Some thoughts on the temporary marking of offshore structures

Whether it is a jacket, a monopile or an abandoned platform, there are many structures offshore that need to be marked for a limited period of time. Examples are jackets waiting to have the topside installed or to be removed, platforms that have been abandoned and are waiting for actual decommissioning or monopiles waiting for transition pieces or met masts to be installed.

Since 2013 we have marked all of the above mentioned structures and therefor have a broad experience.

This blog aims to provide a few suggestions to make the decision on what to use on such structures a bit less complicated, by going through a number of steps.

1. Regulations

In general all regulations need to be met to avoid issues with the authorities. However, in case the marking is required for a very short period, deviations from the regulations sometimes are accepted. For example, in the UK 10 nm mile main lights have been accepted under certain circumstances, whereas the regulations specify a 15 nm main light with a 10 nm backup light. Temporary marking of structures need to be reviewed case by case and when a deviation does not result in an increased risk of an accident, it might be possible to get approval for a system that is smaller and cheaper than what would be required in accordance with the regulations. There are however situations in which it is hard to meet the regulations, eg for a single jacket, with limited space and in case of platform decommissioning, most likely a weak spider deck in the splash zone. 


2. ATEX vs Safe Area

The majority of the temporary markings will be for safe area, since temporary markings typically are required on structures that are classified as safe areas. Of course there are exceptions, and temporary marking of hazardous areas is more complicated. And far more expensive. Most operational platforms are considered to be completely hazardous areas, but for temporary marking, it is very cost-efficient to see if there are spots on the platform that are: a) actually safe area and b) suitable for installing temporary Aids to Navigation systems.


3. Type of structure

Each type of structure provides its own limitations and opportunities. The design of the skid for a monopile will differ from the design of skids for a platform. The way the skids are installed on the structure differs, depending on type of structure and preferences of the client. However, it does not matter if the structure is a monopile, a jacket or a platform, the regulations state that they are marked in basically the same way. Only offshore windfarms are marked differently, with the exception of the sub-station.



4. Power supply

For short term marking, a relatively small system using primary cells typically is a good solution. Of course, after the job is done, batteries need to be replaced for a possible next job, but by avoiding using PV modules, the skid can be made much smaller and total costs are lower. In particular for one-off projects, this is an interesting option to consider.

For long term marking, PV modules are the most reliable and cost-efficient solution. I know companies have tried to use small wind turbines, but the results that I am aware off, are really disappointing. I know of turbines that actually have been blown off the platform.

According to a couple of clients of mine, who made a comparisson between small wind turbines and PV modules, the performance of the turbines was poor. The main reason, favourable wind conditions are not as regular as one might think, very often there is too little wind, or – and this may come as a surprise – too much.

PV modules generate power every single day, even when it is cloudy. Output will fluctuate largely over a year, but it is far more predictable than windpower, for example by using NASA data, as we do.

For temporary Aids to Navigation, keep things simple. Gelled lead-acid batteries are reliable and relatively cheap and you do not use an MPPT or very complicated charge controller to get a very well performing solution.

I once was asked to design a system with top notch PV modules (300Wp or more) and Ni-Cad batteries. I informed the client that this would not be a very good idea, as it would be far more expensive, far more complicated and less reliable than what we usually would design. They insisted on receiving a proposal, and when I sumitted it, with an alternative proposal using our standard solution, it took them less then 15 minutes to decide using our standard lead-acid batteries.

Just keep in mind: you do not need PV modules with a very high Wp, neither as you need the highest quality batteries: you just need to make sure that a handful of lanterns, a fog signal, a visbility detector and maybe an AOL, AIS or remote monitoring system needs to be powered all year round. Selecting the right mix, with very low power consumption and high reliability, allows you to keep the system simple and lean.

On the other hand, autonomy is a very important issue. The standard 96 hour autonomy that typically is required for AtoN installations, is not sufficient for a system that uses PV modules to charge the batteries. Be on the safe side, and add some more, because you want the system to continue to operate for at least 2 weeks even if your worst case scenario becomes reality. Spending a few dollars more on PV modules and batteries always will beat arranging a emergency and unscheduled maintenance trip.



5. Skid design

Obviously, the design of the skid depends entirely on the type of structure, the duration of use, which season the skid is used, and most importantly, the power consumption of the users. Regardless of the size of the skid or the number of skids in use, one thing is vital to me: they need to be strong in order to withstand lifting, gael force winds and the salty environment of the sea. And they need to be as compact as possible, in order to allow for (relatively) easy shipping over land and in a supply boat. And of course, we need to take into account the lifting capacity of the cranes to be used. Other things to consider are ease of commissioning and of decommissioning.  



6. Aids to Navigation

In general, local regulations specify what Aids to Navigation are required, which may differ per country. For all projects we have been involved in, there is one common theme: the lack of a main power supply. We rely on a number of solar panels and a pretty hefty battery pack to keep the system up and running all year round, so reduction of power consumption is absolutely vital.

Typically Morse U flashing marine lanterns are required on the corners of the structure, however, on a monopile or jacket, a single lantern may be sufficient. A fog horn might be required, in which case it is good practice to add a visibility sensor as well, in order to avoid the fog horn sounding 24/7, which consumes a lot of power (relatively). From a certain elevation above Mean Sea Level, Aviation Obstruction Lights (AOL) will be required. An AIS transceiver and remote monitoring is recommended and most clients will require the latter for sure.

As mentioned earlier, in particular the marking of a jacket of which the topside already is removed and which will be removed itself within a reasonable time frame, may be problematic to mark in accordance with the regulation. I will dedicate a separate blog to this topic.

As per today, we have supplied AtoN systems for over 15 platforms, 2 monopiles, and 5 jackets (Offshore wind and Oil/gas). Each platform requires its own approach, its own design, which we achieve by offering a modular system, which can easily be customized. Final design is always in very close cooperation with the client. And we would be more than happy to help finding a suitable solution for your structures as well.

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What it is that I actually do – Part 3 – Commissioning of systems

Commissioning a system, basically is installing it offshore, testing it and hand it formally over (completely functional) to the client. This is one of the most exciting parts of my job, together with offshore maintenance work.

Commissioning is the last phase of a long process, which starts with a request from a client. Together with the client we determine the actual scope required to solve the problem the client is facing, based on regulations, budgets and specific desires and requirements (which can actually change during the process). This will eventually result in a technical and a commercial proposal, which then (hopefully) is accepted by the client.

Model of platform to determine locations of Aids to Navigation

We try to use our standard skid designs as much as possible, but custom made solutions are always possible. Upon agreement with the client, we enter the next phase, which is preparing drawings, start purchasing equipment, start building the skids, assemble them when they are ready, etc. This phase is completed when the client comes to my workshop for a so-called FAT (Factory Acceptance Test). If the FAT is completed successfully, the skids and equipment are shipped by truck to the port from which the skids are taken to the platform. The client is responsible for this part.

One complete system ready to go to the port of Den Helder

Once all equipment has arrived on the platform, it is time for me to go offshore. Typically with support from an offshore engineer, but I also go alone and commission the system with help of the client. A commissioning typically takes 2-3 days, depending on the system, work procedures of the client, weather, other activities on the platform, etc.

At this stage the helideck is typically still in use, so most likely I will arrive by helicopter. Depending on the facilities of the client, we sleep either on an accommodation platform (very nice as you always have access to the platform, no matter what the weather conditions are) or on a vessel.

Supply boat & heli – typical tools I need to get the job done

Once arrived on the platform, the first step is to discuss the work procedures with the client. What needs to be done, in what order, which permits are required, which support do I need from the client (eg welding, overboard work, scaffolding, lifting, etc). Although this is scheduled at an earlier stage already, we are never sure what we can expect and so this is done at the platform as well.

For all jobs, work permits are required, safety measures are taken and last minute risk assessment are done.

Step 2 is unpacking all equipment, removing protective and packing materials, checking whether or not everything has arrived, a first visual check of all equipment and preparing the skids to be lifted to the helideck.

Step 3 is the installation of all equipment on the designated locations: skids on the helideck, marine lanterns on the corners of the platform, fog signal typically on the main deck, etc. This step requires the help of the client, quite some lifting and welding is required and this is the responsibility of the client.

Lifting the skid at its lifting points using a spreader beam with lifting chains (also designed and supplied by us)

Step 4 is the completing the field wiring of all equipment, in other words: running up to hundreds of meters of cable from the skids on the helideck to all the Aids to Navitation on the platform.

Step 5 is making all connections in the control panels of the skids, making connections between skids and start the initial test procedures. In case any problems show up, I solve them at this stage. Sometimes the client uses our systems to power some of their own equipment, in which case they need to connect those items to our control panels. This could, for example, be Pressure Transmitters (PT’s) on the well heads, which need to be power, but which also require monitoring. Our systems provide solutions for this.

System ready for SAT

Step 6 is the final step: once I am completely confident that the system is installed correctly and is working flawlessly, the Site Acceptance Test (SAT) is performed. Once the SAT is completed and the client is satisfied, the system is formally handed over to the client. And with this, my job is completed and it is time for me to pack my gear and return to shore.

Job completed, happy faces!
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When things go wrong – a look behind the scene of trouble shooting

Job well done! Thumbs up. We never experience problems, we are always successful. That goes without saying, of course.

When you read all the succes stories on social media, including LinkedIn, things tend never to go wrong. You only hear the good news. I am guilty as well; my post typically show the progress and succes in projects. Does it mean that things never go pear-shaped? Of course it doesn’t. “Things that can go wrong, will go wrong”. Murphy was a wise man.

Things going wrong is inevitable. It is annoying for the client, frustrating for the supplier, it costs energy, time and money to solve them, and this is particularly true for projects offshore. Depending on the project, the need to re-visit the site to fix a problem may require vessels or helicopters to be hired solely for that purpose. It may prevent vessels or accommodation/work platforms to be moved to the next platform, hence causing delays in other projects. It may force you to use less safe ways to get access to the platform, depending on the situation.

Fortunately, most clients realise that equipment can fail, that things can go wrong and that unexpected action must be taken to make things work properly. It is all in the game. The key point is, however, how quickly and efficient you respond to a system failure. How flexible you are, in order to be able to – for example – take advantage of a weather window early next week (or even tomorrow). Looking at the past 3 weeks, the opposite is also true, thanks to Ciara, Dennis and Ellen and two other unnamed storms that have kept me ashore unwillingly.

I find it very, very discomforting that a system that I have supplied, is not working as it should. I take pride in my work, these systems typically are substantial investments and I aim to solve problems for clients, not to create them. I have seen systems working just fine during the FAT and all of a sudden caused problems during the SAT or even after a successful SAT. In one case an issue was revealed during FAT and required replacing parts during commissioning. And, fair is fair, if you speak of your successes, you should also address things that went wrong. And how you solved it. Balancing things out a bit.

Fortunately, I’ve never experienced problems that resulted in accidents or unsafe situations. Most of the issues were minor, yet unexpected, things that could be solved quickly and without a lot of costs. And in most cases time pressure, turned out to be a key factor.

So, let’s bring it on, here are some things that went wrong with us:

With a project quite some time ago, a third party installed battery boxes for us on a very simple skid, and they did not realise that some of the non-used holes in the bottom of the battery boxes, were actually drainage holes. They plugged them. And I did not notice. Not a big deal, normally, but it is when the battery box is in the splash zone… Result: battery box flooded, batteries dead, system down. And not accessible for repair.

Lesson learned: always check everything twice, just to make sure.

Kind of messy… probably gave some interesting sparks when these 30 batteries got flooded

With another project, we had some issues with a remote monitoring system. Not necessarily our fault, more an unfortunate chain of events. The SIM card for satellite communication, to be provided by the client, was available only 1 day before I was going to commission the system offshore, while the SRM equipment was already on the platform. There were some last minute changes in the SRM software as well. Combine this with very tight schedules and deadlines, and you know that you are running a risk. Basically it meant that the SRM system was installed offshore before and without being fully tested.

The result was that the system was not working correctly, was not accessible remotely and we had to replace it 4 months later with a new, fully tested system. After a thorough research it turned out that all hardware was perfectly in order, but that there was a typing error in the software.

Lesson learned: never ever ship something offshore without completing all tests.

New satellite modem installed

The third issue concerned a failure for reasons we did not expect. Quite recently it was noticed from a helicopter, that a PV module was missing on one of our skids. As it was in December, it was important to replace it. When getting to the platform, it turned out that the material we use to protect against galvanic corrossion between PV modules and skid, had deformed to such extent, that the fixings got slack. This caused the PV module to vibrate and untighten the nuts. Eventually, there was so much slack that the freedom of movement of the PV module caused it to be ripped of the skid during a storm. Fortunately, I had a spare PV module in stock, so replacement could be done very quickly.

Lesson learned: although the nuts may be very tight during FAT, conditions offshore are more severe than you might expect. Always make sure that nuts cannot come undone, for whatever reason.

Vibrations due to very hard wind caused the bolts to break/nuts to get undone. Ultimately the PV module was ripped of the skid. 10 minutes after taking this picture, a replacement PV module was installed.

The fourth and final example, concerns an unexpected product failure. In this case, one of our skids had been offshore for over two years without maintenance. We got the report that the system was working irregularly: one week it was working ok, the other week it was down. Based on the problem description, it appeared that the charge controller was going into Low Voltage Disconnect, in which case all loads are disconnected, allowing the PV modules to charge the batteries. Once the batteries are sufficiently charged again, the load is reconnected and the system goes back into normal operation.

Upon inspection, this was indeed the case. One malfunctioning battery was draining the other batteries, resulting in an overal battery voltage below the Low Voltage Disconnect value. A couple of days charging the batteries without load, would get the system voltage into healthy values again, after which the load was reconnected. It then took about a week to drain the batteries to below the Low Voltage Disconnect again. The system got into a Low Voltage Disconnect / Reconnect cycle. The solution: just disconnect the faulty battery, since there is sufficient spare capacity anyway.

Lesson learned: this battery failure was unforseen and unavoidable, one of those situations that just can occur. To realise this is possible, it the lesson in itself.

After disconnecting the failing battery, this system was up and running again. Now running on 5 rather than 6 batteries, but that is not an issue as there is quite some spare capacity.

In all of the above cases, vessels and personnel had to go to the offshore structure outside of the scheduled maintenance trips and consequently have been expensive operations for our clients. Nevertheless, this has not resulted in losing clients, as our clients know this is part of working offshore. What does make the difference, is our dedication to the project, the client and our equipment. Immediate response, offering solutions to solve the problem and being available when it is required, is key.

On the other hand, failing equipment is not common, it is very unusual even. So far I had to replace 1 marine lantern and 1 fog detector. In both cases this was related to a batch of circuit boards with issues. The only real issue with this was that the problems occurred after a successful FAT and after commissioning offshore. The failing lantern was not an urgent matter, it was covered by a backup lantern. The fog detector had to be replaced however, as a failing fog detector will cause all Aids to Navigation equipment to run 24/7, using far more power than what the system is designed for, consequently draining the batteries. This is not the case in summer, but it is in winter (short daylight period and low temperatures have a large impact on the batteries).

Learning from these experiences is also key, in order to avoid (or at least reduce the possibility of re-occurence of) these issues in the future.

But the most valuable lesson: things tend to go pear-shaped in December, when it is cold, windy, rainy, with rough seas, and when the daylight period is very short. Sounds a bit like karma… I am sure good ol’ Mr. Murphy has some interesting comment about that as well.

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What is it that I actually do – part 2- Before going offshore in the first place


In June 2018 I wrote a blog in which I described what kind of work I actually do, since for many of my friends it is kind of hard to imagine. The office part of my job sounds all too familiar, but the offshore part of the job is something completely different. For most, the offshore industry is something they obviously heard about, but typically they find it hard to understand what exactly is happening there.

I have a non-standard role in the offshore industry: I am not part of the regular crew. I only go offshore for special projects, whether it being the installation of equipment I manufactured or supplied, for trouble shooting relating to that equipment or for maintenance of said equipment.

Explaining what I do, does help people to understand, but they still wonder: “What does your day really look like and what is it like, to do whatever the hell you are doing overthere?” Before actually doing anything, you first need to go offshore and that in itself is an adventure.

As pictures tell more than a thousand words, please have a look at some of the experiences I had over the three years.

It all starts with training, since working offshore is very much focused on safety. Safety for yourself and for the people around you.

For offshore oil and gas in the Netherlands, you need to have either Nogepa 0.5 or Opito Bosiet. This training includes first aid, sea survival, fire fighting, helicopter underwater escape training (HUET) and working with a life jacket with a compressed air cilinder.


HUET training, how to get out of a helicopter after ditching

Yup, this is your ticket to go to work the fancy way: by helicopter. And if your really lucky, you’re the only passenger (had that a few times).


Thanks for dropping me off!

However, if you are working in Offshore Wind, your typical means of transportation is a Crew Transfer Vessel (CTV) and you need to climb the structure, rather than getting out of the heli on a helideck. Thus, more training required:

  • GWO Working at Height (or how to escape from the nacelle of a 100 m wind turbine)
  • GWO Safety at Sea (which is already covered in your previous Nogepa/Opito Bosiet training), primarily to practice boat landings – under bath tub conditions to be honest


A CTV seen from above after doing a boat landing and climbing 30 m of cage ladders

Your training is completed with a medical check and a basic course on safe working in general: VCA in the Netherlands or MIST in the UK. At least, you think your training is completed, because before being allowed offshore, the operator of the platform usually has a few online training courses, with exams you need to pass first.

A special online course is required when going to an offshore structure with a larger vessel equipped with a heave compensated gangway. In other words, a gangway which neutralises the wave motions of the vessel. This is called a walk-to-work vessel.

L7N part 4 12-09-2018

Leaving the platform to go back to the walk-to-work vessel

It seems like a lot of training – and it is – and in case you wonder why: remember Piper Alpha or more recently the Deepwater Horizon? That’s why. Working offshore is generally more dangerous than working onshore and they want you to be prepared as well as possible. Going offshore is expensive to start with and once on the platform or structure, the consequences of ignorance can be severe. Still, although the working environment offshore is more dangerous than most environments, eg construction, onshore. The strong focus on safety is the main reason, however, that the number of incidents, accidents, wounded or killed persons, is much lower offshore than it is onshore (as a percentage of working hours).

In my world, there are two types of offshore structures:

  1. The ones where oil and/or gas is present and being processed. I am not qualified to work here. Nor am I allowed to take pictures. I only visit these platforms to go to other platforms, and use them as a hub. Or to grab lunch, that too.
  2. Structures that have no oil and/or gas, either because the wells are shut down or the structure is not related to oil and gas in the first place, eg wind farms. These kind of structures are the ones at which I am doing my work.

PS I do supply equipment for both types.

And then you’re off to the heliport, check in your toolbag, check in yourself and personal luggage, go through customs, watch the safety induction video for the helicopter, get your survival suit and ear plugs, put on said survival suit, which is quite a struggle. Then you collect the life jacket and you’re ready to board.

Oh wait…. they told you so during your offshore training: “Never forget to keep your boarding pass at hand!”. You remember this vital piece of information when you are asked to hand over the boarding pass and you realise it is still in the pocket of your jeans.

Take off life jacket, open survival suit, dig into your pocket, zip survival suit and put life jacket back on. Now you are ready, at last!

How can you tell you are a rookie? Simple, while you are excited about flying in a helicopter, everybody around you is asleep.

Unfortunately, it is not always possible for me to go offshore using a helicopter. On the abandoned platforms I have supplied skids, these skids are installed on the helideck. Which means there is no space left for a helicopter. The only way to get to the platform then is to hop aboard a vessel.

Although I really like flying in a helicopter or joining on a sea-going vessel, most of the time the fun really starts when you need to get onto the platform. But that will be covered in another blog.

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Maintaining our autonomous Aids to Navigation systems

Even though autonomous skids like the above, typically are a temporary Aids to Navigation (AtoN) solution, often our systems are deployed for more than a year. In general, unless specified differently by our clients, we design systems for which we advise a once-a-year maintenance visit.

Based on our experience, the key equipment of an AtoN system (lanterns, fog signal, fog detector and Aviation Obstruction Light (AOL)), actually do not need any maintenance. Although it does not hurt to clean the lenses of the lanterns, to get rid of salt and possible bird droppings. After 3-4 years it is also recommended to re-calibrate the fog detector.

As far as the batteries are concerned, typically they do not require any maintenance at all, but they might need to be replaced after 6-7 years, provided that the charge controller is working properly and the batteries are not over-charged or depleted too much.

The components we use in the control panels are of high quality and do not require maintenance. Don’t expect to replace any broken items over the first 8-10 years or so, unless glass fuses are used (which we normally don’t). It is advisable to keep some components in stock, just in case, such as circuit breakers and relays. On the other hand, these are off the shelve items, so order them today online and you’ll have them delivered the next day.

Remote monitoring equipment is very reliable and the firmware can be updated remotely. Normally, this equipment does not require any maintenance. As we have experienced, a tripped circuit breaker may prevent remote updating and rebooting, in which case the circuit breaker needs to be closed manually during the next scheduled visit.

So, why do you need to schedule a maintenance trip then? Easy: the PV modules. Depending on the circumstances, PV modules might require a good cleaning in order to perform well. Furthermore, the PV modules are exposed to wind and in fact the most vulnerable part of the skid. I have seen PV modules being hit by birds and consequently being severely damaged. Very strong winds may also damage the PV modules and can cause vibrations, which may cause slack in the fixings.

Whether or not the PV modules need to be cleaned, primarily depends on three factors: the presence of birds on the platform, exposure of the PV modules to salty spray and the amount and interval of rain.

Obviously, if the platform is visited by many birds, the odds of the PV modules getting covered in bird droppings is rather high. However, if there is sufficient and regular rain fall, the modules will actually be cleaned. The same applies if the PV modules are exposed to spray (when installed on lower decks of the platform for example), rain will clean the PV modules.

When using PV modules, keep in mind that a small patch of dirt on the “wrong” place on a PV module, may severely reduce the performance of the panel. During an FAT we put an A4 sheet of paper on various locations on a PV module. There are spots on the PV module, which when covered, results in losing the entire capacity of the PV module. This is also the reason why shading is a very important factor to keep in mind when chosing a location for the skids. Cleaning PV modules therefor is something to take seriously. It does not necessarily matter how much dirt build-up there is, it is important where on the PV module the dirt has built-up.

Skids with clean PV modules after 4 months in deployment – September 2017. Rain has cleaned the PV modules, despite presence of birds (see droppings on helideck)
The same skids 8 months later, in the middle of the dry summer in 2018 (July). Lack of rain prevented the PV modules from self-cleaning. A helping hand is required.

In the Netherlands, there is typically sufficient rain in wintertime to clean the PV modules properly. However, in a very dry summer, like we have seen in 2018, it is very likely that the PV modules need to be cleaned once a year. A soft broom, fresh water and around 15 minutes per skid is all it takes. And while you’re at it, check the fixings of the panels as well.

Cleaning PV modules – not the nicest job in the world. Use water to prevent creating dust…

Obviously, as you are already on the platform, perform a full system test, just to check everything is indeed working as it should. And should a diode, relay or circuit breaker – against all odds – show odd behaviour, just replace it. It’ll take only a few minutes to do so.

Most of our clients are very experienced in working with fixed AtoN equipment, since this kind of equipment is present on all offshore structures and they have worked with them for decades. Autonomous AtoN systems are different though and we always recommend to have them commissioned and maintained by us. And once they have brought back to shore? We’ll prepare them for stocking, so they are ready for use whenever required for the next job.

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What about fog signals? Are they still serving a purpose?


30 year old Tideland Signal fog signal under the main deck, still working. What a great investment!

Audible fog signals have been around for centuries, warning seafarers for hazards ahead in foggy conditions. Initially ringing a bell, or firing a canon, later developed into the electronically powered fog signals we see today, such as the Tideland Signal fog signals.

Fog signals were used both onshore and offshore, on vessels and platforms, but these days you will struggle to still find them onshore. Next to the lovely Kinnaird Head Lighthouse, in Fraserburgh, Scotland, you actually will see them, even though they are not operational anymore. As a result of the fast developments in navigational aids over the last decades, such as radar and – more recently – AIS, they are not needed anymore. The developments in navigational aids have a nice side-effect: improvement of quality of sleep of the people living next door.

Yup, this will keep you awake at night – Fraserburgh, Scotland

On offshore structures, whether it be a platform, a jacket or a wind farm, you still will find fog signals. Mainly for two reasons:

The first being that fog signals tend to have a very, very long life span. Secondly, they are still mandatory in many countries.

There are a lot of old platforms in the North Sea. In the Dutch sector, the majority of the platforms are over 25 years old, and typically still use the exact same fog signals they installed when commissioning the platforms. The reality is, that all good things come to an end, so even the fog signals that have been in service for sometimes over 3 decades, tend to start showing problems. Given the current market conditions, even the largest oil majors need to watch where and how they spend their money, so the question arrises whether or not to retire the old fog signal and replace it by a new one, or not replacing it at all and continue operating the platform without a working one.

But the same question also pops up with platform abandonment, or when new structures are installed at sea (in the oil and gas industry this is very rare at the moment, I admit).

Needless to say, this is rather a hot topic at the moment for operators of platforms that need to make a decision whether or not to buy a new fog signal.

In essence it comes down to the question: “Do we really need a fog signal?”. And the answer is very simple, when in UK or Dutch waters: “Yes, you do, because it is mandatory according to the regulations.” The Norwegians have a different approach, the fog signal is no requirement in their part of the North Sea anymore. Denmark is in doubt, officially it is required, but for abandonment, it is actually allowed not to install one.

Although the answer to the question is very simple and straightforward, the question itself is actually very legit. But the question should be asked slightly different: “Do fog signals, given the technical developments, actually still serve a purpose?”. And if the answer to that question is a (partially) “no”, why would you spend money on it?


Tideland Signal AB-560  safe area, 2 nm fog signal


Fact is, that the regulations are written decades ago, and do not take into account new technologies. Even the IALA O-139 “The Marking of Man-made Offshore Structures”, which is a recommendation, not a regulation, does not even mention AIS as an aids to navigation in the section about marking offshore structures in general, under which oil and gas platforms fall. Its predecessor, the O-114 publised in 1998, has been the basis for the local regulations, such as the Dutch Mijnbouwregeling from 2002. 16 years later, the Mijnbouwregeling has not been updated, hence focussing primarily on visual and audible aids to navigation and basically neglecting more advanced tools.

Strangely enough, onshore there is a tendency to decrease the range of navigational aids: shore based fog signals are long gone and replacement lights for light houses will have less intensity, and thus a smaller ranger, than previously. In Belgium, for example, a typical light house would have a range of 25 nautical miles (nm) or more, but when their light is replaced these days, their range will drop to about 18 nm. The main reason: improved navigational equipment onboard vessels reduces the need for long-range lanterns. And – as a side-effect –  reduce power consumption dramatically, quite an important issue these days.

And of course, this is true. Any vessel sailing the North Sea is required to be able to receive AIS messages. Any vessel sailing the North Sea is required to have radar. We have better night vision than owls, regardless whether it is foggy or not.

And even though collisions between vessels and platforms are considered to be the largest risk in the Dutch part of the North Sea by the governing body, Staatstoezicht op de Mijnen, and even though marine traffic obviously has increased dramatically over the last decades, and even though there are more than 600 platforms and several wind farms in the North Sea, we are more capable of spotting offshore structures than ever before. To put it quite simple, visiting allows me to see offshore structures in the Gulf of Mexico, whilst sitting at my kitchen table at home in the Netherlands.

Collisions are most certainly a threat, and the only reason why we use aids to navigation in the first place. Not only has traffic become more dense, the average vessel size has increased significantly as well. Vessels with a Loa of over 350 meters are a common sight. This means that we are looking at a displacement of close to 200,000 tonnes. Vessels of this size require quite a distance to come to a full stop and the radius of a turn of these giants is given in miles, not in meters. When a vessel of this size and displacement would hit an operational production platform, the consequences are obviously severe. So proper marking of any offshore structure is not just a “nice to have”, it is critical for safety at sea.

But picture this: according to the requirements, fog signals should have a range of 2 nm (1/2 nm for the backup fog signal in the UK). What are the odds that you will hear a fog signal when you are standing in a well insulated bridge of a modern ultra large vessel, with the bridge located at around 3/4 of the ship’s length?

Maybe, a vessel like this:

Large vessel indeed

The answer is rather clear, I would say: the odds are very, very slim. In fact, when you are on the bridge of one of these large vessels, it is not unlikely that by the time you actually hear the fog signal, most of the offshore structure is already gone because of the impact of collission.

The days that people on the bow, on the outside of the bridge or in the crow’s nest, are on the watch to hear fog signals warning them for danger, are gone. These days we stay warm and cosy, with a cup of Nespresso, inside the bridge and watch the screens for upcoming mayham.

I was doing a site acceptance test of an Aids to Navigation skid onboard a modern vessel last year. Maybe I should mention the name of the vessel? The Pioneering Spirit of Allseas, the largest vessel in the world.

The fog signal, mounted on the skid, was approximately 150 meters from the bridge, as the crow flies, but when testing the fog signal, it could not be heard on the bridge. Well, actually it could be heard, but only because we were on permanent comms with the bridge and the sound of the fog signal was transmitted through the portable radios. Important to note: it was a perfect day, no wind at all.


Onboard the Pioneering Spirit, with the skid with fog signal on top of the test platform (top left corner of the platform)

Over the course of last year, I have commissioned Aids to Navigation systems on several abandoned platforms, all including fog signals. Most of these platforms were small satellites, with a length of just over 30 meters. In all cases, the fog signals were installed on the main deck, whereas the power supply was installed on the helideck. During testing of the system, another logical shortcoming of sound became apparent: during strong winds, it was hardly possible to hear the fog signal at all, even though I was less than 40 meters away from the source.


Fog signal on the main deck of an abandoned platform

Sounds can blow you away, but the opposite is also true: sound itself can be blown away. Or blocked, by the structure of the topside, for example.

Dutch regulations state that each offshore structure should be fitted with a fog signal, with a range of 2 nm. It does not, however, require that the fog signal should be heard from all directions, so if you use a single fog signal on the corner of a very large platform, you still comply to the rules. Even though you are certain that the fog signal during most of the time will not be heard when standing on the opposite corner.

So, what’s my point of view?

For structures outside the 12 nm zone, a fog signal basically serves no use anymore. There are much better ways to mark these structures, the odds that the fog signal cannot even be heard on the bridge of passing vessel is high, and these same ships will have noticed the structures way in advance by using radar, AIS or electronic charts. Or, how oldskool, noticed the 10 or 15 nm marine lanterns.


Oldskool? State of the art LED lantern actually.

For structures within the 12 nm zone, it actually makes sense to use fog signals, since there are much more small vessels and boats sailing these waters, many of them for leasure, with less experienced crew. And often less advanced electronic equipment. In particular for near shore windfarms, fog signals still serve a useful purpose.

One final thought:

On operational platforms, power consumption is not an issue. However, on abandoned platforms, where the power needs to be supplied by the combination of batteries and PV modules, it is. In an AtoN system, the fog signal typically is the largest user and avoiding having to use them, will actually make AtoN systems much cheaper, while not reducing safety. Just make a physical AIS transmitter mandatory.

So, I think it is time to partially retire the fog signal. It is no longer needed in the area where predominately professionals are at work. But let it enjoy its retirement in the areas where it still can support marine traffic and can help to avoid accidents, being close to shore.

As I mentioned before, all good things come to and end. So long good friend, you have served your time well.


Disclaimer: a fog signal is an expensive piece of kit and from a commercial point of view, manufacturers will not necessarily agree with me. But hey, this is my personal blog 😉


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Marine lantern design approaches


NOVA 65 HI marine lantern in main/backup configuration, overlooking the North Sea


I recently had an interesting discussion with an operator in the North Sea, about marking platforms and the costs of a complete Aids to Navigation system. We were talking ATEX, so that means that the costs double compared to safe area (or GMU as we call it, general marine use), so marking an entire platform with lanterns, a fog signal and a visibility sensor, and adding a control panel to – ehh, well – control  the equipment, easily becomes a significant expenditure.

What is rather interesting, is that the items with  the lowest price per unit, actually have a massive impact on total price of the system. It is the marine lanterns that really make the difference.

Although there are also differences between fog signals and visibility sensors of the various suppliers, they are relatively easy to compare and price differences are limited. You can save a few thousand EUR maybe, but in the larger scheme of things, this is not really a game changer.

The marine lanterns, and to be more precise, the design approach behind the lanterns, make the difference, however.

Allow me to clarify:

First of all: most, if not all, major and reknowned players in this market, manufacture high quality products, which comply to the regulations. So in terms of performance, you’ll be fine.

A number of our colleagues have adopted the philosophy that the control panel needs to be the heart and brains of the system, let’s call it the centralised AtoN system. The central point here (pun intended), is that the control panel tells all equipment what to do, and when to do it. So synchronising is handled via the control panel. So is using the sunswitch to switch the lanterns on when it becomes dark and switch them off at sunrise. And often also the flash character is determined by the control panel.

Consequently, the lanterns are not very bright… in terms of intelligence I mean. They just follow the orders given by the control panel. Typically a large, complicated and very expensive control panel, I must add. To be a bit rude, it is a bit like flashing a flashlight by pushing the button for evey flash.

Let’s assume you have an issue, your platform went dark, the authorities are putting pressure on you to solve the issue and you want to mark a platform temporarily with lanterns, keeping it as simple as possible, by leaving the lanterns on 24/7, so you do not need to worry about a central sunswitch or a visibility detector.

If you would use a centralised AtoN system, you would not only need to purchase lanterns, but also a control panel. Making the emergency solution very costly, but also with a lead time of several weeks. Not exactly what you had in mind.

Tideland Signal is one of the few, and maybe the only, manufacturer of marine lanterns used on platforms (or anywhere else) that has adopted the de-centralised AtoN design approach. And did so decades ago. And, as it turns out, this provides large benefits.

Tideland Signal lanterns are smart. The flash character can be programmed into the lantern, so you do not need a control panel for that. They have their own sunswitch, so you do not necessarily need a central sunswitch (and a control panel). And the really nice part: they can communicate with each other, so synchronisation is handled by the lanterns themselves, not via a control panel. Furthermore, they are clever enough to tell you they are ill: they have a fail output. Making remote monitoring as easy as making a cup of coffee. To go back to the example of the flashlight: just turn it on and the light will flash automatically. Leaving you the time and opportunity to enjoy that cup of coffee. The “fire and forget” approach the US Airforce likes so much.

So, returning to the emergency example: when using Tideland lanterns, a battery pack (if need be, regular car batteries will do the job) and a couple of 3-core cables, you can build a working system. Trust me, I’ve done this 🙂


3 wires per lantern: positive, negative, sync. And the lanterns flash Morse U in sync, without control panel. They have actually been installed on a platform like this, as the control panel had not yet been completed. The 4 lanterns are fed from a single car battery.

One loop for positive, one loop for negative and one loop for synchronisation, is all you need.

When scaling up the system to a complete AtoN package, with central sunswitch, visibility detector, fog signal and remote monitoring, these advantages remain: you only need a very small and very simple control panel. And there lies you financial advantage as well, the difference in price between a control panel for a centralised system and one for a de-centralised system is huge.

Why is the control panel that simple? You do not need to control that much, really. Basically the control panel is used to distibute power to the various users, collecting and distributing the signals from sunswitch and visibility detector to lanterns and fog signal and collect the fail signals from the equipment. And feed them into the monitoring system. All the other stuff is handled by the lanterns themselves. So no need for expensive and complicated components such as PLC’s, but primarily off the shelf circuit breakers, relais and maybe a few diodes. If a component breaks, order it on RS-online and send a chopper to pick it up from the nearest post office. Job done. Or, if you want to do it fancy, call me, and I’ll replace it against our standard rates 😉

We use some own components as well, and keep them in stock (the UM-1A/F and MBIO-12 units in the picture below).


ATEX control panel for lanterns and fog signal, with remote control and monitoring. Simple and small. And relatively cheap. Picture was taken during FAT in my workshop.

In particular for temporary marking, the Tideland lanterns offer other benefits as well. First of all the size of the lanterns. Tideland has always been a leader in lens technology. We all have seen the ML-300 fresnel lenses, probably the most copied lens type in the marine industry. Introduced by Tideland Signal.

But also with modern LED lanterns, the lenses of Tideland allow lanterns to be very small and light-weight.

But more importantly: power consumption. The Tideland lanterns are among the most power efficient lanterns in the market, making them the ideal choice for any system running on batteries and PV modules.


The very first skid I build, using primary cells, with NOVA 65 marine lantern, AB-560 fog signal, Informer V-20 AIS AtoN and a passive radar reflecter. The best marked monopile ever. Been out offshore for 4 months.

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What is it what I actually do?


Most of my friends and relatives find it hard to understand what I actually do for a living. Explaining them that I supply chains, hooks and related products for lifting, does ring a bell, but when I talk about the stuff I do for the offshore industry, things tend to become a bit blurry most of the time.

So here goes, a brief introduction of the kind of offshore project I am involved in:

First of all, regulations state that every structure installed offshore, needs to be marked with lights and sound, to avoid ships or helicopters crashing into them at night or during low visibility weather conditions. Although all major oil and gas producing countries in the North Sea (the UK, Norway and the Netherlands) have different regulations, they all share the basics:

  • Marine lanterns (10 or 15 nautical mile, flashing Morse Code U, colour white)
  • One or more fog signals sounding Morse Code U with a range of 2 nautical mile
  • One or more red steady Aviation Obstruction Lights in case the structure rises more than 30 meters above Mean Sea Level


Marine lanterns


Aviation Obstruction Light on top of a crane

These products are called navigational aids, or Aids to Navigation (AtoN).

In case the structure is manned or in case power consumption is a critical issue, a visibility detector (or fog detector) is an important component, since it activates the fog signal (and lights) only when it is foggy. That certainly improves the working environment on manned structures, that’s for sure.


Fog signal

Offshore structures, whether being an oil/gas platform, an offshore windfarm, an offshore sub-station, of whatever structure it may be, that is operational, will have it’s own onboard power supply. Marking these structures to avoid accidents typically is straight forward: deliver and install the equipment, a control panel, run some cables, and the system is up and running.

Far more challenging is the marking of structures that do not have their own power supply. Examples of this kind of structures are so-called jackets (the “foot” on which the “topside” of a platform is mounted), monopiles waiting for turbines or meteo masts to be installed on top of them, or – and this is more and more happening – abandoned platforms. The latter are platforms that are no longer in use, have basically been stripped and shut down and they are waiting to be removed.

An AtoN kit of Seaway on top of a GDF Suez jack

Jacket with navigation skid on top

Key for this kind of projects is that you need to bring you own power supply. So, we bring batteries. A lot of them. The next problem to be solved, is how to charge these batteries. We use PV modules, as they are relatively cheap, stable, reliable, quite efficient, require very little maintenance, have short lead times and provide a relatively predictable power output.

Sometimes, the structure only needs to be marked for a short term, as was the case with the jacket shown in the picture above, in which case we do not bother about charging the batteries and supply a system without PV modules. The same was the case with the monopile shown in the picture below:


Monopile waiting for a meteo mast to be installed for an offshore windfarm

Despite the fact that the lanterns, fog signal and other equipment we use (from our principal Tideland Signal) is very power efficient, whenever the structure needs to be marked for more than – say – 4 months, we will need to charge the batteries.

In order to do so, we design steel (or aluminium or stainless steel if and when required) frames or skids, which we use to mount the PV modules. As there typically is sufficient space, we also install the battery boxes on these skids, as well as a control panel.

For relatively small structures, we use these skids also to mount the aids to navigation equipment, as shown on the pictures of the jacket and the monopile above, and the picture of the small platform below:


Single 10 nm skid, teaming up with a 5 nm steady light station

For larger structures, we need to separate the power supply from the marine lanterns and fog signal, to make sure that they can be seen and heard from all approach angles.


PV module skids with battery boxes on a helideck. The lanterns and other aids to navigation are  located elsewhere on the platform

So to answer the question what it is that I actually do::

Together with a number of partners, first and foremost Tideland Signal, I:

  • design solutions to mark structure offshore
  • design, build and assemble the skids
  • assemble the control panels
  • perform the so-called Factory Acceptence Test with the client at my workshop
  • deliver the systems in the port of departure
  • install and commission the system offshore, in case that is required
  • provide maintance and emergency support upon request

And in case the client requests more advanced solutions, we provide radar beacons, AIS transponders, satellite remote monitoring and other features as well.

So next time I tell you I am going offshore, most likely I will be lying on my back in a pool of dirty water, fixing cables underneath a helideck. What I will tell you, however, is that I had to climb on top of cranes, had to do difficult stuff, underneath a clear blue sky, with wires, relais, circuit breakers and other stuff you would like to stay away from as far as possible, or had a very choppy ride in the chopper.



All pictures taken by me, except the pictures of the jacket and the monopile, which are courtesy of Seaway Heavy Lifting.

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Visiting the Oleg Strashnov

In one of my first blogs, titled “A citizen of Lilliput in Gulliver’s World” in November 2010, I wrote about astonishing large man-made objects and made the following comment:

” I can’t wait to have a look or maybe visit the “Oleg Strashnov”, Seaway Heavy Lifting’s new heavy lifting vessel, as you can imagine.”

It took two years before I finally had the chance to visit the Oleg Strashnov, as it was berthed in the Eemshaven, about 40 kms from where I live.

I was actually very excited to visit the vessel, one of the largest single-hull heavy lifting vessels in the world, with a crane that has a staggering 5000 ton capacity. When driving to the Eemshaven it is very impressive to see the crane from miles away, rising above the buildings in the port.

One of the reasons to visit the Oleg Strashnov was to inspect the Yokohama fenders we supplied on behalf of FenderCare Marine. Then again, those fenders being original Yokohama’s, I had no doubt they would be in pristine condition. As far as I am aware, Seaway Heavy Lifting treat their equipment with great care, so the chances something would be wrong with the fenders, was tiny.

I was welcomed by captain Van Poppel and after a very pleasant meeting, he showed me the around the vessel and it is very impressive. I have seen heavy lifting vessels before, but it always amazes me how big they are and what they are capable of. The Oleg Strashnov appeals to me, due to its unique hull shape, while still remain a real ship. It is self-propelled and can move from a to b on its own power, unlike semi-submersibles (well, they can, but are not allowed to).

After showing me the internals of the vessel, captain Van Poppel handed me over to the storekeeper, Mr. Ritter and he showed me around the deck, the crane and gave me the opportunity to inspect the fenders (which were indeed in perfect condition).

It is mind-blowing to stand next to a 5000 tonnes crane, towering up over 132 meters above sea level. I got that feeling again of feeling tiny.

Everything is big about that vessel, the crane, the anchors, the anchor winches, the deck space and it allows them to do very interesting projects such as installation of jackets, top side, foundations, met masts and turbines. While still able to berth in smaller ports.

All in all, it was a fantastic visit and – even though it has been months ago by now – I thank the captain and the storekeeper for their very kind welcome and great tour around the vessel.

Little did I know back then, that I would visit the Strashnov a couple of times later this year and the vessel still amazes me. Hats off for the Oleg Strashnov and its crew.



Posted in Lifting, Miscellaneous, Offshore | 2 Comments

Cleaning up the mess

My first blog in ages, it’s been very busy since October 2012 and basically forgot I actually have a blog. Apologies to the captain and storekeeper of the Oleg Strashnov, as I promised to write a blog about my visit to the vessel. Have visited the same vessel 3 or 4 times since, but did not find the time to write a blog about it. Sorry, will do that soon (I sincerely hope).

This blog is dedicated to another marvellous concept, however.

When thinking of offshore, one typically thinks of production and drilling rigs, FPSO’s, CALM buoys, anchor handling vessels, and the like. Typically oil and gas related. When you are into renewables, you think of offshore wind farms, tidal energy, floating wind turbines, etc. Others first think of tragedies such as the Deepwater Horizon incident, the Exxon Valdez, the Brent Spar and other large accidents. There are also people who immediately think of Shell in the Arctic or Greenpeace in Russia. Only few people will think of large “pockets” of floating plastic in the oceans.

The latter, however, has a stronger relationship with more traditional links to the term “offshore” than one might think at first glance.

Let me go back one step first. The world’s major currents tend to come together at certain locations in the oceans and unite in some sort of a whirlpool, which are called “gyres”. If I understand correctly, the main cause for the formation of these gyres is the wind. There are 5 main gyres in the world’s oceans: North and South Pacific, North and South Atlantic and one in the Indian Ocean.

All over the world, plastic garbage ends up in the ocean, either because it is lost (e.g. fishing nets), disposed garbage at sea or driven by wind or currents from land. We are talking about millions of tons of plastic. Once in the oceans, the plastic is moved towards the gyres by the ocean currents, where they accumulate.

All this plastic forms a serious threat to marine life and as it is spread over vast distances, it is very hard to collect using traditional methods: using nets to collect the plastic (which actually is a threat to marine life in itself). Obviously, getting vessels to the remote areas in the oceans where the gyres are formed, will require lots of fuel in the first place and “chasing” the plastic is inefficient.

A remarkable student from the TU Delft has come up with a different approach, which looks like a very clever idea: rather than chasing the plastic, why not use the currents to bring the plastic to you? The idea is to install floating barriers (arrays) with plastic collecting and processing units every so many meters. The collected plastic is dumped in storage spaces and picked up regularly to be brought to shore for recycling.

In essence a brilliant idea, I think, but there are some major challenges to be conquered. And this is where the connection with offshore (oil/gas/renewables) comes into place. We are talking about floating structures in the middle of the oceans, with significant water depth, large waves, strong winds and a rather hostile environment. This raises questions the offshore industry is very familiar with: how to moor the system, what kind of anchorage to use, how to mark them properly, how to keep the system in one piece and afloat under all imaginable weather conditions? And what about maintenance? How to design the booms to withstand the impact of waves, while at the same time remain stiff enough? When these – and other – challenges are conquered, this project will be at the forefront of offshore technology. And I can’t wait to see it develop.

For more info:

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