Whip
A blow devices (pronounced impact devices ) or Peilstange is a traditional apparatus for measuring the water depth in the IWT .
Appearance
The traditional whip is a round wooden stick for finding the depth of the water, which is octagonal at the top and ends with a ball. The rod is painted in different colors, the lower end is black and this part corresponds to the empty draft of the ship. Above it alternate red and white fields one foot long. The upper octagonal part is often painted in the national colors. Common lengths are five and six meters (previously 16 and 20 feet, respectively). For some time now there have also been aluminum whips .
handling
The whip is used to measure the depth of the water. To measure, you put them into the water against the direction of travel. If it is vertical, the approximate water depth can be read. The seaman gave the skipper the reading of the depth with a hand signal. If he could no longer feel the bottom, he showed a clenched fist, which in shipping meant “North Sea”, meaning enough water under the ship. You can also tell whether the ground is sandy or stony by slowly moving the whip up and down. In the past one often saw ships with their whips attached to the front mast. Striking whips were also used for line direction finding .