Specialist heavy-lifting and transport equipment manufacturer Mammoet has supported ESTA in establishing new stability guidelines for Self-Propelled Modular Trailers (SPMTs) when transporting large and heavy loads. ESTA is the leading European association for the abnormal road transport and mobile crane rental industry.

Leading the project at Mammoet is Ludo Mous, Director of Operations for Europe. With over 30 years of industry experience, Mous has seen the market change and is passionate about enhancing SPMT training and safety.

Mous said: “In the past, there were rules of thumb which, for the time, were practical and acceptable to use. However, these days, with transport becoming more complex and reaching greater limits, the calculations for stability must be correct. By creating awareness of these guidelines, we hope to prevent operations being performed with dangerous and critical transports.”

Mammoet was part of ESTA’s first SPMT working group, established in 2016, which created its original Best Practice Guide for SPMT operation. A second, larger workgroup was later formed to review the existing guide and expand on it.

In October 2023, ESTA published new trailer stability guidelines, which will be referenced in the first upcoming revision of the DNV ST-N001 Maritime Operations Standard, published by assurance and risk management experts DNV.

“The core principle of the guidelines is a calculated approach,” explains Mous. “Past guidance was based on a measured stability method. This new method is calculating stability taking into account dynamic factors like braking, acceleration, wind, road camber, and so on.”

To establish the guidelines, testing was carried out by Mammoet on SPMTs at its quayside yard in Schiedam, the Netherlands. It covered aspects such as acceleration, breaking, tilting and emergency stops.

Currently, the group is reviewing a learning outcome that will be used to establish the minimum training requirements for an SPMT operator, further enhancing user knowledge and safety.