In an offshore installation or transportation project, the role of a marine warranty surveyor (or MWS) is often misunderstood. My colleague Captain Geoff English has written an excellent article summarising who and what an MWS is [read here]. But what does an MWS actually do when they are on-site? This is, of course, like asking the length of a metaphorical piece of string and will vary quite considerably depending on; the type of project, the type of offshore operation, the current location and weather conditions, and even the discipline of the MWS themselves. An MWS Dynamic Positioning specialist on a cable lay vessel monitoring the installation of a cable in the high current of a tidal stream site will be performing quite different tasks to an MWS Structural Engineer on a semi-submersible crane vessel who is checking last minute changes to the calculations for decommissioning an oil platform by heavy lift. Though this article is about an MWS Naval Architect attending the heavy lift installation of an offshore windfarm substation jacket, there are many similarities to our other surveyor’s days.
It’s 06:00 on the heavy lift crane vessel, I wake up to get a cup of coffee and start the day by reading my emails and checking the five-day weather forecast. The procedures have already been reviewed and approved in the office, so it should be straight forward to check the forecast against the Contractors’ procedure. Today the wind isn’t coming from the prevailing direction, so I double-check the dynamic positioning capability analysis and the lifting analysis. The weather is well within the design limits, so it looks like today is going to be ok.
I join the Client Rep, the contractor Superintendent, the Project Engineer, the vessel Master and other team leaders for the daily meeting. The day’s activities, weather forecast, and 3 day look ahead are discussed. Everyone is satisfied with the weather and are ready to install the jacket later this afternoon. Following the meeting I head out onto the vessel back deck and perform a final check of the rigging and equipment on crane vessel deck. I was given the rigging certificates the day before, so today I just need to do a quick visual check of what is on deck. I can’t access the main jacket rigging just yet as it was pre-installed on the jacket in the yard.
At 8:30 project operations are suspended whilst the ship performs a muster drill. I head to my assigned lifeboat muster point and check in on the electronic system using my ID pass. I’m pleased to see that the drill is finished quickly and efficiently, it’s small things like this that give me confidence that I’m working with reputable contractors who follow good industry practice.
After the drill, I head back upstairs to the client’s office and I start to check my emails when the phone rings; the vessel is ready to perform DP trials and enter the 500m exclusion zone around the installation site. After witnessing the DP Officer run through his DP checklist and confirm the system is working correctly, I sign the Certificate of Approval (COA) to enter the 500m zone and give it to the Client Rep. This certificate signifies that Waves Group have reviewed the procedures and witnessed preparations for the specified operation, and therefore the Client has met their obligations to avoid undue risks, in line with the requirements of their insurance policy.
While things are quiet, I get some rest and have something to eat. This means lunch is much earlier than I would have when I’m working in the office, but I’ve learnt the hard way; a surveyor should always rest and eat when they get the chance – you never know when you’ll next have the time to get a meal.
By 12:30 the heavy lift vessel is ready, a tug brings the barge alongside and it is moored to the starboard side. The jacket, a cluster of yellow and brown legs, trusses and tubes, waits along with 6 skirt piles, on the pontoon barge. The jacket is more than 50m tall and while it is not as big as a large oil and gas jacket, it still weighs three thousand tonnes and will support a four thousand tonne substation when completed.
Whilst the moorings are finished and the gangway is lifted into position, I head down to the changing room to don my deck PPE. Out on the main deck, in the coffee room the HSE officer and Assistant Superintendent are holding the shift change toolbox talk where they explain the planned operations to the riggers, welders and other technicians.
The safest and quickest way to get to the top of the jacket is by crew basket, along with the Client Rep I’m lifted by an auxiliary hook of the main crane onto the top of the jacket. Tree trunk thick slings are connected to the padeyes on the top of each corner of the jacket. I’m able to confirm these slings match the certificates and I can see the shackles are properly secured. It only takes me about 15 minutes to do my visual checks, but I’m stuck on top of the jacket for the moment. The Assistant Superintendent and half a dozen riggers are ready to start manoeuvring the slings onto the HLVs main hook, so the crew basket is unavailable. After half an hour waiting for my lift back down, I’m able to get off the jacket and back onto the Heavy Lift Vessel (HLV).
When I get back to my office at about 14:30, the Assistant Field Engineer is waiting for me. The HLV is moving into position above the installation site and it will soon be time to cut the sea fastenings. I log into my laptop and check the mid-day weather forecast, which still looks good. Next, I call the bridge and speak to the First Officer, all systems are operational, and the ship is ready. The Client Rep tells me he is happy to go, so I sign the COA for the cutting of the sea fastenings and installation of the jacket.
I head down onto the HLV deck with the Client Rep and observe the cutting of the jacket sea fastenings. Once done, the small team quickly disassembles the scaffolding around the jacket legs and come back aboard the HLV, leaving an Assistant Superintendent to guide the lifting of the jacket from the barge. The jacket starts to lift upwards, slowly at first, as the weight comes off the barge until daylight can be seen between the legs and the grillage beams. Once the jacket is a few meters above the barge the HLV main crane gradually slews away from us, around the stern of the ship. Two hours later only the top of the jacket can be seen above the calm sea on the port side of the HLV.
It’s going to be a long night, so I nip into the mess and grab a sandwich. Dinner sorted, I check of the weather forecast again. Following discussions with the Client and Contractor, I sign the COA to remove the pile seafastenings and install the skirt piles. The first of the 250 tonne piles is lifted from one end tipping up and rotating about the pile bottom. During our review of the pile lifting documents it was noted that there would be high stress in the pile bottom as it was rotated from horizontal to vertical. Although the calculations said the pile would not be damaged, we want to be sure that it is not deformed before the piling operation starts. With the pile now hanging from the HLV crane hook above the barge deck, the Client Rep and I go across the gangway and take a closer look at the pile tip. Without getting too close to the suspended load, we can see scratches in the pile tip, but no significant deformation.
It’s now after 22:00 and the summer sun has set, flood lights show the first pile being lowered into the sleeve on the side of the jacket. From the HLV I watch the next two piles rotated, lifted and lowered into position on the jacket. Grabbing rest whenever I can but never far from the action, I witness the last of the piles lifted into in place. As the 400 tonne hydraulic hammer is used on the first pile the sun is starting to come up. With the first pile driven halfway to depth it’s time for me to get some rest. At 05:30 I get back to my cabin and go straight to bed, finishing another day as a Marine Warranty Surveyor.
