Guidewire anchor failure

A member has reported that during subsea operation, the upper part of a guidewire anchor disengaged from the main body of the anchor, resulting in the unintended release of the guidewire.

Upon investigation, it was found that the shear pin, which was secured in the guidewire anchor housing by the use of a setscrew, had become unscrewed (probably due to vibration), allowing the shear pin to drop out.

During interviews, it was also established that on some sites, the shear pin had been removed by force, without the setscrew first being set or unscrewed. This misuse would, in due course, cause damage to and weaken the shear pin.

Action taken:

The manufacturer involved in this instance, as a result of the investigation, has carried out modifications to the outer sleeve on the upper part of the guidewire anchor, to secure the shear pin when the outer sleeve is in the ‘set’ position. Its user manual has also been updated accordingly, emphasising the correct use of the setscrew. The manufacturer is offering the improved guidewire anchor as both a modification kit for existing anchors and as a new product.

The member involved has issued an instruction that only the modified guidewire anchor is to be used in its operations.