The mines weighed 1430 kg and were buoyant, so needed to be moored with sinkers, up to 25 metres below the surface.
en.wikipedia.org The swivel sinker is similar to the plain one, except that instead of loops, there are swivels on each end to attach the line.
en.wikipedia.org Other common types of pitches are the curveball, slider, changeup, cutter, sinker, screwball, forkball, split-fingered fastball, slurve, and knuckleball.
en.wikipedia.org These materials present a non-toxic alternative to lead sinkers at a lower monetary cost than alternative metallic sinkers.
en.wikipedia.org