trawl towed by a single boat. Its horizontal opening is obtained by otter boards, relatively heavy and equipped with a steel sole designed for a marked contact with the ground., a strong fishing net for dragging along the sea bottom, otter trawl - a large, conical net supplied with two otter boards which keep the mouth of the net open horizontally, traal - spetsiaalse kujuga võrkkott, mida pukseeritakse mööda põhja (põhjatraal) või teatud sügavuses ja mis püüab teele ettejäävat kala