Ship Construction

Construction of ship

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At this time islands spread over vast distances across the Pacific Ocean were being colonised by the Melenesians and Polynesians, who built giant canoes and progressed to great catamarans. With the development of the carrack , the west moved into a new era of ship construction by building the first regular oceangoing vessels. In a relatively short time, these ships grew to an unprecedented size, complexity and cost. Shipyards became large industrial complexes and the ships built were financed by consortia of investors.

These considerations led to the documentation of design and construction practices in what had previously been a secretive trade run by master shipwrights, and ultimately led to the field of naval architecture , where professional designers and draughtsmen played an increasingly important role. The ships of the Napoleonic Wars were still built more or less to the same basic plan as those of the Spanish Armada of two centuries earlier but there had been numerous subtle improvements in ship design and construction throughout this period.

For instance, the introduction of tumblehome ; adjustments to the shapes of sails and hulls; the introduction of the wheel; the introduction of hardened copper fastenings below the waterline; the introduction of copper sheathing as a deterrent to shipworm and fouling; etc. The industrial revolution made possible the use of new materials and designs that radically altered shipbuilding.

Iron was gradually adopted in ship construction, initially in discrete areas in a wooden hull needing greater strength, e. Then, in the form of plates riveted together and made watertight, it was used to form the hull itself. Initially copying wooden construction traditions with a frame over which the hull was fastened, Isambard Kingdom Brunel 's Great Britain of was the first radical new design, being built entirely of wrought iron. Despite her success, and the great savings in cost and space provided by the iron hull, compared to a copper sheathed counterpart, there remained problems with fouling due to the adherence of weeds and barnacles.

As a result, composite construction remained the dominant approach where fast ships were required, with wooden timbers laid over an iron frame Cutty Sark is a famous example. Later Great Britain ' s iron hull was sheathed in wood to enable it to carry a copper-based sheathing.

Shipbuilding

Brunel's Great Eastern represented the next great development in shipbuilding. Built in association with John Scott Russell , it used longitudinal stringers for strength, inner and outer hulls, and bulkheads to form multiple watertight compartments.

Steel also supplanted wrought iron when it became readily available in the latter half of the 19th century, providing great savings when compared with iron in cost and weight. Wood continued to be favored for the decks. Sailing ship technology vastly improved during the early Industrial Revolution between and , as "the risk of being wrecked for Atlantic shipping fell by one third, and of foundering by two thirds, reflecting improvements in seaworthiness and navigation respectively. Driving this steady progress seems to be continuous evolution of sails and rigging, and improved hulls that allowed a greater area of sail to be set safely in a given wind.

By contrast, looking at every voyage between the Netherlands and East Indies undertaken by the Dutch East India Company from to , we find that journey time fell only by 10 per cent, with no improvement in the heavy mortality, averaging six per cent per voyage, of those aboard. During World War II , the need for cargo ships was so great that construction time for Liberty ships went from initially eight months or longer, down to weeks or even days.

They employed production line and prefabrication techniques such as those used in shipyards today. The total number of dry-cargo ships built in the United States in a year period just before the war was a grand total of two. During the war, thousands of Liberty ships and Victory ships were built, many of them in shipyards that didn't exist before the war.

And, they were built by a workforce consisting largely of women and other inexperienced workers who had never seen a ship before or even the ocean. After the Second World War, shipbuilding which encompasses the shipyards, the marine equipment manufacturers, and many related service and knowledge providers grew as an important and strategic industry in a number of countries around the world. This importance stems from:. Historically, the industry has suffered from the absence of global rules [ citation needed ] and a tendency towards state - supported over-investment due to the fact that shipyards offer a wide range of technologies, employ a significant number of workers, and generate income as the shipbuilding market is global.

Shipbuilding is therefore an attractive industry for developing nations. Japan used shipbuilding in the s and s to rebuild its industrial structure; South Korea started to make shipbuilding a strategic industry in the s, and China is now in the process of repeating these models with large state-supported investments in this industry.

Conversely, Croatia is privatising its shipbuilding industry. As a result, the world shipbuilding market suffers from over-capacities, depressed prices although the industry experienced a price increase in the period — due to strong demand for new ships which was in excess of actual cost increases , low profit margins, trade distortions and widespread subsidisation.

All efforts to address the problems in the OECD have so far failed, with the international shipbuilding agreement never entering into force and the — round of negotiations being paused in September after no agreement was possible. After numerous efforts to restart the negotiations these were formally terminated in December Where state subsidies have been removed and domestic industrial policies do not provide support in high labor cost countries, shipbuilding has gone into decline. The British shipbuilding industry is a prime example of this with its industries suffering badly from the s.

In the early s British yards still had the capacity to build all types and sizes of merchant ships but today they have been reduced to a small number specialising in defence contracts, luxury yachts and repair work. Decline has also occurred in other European countries, although to some extent this has reduced by protective measures and industrial support policies. A, the Jones Act which places restrictions on the ships that can be used for moving domestic cargoes has meant that merchant shipbuilding has continued, albeit at a reduced rate, but such protection has failed to penalise shipbuilding inefficiencies.

The consequence of this is that contract prices are far higher than those of any other country building oceangoing ships. China is the world's largest shipbuilder. As freight rates continue to decline into , production delays, and overcapacity in the industry have led South Korean shipbuilders into financial distress. Consequently, significant market share has been ceded to their Chinese and Japanese rivals.

The market share of European ship builders began to decline in the s as they lost work to Japan in the same way Japan most recently lost their work to China and South Korea. Over the four years from , the total number of employees in the European shipbuilding industry declined from , to , Modern shipbuilding makes considerable use of prefabricated sections. Entire multi-deck segments of the hull or superstructure will be built elsewhere in the yard, transported to the building dock or slipway, then lifted into place.

This is known as "block construction". The most modern shipyards pre-install equipment, pipes, electrical cables, and any other components within the blocks, to minimize the effort needed to assemble or install components deep within the hull once it is welded together. Ship design work, also called naval architecture , may be conducted using a ship model basin. Previously, loftsmen at the mould lofts of shipyards were responsible for taking the dimensions, and details from drawings and plans and translating this information into templates, battens, ordinates, cutting sketches, profiles, margins and other data.

Ship construction

Modern ships, since roughly , have been produced almost exclusively of welded steel. Early welded steel ships used steels with inadequate fracture toughness , which resulted in some ships suffering catastrophic brittle fracture structural cracks see problems of the Liberty ship. Since roughly , specialized steels such as ABS Steels with good properties for ship construction have been used.

Although it is commonly accepted that modern steel has eliminated brittle fracture in ships, some controversy still exists. All ships need repair work at some point in their working lives.

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A part of these jobs must be carried out under the supervision of the classification society. A lot of maintenance is carried out while at sea or in port by ship's crew. However a large number of repair and maintenance works can only be carried out while the ship is out of commercial operation, in a ship repair yard.

Prior to undergoing repairs, a tanker must dock at a deballasting station for completing the tank cleaning operations and pumping ashore its slops dirty cleaning water and hydrocarbon residues. From Wikipedia, the free encyclopedia. This article is about the construction of ships.

For the song, see Shipbuilding song. For other uses, see Shipwright disambiguation. Not to be confused with boatbuilding. Archaeological Institute of America. The Indian Ocean in Antiquity. One of the location where stringer is mostly used is the forward part of the ship. Bow of the ship has to bear lots of stress and so requires extra strengthening.

I will limit myself with discussion of bow construction just to understand stringers. I will cover bow construction in detail some other day. So among many other strengthening members, panting beams are used in this area to counter these stresses. But even these beams need to be stiffened at the point where these connects with the side frame. Panting stringers does this job. As I said stringers are horizontal stiffeners parallel to the water line.

Ship construction is something that requires a lot of imagination to understand. These 10 terms are the basic of ship constructions and once we know these, ship construction will be a little easier task. Rajeev Jassal has sailed for over 19 years mainly on crude oil, product and chemical tankers. He has done extensive research on quantitatively measuring Safety culture onboard and safety climate ashore which he believes is the most important element for safer shipping.

Sir i have recently completed my JET for 6 months. Now preparing for class4. This information you gave is not new to me. But the way you explained things was awesome. I am definitely not going to forget this. Looking forward for same great stuff. Also try this one on the web.. It's about hull structure, It's very good First of all l take this oppertunity to appreciate you, for your efffort taken to post this very usefull Blog. This blog is very usefull to everyone in shipping field.. Sir,first of all i would like to thank you for the blogs,these are so simply written so that everyone can understand,quite helpful also to understand the basics.

If you can write something about MS Act ,it can be more helpful. Sure I will consider writing on MS act. Meanwhile if you have any particular question, you can ask on our new section "Questions". I have been going through your blog from quite sometime now. They are really helpful! Ur explanation is very helpful with supportive pictures. Even as a senior ranked engineer I felt ur article was much helpful. Sir, really thankful to you making such a clear and good explanation of ships construction, it was well labeled and very simple words used in explanation, and the image ugh too good.

Hello Sir , Was going through the page and was confused about the part " identification of plates for the box shaped ship would look something like this" if i am not mistaken you were trying to explain about the shell expansion plan in here right. Wanted to know if thickness of side shell platings will be mentioned in the Shell Expansion plan. Yes, Thickness is mentioned in shell expansion plan. I will cover this topic in one of my future blogs. Due to this now i have understood most of the things..

Ship construction is really tough topic for us Very helpful thank you so much sir for these information helped me in preparation for the 2nd mate orals. Good day, Mr Rajeev am very greatful for your articles, it really improve me a little, because am preparing for my oow examination in Nigeria maritime academy. Thank you for your good explanation of those basic ship construction terms.

I have some questions to ask sir. What are the structural members of the ship that counters yawning. I am really impressed.. Dear Sir, It's lot easier to learn Ship Const.

Ship Construction

Thank You soo much sir, for the easy and beautiful explanation. Preparing for Chief Mates oral exam and all your articles are really very helpful. Thanks a lot Sir. Captain, this was a really good lesson in understanding the basics first of ship construction. I'm going aboard soon as deck cadet and this will surely help me in my pre sea course. Learn the difficult concepts of sailing described in a easy and story-telling way. These detailed and well researched articles provides value reading for all ranks.

Ask or answer a question on this forum. Knowledge dies if it remains in our head.

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Share your knowledge by writing answers to the question. This podcast on the maritime matters will provide value to the listeners. Short, crisp and full of value. Stay tuned for this section. Written by Capt Rajeev Jassal on October 13, In this post I will discuss and explain 10 basic terms used in ship construction.

What are ships made of Ships are made of steel and we all know that. Plate We all know what we mean by plate. Bar There is only one principle difference between steel plate and steel bar. Beam A beam is a structural element that increases load bearing capability and avoid bending of the structure. Shape of the beams are not limited to these ones. It can be in many other shapes. Keel First thing first. Keel of the ship is the bottom most plate of the ship laid along the entire length of the ship.

Shell plating Again when we say shell plating, we are referring to a steel plate. We can further divide this area in two broad parts, which is Bottom shell plating Side shell plating I am so much sure that you already would know what these two terms mean. To a certain extent we can say that even keel of the ship is also bottom shell plate.

Deck plating This is one is too obvious. Strake To understand what strake is, we need to again understand the construction of shell plating. In old days these were riveted instead of welding. The plates are identified by a letter and a number Each plate is given a letter in the vertical direction starting with A from the bottom. Each plate is given a number in the horizontal direction starting from aft. So in the above example, we have A-Strake, B-Strake and so on.

Plates and given a number starting from the aft So the plate adjacent to the keel plate will have a identification of A1, A2 and so on starting with A1 from the after most plate.

What are ships made of

Shear Strake Shear strake is the top most strake of the Side shell plating. Keel Strake I earlier said that keel is a plate that is back bone of the ship. Unlike other strakes, keel strakes do not have letter associated with its naming. Garboard Strake Garboard strake is the first strake on each side of the keel strake.

So we can also say that Bottom A-strake is called Garboard strake. So below picture shows how shell plating and Strakes are connected with each other. Stiffners A steel plate of 2mm thickness can be easily bent. Girder Girders are one form of longitudinal stiffners.

These are Big size steel plate or sometimes beams connected to bottom of the ship Runs in fore and aft direction strengthen the ship against bending moment Girders are also named according to its location. Depending upon the breadth of the ship, there can be more than one side girder on each side. Longitudinals Longitudinal is short name for longitudinal stiffners.

Frames are Big size steel plate connected to bottom of the ship Runs in athwartship direction strengthen the ship against buckling and bending. If keel is the backbone of the ship, the frames are considered to be the rib cage. Frames are numbered starting from aft perpendiculars. Stringers In the above photo, notice how the girder is stiffned. Conclusion Ship construction is something that requires a lot of imagination to understand. Follow us Today on our social network. About Capt Rajeev Jassal Capt. Akash Pachghare Oct 14, Rajeev Jassal Oct 16, Gopalakrishnan P Oct 15, Abhishek Kumar Oct 15, Soumen Guha Roy Oct 30, Rajeev Jassal Oct 31, Rajeev Jassal Dec 29, Aman Tandon Feb 1, Rajeev Jassal Jul 2, Rajeev Jassal Nov 29, Ridwan Parindang Sep 25, Informative article, easy to understand, thanks.

Satya Pranay Dec 6, Rajeev Jassal May 12, Btw great blog sir!!! Thanks for the detailed info: Ercan Altay Jan 9, Thanks a lot for your all efforts making all topics so easy to understand.

Mohamed Elhefny Jan 14, Krunal Jan 31, Sir your explanation is very good. Please provide more information about ship construction.. Glad you liked it Mukesh. I will cover more topics on ship construction in future

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