Feature 4 | PATROL AND RESCUE BOATS Figure 4


each, wired with acceleration sensors and data loggers and monitored over a period of four to five months. Agencies in 15 countries have expressed interest in participating. All subject data will be anonymous and boat data stripped of sensitive info regarding coordinates and whereabouts of operations before they are submitted to the common database.


Hull and human impacts Whole body impact will be monitored on two people onboard each boat at all times. Each boat will have a Marine Acceleration Recorder (Marec) data logger installed for


Figure 5


the entire period of the study. Tis will be connected to a 3-axis accelerometer attached to the hull, close to the platform’s centre of gravity (COG). Acceleration sensors mounted to kidney belts will be worn by two crew, preferably the coxswain and navigator, and connected to the data logger. Recorded data will indicate the real-life impact exposure, and hence the forces acting on hulls and humans. Tis data shall show the actual exposure and the relation between hull impacts and human impacts for each boat type. Figure 4 illustrates one way to present exposure data from the Marec. Graphs


with data from one entire day can be ‘zoomed in’ on, enabling analysts to see the shape of a single impact in detail. Here, we see 400 seconds on the X-axis. On the Y-axis, leſt acceleration is measured in g = 9.81m/s2 with red for ‘driver’ and blue for ‘boat hull’; and on the right Y-axis, boat speed, with green line.


Data logger and sensors The


bespoke Marec was designed


specifically for this study. Once installed onboard and connected to 12V/24V DC, it will automatically start recording as soon as the boat goes above 3knots.


48


Ship & Boat International November/December 2018


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