24 Jun - Is your member flooded ?
RRS Ernest Shackleton Diary
Position @ 1200: 53°59'North 000°47'East. Inside 500 m zone of Neptune Platform.
Conditions: Wind SSE x 17 kts; Barometer 1021.9 mb; Air Temperature 14.1° C; Sea Temperature 11.1°C; Sunny with haze.
Map of survey sites (Neptune Platform is not shown, but is close to Cleeton).
This week has seen RRS Ernest Shackleton continue to work in the West Sole, Cleeton and Ravenspurn fields. Last Sunday we carried on with the ROV inspection around the West Sole Bravo Platform, completing the work on Monday morning when we move to West Sole Alpha, taking about fifteen minutes to complete the transit. The two Lynx ROV's were deployed for three hours in the afternoon before being retrieved back onto the deck so that we could prepare for a helicopter visit. At 1725, with the vessel steaming at about 4kts (to help ease the ships motion due to the sea conditions at the time) a SK76 helicopter landed on deck, carrying four charterers personnel. The helicopter was on deck for eight minutes, before continuing on its way to Ravenspurn North Platform.
A visit from a helicopter involves a large number of the ships crew. The Captain acts as the Helicopter Landing Officer (HLO) and is the person in charge of the helideck, ensuring that it is safe for the aircraft to land. This means a thorough inspection is made of the surface, that the netting on the deck is tight and has been watered and that there are no Foreign Object Debris (FOD), - small items of litter that could be sucked into the helicopters intake and cause damage to the engines. The HLO advises that the deck is clear for landing just moments prior to the aircrafts arrival.
The HLO also has two team members whose role is to put chocks under the wheels of the aircraft and once permission has been given by the pilot they then unload any baggage and cargo. Two personnel are required to man the Monitors, these being large, fixed, fire fighting appliances that can spray either water or foam over the entire Helideck area at great pressure. They are fixed to the deck, one at Helideck level and one raised about 2 m above the Helideck. They are manned during for the whole period that the aircraft is on the deck.
Two more personnel are required to stand by the Fast Rescue Craft, which is ready for launching. Finally there is one person on the Bridge who is involved in flight following the aircraft and passing on the vessels position, speed, heave, pitch and roll information. There are stringent limits to the movement of the vessel that will determine if an aircraft can land. In our case, the pitch and roll must not be greater than 2.5° and the heave less than 1m. Rolling is generally not a problem, but the pitch is often on limits and this is why we had to steam at 4 kts on Monday, so that the pitch was reduced to a minimum.
And last, but not least, a 'goodies' bag is prepared by the catering department for the aircrew, as they always seem to be hungry and thirsty by the time they arrive, even if it is only a 30 minute flight ! Last summer, on a very hot and sunny day they called up and requested some ice-cream !!!!
Following the arrival of the new personnel the ship returned to West Sole Alpha to finish the tasks and by midnight on Monday we had moved to West Sole Charlie and deployed the two Lynx's again.
Tuesday 19 June and we had returned to West Sole Bravo and worked there again for most of the day, completing in the early evening and then making the two hour passage to Ravenspurn Alpha Platform.
The remainder of the week was spent working around the Ravenspurn Platforms, with Thursday, Friday and Saturday morning spent working around the Ravenspurn North Central Platform, which dwarfed the vessel.
With the Ravenspurn work completed on Saturday morning, the vessel departed and made for the Neptune Platform, in the vicinity of Cleeton, to carry out specialist work on the platform, checking on the status of the members and if they are flooded or not.
This week has also seen us thinking of our colleagues down South. Thursday 21 June was midwinters day for those working on the bases and this time is traditionally celebrated, much in the same way that at home we would celebrate Christmas. It is the big highlight of the winter. Much planning is made for this day, with all the base members making presents for their fellow winterers.
Flooded Member Detection
What is a member? There are two main types of member, a horizontal and a vertical diagonal. These are used as bracings between the legs to provide strength to the platform.
One thing that is often difficult to determine is if a member is flooded. This can be determined by using a low level radioactive source and sensor. An open ended frame is fitted to the ROV and on one arm of the frame the radioactive source is fitted, the other arm has a very sensitive radiation detector fitted. Once the frame is placed over the member, a measurement is made and from the results it is possible to determine if the member is flooded.
...... And finally a picture of the Second Engineer, Malcolm Inch, busy working on one of the ships two Auxiliary Engines. A problem was detected by the monitoring equipment and it was decided to remove all the cylinder heads and clean them out in order to return the engine back to its normal operating condition. This job took a number of days, with all the Engineers taking turns at working on it, due to the watch system in operation, and it is now back together and working correctly.
Forthcoming events. Work northwards into Scottish waters. A port visit to Aberdeen later in the week for a charterer crew change and take on bunkers for the next work period.