200627 Confusing wire specification

I joined a vessel which was due for renewal of lifeboat wires; the store requisition had already been sent to the company by the previous master and chief officer. On crosschecking this, I noticed that they had asked for wire of a lesser diameter. I informed the company immediately and raised a new requisition.

On further investigation I found that the wrong specs sent by the previous master were taken from a sketch of the lifeboat davit (pasted on the boat deck bulkhead) whereas the lifeboat manual and class certificate, which gives the details of life saving appliances/fire fighting appliances, gave the correct diameter. Also both the boat manual and this class certificate clearly gave the length of the lifeboat falls, four pieces of 35 m each. When the wire was finally renewed it was realised that the length was much shorter than that required. My mistake was that I trusted the wording in the manual and certificate and did not calculate on the basis of the number of turns of wire on the winch.

In another incident, a new wire was requisitioned. It was the correct length but when it came on board there was an argument which lasted for about an hour between the workshop engineer supplying the wire and the vessel's chief engineer, second engineer and chief officer about the wire's breaking stress. The manual and certificate gave this in different units and the new wire's certificate was in another unit the main problem was conversion of kn to n/mm square. Finally we accepted the wire and changed it.

When we had our annual class survey the surveyor noticed the breaking stress and expressed his doubts about it (he represented a very prestigious society and has been a surveyor for more than 20 years). Again the boat manual etc were consulted and again a discussion started with the surveyor. Finally he suggested that the best solution would be to contact the boat davit manufacturer and ask them.

I have often noticed before that the breaking stress given in a manual is different from that in the actual wire certificate and conversion is not easy. I have also come across crane wires which have a totally different construction than that which is usually on board (although it has the correct diameter/breaking stress/length) and it's not very easy for ship staff to decide whether to accept the wire or reject it.

What I recommend is that all specs of wires must be clearly given in the manuals with the breaking stress being given in all different units and all possible accepted construction details also given in the manual. Class must make the above mandatory.

In this modern world of ISM, ISO etc the ship staff will be blamed fully for any problem with the wire specs in the case of any accident possibly the mate/master will be imprisoned. So I request the authorities to take some action over this.