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Powerboat & RIB Magazine - WBV Article

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10.01.2012

By John Haynes - Operations Director - Shock Mitigation

Every time you get a powerboat or RIB on the plane you are experiencing the sensation of speed. High speed on flat water, lakes and calm days, is only limited by hull design and how much horsepower. If you are cruising in flat conditions you may decide to burn less fuel and ride at a lower planing speed but if you are racing the throttles will be wide open and the boat will be trimmed out for maximum speed.

On a ‘flat day’ there is vibration from the engine and gearbox but you are not exposed to harmful vibration. Waves change everything when you are running fast boats. Waves can be created in seconds by another craft, they can be wind blown and build up in a few hours or they can be the result of a long ground swell that has travelled for days from a storm thousands of miles away. Vibration on powerboats and RIBs is usually caused by continuous 'hammering' from short steep seas or wind against tide conditions. Shock on powerboats and RIBs is usually caused by random 'hits' from head sea impacts, crossing seas or overtaking following seas.

A well built powerboat can handle moderate waves but what about the crew? The ‘Human-Boat-Interface’ is the technical name for how you come into contact with the boat. Certain designs of suspension seating can have feet off the deck, but generally there are three points of contact. Your hands are in contact through a handhold or for the helmsman through the wheel and throttle. Your feet are in contact with the boat through the deck. Your backside is in contact with the boat through the seat base, and depending on the seat height and design may be carrying most of your body weight.

Anyone using a powerboat at planing speed needs to be aware of how much attention the professional sector is giving to vibration at sea. Millions of workers around the world are exposed to mechanical vibration transmitted to the whole body through industrial seating and flooring or decks. Whole Body Vibration, or WBV, can affect back, neck, knees and joints. The latest MCA Marine Guidance Note (MGN 353) states that, ‘Whole-body vibration may be most apparent in smaller, fast craft such as fast rescue boats, RIBs or work boats, particularly when operating in choppy conditions.’

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The maritime sector recognises the need to reduce the effects of Whole Body Vibration but this is not a straightforward process for those operating RIBs and High Speed Craft (HSC). These vessels can expose crews and passengers to high levels of repeated shock and vibration which has been shown to increase the risk of injury.

Professional maritime organisations use RIBs and planing craft to perform a wide range of operations. The consistent objective is that crews are not injured and passengers arrive safely at their destination ready to perform a task. The tasks performed by Fast Response Craft (FRC) personnel after a boat transit are usually physical and can range from ship boarding, law enforcement and sea rescue to wind farm maintenance.

FRC International provides expertise for Fast Response Craft personnel. This includes understanding risk, duty-of-care, legislation, evolving technologies and new operational tasks and scenarios. Crews also need to be aware of the roles and responsibilities of organisations such as the MCA (Maritime Coastguard Agency), the MAIB (Marine Accident Investigation Branch) and HSE (Health and Safety Executive).

FRC International has developed two specialist FRC WBV Awareness Courses, recognised by The Nautical Institute, that are relevant to all sectors affected by this major health and safety issue. This includes military, search & rescue, government agencies, local authorities, police, wind farm, oil & gas, thrill rides, charter, powerboat schools and all organisations operating  planing boats under 24 metre. The courses define and benchmark best practice and provide a consistent approach to WBV compliance across the maritime sector.

The WBV awareness courses are run as interactive workshops with the objective of understanding that Whole Body Vibration is a global issue affecting all personnel using RIBs, HSC and planing craft in the professional maritime sector. WBV MANAGER is a one day awareness course aimed at all managers, officers and supervisors. WBV CREW is a one day awareness course aimed at all coxswains and crew. Management and crew knowledge can improve employee engagement and shared responsibility for duty of care. Attendees of the FRC International courses will also understand the implications of WBV for passengers.

WBV MANAGER and WBV CREW courses provide the background to the European vibration legislation, an understanding of WBV and the risks of repeated shock exposure. Courses introduce control measures and the requirements for compliance. The EC Physical Agents Directive, that came into force on 6th July 2010, requires employers to control exposure to a number of hazards including noise and vibration. The EC Directive advises employers that they need to provide, 'adequate information and training to instruct workers to use work equipment correctly and safely in order to reduce their exposure to mechanical vibration to a minimum'.

How much vibration is too much vibration for the human body? This is a question that academics around the world have been considering at length. The UK Health and Safety Executive consider Exposure Action Value (EAV) and Exposure Limit Value (ELV) to be the most relevant. The Exposure Action Value is a daily amount of vibration exposure above which action needs to be taken to control exposure. The greater the exposure level, the greater the risk and the more action will need to be taken to reduce the risk. The Exposure Limit Value is the maximum amount of vibration a person may be exposed to on any single day. It represents a high risk above which a person should not be exposed.

The International Maritime Organisation (IMO) states that, ‘the cornerstone of good safety management is commitment from the top. In matters of safety prevention it is the commitment, competence, attitudes and motivation of individuals at all levels that determines the end result.’ FRC International believes that everyone from stakeholders and managers onshore to coxswains, crews and boat passengers need to understand the effects of vibration on fast craft.

The objective of shock mitigation at sea is to make a violent collision or impact less intense. The professional sector needs a shock mitigation strategy that combines technical solutions with specialist training so that crews and passengers are capable of doing their job when they arrive at their destination. Technical shock mitigation solutions can include more efficient hull forms, responsive controls, ergonomic layouts and improved crew seating. Coxswains and crews need specialist training to understand the forces involved when operating fast craft in waves.

With an effective shock mitigation strategy the helmsman, crew and passengers benefit from increased comfort and reduced injury, while the organisation has increased operational efficiency. Stopping fast craft operations is not a realistic option, but making them safer is essential. Whole Body Vibration on small craft is a global problem and everyone from leisure users to the professional sector can learn more about the solutions. Boat manufacturers and private owners operating fast planing craft are able to attend the FRC WBV courses.

For further information www.frc-wbv.com
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