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flatfish such as sole, plaice or megrim together with
angler and other species found hard down on the
seabed. Each net is fished from an outrigger boom,
one on each side of the vessel (Figure 14), and
towed from here on a single warp (a) shackled to a
three chain bridle (b) attached directly to the beam
(c) which holds open the mouth of the trawl. The
beam, 9-12 m in length, is constructed from heavy
steel tube and supported on each side by rugged
steel trawlheads (d) which slide over the sea
bottom. Ahead of each groundrope several tons of
tickler chains (e) or chain mats (f) are used to
disturb fish, causing them to rise up and be taken
by the trawl following immediately behind. Towing
speeds are generally higher than otter trawling,
reaching 6 or 7 knots on clean ground with ticklers,
whereas on rough ground stone mats are towed at
around 4 knots. Beamers usually operate on the
continental shelf (200 m) with warp length/water
depth ratios of between 2
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