Failure of plastic floatation buoy

We have received the following information concerning a failure of a plastic floatation buoy. During deepwater operations on one of our member’s vessels, a sling had been recovered to surface and riggers were in the process of removing a cluster of plastic flotation buoys. These buoys were rated for 150 bar external pressure and were hollow air filled types.

Without warning or any obvious signs of damage, one of the buoys exploded, resulting in two halves of the float flying apart with some force (see picture below). Fortunately no-one was injured, however this serious near miss serves to remind us, that such events are not unknown and for this reason, IMCA produced IMCA Guidance Note IMCA R 001 –Plastic spherical air-filled fishing buoys – concerning failures of this type of buoy giving recommendations on their use.

Whilst the floats being used were suitably pressure rated, the company concerned cannot be sure that either through manufacturing defects or due to rough handling that fissures in the seam of the floats allowed the internal void to be pressurised.

A number of IMCA member companies have a policy of not using plastic buoys.