Human centred design makes a difference

So, the new Tamar class lifeboat, it’s the fastest one? No. The biggest then? No.

Typical questions I’ve been asked as the first of this new class of slipway launched lifeboat enters operational service, but few have asked about the human centred design which makes this latest RNLI 25 knot all weather lifeboat different.

Although 7 years of development may be excessive for any commercial 16 metre design, the RNLI’s demanding search and rescue role, which requires volunteer crews to go at immediate notice into any weather up to 100 miles off shore, necessitates a rigorous design process, central to which is the belief that if we look after the crew, they can look after the casualties.

Over the past 50 years lifeboats have progressed from simple 8-knot designs to 25 knot boats packed with technology, but essentially using the same volunteer crews, with the same limited training time, and the same human capabilities. So a major factor in achieving mission success is to ensure that the technology employed is safe, effective and intuitive.

The RNLI has undertaken collaborative research into human structural response to shock loading resulting in a seat that will not ‘bottom out’ due to shock loadings. The seat bucket (widened by 50mm to accommodate ‘larger crew’ in foul weather gear) has a large amplitude motion on 2 inclined rails. This motion on a tailored spring and damper system mitigates vertical and forward decelerations, however the relative motion to fixed consoles means that essential controls have been engineered onto seat arms.

Since crew are safer seated, the need to move around the boat at sea is reduced through an integrated electronics system which provides remote monitoring and operation of onboard systems. Although integrated systems provide the capability to present a plethora of information and controls, they could also confuse, mislead and overload crew unless the interface is clear, intuitive and tested. The Systems and Information Management System (SIMS) developed as part of the project presented an opportunity to develop a bespoke user interface.

Since the inception of the project, it was always recognised that the development of a common, effective and simple Human Machine Interface (HMI) would be fundamental to the success of SIMS. The plethora of different HMI’s assembled in a typical search and rescue vessel presents organisations with usability and training challenges, not to mention the potential for misinterpretation and misunderstanding by users. An early

own and other similar vessels failed to reveal a suitable HMI for adaptation across other applications.

Furthermore, since the success of SIMS will ultimately be judged by the end users, crew involvement was essential to ensure:

• Simplicity of use;
• Clarity of presentation of information; 
• Robustness and reliability; 
• Redundancy in the event of failure.

This development therefore involved RNLI staff and crews together with Human Sciences experts.

The resulting prototype version of SIMS was fitted to the Tamar for an intensive period of crew evaluation of the system. The evaluation trials structure was developed in conjunction with ergonomics consultants to ensure that the trials were relevant and would produce appropriate input to any re-development of the system prior to introduction to service.

Seven years is indeed a long time to develop one boat; however with the seats and SIMS we now have components that can be applied to future lifeboat designs and perhaps retrofitted to current ones to enhance the safety of our volunteer crews.

Further information on the design approach to the Tamar Class lifeboat can be found at HE00495 & HE00500).