200222 Recovering Freefall Lifeboats

Recovering Freefall Lifeboats
Report No. 200222

One day last year our vessel anchored awaiting berthing orders. We were expected to stay there for at least two days. It was a bright day with no wind or waves, a rare fact in the area indeed! Thus, I decided that it was a good opportunity to test our freefall lifeboat as per SOLAS regulations. The Chief Mate and myself inspected the lifeboat before launching and we personally instructed the volunteers on how to properly strap themselves in to avoid any accidents. When the Chief Mate was secured at the wheel and the outside door closed, I asked him by VHF to let go the boat. All went quickly and smoothly and with the weather being very good, we went on with all possible tests including the spray system.

About an hour later, without encountering any problems, I stopped the exercise and called back the boat for retrieval. As the boat had to approach stern first in order to be picked up, two lines were passed to the crew to facilitate her positioning. The boat was hooked on about 15 minutes later. The crew went back inside the boat and strapped themselves in. The Chief Mate once again checked that everything was done as required and prepared himself for the lift up. When I received his signal, I started to heave up the boat from the poop deck winch station while two seamen were guiding the aft part of lifeboat on to the slides. The Bosun was standing by on the upper winch station to take over as soon as the lifeboat was on the slides.

Just as the lifeboat was on the verge of reaching the slides, one of the stern suspending wires suddenly broke, consequently, the other stern one was also torn off. Subsequently, the stern of the lifeboat fell and caught her propeller on the vessel's after bulwark and eventually rested on it, only hanging by her forward suspension wires. I directly ordered all crew out and looked for a way to secure the boat. There were no injuries but the boat suffered quite heavy damage.

On further inspection to the basic cause of this accident, we found that the core of the suspending wire, which was protected by plastic, was rotten, although there were no apparent external signs of deterioration. It was decided to change the plastic covered slings as soon as possible, a fact that was approved by company and class society. Some time later, it occurred to me that more basic lessons should be learnt from this event:

1) The testing of freefall lifeboats.

The SOLAS rules for periodically testing the lifeboats were created in a time when the lifeboats were from the classical davit type. The purpose of the rules was, firstly to ensure that all mechanical parts (brake, davit, release hooks, retrieving motor) were periodically used and thus tested, secondly to ensure that the crew members were fully proficient in the launching and retrieving of the boat. Indeed, we have to remember that those lifeboats were, and still are, not only escape boats but also rescue boats.

A freefall lifeboat is quite a different case. First of all, it isn't designed to be retrieved. It is a pure escape boat. Secondly it is built in such a way that it requires no special skills from the crew to fall. They only have to board, properly strap themselves in and, as soon as it is released, the boat will fall by its own means, using no mechanical devices. (this is why freefall boats are such fantastic safety equipment!). It can clearly be seen that the purpose behind the SOLAS rules is, in this case, quite irrelevant. On the contrary, as these boats were not built to be retrieved, this action is always hazardous. Firstly, although the boat has to approach stern first, the helmsman has no view astern. The aft door has to be opened, a fact that endangers the boat's safety when waterborne. Furthermore, the boat being enclosed, there is no place to stand on the sides. The AB in charge of re-hooking has somehow to climb on the roof and try to re-hook with no real way to secure himself. As soon as some waves are experienced, it is like a circus presentation. Then, when the boat is up and near the glides, if the vessel is slightly rolling, it is also quite difficult to engage her without problems. Finally, when the boat is re-hooked again in her final position, it is still quite hazardous to release the suspending wires from the davit's hooks.

We can see that the freefalling apparently has two main reasons - to test the release mechanism and to test the spray system. The latter could be easily tested when the boat is in place, if we add a connection from the spray pump to the vessel's fresh water line. In new ships, a dedicated fresh water tank could be incorporated. The result of this is clear - more tests and less deterioration of spray line and nozzles by using fresh water instead salt water for the testing.

The release mechanism could also be tested when the boat is on her glides by using other means to secure her by. The best solution would be to have another strong point built on the boat itself, that could be used to hook to the davit using a turnbuckle and a chain, for example, before testing the release mechanism. If, furthermore, we have a hooked/non-hooked light in the boat's cockpit, to ascertain that the boat is hooked again, this would be quite safe. Even without this, we still can secure the boat using the davit and the slings or some chain blocks. This will be of course slightly more hazardous, but not more than the whole retrieving process after a freefall.

Some could argue that if we do not test the boat in freefall, we will never be sure of her hull integrity. Furthermore, the small plastic wheels, located on the cradle's glides will never been tested. The ship's crew also will never get the possibility to do a freefall launch. I believe, from my experiences, that the less we move these boats, the less their hull will suffer. As said before, and this incident is a good example, they are not manufactured and conceived to be retrieved at sea. Nevertheless, hull integrity and the working of the small plastic wheels can be ascertained during each dry-docking when the vessel is at her lay-by berth.

As for the crew, I believe that they should have, a freefall exercise included in their safety training course and survival craft proficiency course. Once you have been through one, you know what to expect and where to be careful, as said, those boats were designed to be easy to handle in case of rapid evacuation.

2 The plastic protected wire slings.

Everybody knows that the plastic protected wires are problematic. Firstly, you can never ascertain the quality of the material, as the majority of the wire is covered. Those who have sailed on conventional ships know that defaults in wire's fabrication are frequent. Furthermore, even by shortening the life span of those wires, you will never be sure of their real condition, humidity between the plastic and the wire itself plays an important role in the deteriorating process.

The reason put forward for the plastic around the wires is that it serves as protection for the crew members having to handle it as well as for the wire's protection. Why not directly use synthetic materials? They are of very good quality today, more resistant to sun or humidity than wires and are lighter for the same safe working load. So in short - safer! You can directly ascertain their condition, you can handle them very easily and they have a longer life. One of the reasons which I heard for the use of wires is that they are fire resistant. Well, I believe that to be a nonsense! In the case of a fire reaching the freefall lifeboat, you will probably be on the verge of abandoning the vessel anyway.

Freefall lifeboats are very efficient for abandoning ship. However, I hope that this report can help in triggering a review of SOLAS regulations concerning the testing of freefall lifeboats and also as a help in improving the design and safety of them.

Readers Feedback:

One can fully sympathise with the master of the vessel and applaud him for his actions taken to recover the boat plus his assessment of the problem. This in fact is not about recovery of a lifeboat (be it davit launched or any other type) but about what is normally termed offshore lifting. Recovery of floating objects is not normally a practice that those at sea are familiar with, it not being their day to day occupation. 'Lifting' in the offshore environment is something of a specialist art and must be regarded as such. Whether the lift is a single point lift, a static lift or quasi-static, it needs 'an in depth' knowledge of the subject regardless of the mass of the object to be lifted.

Reading between the lines of the report, I would suspect either of the following to be to blame for the near accident that occurred:

1. I agree with the master's comment regarding hidden defects in the wires being plastic covered and inaccessible.
2. Loss of strength in the termination splices (bending radius around thimbles and type of splice used).
3. Use of incorrect types of wire. Did the wires have Fibre hearts or IWRC?
4. What were the tensile strengths of the wires?
5. Were the wires compatible with sufficient Factor of Safety =>2.0 for skew, slew, snatch and correct geometry of the lifting system?
6. Were the lifting wires of the correct length to give a balanced system?
7. Were the wires of the correct quality? What category did they fall under? Were they designated as lifting wires or just ordinary shipping wires?
8. Did the master have in his possession the relevant test certificates and were the wires correctly colour coded?
9. Although the Master states the sea conditions were good for such an exercise, it is likely, there was an underlying (very low) swell running that may have had an influence.

These and many other questions need to be asked in such an incident. It is not much use changing the Solas regulations yet again. Many standards (for instance the Norwegian codes for offshore lifting) can be used to forestall the possibility of re-occurrences and these should be looked into before yet another committee is set up and a resolution reached.

As a general guide for this type of rigging (rule of thumb that does work, but to be checked by calculation) would be made up as follow:
Weight to be lifted (say 10 mt total including people)
SF 1.313 - Contingency 1.3 - DAF 1.2 - Skew 1.25
Sin 60 = 0.866 Therefore the SWL = (W * 1.313) * ((1.3 * 1.2 * 1.25)/0.866)
For a 10mt lift this will give an SWL for rigging of 29.5mt. Wire should be sizes on a factor of 5 on breaking. Using a 6*37 (IWRC) this comes out at approx 38 mm diameter.
It is appreciated that this is 'heavy' rigging but it is safe.