Lift boat accident in the GoM


#1

https://gcaptain.com/15-rescued-from-listing-lift-boat-in-gulf-of-mexico/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+Gcaptain+(gCaptain.com)&goal=0_f50174ef03-323b3d6ba2-169863069&mc_cid=323b3d6ba2&mc_eid=4674ba0fbe

Anybody know what happened here?
Looks like it could be a case of what in the business is called a “Punch-through” I.e. the foundation under one of the legs gave way, either while pre-loading, or because of uneven or excessive weight on the legs during operation.

PS> Some parts of the GoM is known to have punch-through problems, but I’m not familiar enough with which part(s), although soft mud off delta areas are a known problem.
Stratified soil is also a common cause of punch-through.


#3

Looking at the pictures, it appears that one leg somehow came unlocked. If you look, the near one is wayyyy higher than the other two. Maybe the bottom is that uneven, but it looks strange to me.


#4

Sometimes there can be very different penetration between the legs due to difference in soil bearing strength. This is especially so where there are crush, which is the most common cause of punch-through, or uncontrolled rapid penetration.

Here is a list of the Aries Marine Lift Boats. The RAM XVIII being the largest type w/175’ WD capacity: https://www.ariesmarine.com/liftboats

With only short legs above guides she would have been close to her max. WD limit.
She is unlikely to be transiting with the legs lowered, except for VERY short in-field moves

This being a 3-legged unit they would need to take on pre-load to test the bottom conditions before elevating the hull to working height, unless she is a mat-supported unit(??)

Pre-loading should not be done more than 5’ above surface to ensure that the barge would pick up buoyancy before getting too much list, or breaking legs, in case of punch-through.

Most lift boats in other parts of the world (and all wind farm construction vessels) has 4 or more legs. They are thus able to pre-drive, in stead of pre-load, to test bottom conditions. This can be done with the hull still at 1-2’ draft. If they encounter rapid penetration they do not fall over.

I cannot find any news report that make any sense, or contain any clarification. (Not surprising)