The distinctive feature of the Anti-Motorboat Boom is the BAULK:
As shown in the sketch the standard baulk is a heavy iron-strapped wood and metal tank fitted with eye bolts and links for connecting the boom jack-stays, two pairs on top and one pair across the center line of the bottom. Two watertight iron tanks occupy the interior of each baulk to provide flotation. The steel tanks proved popular with Orkney farmers and can often be found in fields used as cattle troughs.
