Marine Accident Investigation Branch (MAIB ) - Safety Digest 2/2004

Case 13 - Be Careful How You Rig Your Tricing Pendants

Lifeboat being released

Narrative
A lifeboat drill was being carried out on a cruise ship in port.  The gripes were slipped and the winch brake was released to begin the launch.  As the davit arms swung out and the boat began to lower, a tricing pendant at one end became caught beneath the suspension hook's balance weight.  As lowering continued, the tricing pendant tightened until it lifted the weight and opened the hook.  The fall released and the boat swung; it was left hanging by the other fall (see figure).  Fortunately no one was in the lifeboat at the time.  

Gripe, Tricing pendant and Unguarded suspension hook balance weight

The Lessons
1. Some lifeboats have cheek plates fitted either side of the suspension hook balance weight to prevent anything becoming caught underneath.  However, this makes the weight more difficult to lift when the lifeboat needs to be released when afloat. Lifeboats like the one involved in this accident, where the balance weight is unguarded, must be prepared to prevent them being lifted inadvertently.  

2. (Figure 2) shows a lifeboat rigged in such a way that this problem could occur.  When the gripe is removed, the tricing pendant will drop down under the suspension hook balance weight.  When the boat is lowered, the tricing pendant will tighten and lift the weight.  

3. When the mate or other responsible officer does his rounds of the lifeboats, he should check that tricing pendants are laid clear of unguarded suspension hook balance weights.  

4. If unguarded balance weights are fitted, they should be observed while the lifeboat is being lowered, to ensure they are not lifted accidentally.  If crew are in the boat when this happens, a serious accident could result!