Commercial Yachts & Charter Fleet
Regulatory compliance under MCA MGN 681(M), Malta Commercial Yacht Code 2020 section 11.2.1.4, and Marshall Islands Yacht Code MI 103 2021 section 13.5.4, delivered with the Lloyd's Register appraised RAMBSS.
Classed commercial and charter yachts carry a different risk profile to private pleasure craft. Higher guest numbers, larger toy inventories, permanent crew on board, and scheduled flag state inspections all raise the bar for how lithium-ion batteries must be stored and charged.
A modern 40m charter yacht routinely carries two eFoils, a pair of Seabobs, multiple jet surfboards, drones, e-bikes, dive scooters, and crew power tools. That's easily 30 to 50 kWh of lithium-ion storage moving through the toy garage every week. Each device has its own charger, charge profile, and thermal behaviour.
The risk isn't theoretical. Thermal runaway events on yachts have prompted insurer bulletins from the IUMI and major underwriters, and the MCA's MGN 681(M), published to address small electric-powered craft on yachts, is now the reference text across Red Ensign, Malta, and Marshall Islands fleets.
For classed vessels the exposure stretches beyond the fire itself. Flag state surveyors check storage arrangements at annual survey. P&I clubs increasingly ask for documented battery safety procedures. Charter operators lose revenue if a toy garage fails survey and can't be signed off for the season.
Three regulatory regimes set the framework: the UK MCA's MGN 681(M) for Red Ensign yachts, the Malta Commercial Yacht Code 2020 section 11.2.1.4 for Malta-flagged commercial vessels, and the Marshall Islands Yacht Code MI 103 2021 section 13.5.4. They align closely, and the Lloyd's Register Design Appraisal for RAMBSS was issued against all three simultaneously.
MGN 681(M) Amendment 1 sets out the fire safety and storage requirements for small electric powered craft on yachts. Each section below quotes what the note requires, then shows how RAMBSS satisfies it, per the RAMBSS compliance datasheet and the Lloyd's Register Design Appraisal Document TSO-24-013730-F01-DAD.
MGN 681(M) requires lithium batteries to be stored in a dedicated cabinet constructed to a recognised international standard (EN 14470, EN 16121, EN 16122), or an approved dedicated battery storage and charging cabinet. The RAMBSS cabinet is tested by the Research Institute of Sweden to UL 1487, carries a Lloyd's Register Design Appraisal (DAD: TSO-24-013730-F01-DAD), and uses FIPRO non-combustible vermiculite panels certified under Bureau Veritas MED type examination certificate 07000/E0 MED.
Section 4.12.1 requires charging to take place while the cabinet is closed. RAMBSS has internal charging sockets and door lock sensors that permit charging only when both locks are engaged.
Section 4.12.2 requires detection of temperature rise inside the cabinet with over-temperature indication. RAMBSS carries three independent thermal sensors, two independent control boards, and audible plus visual alerts on the OLED touchscreen.
Section 4.12.3 requires a suitable extinguishing medium that can be applied to the battery without opening the cabinet. RAMBSS deploys a multi-nozzle TRIDENT extinguishing and cooling spray, then continues with fresh water once the TRIDENT concentrate is depleted, per the RAMBSS technical datasheet.
Section 4.12.4 requires venting of off-gases to prevent overpressure and explosive gas build-up. RAMBSS uses a multi-stage EXO exhaust filter that scrubs H2, HF, and VOCs, reduces off-gas temperature below 100 degrees C, and acts as a flame arrestor.
The cabinet must automatically stop charging if any fault or overheating is detected. RAMBSS isolates power to the charging circuit on temperature rise or smoke detection, then triggers the alarm via dry contact to the vessel alarm monitoring and control system.
Each storage or charging cabinet must have a defined maximum kWh capacity that can't be exceeded. RAMBSS is rated at up to 5.25 kWh per module, confirmed in Lloyd's Register DAD section 2.3. The Raclan Square Marine Box rating is 3.5 kWh.
MGN 681(M) sets 1 January 2027 as the deadline for product type approval. RAMBSS holds a Lloyd's Register Design Appraisal today and type approval is in progress. Per DAD section 2.2, the product isn't LR type approved yet because no type approval standards currently exist for this category. The design appraisal confirms the product can form part of a compliant shipboard arrangement.
Two further sections of MGN 681(M) matter for installation planning. Section 4.7.3 sets a 1 metre minimum distance from Category A machinery spaces, switchboards, and main electrical sources. For yachts above 500 GT it's a firm requirement; for yachts below 500 GT it applies where practicable, with a risk assessment otherwise (DAD section 3.8). Section 4.11.2 allows A-0 insulation instead of A-60 where sufficient cooling is provided, which RAMBSS achieves through its TRIDENT and fresh water spray system.
For the full compliance matrix against every clause of MGN 681(M), see our guide to MGN 681 lithium battery safety for yachts.
For Malta-flagged commercial yachts, the operative text is section 11.2.1.4 of the Commercial Yachts Code 2020, covering the storage of battery-operated water sports equipment and toys.
The Malta CYC requirements for the garage space in which the battery cabinet sits are close to those in the Red Ensign Yacht Code. Independent ventilation of at least 6 air changes per hour, fixed fire detection, and a fixed waterspray system inside the space. The Lloyd's Register DAD explicitly lists Malta CYC 2020 section 11.2.1.4 alongside MGN 681(M) and MI 103 as one of the codes RAMBSS has been appraised against.
What does this mean in practice for a Malta-flagged yacht? The vessel's toy garage still has to meet the yacht code space requirements. RAMBSS sits inside that space and handles the cabinet-level requirements: containment, detection, automatic suppression, charging control, and off-gas filtration. Together they form the compliant arrangement.
Lloyd's Register DAD section 2.5 confirms the placement rules: RAMBSS is to be on open deck or inside a space that meets CYC 2020 section 11.2.1.4 (for Malta commercial yachts), the Red Ensign Yacht Code part A chapter 14.1 (Red Ensign commercial up to 12 passengers) or part B chapter 6.15 (passenger yachts 13 to 36 passengers), or MI 103 section 13.5.4 (Marshall Islands commercial).
The full Malta Commercial Yacht Code overview walks through the other 2020 code chapters that interact with battery safety: fire integrity, machinery space classification, and garage space hazardous zoning where petrol vehicles share the space.
The Marshall Islands Yacht Code MI 103 2021, including amendments from August 2023, addresses lithium-ion battery storage for commercial yachts under the RMI flag in chapter II section 13.5.4.
MI 103 section 13.5.4 calls for the same core arrangement: independent ventilation of at least 6 air changes per hour in the space housing the battery cabinet, with fire detection. The Lloyd's Register DAD for RAMBSS lists MI 103 2021 section 13.5.4 as one of the three codes the design was appraised against, alongside MGN 681(M) and CYC 2020 section 11.2.1.4.
For fleets that move between Red Ensign registration, Malta flag, and Marshall Islands flag through their operating life, a single RAMBSS install covers all three regimes. That matters on yachts being prepared for charter in one jurisdiction and ownership transfer in another, where the documentation pack needs to satisfy more than one flag state surveyor.
The DAD is the core deliverable. It's accepted by Lloyd's Register EMEA, referenced by Bureau Veritas and DNV surveyors when reviewing RAMBSS installs on vessels under their class (subject to individual surveyor satisfaction, per DAD page 1), and forms part of the compliance file every classed yacht carries.
RAMBSS ships in three module sizes, stackable and interconnectable. All share the same electronics, filters, and extinguishing system. The difference is internal volume, which dictates how many batteries and chargers each module accepts.
External: 600 by 600 by 500 mm. Internal: 550 by 550 by 300 mm. Designed for batteries up to 4.35 kWh plus charger, per the RAMBSS technical datasheet dated October 2024.
Typical use: a single eFoil or jetboard battery and charger, or a pair of smaller drone and e-bike batteries. Lowest-profile module, suits toy garages with limited vertical clearance.
External: 600 by 600 by 750 mm. Internal: 550 by 550 by 500 mm. Capacity up to 5.25 kWh plus charger.
The most common configuration on charter yachts: fits the battery plus charger for a single large-capacity device (Seabob F5S, high-capacity jetboard), with room for accessory batteries alongside. Stackable with Module 500 or 1500 to build the right total capacity.
External: 600 by 600 by 1520 mm. Internal: 550 by 550 by 1300 mm. Same 5.25 kWh per-module capacity limit, but taller internal volume accepts a Seabob upright on its charger, which is the preferred storage posture for several crew teams.
On larger charter vessels with a well-organised toy garage, Module 1500 usually houses the flagship water toy (Seabob, large jetboard) and leaves smaller batteries to a shorter adjacent module.
All three modules share the same feature set: three integrated thermal sensors, two independent control boards, TRIDENT plus fresh water extinguishing, multi-stage EXO exhaust filter (H2, HF, VOC), water-resistant OLED touchscreen, LAN/Wi-Fi/dry contact connection, 110/230 V operation, half-inch fresh water connection, alarm buzzer above 80 dB, sabotage protection, integrated attachment points, and six-week emergency power supply (extended to 90 days in some configurations per the LiVault compliance datasheet).
Modules stack and connect, so a yacht with 20 kWh of toy batteries can run four Module 750s in series, sharing the fresh water supply line and alarm connection. Installation clearance requires at least 20 cm above and 10 cm behind each unit.
For deck-mounted or lighter storage where a full RAMBSS install isn't needed (for example a tender bay with a single spare battery), the Raclan Square Marine Box handles up to 3.5 kWh and carries the DMT TÜV Nord programme M 02-2022 certification as a watertight deck-rated solution.
Supplying the cabinet is the easy part. Getting a classed yacht through survey needs the right documentation pack, surveyor-ready drawings, and practical installation work by marine electricians who know the yacht.
Ritz Marine handles the product supply and logistics from Malta. Mercer Yachting coordinates the vessel-side work: pre-install surveys, documentation prep for flag state and classification society, and scheduling alongside other refit activity. The combined model means one point of contact for the captain or fleet manager, not three.
Step one is a remote survey: deck drawings, toy garage layout, existing ventilation scheme, nearest Category A machinery boundary. We check whether the 1 metre separation from the engine room (MGN 681 section 4.7.3 and DAD 3.7) is met, and flag it if the vessel is below 500 GT and needs a risk assessment.
Step two is module sizing. Based on the yacht's toy inventory and charge cycle pattern, we specify Module 500, 750, 1500, or a stacked combination. The rated capacity of 5.25 kWh per module is a firm ceiling, set in the DAD section 2.3 to keep the extinguishing system effective.
Step three is delivery. Mercer Yachting ships from Malta under EU intra-community supply rules to any yard in Italy, Greece, France, Spain, or further afield. For yards in the exclusive territory (Malta, Sicily, Greece), we deliver quayside. For other Mediterranean locations, delivery is to the yard or vessel as agreed.
Step four is install. A marine electrician hooks up 110/230 V power, fresh water supply (half-inch), and the dry contact alarm connection to the vessel AMCS. RAMBSS is mechanically fixed through the floor fixing plates and optional wall connecting elements. Clearance is 20 cm above and 10 cm behind, per the RAMBSS technical datasheet.
Step five is surveyor sign-off. We provide the full documentation pack: Lloyd's Register DAD (TSO-24-013730-F01-DAD), RAMBSS technical datasheet, DMT TÜV Nord programme M 02-2022 report for the Raclan range, Bureau Veritas MED certificate 07000/E0 MED for FIPRO panels, and as-installed drawings. Final acceptance still depends on surveyor satisfaction, as the DAD cover page states.
For charter yachts based in the wider Mediterranean, regional delivery pages cover Sicily and Greece with port-by-port logistics.
Three independent certification bodies underwrite the RAMBSS compliance position. Each documents a different aspect of the system. Together they form the compliance file a surveyor expects to see.
It's worth being explicit about what the current certification does and doesn't cover. Per the Lloyd's Register DAD section 2.2, RAMBSS isn't Lloyd's Register type approved (there are currently no type approval standards for this category of product). The product may not carry the LR logo. The product doesn't hold an MCA product approval certification, because there's no MCA agreed standard for these products yet.
What the DAD does confirm is that the product as designed can form part of an arrangement compliant with MGN 681(M), CYC 2020 section 11.2.1.4, and MI 103 section 13.5.4. That's the regulatory position as of the DAD date, and it's what flag state surveyors work from today.
Tell us your vessel details, flag state, and toy garage inventory. We'll size the right RAMBSS configuration and prepare the surveyor documentation pack.
No. RAMBSS holds a Lloyd's Register Design Appraisal Document (DAD reference TSO-24-013730-F01-DAD, issued 11 November 2024), which confirms the design can form part of an arrangement compliant with MGN 681(M), Malta CYC 2020 section 11.2.1.4, and Marshall Islands MI 103 2021 section 13.5.4. As stated in section 2.2 of the DAD, the product isn't LR type approved: there are currently no type approval standards for this category of product. Type approval is in progress. Final acceptance on any specific vessel depends on surveyor satisfaction.
Yes. Section 11.2.1.4 of the CYC 2020 addresses the storage of battery-operated water sports equipment and toys, and calls for a dedicated space with independent ventilation (minimum 6 air changes per hour), fire detection, and a waterspray system. The RAMBSS sits inside that compliant space and handles containment, early detection, and automatic cooling and suppression at the cabinet level. The Lloyd's Register DAD confirms RAMBSS fits into an arrangement compliant with CYC 2020 section 11.2.1.4.
A Design Appraisal Document (DAD) is a formal review by the classification society confirming that the design meets the cited regulations and can form part of a compliant shipboard arrangement. A type approval is a broader product certification issued against a specific product standard, allowing batch production under surveillance. For lithium battery safety cabinets there's no industry type approval standard yet, so the DAD is currently the strongest class-society recognition available for RAMBSS. LR type approval is in progress.
MGN 681(M) is a UK MCA Marine Guidance Note, so it applies directly to Red Ensign commercial yachts. For Malta-flagged commercial yachts the equivalent provision is CYC 2020 section 11.2.1.4, which is closely aligned. In practice, many owners and managers of Malta-flagged yachts reference MGN 681(M) as best practice since it's the most detailed regulatory framework published on this topic, and insurers increasingly expect the same level of control regardless of flag.
Yes. RAMBSS modules are designed for retrofit. Each unit has external dimensions of 600 by 600 mm, with heights of 500, 750, or 1520 mm. They connect to 110/230 V shore or vessel power, a half-inch fresh water line, and a dry contact for the vessel alarm monitoring and control system. Minimum 20 cm clearance above and 10 cm behind is required. Installation is typically scheduled alongside other toy garage or tender bay work during winter layup or scheduled refit.
Mercer Yachting, supported by Ritz Marine, is the exclusive dealer for Malta, Sicily, and Greece and coordinates direct delivery to shipyards and quaysides across the Mediterranean. For installations in France, Spain, or other Mediterranean regions outside the exclusive territory, we can still coordinate supply and delivery, then work with the yard's marine electricians on installation. We provide installation guidance, surveyor documentation, and post-delivery technical support.
For a RAMBSS installation on a classed commercial yacht, we supply: the Lloyd's Register Design Appraisal Document (TSO-24-013730-F01-DAD, issue 0), the RAMBSS technical datasheet dated October 2024, the DMT TÜV Nord test programme M 02-2022 report for the Raclan range, the Bureau Veritas MED type examination certificate 07000/E0 MED for FIPRO non-combustible panels used in the RAMBSS inner layer, and installation drawings for the space. Surveyors from Lloyd's Register, DNV, ABS, or RINA use this pack to verify compliance against the applicable yacht code.
Per MGN 681(M) section 4.7.3, on yachts above 500 GT the storage and charging of these batteries must be at least 1 metre from any boundary with a Category A machinery space or a space containing the main electrical source or switchboard. On yachts below 500 GT the same 1 metre distance should be achieved where practicable, with a risk assessment otherwise (per the LR DAD section 3.8 and 4.15). The DAD notes that A-30 insulation toward the essential space is recommended where the 1 metre cannot be met.
RAMBSS modules ship through Ritz Marine's WooCommerce catalogue. The three product pages below carry current pricing, specification, and order lead time.
4.35 kWh, Lowest Profile
Single battery plus charger, 600 x 600 x 500 mm external. Lowest-profile module for garages with limited vertical clearance.
View on Ritz Marine5.25 kWh, Charter Standard
Most common charter yacht fit. 600 x 600 x 750 mm external, full 5.25 kWh capacity. Stacks with other modules.
View on Ritz Marine5.25 kWh, Seabob Upright
Full-height 1520 mm module. Fits a Seabob on its charger upright. Same 5.25 kWh rated capacity as Module 750.
View on Ritz MarineFor the broader lithium safety range and pillar overview, see the Mercer Yachting lithium safety hub or the exclusive Mediterranean dealership announcement.