 what will we discuss in this course well first of all you can see some nice pictures and the course is part of the program offshore and dredging engineering here you can see that and what exactly is offshore and dredging engineering because many people yeah they think only of oil and gas or well it's easier to tell what it's not and what it's not is transporting people or goods from A to B because that's what we call marine technology yeah so if you build ships with the purpose to transport things that's marine technology also fishery is not part of offshore engineering but almost everything else so whether it's in oil and gas or it's dredging or it's recovering a sunken submarine it's all offshore engineering some of the latest developments you will see in in other courses is what we call renewables for example we just have a student who started his master thesis for tidal current energy there is an area north of Scotland where between the islands you have very strong tidal currents 2 meter 3 meter per second and they want to put huge turbines in that area and try to get energy from that the biggest problem is the installation of the whole system because you constantly have those huge currents yeah in one direction or in the other direction but if you have 2 3 meter per second current it's very difficult to install something on the seafloor but anyway that's the master thesis to find out how to deal with that yeah what will we do in the course I made a overview of the course first that's today we do an introduction tomorrow morning 10 30 we will do soil mechanics and that's also something I already did briefly in the introduction course but I will rehearse then we will go on with sand cutting in different ways specific energy which is a topic that is important for all types of soil but I will show you that during those lectures then clay cutting and rock cutting December 12th production estimation so with all the theories you get how can you estimate the production of a dredge or a drilling device whatever then case my rate will take over three lectures talking about sedimentation in hopper dredges so the load whole loading process of trailing suction hopper dredges and in January on January 9th he will talk about breaching most people don't know exactly what breaching is but if you dig a hole underwater the walls will start collapsing and they actually use that to get production so you you you have some sort of suction mouth at the bottom it's constantly sucking up the soil and then because you get steep slopes the sand starts moving down and that way you can create production an example of where they use that maybe some of you may know if you go close to here to force gotten you have a lake which is now a tourist lake but when I was a student that lake didn't exist it was farmland and what did they do they started making that lake to get sand for the Prince Claus plane so there was a pipeline all the way from force gotten to the Prince Claus plane to get sent over there and they just put a pipe into the ground start sucking up the sand and then the lake automatically becomes bigger so that's what the case will do and then the last lecture on January 10th I planned some some examples of the examinations and you can ask questions yes so if there's still something you don't understand you can ask what are the fields of interest of our program and I will show you many pictures today and many equations in the other lectures well we have bottom founded structures so you have structures that stand on the seafloor it's one of our specializations it can also be in Arctic regions but in Arctic regions it's a problem because the ice in this picture it looks like the ice is not moving but in reality the ice is constantly moving one way of movement is because of the earth rotation the ice also has a rotation with respect to our planet so that's one reason why it's moving and the other reason is currents that are under the ice and want to take the ice with them and that also makes the ice moving so what happens here the ice is constantly moving against a platform and wants to to push the platform away so working in the Arctic could be very difficult by the way this both those bottom founded structures we use maximum 600 meters water depth usually the limit is at about 400 but we could go up to 600 a new development what you see here is off your wind farms and if you look at the policy of our new government they want to spend a lot of money on renewables and one of the renewables is wind energy so they want to put them in the sea because if you put all those windmills on land yeah it becomes too busy so they want to build huge wind farms up to a certain water depth you can use bottom founded wind farms now around yeah 2010 they decided we also want to go to deeper water in deeper water you cannot use bottom founded anymore so they are making floating wind mills at sea and that gives some new challenges well if you have those windmills each windmill needs an electricity cable yeah because you like to use the electricity but if you have 100 windmills in a short area in a small area you don't want 100 cables to go to shore so in the area of that wind farm you have to dig trenches and that's part of this course how to dig trenches you have to dig trenches connect all those cables somewhere in the wind farm we call that a manifold where all those cables come together and then you make one huge cable like this on shore yes so that's the way to do it but you need a lot of trenching because you cannot leave those cables on the seafloor if you do that and a fishery ship throws out the nets and and all those things and it will drag against the cable the cable will break and that's it and by the way the same may happen if you have pipelines then floating yeah since most of the easy oil has already been found so easy oil is oil that we find on shore on the land and it's oil that we find in in the shallow water most of it has already been found oil and gas by the way we have to go to deeper waters and currently we go up to 3,000 meters of water depth and that means all your constructions have to be floating so this is a so-called TLP TLP stands for tension leg platforms and those it looks like they are cables but in fact they are tubes they are under huge tension so first what they do is they pump this platform full of water so it's very low then they mount all those small tubes or pipes whatever you want to call them and then they pump the water out so the platform wants to go up and then you put all those pipes under a huge tension here you need very strong anchors in the ground to hold those forces so that's how this is anchored and that's why you call it a tension leg platform this is a an FPSO which is a floating production and storage facility the oil either comes from here to this FPSO or from the seafloor with the riser it's stored temporary in the FPSO in the FPSO on deck you can see complete chemical factories so they do already do a lot of preprocessing on top of the FPSO store the oil and then once a week a shuttle tanker like this will drop by they pump all the oil in the shuttle tanker and the shuttle tanker will bring the oil away the nice thing about an FPSO but you cannot see it on this picture it has a so-called turret and the turret is a vertical bearing because what happens if you have a storm from a certain direction the ship wants to move in that direction so the turret is a vertical bearing and that's connected with anchors to the seafloor and the ship can rotate around that bearing all the oil will come in into that bearing so you don't have a problem with the risers and the oil connections in the course on floating you will get more details on such kind of ships and then we have dredging dredging is a typical Dutch Belgium profession in Holland we have two big companies and in Belgium also there used to be many more but they merged and merged until there are just two left in Holland and two in Belgium they call them the big four because and they all speak Dutch by the way so no French companies everybody speaks Dutch the big four dominate the free world market and the free world market is the market where you can try to get a job there's also the not free world market because in some countries they use protectionism and you can never get a job there those four companies they have 60 to 70 percent of the free world market worldwide so they are quite big a country that is not free is the United States and it sounds strange because they always like to have a free market economy but in the US they have a law and also marine technology engineers should know about that that law is called the Jones Act and the Jones Act tells you that ships where the keel and the keel is the bottom of the ship where the keel has not been laid in the US are not allowed to work in the US so they have a problem now themselves because of this protectionism it's much more expensive to build ships in the US if you want to build a dredge in the US probably the price is about 50 percent higher than in the free market if a Dutch company builds a dredge you can go to Korea to Dubai and look for the cheapest places to build the hull and then the complicated machinery you order from Holland from IHC or and that way you can combine all the benefits of the free market but in the US that's not really possible so they have to build in the US and yeah that means American dredging companies are not competitive on the world market because their ships are already 50 percent more expensive so you cannot really compete the only place where they work international is in the Middle East and I'm not sure whether that's by free market or by compensation orders from the Gulf War you never know they will not tell you well what do we have here a hopper dredge and in this case I will tell more about that later you see the hopper dredge rainbowing I will tell later what that's about deep sea mining I also have some extra slides about deep sea mining this is one of the biggest cutter dredges with here at the front a cutter head and this is a device for trenching cables in the North Sea but we have many more devices on the field of trenching subsea and in fact deep sea mining is part of subsea since we go to deeper and deeper waters what you have is that everything at the surface is subject to storms and hurricanes and so it's very vulnerable if you put something at the surface well they already know that for a long time so everything they can put on the seafloor they will put on the seafloor many people think oh if I have an oil field that means the oil company drills one hole and that's where the oil comes out but in fact they drill many holes maybe in one field they have 20 or 30 holes wells as we call them and all those wells just like with with the offshore wind farm with the electricity cables every well has a pipeline with oil or gas but you don't want 20 or 30 pipelines going to the surface that makes the system too vulnerable so what do they do they connect all those pipelines at the seafloor with control units to control the flow and everything and then they connect at one point which they call a manifold and from that manifold everything will go with a riser to the FPSO or whatever by the way right now there is also the course on subsea engineering from Mr. Preedy he started yesterday as far as I know and there you can learn much more on everything that happens at the seafloor yeah well what is driving the market and I'm talking about the whole market for offshore and dredging engineering well to start with a picture some some graphs of the world trade this is container throughput and I thought this was bulk throughput and you can see it's constantly increasing so every year we need more containers we want bigger ships and sometimes people say hey Rotterdam used to be the biggest port in the world and now it's one of the Chinese ports isn't that a pity well it's not because Chinese ports are not competitive with Rotterdam in fact they supply Rotterdam with more containers and more goods if Antwerpen would be one of the biggest ports that would really be a competitor or Hamburg for example but if you have a lot of container activity in China in Singapore and Malaysia then that's only good for Rotterdam it means we get more ships etc well why is that important for us first of all if the the total throughput of containers is increasing it means you need bigger ports and as you may know in Holland we just we are finishing this trade a mass factor which is an extension of Rotterdam port into the sea to make it a bigger port but to make the port bigger first of all you need a lot of sand to create that extra port the sand comes somewhere from the North Sea and it's the dredging companies that supply the sand so the dredging companies usually make the land and then other contractors finish it they make it a real port with the infrastructure in the ground and all the electricity and sewer systems and whatever but another thing is that because we have more containers they like to build bigger ships bigger ships that can contain many more containers at once if you do that the draft of those ships will increase and that means you need to deepen the entrance channels to your port so you also need deeper entrance channels channels that's also good for us because that's dredging yeah you need hopper dredges to deepen those channels if you look at the list and i'm still surprised about that if you look at the list of biggest ports in the world and biggest container ports you will not find any us port on that list and one of the reasons is they have so many ports and we always think the US is one country with one government well basically it's not every state is still quite independent with their own regulations and within a state every city or county is quite independent that means that in America in the US all those local ports are competing with each other but there is no federal policy to build one huge container port so in fact in America those the biggest container ships cannot go there because they don't have any port that's deep enough but in Europe Hamburg Antwerp Rotterdam they can handle those ships and yeah this is an example of Singapore Singapore is one of the biggest container terminals you can see how big it is and what you can also notice if you look here you'll hardly see any people there are still people but you hardly see them why is that well if a container comes from a ship it goes on an AGV an automatic guided vehicle and those vehicles sort of a truck those trucks do not have a driver they are completely controlled by computer from some central place so they make container terminals without people they found that there is only one thing the machines cannot do and that one thing is that containers are connected and and you just have a steel pin through the containers to connect them to get those pins out you cannot do by machine you need a big hammer to to get those pins out especially if you have ships coming from the Arctic very often those pins are frozen there's a lot of ice and there's no machine that can do that automatically so there's still people to to disconnect the containers from each other but for the rest everything is fully automatic oh then energy um this is not the latest picture but this this picture is made before the economic crisis and there are some some small differences because of the crisis but not too much one of the interesting thing is well first of all if you look at the red line that's oil well everybody knows most of the energy comes from oil but then this purple line is coal and many people especially in the west they feel oh we don't use coal anymore and when i was young we used the coal for the heating system and then we get later we got the central heating system but uh coal is still used a lot and you can see it's increasing for for the big power plants so in many countries they still use the coal for the big power plants and they can do it very efficient and very clean so it's not the dirty way of getting energy like it used to be so you don't get that uh acid rain like we had 20 years ago and after that nobody ever talked about it anymore but uh so coal can be used rather clean uh and it's still one of the biggest sources of energy but what you can see with the blue line is natural gas it's upcoming and more and more we will use natural gas and by the way 30 40 years ago natural gas was a by-product and all the companies just felt yeah it's it's it's uh difficult so we just burn it and you saw on all the platforms a huge flame we call it flaring and they just burned all the natural gas and they didn't use it until they discovered later that you can also sell it and make money from natural gas and now LNG is one of the biggest uh uh providers of energy here you see the the nuclear hydro and and other renewables uh in fact whether it's it's it's stable or it's increasing depends hugely on policy of governments if a government stimulates uh using renewables it will increase uh one of the problems of course is that uh if you do something new you cannot do it perfect in the beginning yeah it's like if you want to use a different type of engine in a car like the vankel motor or whatever in the beginning it's never competitive with the existing combustion engines because the the the standard engines are already perfect yeah you cannot really improve them much more but if you start a new development yeah you still have to go through that phase of making it more perfect and that's what you have with renewables like solar cells wind energy fuel cells probably uh 10 or 20 years from now it can be competitive right now it's not yet so governments have to subsidize the development and then we will hope that one day it will be competitive with oil and gas and we can use more clean sources of energy uh then if you see where where do they actually use the energy but this picture is not true anymore because uh uh i yeah i just saw a new picture and what you can see here is the enormous increase of energy in the usa over the last 30 years well in 2007 this stopped so the peak that you see here is uh already too high in 2007 in the us the increase stopped and now it's rather stable but and you can see uh western europe was already quite stable because we are busy with uh saving energy for a long time uh you can see india and china here increasing a lot and what i heard from somebody is that china the the highest peak in china is is already at the same level as the us well that's logic in china you have 1.5 billion people uh something like that in america 300 million so china has five times as much and that means if everybody would use the same amount of energy as in the us then the highest bar would be five times as high as in the us and let's hope they will take care of the energy a little bit better otherwise we uh are in trouble but what you can see of in in those developments is that the uh demand of energy so the demand of oil gas coal is still increasing and that's one of the reasons that the uh oil and gas industry in holland the offshore industry is still booming business we had a conference in november the the offshore energy 2012 uh i was at the opening and in fact the offshore companies and also the dredging companies they asked for more skilled staff and i told them yeah we already have 100 master students in our program uh is that enough or do you need more and then one of the ceo said well we could use two maybe three times as much engineers in uh our business what's good for you is that until now from what i know we don't have any students who didn't have a job at graduation date everybody has a job usually in the company where you do your master thesis but uh it can also be another company so the the there is plenty of work there um well if you look at uh where does the oil come from where is it going to you can see that there are huge uh transports of oil sometimes by pipeline but also very often by ship those ships need ports again and if you have more oil to be transported you need more ships you need bigger ports so it's good for the marine technology industry it's good for the dredging industry to make more ports yeah it's good for the whole industry and that's also increasing um in the energy like i already showed you one of the things is uh Arctic engineering and it has just been in the news from shell oil at a day uh greenpeace protested that they started drilling in the Arctic one of the things the public doesn't know but you should know shell will not start such an activity without research without investing they already invested maybe three billion euros in investigating how to deal with the Arctic environment so it's not a matter that today they phone somebody or can you start drilling for me in the Arctic they really prepared it and companies like shell exxon BP uh they cannot have a situation where there's a environmental disaster in the Arctic because that's the end of getting oil from the Arctic and then the whole public opinion will be against it so those companies will prepare well but still right now they postponed drilling in the Arctic uh and one what is one of the problems well what you can see here if you have icebergs and those are just small icebergs 90 percent of the iceberg is underwater that means you have those peaks underwater and those peaks can be 50 60 meters yeah it's not just five meters it could be 60 meters that means if you have a water depth of 50 meters and and you have an iceberg of 60 meters and the iceberg is floating yeah at a certain moment it will hit the seafloor and make a trench in the seafloor if at that point there is a pipeline like you can see here and and this iceberg would hit the pipeline it will just cut through the pipeline and you get a huge oil spill on the seafloor nobody wants that so what do we have to do we have to dig trenches yes so we have to make a trench in the seafloor and bury the pipeline so deep that we are sure the iceberg will never hit it well if we do that in normal regions we have to protect from anchors and from fishery gear and so on we have to go maybe up to five meters of water depth to bury pipelines and to to make it safe we this friday we have a graduate who is his graduation is on arctic trenching and the first thing he did in his for his thesis was to investigate how deep are those trenches that you get from those peaks we call it ice scour by the way how deep are those trenches he found out from research they did in the past that it can be up to six seven meters deep well that means the pipeline has to be below but you cannot say okay the iceberg is seven meter i put the pipe the top of the pipeline at seven meter then it's safe because if this iceberg is moving through the soil it will also deform the soil and that means you have to be maybe one or two meters below that level not to have the deformations that you get from the soil that's moving with the ice so in in our opinion if you do arctic trenching you have to make trenches up to 10 meters deep now the problem of course is if normally they will make a fee shaped trench but yeah the deeper it is the bigger the cross section of the fee shape and you need to remove more soil so now because in in that arctic region they have hard clay we are thinking of a box cut and then the amount of material you remove is proportional to the depth of the cut what he is actually graduating on is if you have a such such a box box cut let's say two meters wide and 10 meters deep and the pipe laying vessel of all seas is coming or of here and that pipe is maybe 80 centimeters in diameter yeah the ship at the surface is moving so the whole pipe is moving a little bit that means if the pipe is partly in the trench and then moving up to the ship it will constantly hit the sides of the trench and then the trench may collapse and you have a problem because yeah if it once it collapses you can start all over again so he developed a device to put in the trench that can move with the ship to protect the sides of the trench and to put the pipeline in the trench in a safe way so if you are interested his name is Jules Peinenborg and he I think he has his presentation two o'clock Friday from what I remember by the way they can use hopper dredges this is a hopper dredge for making trenches like that and hopper dredges with one drag arm can go up to 120 130 meters of water depth and then population if we look at the world population in many regions not in in europe maybe but like here in china most people live near the sea most of the activity the industrial activity is near the sea if you look at japan which is completely red java you cannot even see here it's so red but in japan japan is a country with a lot of mountains and near the sea you have some flat areas that's where the people live that's where you have all the activity but it means if you want to increase your port or make a new airport or whatever there is no space anymore if you go to singapore singapore is an island the island is full no more space and singapore has some some tension with malaysia so they cannot extend in the direction of malaysia so what can they do well the only thing you can do is reclaim land from the sea and go into the sea what case always tells case van re is the price you pay for land that you reclaim from the sea if the water is not too deep is about 200 euros per square meter if you know that ground that you can use for building buildings and so on like in delft you pay up to 2000 euros per square meter let's say in holland between 1000 and 2000 so if i can reclaim land from the sea it's much cheaper than buying land somewhere in the country so if i extend the country into the sea it's cheaper and that's one of the reasons why dredging companies do huge land reclamation projects and in fact extend countries into the sea this is a picture of hong kong airport this here is the airport and it used to be an island with a mountain well then you use some dynamite first to blow away the mountain the the the surroundings of the island are not nice smoothly but you have some bays and so you fill it up with the rock you get from the mountain and then with hopper dredges you get a lot of sand to make the whole area flat the policy of this was two things first of all the old airport in hong kong was a little bit dangerous and if you want to see why you had a mountain ridge here you had the city of hong kong and here water and the airport was like this so in the middle of the city here you have mountains so if if an airplane would arrive it would always arrive like this and i i have actually been there at that time so the plane is arriving has to make a 90 degree turn then fly to the landing strip but when you fly to the landing strip on both sides if you look out the window you feel you can shake hands with some chinese standing in the high living in those high buildings when they stand on their verandas it's so close you can see what they eat and that was very dangerous because if if you have a storm and and wind and so on if the airplane is just separating a little bit from the direction you could get a crash for for departure they always went in this direction which is also not good because the best way to to make a plane depart is against the wind and in this case you cannot choose it depends on where does the wind come from but so they decided to make a new airport 50 miles outside of hong kong on an island so the whole airport is so far away of the urban areas that people have no problem with airplanes anymore but that also means you need to build a highway that's this highway and there's also a subway going to hong kong and in fact if you travel to hong kong you will see that your suitcases so your luggage can be transported all the way to a subway station in the center of hong kong automatically you don't have to tell anything and just pick up and if you have to check in you just check in at the subway station there you deliver all your luggage and in Amsterdam you pick it up again and you don't have to carry everything to the airport and and have a lot of trouble so they really organized everything well but you can imagine this is a lot of dredging work a lot of land reclamation also building those roads and it's it's a huge infrastructural project so that's one of the things they do another picture here is Singapore I already told you Singapore is full and in fact in Singapore you would like to separate urban areas with heavy industry especially the chemical industry well now it's mixed or it was mixed Singapore didn't have any land anymore so what can they do well in the front of Singapore in those areas there were a lot of small islands if you connect those islands and that's what you can see here they connect all those islands reclaim land and put all the oil and gas industry and chemical industry on those on that new land that way you take it out of the city so the city has a more clean environment it's also much safer the only problem here was that in the whole surrounding of Singapore there was no sand on the seafloor anymore they already use everything well then you can go to the north to Malaysia but they didn't give permission so they went to the south to Indonesia to get the sand and that had some complications because yeah in Indonesia if you don't have the right permissions and if you don't know the right people you are in trouble so in fact they started the project that was in 2000 2001 then apparently they forget to bribe somebody and every time when the ships came back to get sand they crossed the 200 mile zone so they crossed the border so at a certain point the Indonesian government said hey you didn't went to customs with the ship so now the ship is ours and well the ship was not theirs but they put it on the anchor and the ship was there for a couple of years and it caused a lot of trouble so if if you are in this international business whether it's oil or gas or dredging you have to learn something about the habits in other countries the culture in other countries because we are if you compare it with the rest of the world Holland is still a little bit heaven we don't think so if we look at the current government but anyway in general it is and in many countries they have different habits and you shouldn't say it's better or it's worse it's different and you should be aware of those differences in in cultures in habits in order to do international business okay we have a break of 15 minutes um another topic in the world is tourism here you can see how the tourism is increasing over the years and for example in a country like China many people have money now and in fact we know from China 10 percent is relatively rich 10 percent is medium and 80 percent is poor but if in a country like China 10 percent is relatively rich you talk about 150 million people so they like to see their own country they start tourism and one of the things they did in the past 10 years is build a disney land in Hong Kong but where they built the disney land there was no land it was a bay so it was water and the Dutch dredging companies had to reclaim the land and after that they built disney land there another big thing is the Middle East Dubai Abu Dhabi 12 years ago they wanted to extend the coastline because the total beach length is not too much and they said how can we do that well if you build such kind of structures this one they call palm island because they make it in the shape of a palm tree this is also a palm but they wanted to extend it like this and then here you can see some dark spot that's supposed to be an artificial river inland water with a lot of trees around it and it should be a tourist area this is the world and the world is built by fenord i think one of the palm islands also and the whole idea was every country is an island you can buy the island of your country and build a villa on that and then the whole country is yours but unfortunately in 2008 we had the financial crisis the whole market went down many investors walked away and they didn't actually finish this i think one of the palm trees is finished with a lot of buildings and roads on it but the world is not finished and now the problem is if you don't do anything if you don't take care of shore protection then by erosion in 10 years most of the islands will be under water and if later you want to finish the project well you don't have to start all over again but it will be a lot of extra work moorings in the offshore and dredging moorings is a special topic because all the floating structures need a mooring system and a mooring system means very long cables but also something on the seafloor that has enough holding capacity for all the huge forces so you can see anchors like this we call drag embedded so it's an anchor you pull into the soil and then it has a certain holding capacity but you also have anchors like this which we call suction anchors which are huge cylinders with a pump on top you put the cylinder on the soil it should be soft soil then with the pump you pump the water out creating a huge under pressure and then because of that under pressure it moves into the ground and has a certain holding capacity so that's also a way to anchor you also have gravity based anchors which is just a huge dead weight yeah some something very heavy you can put on the seafloor so there are many ways in in one project we are busy with now and that's the renewable project north of england north of scotland the problem is the seafloor is rock and how to anchor those tidal energy constructions in rock so that's in fact what the student has to find out how to anchor something if the seafloor is rock because normal anchors won't work maybe you have to dig a trench with some special trenching machine pull it full full of concrete and anchor in the concrete or something but we don't know yet subsea i already showed you a picture but subsea is also deep-sea dredging of which i will tell more and in fact this is a clamshell to dig material but the clamshell is hydraulic and it has propellers here for dynamic positioning because if you have to use such a clamshell at 1000 to 3000 meters water depth you cannot control where the clamshell is that's a problem in general so we have dynamic positioning video cameras and then actually the operator can see on the mothership where the clamshell is and control with joysticks by means of the dynamic positioning then i want to show something about the peter schelter for those who don't know we have a company in delft named all seas and all seas is famous for in general pipe laying vessels but all seas the director edward herma he is the ceo of that company in fact he's the owner of that company he said well in the north sea we have a problem there are many bottom founded platforms in the north sea not only in the north sea but worldwide when they were built nobody taught about it that one day they have to be removed because 40 years ago when they built those platforms people were not in general were not so busy with the environment now everybody is busy with the environment and according to the current standards yeah if if a platform is finished if there's no more oil in the field you cannot just leave the platform there you have to remove it but the platforms are not built for removal they are built to stay there forever so he had an idea he said if i can build a ship and on one side which is this side i can put the whole top side of a platform and this is the top side by the way so everything above water we call the top side if we can put the top side on one side of the vessel and we make construction with those bars that we can lift the whole feet on the other side then we have a ship that can remove those platforms well what i really like is that this ship it's 340 meters long and 120 meters wide and for the water displacement it's the biggest ship in the world so a company in this city has the biggest ship in the world the price of this ship is about 1.5 billion euros and from what i know well probably they financed some but knowing at what here but he paid a lot just cash and that's the policy of those kind of companies so how does it work well here you can see the the the foot and this is the top side so they have a mechanism to cut those steel bars they just cut it then with those devices they can lift the whole top side well in fact what they do it's not a lift what they do is pump water out of the ship so the whole ship will go up and that's the way they lift the top side and the maximum weight of the top side is 25 000 ton and to give you some impression a normal modal car we use the word modal in in holland a medium car would be about one ton 1000 kilos so 25 000 ton you talk about 25 000 cars at once that's the lifting capacity on this side of the ship once the platform as you can see here is on that side of the ship the ship will move back turn and then on the other side you see those steel bars they connect the steel bars with the foot like here and then here you have huge cylinders that can pull those bars so they just tilt the whole foot on deck and then they will sail to some port and that's where everything will be disassembled yeah they just cut everything into pieces and probably at Tata steel they will use the steel again so that's the way it works but you can understand if if this foot well this is not really a big one but it could be hundreds of meters high so it's really a huge construction they are building it now in Korea and one of the problems of course is you can not just lift that foot because the at the bottom of the foot you have concrete piles through the foot of to connect it to the seafloor so this is a sort of device that you could use to cut the steel bars and the concrete at the seafloor so that's also a new type of business equipment I will show you briefly a lot of equipment that has to do with cutting processes because this is a course where we mainly focus on cutting processes this is a picture of how we did it years ago 200 years or maybe 300 years ago five people on a treadmill uh making something rotate that's why the bucket chain is rotating cutting a little bit soil at the bottom and five people is well one person could could deliver about 150 watts for a whole day five people is 750 watts which is one horsepower so the power here is one horsepower and that's 0.75 kilowatts maybe they produce one to cubic meter per hour and if you compare that with the current machines with which I will also show you now we are talking about 25 to 30 megawatts installed power just 15 people on one ship and you talk about productions that can go up to maybe five six cubic meter per second yeah so the dimensions completely changed but first when they started automating it they they made machines like this so this is a bucket wheel in Holland we used to have a lot of well we call it bucket ladder dredges so with with the bucket chain uh and in fact it's rotating from the top and then dumping the material in in such a car on railroad uh but you can imagine that such a machine has a lot of friction it's not very energy efficient uh but yeah in those days that was all they had um in the fifties most of those machines were still operated on steam engines and because of the developments in the second world war with diesel engines in the fifties and sixties they replaced the steam engines with diesel engines but this is uh yeah a machine the way when I was young they still use those kind of machines this is a modern dredge a cutter dredge um well you like to see some pickpoints later so you will see them this is a cutter dredge the way it operates is you have a spud pole which is a huge steel cylinder maybe two meters in diameter with quite some weight they will drop it in the soil and because of gravity it will penetrate a couple of meters in the soil if the soil is not too hard and then the ship can rotate around that spud pole at the front you have the ladder this is the ladder this one is 50 meters long and weighs about 1000 tons and at the top of the ladder you have a cutter head and I have some nice pictures of that later the cutter head is cutting the soil so it makes circular movements cutting uh the soil once it's finished with one circle the ladder will go down next circle until you cover the height of the bank we call this is what we call the bank inside the cutter the sand or rock or whatever is mixed with water transported through a pipeline and here you see the pipeline leaving the ship going to wherever you need the sand and that could be a beach it could be you are making a port sometimes you need the sand so you are dredging to get sand but sometimes you just want to remove it if you build a port in an area what which was land it means you have to remove the soil and dump it someplace else here you see the axis and at the top you have a huge electric motor driving the cutter head usually on such a big ship the cutter head would have five megawatts of power on the axis what's the advantage of that well if you cut rock uh yeah the problem is rock is very hard so if you cut rock then the cutter head at a certain point will will will get stuck in the rock but because an electric motor has a huge mass moment of inertia the electric motor will just continue turning the electric motor will not notice that the cutter head is blocked you have an axis like this 20 30 centimeter in diameter the whole axis will wind up yeah even though it's it's this big so that means the torque on the cutter head is increasing increasing until it's big enough to to to make the rock collapse then suddenly the rock will collapse the uh speed of the cutter head which is normally something like five six meters per second could be double so so a lot of rock breaks out and then after that the same thing happens again he gets stuck again you get so it's what we call a torsion spring system and you can compare it with the the drilling the the vibrating drilling machine that you use to drill in in your house and if you use a hammer drill yeah if you have a new house made of concrete you you need a hammer drill otherwise you can't get into the wall well it's that vibration and and the shocks that take care you get into the wall and in this case it's a torsion spring system that makes it possible to to uh cut rock uh this is an example uh the other one was a picture of course this is one of the belgium biggest uh cutter dredges and this is a special one because this is a self propelled cutter dredge most of the cutter dredges are not self propelled they are just a rectangular barge with a huge uh ladder and a cutter head and if you want to bring them to australia you have have to put them on a heavy load ship heavy loading ship uh and bring them to the other side of the world this one can sail by itself so that's on one side an advantage but it's also a disadvantage because you create extra functionality on board of the ship which makes it more expensive but it's a nice ship and this one also has so-called swell compensation well here you have a cutter head and you can see the size because here you see a person and this is a typical rock cutter head with pickpoints so all those teeth that you see here we call pickpoints and maybe you can see there's a steel bar at the end of the pick point which is through the pick point connecting the pick point with the rest of the cutter head and once the pick point has too much wear or maybe it's broken you with a big hammer you can hit that steel bar remove the pick point and put a new pick point on and there are cases where the wear is so huge because the rock is so hard that all the teeth are worn out in one hour and i know from that specific project they spend half a million euros a week on new pick points just on new pick points and then you can imagine if you can reduce the wear and maybe by changing the working method or by improving the teeth yeah you can save a lot of money and so those companies are interested in doing research to improve this maybe for for those who don't know having a phd on such a topic in total would cost about 500 000 euros well that's what they spent in a week so if you can improve that by 10 percent you need 10 weeks to get the money back from the phd so yeah it's it's worthwhile doing research and that's what the dredging companies do this is another picture an artist impression of ihc of such a cutter head you see all the teeth mounted here and in fact this is the start of the suction line one of the problems and that's i think that's your phd is that if you cut the rock the pieces of rock are so big and when when they are actually cut they just don't don't fall down they have a high kinetic energy because from from the breaking they shoot away so you get particles that can be quite big that go in any direction so that's one problem they do not follow the flow still you like all those pieces of rock to go into the pipeline and yeah be part of the production if they fall on the sea floor we call it spill you have to remove them again and that's extra money so his phd is on improving this process we call it mixture forming improving the mixture forming so you get a higher efficiency of all those pieces of rock going into the system uh but one of the problems you you will notice is this thing is rotating and if you have something that is rotating you have centrifugal force and centrifugal force is always outwards so the fact that it's rotating and that it wants to take the particles in this rotating motion already creates a centrifugal force which wants to push all the particles out so how to deal with that well with small particles you also have this centrifugal force but the particles are so small that the forces of the fluid on the particles are much higher so the fluid will take them into the system and the spillage with very fine particles is much less yeah uh so we like to understand all the physics involved in such a process and that's why we have phd's on such a topic and this one i will skip but it's uh i put this already on blackboard the whole slideshow so you can look at all the pictures again this is a hopper dredge basically a hopper dredge is a ship a sailing ship self propelled with a huge hopper in the middle the hopper is to be filled with sand or clay but usually we use it for sand you have two drag arms and the drag arms are like a vacuum cleaner so you are moving something over the ground there's water flowing through the pipe and the water should take as many particles with it uh so you have two drag arms and to improve production uh we know that the pump on the entrance of the pump the pressure is limited you can never have more under pressure at the entrance of the pump than the let's say the atmospheric pressure because once you are at zero pressure you can't get lower so the suction pressure which is always under pressure is limited well if i increase the density of my mixture at a certain point the pump is not strong enough this under pressure is not strong enough to pull all the mixture inside so what you do over here you place the pump as low as possible in the suction pipe then you can have a higher density and thus a higher production i think case maré will tell you more about that in detail this is the same dredge with one suction pipe but as you can see they extended the suction pipe and in this case you can use this ship for making trenches for burying pipelines or cables or whatever and in in this way the ship could go up to at least 120 meters this is an example of the biggest uh hopper dredge 46 000 cubic meters but that number is the size of the hopper not the size of the whole ship it's the size of the hopper so this ship can carry theoretically 46 000 cubic meters of sand and uh i would say you can fill the ship with sand in about two hours so that's roughly what you talk about um but yeah it's nice that you can fill the ship you also have to empty it and to empty it there are three ways this is one way we call rainbowing so at the bottom of the hopper you have a lot of water jets those water jets can make the sand fluid then it can flow in a pipeline that's at the bottom of the hopper it goes through the pump and the pumps will pump it through this nozzle this yet and it could go up to like uh 100 150 meters you should realize that in the pipeline suppose the pipeline has a diameter of about one meter and the velocity inside the pipe is let's say five six meters per second that's normal in dredging so if i make a jet with let's say 20 centimeter opening that's one fifth of the diameter so that's one 25th of the cross section that means the velocity is 25 times as high uh so the velocity of the water coming out of the jet would be like 125 meters per second something like that don't put your hand there because it will not last for one second and your hand is gone yeah the the because this is water with sand it will erode everything that's also a reason that inside the pipeline when we calculate pipeline resistance because we have to calculate powers we always count that the pipeline is smooth inside even if you start with a rusty pipeline completely rusty after the sand with water has flown through the pipeline for one minute it's blinking on the inside yeah the sand will take away all obstacles don't put any valves or whatever in such a pipeline it will not last for very long the sand will remove everything yeah so you just want to have a straight pipeline that's it the second way of emptying the ship is bottom doors uh so they have valves or doors in the bottom of the ship you can open them and let's say in in five minutes because of gravity all the sand is out and you dump it so that's in fact that's the most traditional way second way was this uh rainbowing and the third way is that with the same pipeline here you can connect a floating pipeline that's floating on the sea you can connect in this coupling and then you can pump the sand wherever you want so if you have to pump sand on a beach usually that's what they use and they they use a floating pipeline pump it to the beach but if the water is deep enough and the ship can use rainbowing so yeah but that's only if the water is deep enough so the ship can get close to the shore you can use rainbowing to dump it uh pumping by floating pipeline or by rainbowing takes about the same time as filling the ship uh while bottom doors are very fast there is a ford system used in the usa but that's for ships that are not too big about four or five thousand cubic meters i would say we call it a split hull uh barge so you have a ship in the length direction it's completely split so you have two half ships at the top of the ship so at the deck you have huge bearings in the front and in the back and in the bottom you have used huge cylinders and the ship is constructed in such a way that if the ship is full and you release the pressure the ship will open and all the material will just drop down in less than one minute i have been on such a ship and in the beginning it's scary because yeah you stand on a ship but it's two half ships just connected by a cylinder and when they empty the ship you actually feel that you move up yeah it goes so fast you can feel it and yeah the first time you think will the ship not sink but yeah they already used those ships for 30 years so it will not sink the reason they are not using that in europe is that uh those bearings and cylinders uh for the if you consider the forces they are limited to a certain size with those huge ships like 46 000 cubic meter if you would use the bearings on the deck and then cylinders in the bottom they would become too big and it would become too expensive yeah it's not competitive anymore probably technically they could make it but if the ship has the double price yeah it's not competitive uh this is an example of some drag heads they used to start with drag heads yeah so this is at the end of the suction pipe was over going over the sand in the beginning you just have a drag head and the whole idea is if i pump enough water the water will flow under the drag head you get erosion of the sand and the sand particles will flow with the water into the system but you can imagine if you do that that the amount of sand you get is uncontrollable it depends on the erosion speed but it also depends on the particles and if if there would be some silt in between the particles and the part the material is a little bit cohesive yeah you have much less erosion you have very low production it won't work so at a certain point they said if we put teat or blades in the drag head and we drag it over the ground well you can control how much are the teat below the drag head let's say 10 centimeters or 20 centimeters and that way you can control your production because you know the width of the drag head you know the the thickness of the layer you are cutting you know the trailing speed of the ship so you know your production and you can calculate the density and so on and so on so that's those teat now the problem is that if if you cut sand or clay or they even cut rock with those machines so they also put pickpoints in and cut rock the problem is that the the force to pull it through the material has to come from the propulsion of the ship you know because the ship screws or whatever you use for that they have to push the ship and that way pull the drag heads through the soil now what is the efficiency of a ship propulsion who is marine technology nobody well if you if you look at the efficiency of a ship propulsion maybe it's 30 percent maybe yeah but not much more that means my diesel engine has to deliver at least three times the power that I need for this cutting process with 30 efficiency to get the right power at the drag head yeah so if I need one megawatt cutting power then I need at least three megawatt for my diesel yeah to to for the propulsion of the ship so I lose a lot of energy so it's not very energy efficient one of the problems of the cutting is that what we will see later that you get under pressures in the sand you get cavitation in the sand and that results in very high cutting forces so if I could prevent those things to occur yeah the under pressure in the sand so what did they do here this is the heel they put water jets in they said if we can fluidize the sand before those under pressures occur yeah we just make it quick send then we don't have those huge cutting forces anymore and in fact we still use the teeth because that fluidized sand should be guided into the drag head it has to make a 90 degree turn almost or almost 180 degree depending on on the angles so we use those teeth to guide the material into the system but we don't use them anymore for the real cutting process so we use water jets to fluidize the sand make it completely fluid and then if you look at energy you can say okay so somewhere on the deck I have what we call jet pumps centrifugal pumps that feed the jets with water and then from that jet pump you get a pipeline over your drag arm all the way to the drag head so how much energy do I lose in such a pipe if I make the pipe a little bit bigger I lose less so I can optimize that okay maybe I still lose 10% of the energy something like that that means I still have 90% of the energy available for those water jets then you could have the question if I use water jets is the amount of energy in the sand the same for jets or for cutting yeah because if jets require 10 times as much energy as cutting then you still didn't solve the problem well from experiments we know that if the jets have the correct combination of pressure and flow because power is pressure times flow so you can use a higher pressure and a smaller flow or reversed but if you have the right settings then jets require about 70% of the energy of the cutting process so I can save some energy directly on the process because jets use less energy 30% less but my my gain is the most because I only from from the diesel engine I only lose about 10% in the process of getting the water there while with cutting to the propulsion system I lose like 70% yeah so jets are much more energy efficient and another advantage is that since I don't have the the pulling force anymore yeah because I'm not cutting anymore I can control the speed of the ship much better yeah the speed of the ship does not depend on the strength of the soil anymore because I already make it lose with water jets so that about then we have back hose I see we just have five minutes left so I will quickly go through it uh back hose used to be uh more on land but nowadays those are called back actors uh are very huge back hose I have a picture of a back hoe uh this one this is the back hoe called the New York and this is a picture taken in New York and in fact this is me 12 years ago I have another picture of 20 years ago but you know that's when I was still slim and and so on but anyway you can see this is already a big back hoe but the back actors that you saw in the previous picture they are unlike 10 times as big they are really huge one of the problems is they just scale up the design and when you just scale up the design you you neglect that certain forces are not proportional to the length but maybe to the volume or to the weight of a system and that's what happened with those huge back hose uh last year we had a student investigating that because they have a lot of fractures on those back hose you have a lot of shocks in in those things so you get fatigue and certain things constantly broke down failed and they wanted to know why and well the main reason is that if you just scale up everything linearly you forget that certain forces are not proportional but maybe squared or to the third power so those are the huge back hose uh clamshells well this is a clamshell also in the us used to be the biggest one this clamshell is 45 square meter and it has a total cycle time of 45 seconds that means from the bars where you this is the bars where you dump the material from the bars you go to the place where you want to dig drop dig go up go back dump in 45 seconds well with 45 cubic meters that means one cubic meter per second so such clamshell can have a production which is comparable to a medium-sized cutter dredge so it's quite a lot to give you a yeah this is a picture showing the whole setup and this is a picture showing this 45 cubic meter clamshell it weighs 36 tons if i'm right so it's it's big and it's heavy and they have different configurations you have the very heavy one with with smaller cubic meters for heavy soil and the biggest one is for relatively uh soft soil uh this again is that clamshell i showed you before it's a hydraulic one the previous one is controlled by a closing wire so they use wires to close the clamshell uh but if you are going to use it at hundreds of meters of water depth and you have a closing wire and a hoisting wire the whole thing will start spinning and those wires will twist it doesn't work anymore so if you go to very deep water what you do is you use a hydraulic system with hydraulic cylinders instead of wires to close the system and that's one of the things they are going to use in deep sea dredging this is the trench we also just had a student the he had to make a model of the forces of those trend this trench this is in fact just a plow you can see you pull in this direction and you just pull the plow through the soil the cables go in here through this system and so so they are guided to the bottom of the trench and this is for making for putting cables on the seafloor for offshore wind farms this ship is pulling the plow here they did tests on the beach and the pulling force in this case the maximum pulling force on the plow is 400 tons so that's also quite a lot so you can see in offshore and dredging you you always talk about large quantities large forces large powers everything is quite large and yeah this is the last one i will show you this is the digging donald from all seas and the digging donald is a trencher to put pipelines under the soil so in fact what do you have you have a pipeline that would fit in between here then here you have digging devices they make a v-shaped trench and the whole device is moving on tracks like a tank so the pipeline comes in the front goes under here you make the trench and behind the the vehicle it will drop by gravity into the trench and then in fact the material you remove you just put on the sides and you hope that by current and waves this material will flow back on top of the pipeline and cover the pipeline well after a while that will happen so you use the material that first you removed from the trench you use the same material to put back on top of the pipeline okay that's it for today tomorrow i think 10 30 again so see you tomorrow