Safety At Sea Studies - Harness and Tether Test Methodology
|
Our
first phase was an in the water test, to determine the characteristics
of safety harnesses in actual use in a crew overboard situation. We
evaluated the attitude of the Crew OverBoard (COB) as they were towed
through the water, the relative comfort for the wearer, whether the
harness slipped under load, ease of breathing under load, and ease of
reboarding the vessel. We also tested a quick release tether shackle
under load to see if it would release. When being towed, each harness
was evaluated using both a three foot and six foot tether.
Each harness was donned both with and without foul weather gear, to simulate both cold and warm weather sailing conditions. The harnesses were donned; the time to do so was measured, as well as any comments about the ease or difficulty of doing so recorded. The harnesses were subjectively evaluated for things such as whether they felt heavy, how easy they were to adjust, whether the harnesses had pinch points or features that might cause discomfort (such as a shoulder strap rubbing against the neck), did it interfere with the use of a life jacket, etc. We then went to a dinghy hoist and hauled ourselves off the ground wearing each harness. The harnesses were evaluated for comfort, ease of breathing, and pinch points. We also tested whether there was any tendency to fall out of the harness particularly with arms raised, as a COB might do when trying to crawl back aboard. The
dinghy hoist test was repeated by members of the Tacoma Women's Sailing
Association, to evaluate both unisex harnesses and harnesses marketed
specifically toward women.
For the last phase, we rented a test facility to do a dynamic load test. For this test, the harness was attached with a tether to a 220 pound dummy and dropped 6.6 feet. For each harness a brand new tether was used, to eliminate the tether as a variable. When testing the tethers, we used the same type of harness to eliminate it as a variable. Each harness and tether was soaked in water before the test, per the International Sailing Federation Special regulations Governing Offshore and Oceanic Racing for 2002-2003 including US SAILING Prescriptions. It should be noted that this improves the shock absorbing qualities of nylon webbing. Failure criteria include "flaws, defects, or deterioration after testing that would jeopardize the safety of the wearer". It can be debated whether this means any deterioration at all. There were some harnesses and tethers that either had bent or slightly deformed hardware and one instance where the webbing was shredded, but the equipment still held.
|
