This International Standard specifies the design, size and technical requirements for universal fairleads with upper roller(s) installed to lead the mooring rope of a ship.
ISO 13733:2012 history
2020ISO 13733:2020 Ships and marine technology — Ship's mooring and towing fittings — Universal fairleads with upper roller
2012ISO 13733:2012 Ships and marine technology - Ship's mooring and towing fittings - Universal fairleads with upper roller