I have been asked a few times what can fail in layup? Having been involved in layup since 2004 I decided to look into some of the common failures that can be expected during layup, for hot stacking, warm and cold layup. It does not matter if you assets are located at a Singapore anchorage, Batam or in Labuan in the Bay of Brunei the following conditions could occur.
Hot Layover & Warm Layup
General issues are found as crew are unaware of basic preservation techniques and leave systems in an as is condition. This causes corrosion issues, seizure issues and well as reduction in overall reliability of the equipment. With warm layup issues are pretty much the same as hot layup but as the time passes and no certainty of when the vessel will be reactivated the problems will start to manifest into bigger issues. Currently I have visited vessels sitting idle in the arrival condition 17 months later. Engines not turned properly, sea water systems left full of water on the expectation that tomorrow they may get the word to reactivate. Basically the planned maintenance system has not changed and if the equipment is not in use the maintenance is not completed. For this reason I have done a lot of work creating warm stacking maintenance variants as well as suppling basic preservation equipment. The below is indicative of problems that can be found but is not a complete list.
- Sea water systems shut down without proper basic preservation.
- Sea water fouling of heat exchangers
- Pipe corrosion due to localised corrosion
- Stagnant water causing stainless fitting corrosion & Failure
- Treated fresh water systems shut down without proper positive pump circulation
- Localised loss of corrosion inhibitor & therefore corrosion
- Fuel Systems left as per arrival without tank circulation
- Stratification of IFO & HFO fuel systems
- Microbial degradation of fuel left standing for a long time
- Solidification of HFO
- Engine start systems
- Malfunctioning regulators
- Malfunctioning control systems
- Funnel Blanks not fitted and exhaust spaces not clean
- Rain water entering economiser spaces and localised corrosion occurs
- Hardening of soot and cannot be removed by soot blowing
- Jackup rig legs get stuck in the mud
- Currently up to 4 day delays have occurred in Labuan due to this event
- Transformer oil contamination
- Large transformers with coolant not fitted with a nitrogen blanket as part of a basic layup preservation
Failures due to equipment deterioration in general. The atmosphere and especially the humidity may not have been monitored during lay-up, resulting in corrosion and deterioration.
- Electronic equipment start-up failures after months without power.
- Electronic Failure
- The equipment does not start when power turned on such as computers, servers, navigation systems etc.
- Control system calibration settings off specification
- The hysteresis curve is out of specification and locks out the system from starting such as DP control systems, boiler combustion systems, other computer or PLC control systems.
- High moisture levels in electrical/ electronic components
- All products & components both electrical & electronic has operating specifications which generally specify a temperature & humidity range. An enclosed space with no dehumidification will increase the humidity to in excess of most rated devices and can/ will lead to deterioration and component failure. Layup with VCI spray only will cause issues.
- Different battery types have different requirements and it does pay to check type and see advice from the manufacturer
- Hull fouling
- Sea chest fouling reducing water flow, Growth build up in tropical waters is fast
- Growth around stern tube seals
- Impressed current system turned off
- Corrosion in sea chests
- Hull corrosion, subject to paint condition
- Ships side valve seizing in the closed position
- Unfortunate but true even with proper layup greasing prior to shutting
- Corrosion & failure of pressurised sea water pipes or pipes passing through ballast tanks
- Live sea water pipes will always pose an issue and unless drained and dehumidified cannot be actively controlled. Preservation VCI products may assist with this issue but unless opened and condition assessed it cannot be guaranteed
- Machinery sitting static for long periods or turned with improper lubrication
- Pedestal bearings without forced lubrication are on to watch out for.
- Dry powder extinguishers
- Compacting of powder due to not being turned upside down monthly
The above is only part of the problem with incorrect layups. As part of the solution MLS is able to provide a reactivation schedule in advance if required so that parts can be identified as being required for reactivation, estimation of pipe spool replacement time and system readiness. This is to ensure that consumables, materials & specialised labour can be identified in advance and time to reactivate better judged. The reactivation schedule should be completed within 1 month of vessel being declared laid up. So whether you’re sitting in Singapore Anchorage, Bay of Brunei or elsewhere in SE Asia MLS can provide you with a consultancy service to that suits your needs & budget