leadline

noun3

1. •
   A sounding line; an instrument used in navigation to measure water depth.

   • Approximately 60% of inshore hydrography was acquired by leadline (pre-1940) sounding technology. — 2004
2. •
   A weighted line for holding down the lower edge of a gillnet.

   • To attach the bridles, start measuring from the point on the gavel 16 metres from the floatline wheree you have seized the end of the leadline. — 1987
3. •
   A leash or strap for leading an animal.