battery containment products for yachts: the RACLAN Box and Square Marine Box for individual watertoy batteries (e-foils, Seabobs, tenders), and RAMBSS (the RAclan Maritime Battery Safety System), a modular, stackable system pitched at larger fleets of watertoys on bigger yachts. RAMBSS holds a Lloyd's Register Design Appraisal Document, and features active monitoring, an integrated extinguishing agent, gas filtration, and an audible alarm tied into the vessel's own alarm system. It is not the only product in this space — ZARGES cases are another example marketed for the same purpose — and it is not itself a rule, standard, or MCA requirement. The rule is MGN 681.

What MGN 681(M) Amendment 1 Actually Requires

MGN 681(M) — the MCA's guidance on fire safety and storage of small electrically powered craft on yachts — was first published in June 2023 and superseded by Amendment 1 on 19 December 2025. It applies to any UK-registered yacht carrying electrically powered watertoys with lithium-ion batteries above 100 Wh: e-foils, Seabobs, electric tenders, jet skis, and similar equipment. It sets out requirements for dedicated storage and charging arrangements, ventilation, fire detection and suppression, and appointing a named person responsible for battery safety on board — someone who oversees compliance, keeps training records, and feeds into the vessel's safety management system.

The Deadline That Matters: 1 January 2027

By 1 January 2027, lithium battery charging and storage containers on UK-registered yachts must be certified by a UK Nominated Body as meeting MGN 681 Amendment 1. Existing installations can remain in use until that date, but the MCA has explicitly said early replacement is "strongly recommended" rather than waiting for the deadline to bite. This is the actual compliance question crew and management should be asking — not which brand of box is fitted, but whether it carries current Nominated Body certification against this specific guidance note.

What This Means for You, Day to Day

• Know who your vessel's named responsible person for lithium battery safety is — MGN 681 expects one to be appointed, not assumed
• Ask whether your watertoy storage and charging arrangement is certified against MGN 681 Amendment 1, or still running on the pre-2025 standard
• Treat any lithium battery storage box — RACLAN, ZARGES, or otherwise — as a containment and detection system, not a guarantee. Thermal runaway is still a genuine risk; the box is there to buy time and limit spread, not eliminate the hazard
• Charging habits still matter regardless of what containment system is fitted — unofficial chargers, overnight charging outside the designated area, and skipping visual checks for swelling or damage all undermine even a well-specified system
• If you're joining a new yacht, ask this during handover, not after an incident: where are the watertoy batteries stored, charged, and what's the evacuation and suppression plan if one goes into thermal runaway

Test Your Knowledge

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Related Reading

• The Fire in the Box You Cannot See — how thermal runaway works and why conventional firefighting struggles against it

Sources: MGN 681(M) Amendment 1 — Fire Safety and Storage of Small Electric Powered Craft on Yachts (MCA, published 19 December 2025) | Mercer Yachting, "Lithium Fire Safety Boxes for Yachts: The Complete 2026 Guide to RACLAN Boxes, ZARGES Cases & MGN 681 Compliance" | Ritz Marine, product pages for RACLAN and RAMBSS | HFW, "MGN 681: New lithium-ion battery rules – key updates for yacht owners"