ROVworld Subsea Information

Advertise on ROVworld.com!
ROVworld Subsea Information: Forums

View next topic
View previous topic
Quote
Alright floks,

Was just on a job for a few days where I was concerned by the state of the ROV's main lift. The sub had been in the water during the first day & night then came back on deck to fix a leak in a hotstab, but anyway. When it was about 5 / 10 M from the splash zone I noticed some stray wires starting to appear while looking over the side. As the garage came out of the water it became apparent that the umbilical had been starting to give way aprox 10M from the bullet & 3 or 4 of the wires on the umbilical! These wires had started to cluster into a nest just above the bullet as it was obvious that they had been like this for some time now. I know for a fact that the system is around 6 months old & would thus be due a 6 monthly cut & slip so surely this would have been a further factor to get it done immediately!!

When I spoke to the Supervisor regarding this he just sort of shrugged & said that he had noticed it & that they had "taped" the broken strands further up the umbilical after cutting them away, it was nothing to worry about!

I then spoke to the night shift company man who wasn't overly bothered either!! He obviously has bigger issues than trying to recover a dead sub once the thing decides to give way completely!!

I tried to help the guy on the winch out by pointing out that he was turning the sub in the snubber while the main lift was still under tension & obviously causing stress on the umbilical but he wasn't having any of it!! Why bother!!

IS IT JUST ME OR WOULD ANYBODY ELSE SEE THIS A TIME TO CUT IT BACK????
Quote
Subseascott

I wonder how the strands got broke 5 -10m from the TMS and on a system sounding relatively new? You don't mention how many layers of armour are on the umbilical?

I've worked with double and tripple armour wired systems which have bird-caged so much the lift is all on one layer of wires, no wires were broke and there were no surface GFDs so we just carried on until a suitable time came to reterm.

6m reterms are controversial but if it's a busy system and shows damge to the extent of broken wires then something aught to be done about it. It's always wise to check the umbilical spec if it's damaged to give you an idea on limitations of future use before failure in terms of armour, conductors or fibres.

Lets face it, you can reterm a double armour umbilical in 10 hours or you can recover a dead sub/TMS (if it's positively buoyant!) and reterm in 10 hrs plus recovery time....I know what I'd rather do....

Rotating the docking head whilst under tension is a no-no, sounds like you're working with an inexperienced team for sure.

What company was this with? Are you agency?

Wink
Quote
As stated, it depends on the number of broken strands versus the size of the umbilical and if its single/double/triple layer.

Broken wires on their own are not a show stopper. Many systems can safely run on a few broken wires (I've seen some crackers when the wire breaks at 100-150m, imagine the birds nest of broken wires at the bottom of the snubber during recovery!)

The normal way to deal with it is to tape up the loose ends or use bits of Stainless cable ties to secure the broken end in by tucking the SS tie under the adjacent 2 wires.

If you do have broken wires, you just have to be aware during launch n recovery - especially at night - that the ends dont get loose and catch in the snubber.

Display posts from previous:







View next topic
View previous topic
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You can attach files in this forum
You can download files in this forum