U or D shaped handhold made from metal rod, fixed to an astragal to provide additional security for personnel when using a ladder outside the lantern.
Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)
diameter at the waterline (m)
change in the value of a term
Solar declination angle (in degrees)
International Association of Marine Aids to Navigation and Lighthouse Authorities - AISM