and two above-water (Amalgamated Instrument Company–AIC; model noPA6139) and two underwater load cells (Delphi Measurement PtyLtd) with associated data loggers. The above-water load cells werebolted to each side of the vessel and clamped onto the bridles tomeasure their tension (kgf). The underwater load cells were config-ured so that they could be attached to the ground gears of the tested trawls, with 30 m signal-cables extending forward to the vessel (seebelow).