Interlock failed. Three crew fell 14 metres in MOB Boat
Make sure that the interlock lever is in the locked position every time after the MOB boat has been used and before releasing the lashings of the boat during drills says Sweden’s Transport Agency. The warning comes after an accident during a drill involving a Schat-Harding MOB boat which fell 14 metres from its davits with three crew onboard.
The incident occurred because the interlock lever on the hydrostatic unit did not work.
This piece of video, from John Konrad at one of our favourite sites at gCaptain. We have no details about this incident but it appears to be a familiar situation in which the aft suspension hook or ring fails and the shock load on the forward falls causes them to fail, too.
What we see on this video is similar to what happened aboard the Lowlands Grace with resulting fatalities.
Analysing the video is difficult due to compression artifacts but there appears to be a slight jerk in the hook/suspension at around second 15. The lifeboat fell as the davits came to rest bringing it inboard . The suspension ring appears to be intact after the release at 1:24.
Going by previous incidents it would appear that the hook were not fully set prior to the lift and the slight shock of the davits hitting home was enough to open the hook.
As the boat falls one can see the painter. It seems likely that as the boat swung downwards the elongated suspension ring caught on bolts on the forward hook causing it to open.
We don’t know the manufacturer’s recommended style of suspension ring.
So, the lesson is: Make sure that on-load release hooks are properly reset both before and after the lifeboat is recovered and, of course, recheck that they are set properly before launch – which sounds obvious but never overlook the obvious.
Also, check that suspension rings comply with manufacturers’ recommendations.
If you are required to launch with persons onboard the lifeboat, consider the use of slings or other arrangements, just in case.