For marine installations, class certification is essential, it determines whether a motor is allowed on a ship under a specific flag. This guide explains the six major class societies, the shared IACS UR E11 standard, and the difference between essential and non-essential service that drives documentation scope and price.
The six major class societies
Six classification societies dominate the marine industry, each with distinct regional strongholds:
- Bureau Veritas (BV), French society, strong in Europe, Africa, Middle East
- Lloyd's Register (LR), British society, oldest and most globally recognized
- DNV, Norwegian-German society (merged 2013), dominant in offshore and gas carriers.
- American Bureau of Shipping (ABS), US society, strong in Americas and oil & gas.
- RINA -RINA, Italian society, Mediterranean focus, growing global presence.
- ClassNK (Nippon Kaiji Kyokai), Japanese society, dominant in Asian shipping.
IACS UR E11: the common standard
The International Association of Classification Societies (IACS) publishes Unified Requirements that all members implement. UR E11 is the requirement for electrical equipment including motors. It specifies insulation class, temperature rise, enclosure protection, vibration, noise, and environmental testing for marine service.
UR E11 cUR E11 compliance means a motor meets the minimum requirements of all 6 major class societies. Individual societies may add specific requirements, particularly for essential service equipment, but UR E11 is the common foundation.
Essential vs non-essential service
Not all motors on a ship have equal safety criticality. Class societies distinguish essential service (motors whose failure affects ship propulsion, steering or safety) from non-essential service (auxiliary systems where failure is inconvenient but not dangerous).
Essential service motors require type approval, extensive testing before the first unit is supplied, with formal approval documents from the class society. This process can take 6-12 months and cost significantly. Non-essential service uses lighter "class certified for non-essential duty" documentation, faster, cheaper, still formally accepted.
Our class-certified portfolio
Van Bodegraven supplies class-certified motors across our entire range. ABB's marine motors (M3AAMM, M3BPMM, M3JP, M3BM series) carry type approval from all 6 major societies for both essential and non-essential service up to 1000+ kW. Dormot Core is class certified for non-essential duty by Bureau Veritas, Lloyd's Register, DNV, ABS, RINA and ClassNK, ideal for auxiliary motors, deck pumps, ventilation, cranes.For bow thrusters, stern thrusters and essential propulsion auxiliary motors up to 5000 kW we build to spec with full class documentation. Survey scheduling runs in parallel with manufacturing; plan early.
Frequently asked questions
Can a motor certified by BV also work on a DNV-classed vessel?
Yes, typically. All 6 major societies follow IACS UR E11 and accept cross-certification for most non-essential applications. For essential service, some crossover approvals apply but specific flag requirements may need additional validation.
How long does type approval take?
Typically 6-12 months for a new motor type. This includes factory audit, prototype testing, documentation review and final certification. Once approved, each individual motor produced to that type carries the approval automatically.
What's the price difference between non-essential and essential service motors?
Non-essential duty adds typically 10-20% to a standard industrial motor price. Essential service with type approval can add 40-100% depending on society and testing scope. The difference reflects documentation depth and testing rigour.
Need advice on motor selection?
Our sales engineers are happy to help you find the right motor for your application.