Feature 4 | PATROL AND RESCUE BOATS


Authors Johan Ullman M.D. Assoc. RINA is a specialist in anaesthesiology and intensive care and occupational medicine and a Surgeon Lieutenant (N) Reserve, Centre for Defence Medicine, Swedish Armed Forces: johan@hsbo.pro Carl Magnus Ullman M.Sc. is president


of the High Speed Boat Operations Forum (HSBO), Sweden and CEO of Ullman Dynamics Sweden: carl@hsbo.org


Figure 6 The PainDrawing app was developed


for the purpose of this study. It is built on two scientifically validated methods. One is the Nordic Council of Ministers’ pain drawing form, which has been used for decades to follow development of pain; the other is the Visual Analogue Scale (VAS). PainDrawing can be downloaded for free.


Separate sub-studies As the data loggers have 10 channels, and only five are occupied in the basic study design, further data can be collected during the same trial period and separate specific sub-studies can be carried out without involving all the participating agencies, and without compromising the validity of the database. Such studies could involve measuring


electromyography (EMG) on muscle groups in extremities known to produce a protective, reflex reaction when exposed to whole body impacts. Specifically, the role of reflex response


and even voluntary response in M. erector spinae (back stretchers)and M. rectus abdominis (‘the abs’) would be relevant to study, as these have a stabilising effect on the torso and spine. It would also be possible to connect


gyro sensors to log hull movement in all degrees of freedom. Alternative kinds of accelerometers can also be connected and accelerometers can be positioned in different places along the hull on seats or onseat cushions. Any sub-studies should be designed and conducted to be compatible with the collection of base data for the main study.


50


Results and applications Based on the expected results of the study, it will be possible to calibrate instruments with dashboard-mounted indicators, telling operators when hull impacts exceed safe levels by using green, yellow or red signals, where red would indicate ‘out of boundaries’. The results should also indicate


further the significance of horizontal components in the impacts, indicating if they should be weighted for risk of injury differently than the factor of 1.4 higher risk level normally applied. The results should also indicate the


significance of the rise time, and how the jerk factor (the derivative of the rise time) should be weighted for risk of injury. Ultimately, the results could lay a base


for a new relevant standard, defining limits for allowable versus dangerous exposure to whole-body impact. To protect people from injury, such a standard must consider the forces affecting the human body at sea. Participating agencies will gather


information about how their various boats perform, producing slamming impacts in real use. Tey will also be able to compare operator skills, in regards to producing smoother rather than rougher rides.


Conclusion Current standards and regulations cannot quantify or help control human impact exposure at sea. New knowledge is needed and can only


be established by studying what happens in real life. To find out more about the study or how to participate, please send us an email. SBI


References 1. Ensign W, et al. A Survey of Self-Reported Injuries Among Special Boat Operators. 2000, Naval Health Research Centre San Diego.


2. Kearns, S.D. (2001) Analysis and Mitigation of Mechanical Shock Effects on High Speed Planing Boats. Massachusetts Institute of Technology


3. EU directive 2002/44/EC, on Minimum health and safety requirements regarding the exposure of workers to the risks arising from physical agents (vibration)


4. ISO Standard 2631:1 Mechanical vibration and shock - Evaluation of human exposure to whole-body vibration


5. Bovenzi M. Low back pain and exposure to whole-body vibration and mechanical shocks (keynote), 6th International Conference on Whole Body Vibration Injuries (WBV2017)


6. Griffin M. Predicting discomfort caused by whole-body vibration and mechanical shock, 6th International Conference on Whole Body Vibration Injuries (WBV2017)


7. Ullman J. Vibration Exposure Standards are NOT relevant for Impact Exposure, 6th International Conference on Whole Body Vibration Injuries (WBV2017)


8. Peterson R. At-Sea Evaluation of NSW High Speed Planing Boat Shock Mitigation


9. Schmidt BS, Bass C et al. (2012) Risk of Lumbar Spine Injury From Cyclic Compressive Loading


10. Dobbins T, Myers S. et al ICI Impact count index for high speed craſt motion assessment, RINA SURV 7


11. Peterson R. Pierce E. Impact-Injury Assessment for Combatant-Craft Medium, Industry day 2008


For complete reference list and links, see www.HSBO.pro/science/references/ISNM


Ship & Boat International November/December 2018


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