(Figure) Seamark
1 - rod;
2 - float;
3 - anchor;
4 - rope;
5 - drum;
6 - signaling device.

SEAMARK (EN: landmark, survey stake, peg or rod; DE: Markscheiderstock, Absteckpfahl, Absteckstange, Fluchtstab; FR: jalon, repere; ES: jalyn, estaca de referencia; RU: веха) is the floating anchored rod sign, with the fixed coordinates of the location. They use the seamark for the indication of the contours for the excavation and sub-standard places at the deposits, of the entrances, of the waste dumps, and as the beacons for the marine mining craft. The seamark comprises the rod, float, anchor, and rope (see the Figure). They achieve the compensation against the vertical movements of the float, using the installation of the spring-loaded drum, which is regulating the length of the rope. The sizes of the seamark are from 6 to 19 metres, the mass of the anchor of the seamark is up to 100 kilograms. They install the seamark using the motor boat, fixing the point of the installation according to the landmarks of the shore network with the precision of up to 2 metres. They ensure the adjustment of the direction for the movement of the extracting equipment according to the signaling devices of the seamark. Sometimes they use as the signaling seamarks the small buoys.