Jacobs Ladder
F5. The Reference Layer: Glossary, Units, Signals and Information SourcesDefinition
Rope or wire ladder used for boarding pilots and others.
A Jacob’s ladder is a portable rope or wire-rope ladder with rigid rungs, hung over a ship’s side for boarding by pilots and crew or rigged from a yard or platform aloft. The pilot version is governed by SOLAS Regulation V/23 and IMO Resolution A.1045(27) on pilot transfer arrangements, which specify rung spacing of 310 to 350 mm, equal rung lengths of at least 480 mm, spreader steps, and certified manropes. The same term covers any flexible ladder with hardwood treads used for access aboard.
Source: SOLAS Regulation V/23 (pilot transfer arrangements); IMO Resolution A.1045(27).