Crane and davit wire rope changing intervals 1

[Swedishrigpig]

Gents

Our off shore vessel is aproaching five years since built.
The deck crane wire ropes looks fine, the cranes have been load tested yearly. Do we still have to replace all the wire rope (that are five years old)?
We use ABS class.
I assume the same applies for lifeboat/ rescue boat davit wire ropes? If so, who decides this, class, flag state, SOLAS?

Thanks

 

[chicopee]

I don't have the specs on crane wire rope readily available and I have been out of this type of loop for 10 years, however, I do remember a few critical items on wire rope replacement and these are: reduction in the OD if the wire rope, wear of the strands, internal corrosion of the inner core, broken number of wire in one lay and in one strand. Check with the ANSI standards on cranes and I am certain that your wire rope distributors have related technical material for their clients.
I know that our wire distributors in CT. were providing us free of charge this type of material.

 

[ss770640]

chicopee is talking about general viusual inspection which in the Uk is to be conducted every 6 months as part of LOLER regulation. (Lifting Ooperations and Lifting Equipment Regualtions).

Wire ropes are a complex class of their own. Visual inspection is not adequate. (Although i believe it depends on lifting requirements.) We had a dedicated expert to wire ropes in our company. I work with subsea pipelay and heavy lift wires all the time.

Small sections should be cut and a load test performed on them as per design code. (cant remember name). (Google Cosalt company, they do testing). The fail/pass criteria is generally a function of minimum breaking load (MBL) as a % when compared to the MBL when the wire was purchased.

 

[BrianBT]

There is nothing that forces you to discard a wire rope based on time (except for lifeboat falls). However as the metal in the rope fatigues it will have a service life based upon its load cycles (load carried and the torturous nature of how it is rigged)
Is your company required to comply with IMCA- of this is the case then down load IMCA SEL 022 Guidelines on Wire rope integrity management

You don't sat where you are working but if in the european area then you should be managing and discarding based on ISO 3018 and 4309 inc sub parts.

I sit on the IMCA Crane and Winch committee and the sub-committee that dealt with issues surrounding wire rope discard based on loss of original manufacturer recorded ABL ( not MBL). To prevent punitive action from clients such as BP you need to be carrying out yearly NDT ( magnetic anomaly testing to understand the condition of your ropes which you cannot effectively visually examine. Annual break testing should be carried out to ensure retention of FOS.
At all times the primary method of determining rope condition is visual examination. There is more, I especially like assurance activities such as retest and examination of rope that has reached the end of its life ( based on time based discard) to ensure that your are discarding at the time periods.

Hope this helps

 

[Swedishrigpig]

BrianBT, shicopee and ss760640

Most interesting information.

We work in the Americas. Our company is a member of IMCA, not sure how to log into their page to get the guidelines though. I'll see what I can do.
Seems like MODU is what we are following here, or that seems to be what our Class society uses.
Interesting to hear that lifeboat falls has to be replaced after 5 years (what if they are perfect?).
On Equipment like drilling riser tensioners we calculate ton x miles to determine the life.

I have also seen nylon sheaves on cranes saving the outside of the wire ropes so much that they where worn and finally parted, but looked perfect on the outside, so we ended up having to install a few steel sheaves just to wear them on the outside as well so a visual inspection is not all that reliable.

Regards,

Rigpig

 

[BrianBT]

Sir

Lifeboat falls- check with your flag state but the rules have recently been changed to reflect new guidelines which removed the end-for-end requirement.

ton x miles- sounds spot on.

If you are following MODU you must be an installation or behave as an installation. I am the Global Marine Manager of a company that have single and mono hull vessels that carryout WI and coil tubing so come under both MODU and SPS regulations.

Either way the same rules apply for wire rope. I could write for ever on wire rope as I am a bit anal about it ( due to the potential for harm).

Are you looking at your winch drums against the newly recognised issue of hoop stresses when retrieving. This is potentiallly the next big ticket issue with one major operator threatening to 'go to the clients' unless we all follwo suit in de-rating winches without adequate FOS. This reflected in the most recent DNV build code.

Brian

 

[Swedishrigpig]

Brian

I will check marineengineering for further details.

Please clarify a few of your inputs for me:
What does SPS stand for? Special Survey?

The last section about hoop stress. Could you expand a little, this is new to me.

What does FOS stand for?

Atb.

 

[BrianBT]

SPS stands for special Purpose Ships and applies to all ships which carry more than 12 special persons. A special person is somebody who is not marine crew or provding a service to marine crew directly (e.g catering) but is actively employed on the vessel. i.e. they are not a passenger and they are not crew. You can download the code for free I think and have a read. For new vessels it has a signficant impact in its construction and application of SOLAS as passenger ships regulations apply including in INtact stability. There are 3 countries that have fully ratified (canada, India and Australia - i think) with others nto doubt following suit

FOS- factor of safety which is typically 5:1 but may be reduced through risk assessment.

imagine the second layer of rope sitting on the first. The rope will sit between the lower two wraps. Under tension it reacts at angless through these lower wraps so there is both a radial and an axial loading. The effect can be that the axial component loads up the flanges to an extent they fail and the drum collapses- as happerned on one major companies new build recently.
IMCA is a good source

 

[WillShi]

There is an ISO Standard for determining lifting appliance wire rope condition as advised by BrianBT.

For lifeboat falls, each flag authority has their own requirements generally. Your class society should be able to advise specifically, or if you give me your flag, I can find out for you.....

 

[Swedishrigpig]

WillShi

Flag is Singapore
Class is ABS

Thanks

 

[topes]

Now I'm am most definitely not an expert... I am chief engineer on a tanker in Japan (US flagged) classed by DNV, but I would suggest speaking with the class (ABS). I'm sure they would be happy to explain it for you, and be very happy that you even asked in the first place. I have found (at least with my guy in Japan for DNV) that he is very happy to answer questions and help in any way he can. It makes his job easier to know that we are soliciting his info and following class advice. Just a thought, I know my post doesn't really help you, but I hope you find what you need.