When securing a pilot ladder at an intermediate length the accepted practice is to use a rope of equal strength to the side ropes (48kN) and secure this to the ladder via means of a rolling hitch to the side ropes such that the weight of the ladder is bourne by the side ropes and that none of the weight is bourne by the chocks, steps and spreaders. Shackles over side ropes should never be used as this damages the chocks and steps.
Work carried out by the late Troy Evans, a New Zealand maritime pilot in the port of Tauranga, had shown potential in the use of cargo lifting strops secured to the side ropes of the ladder. Sadly Troy passed away before any further trials could be carried out to further investigate this method.
The investigation was however taken up by the International Maritime Pilots Assosciation in cooperation NC2 Engineering Consultancy and University of Southampton. The report was published last week on behalf of IMPA regarding scientific tests undertaken to determine the most effective means of securing a ladder at intermediate lengths.
The most significant conclusion of the report is that shackles do indeed damage the chocks, steps and side ropes of a pilot ladder so MUST NEVER BE USED as a means of securing a pilot ladder.
The second finding was that cargo slings were and ineffective method of securing as whilst the didn't damage the side ropes they had a tendency to slip and consequently came to be braced against the chocks and steps which again would lead to damage over time.
The most effective means of securing the ladder was indeed the rolling hitch with either a synthetic or manilla securing rope. We would recomend the use of a 20mm polypropylene rope as this combines the required breaking strain in a useable diameter of rope.
Whilst the investigation didn't discover a better way of securing the pilot ladder at intermediate lengths it was successful in confirming the assertion that pilot ladders should never be secured using shackles or slings.
The full report can be accessed here