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61-455: The boat building industry provides for the design, manufacturing, repair and modification of human-powered watercrafts , sailboats , motorboats , airboats and submersibles , and caters for various demands from recreational (e.g. launches , dinghies and yachts ), commercial (e.g. tour boats , ferry boats and lighters ), residential ( houseboats ), to professional (e.g. fishing boats , tugboats , lifeboats and patrol boats ) . Wood

122-459: A fouling community . Marine fouling is typically described as following four stages of ecosystem development. Within the first minute the van der Waals interaction causes the submerged surface to be covered with a conditioning film of organic polymers. In the next 24 hours, this layer allows the process of bacterial adhesion to occur, with both diatoms and bacteria (e.g. Vibrio alginolyticus , Pseudomonas putrefaciens ) attaching, initiating

183-464: A 40% increase in fuel to compensate. With fuel typically comprising up to half of marine transport costs, antifouling methods save the shipping industry a considerable amount of money. Further, increased fuel use due to biofouling contributes to adverse environmental effects and is predicted to increase emissions of carbon dioxide and sulfur dioxide between 38% and 72% by 2020, respectively. Biofouling organisms are highly diverse, and extend far beyond

244-500: A breakthrough, with self-polishing paints that slowly hydrolyze , slowly releasing toxins. These paints employed organotin chemistry ("tin-based") biotoxins such as tributyltin oxide (TBT) and were effective for up to four years. These biotoxins were subsequently banned by the International Maritime Organization when they were found to be very toxic to diverse organisms. TBT in particular has been described as

305-565: A builder should choose the most appropriate one for the boat's intended purpose. For example, a sea-going vessel needs a hull which is more stable and robust than a hull used in rivers and canals. Hull types include: Human-powered watercraft Human-powered watercraft are watercraft propelled only by human power , instead of being propelled by wind power (via one or more sails ) or an engine . The three main methods of exerting human power are: While most human-powered watercraft use buoyancy to maintain their position relative to

366-410: A covering of paint). Modern steel components are welded or bolted together. As the welding can be done very easily (with common welding equipment), and as the material is very cheap, it is a popular material with amateur builders. Also, amateur builders which are not yet well established in building steel ships may opt for DIY construction kits. If steel is used, a zinc layer is often applied to coat

427-522: A high correlation between their resistance to bacterial adhesion and their hydrophobicity . A study of the biotoxins used by organisms has revealed several effective compounds, some of which are more powerful than synthetic compounds. Bufalin , a bufotoxin , was found to be over 100 times as potent as TBT, and over 6,000 times more effective in anti-settlement activity against barnacles. One approach to antifouling entails coating surfaces with polyethylene glycol (PEG). Growing chains of PEG on surfaces

488-474: A larger effort by the Office of Naval Research to develop environmentally safe biomimetic ship coatings. Biocides are chemical substances that kill or deter microorganisms responsible for biofouling. The biocide is typically applied as a paint, i.e. through physical adsorption . The biocides prevent the formation of biofilms . Other biocides are toxic to larger organisms in biofouling, such as algae . Formerly,

549-467: A manageable level. However, the rate of accretion can vary widely between vessels and operating conditions, so predicting acceptable intervals between cleanings is difficult. LED manufacturers have developed a range of UVC (250–280 nm) equipment that can detect biofouling buildup, and can even prevent it. Fouling detection relies on the biomass' property of fluorescence. All microorganisms contain natural intracellular fluorophores, which radiate in

610-616: A material or coating with a slippery surface, creating an ultra-low fouling surface with the use of zwitterions , or creating nanoscale surface topologies similar to the skin of sharks and dolphins, which only offer poor anchor points. Non-toxic anti-sticking coatings prevent attachment of microorganisms thus negating the use of biocides. These coatings are usually based on organic polymers. There are two classes of non-toxic anti-fouling coatings. The most common class relies on low friction and low surface energies . Low surface energies result in hydrophobic surfaces. These coatings create

671-564: A mixture of train oil (whale oil), rosin and sulfur ; "Black stuff", a mixture of tar and pitch ; and "Brown stuff", which was simply sulfur added to Black stuff. In many of these cases, the purpose of these treatments is ambiguous. There is dispute whether many of these treatments were actual anti-fouling techniques, or whether, when they were used in conjunction with lead and wood sheathing, they were simply intended to combat wood-boring shipworms . In 1708, Charles Perry suggested copper sheathing explicitly as an anti-fouling device but

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732-459: A single oar, is sweep or sweep-oar rowing . In this case the rowers are usually paired so that there is an oar on each side of the boat. Sweep-oared craft include: Moving a single stern-mounted oar from side to side, while changing the angle of the blade so as to generate forward thrust on both strokes, is single-oar sculling . Single-oar sculled craft include: Paddled watercraft, or paddlecraft, uses one or more handheld paddles , each with

793-469: A smooth finish. In the 1960s and 1970s, particularly in Australia and New Zealand, the cheapness of ferro construction encouraged amateur builders to build hulls larger than they could afford, not anticipating that the fitting-out costs of a larger boat can be crippling. The advantages of a ferro hull are: The disadvantages are: See also : concrete ship , concrete canoe . There are many hull types, and

854-430: A smooth surface, which can prevent attachment of larger microorganisms. For example, fluoropolymers and silicone coatings are commonly used. These coatings are ecologically inert but have problems with mechanical strength and long-term stability. Specifically, after days biofilms (slime) can coat the surfaces, which buries the chemical activity and allows microorganisms to attach. The current standard for these coatings

915-484: A variety of energy methods to address bioburden issues associated with biofouling. Autoclaving typically involves heating a medical device to 121 °C (249 °F) for 15–20 minutes. Ultrasonic cleaning, UV light, and chemical wipe-down or immersion can also be used for different types of devices. Medical devices used in operating rooms, ICUs, isolation rooms, biological analysis labs, and other high-contamination-risk areas have negative pressure (constant exhaust) in

976-411: A very effective antifouling metal. Cupronickel may be found on the hulls of premium tugboats , fishing boats and other working boats ; and may even be used for propellers and propeller shafts . Fiberglass ( glass-reinforced plastic or GRP) is typically used for production boats because of its ability to reuse a female mould as the foundation for the shape of the boat. The resulting structure

1037-444: A widened blade on one or both ends, to push water and propel the watercraft.. Commonly seen paddlecrafts include: Pedals are attached to a crank and propelled in circles, or to a treadle and reciprocated , with the feet. The collected power is then transferred to the water with a paddle wheel , flippers , or to the air or water with a propeller . Pedaled craft include: A pole is held with both hands and used to push against

1098-400: A wooden hull provided the risk of galvanic corrosion was minimised. Fast cargo vessels once were copper-bottomed to prevent being slowed by marine fouling. GRP and ferrocement hulls are classic composite hulls, the term "composite" applies also to plastics reinforced with fibers other than glass. When a hull is being created in a female mould, the composite materials are applied to the mould in

1159-671: Is polydimethylsiloxane , or PDMS, which consists of a non-polar backbone made of repeating units of silicon and oxygen atoms. The non-polarity of PDMS allows for biomolecules to readily adsorb to its surface in order to lower interfacial energy. However, PDMS also has a low modulus of elasticity that allows for the release of fouling organisms at speeds of greater than 20 knots. The dependence of effectiveness on vessel speed prevents use of PDMS on slow-moving ships or those that spend significant amounts of time in port. The second class of non-toxic antifouling coatings are hydrophilic coatings. They rely on high amounts of hydration in order to increase

1220-411: Is applied by a team of plasterers. The cement:sand ratio is a very rich 4:1. As the hull thickness is typically 2.5 to 3 cms, ferrocement is unsuitable for boats less than about 15 metres LOA as there is a weight penalty; above that length there is no penalty. Properly plastered ferrocement boats have smooth hulls with fine lines, and amateur builders are advised to use professional plasterers to produce

1281-594: Is commonly used against diatoms . Plasma pulse technology is effective against zebra mussels and works by stunning or killing the organisms with microsecond-duration energizing of the water with high-voltage electricity. Similarly, another method shown to be effective against algae buildups bounces brief high-energy acoustic pulses down pipes. Regimens to periodically use heat to treat exchanger equipment and pipes have been successfully used to remove mussels from power plant cooling systems using water at 105 °F (40 °C) for 30 minutes. The medical industry utilizes

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1342-585: Is estimated to cost the US Navy alone around $ 1 billion per year in increased fuel usage, maintenance and biofouling control measures. Increased fuel use due to biofouling contributes to adverse environmental effects and is predicted to increase emissions of carbon dioxide and sulfur dioxide between 38 and 72 percent by 2020. Biofouling also impacts aquaculture, increasing production and management costs, while decreasing product value. Fouling communities may compete with shellfish directly for food resources, impede

1403-524: Is laid to the mould, but before the inner skin is laid. This is similar to the next type, composite, but is not usually classified as composite, since the core material in this case does not provide much additional strength. It does, however, increase stiffness, which means that less resin and fiberglass cloth can be used in order to save weight. Most fibreglass boats are currently made in an open mould, with fibreglass and resin applied by hand ( hand-lay-up method). Some are now constructed by vacuum infusion where

1464-452: Is most commonly found in yachts, pontoon and power boats that are not kept permanently in the water. Aluminium yachts are particularly popular in France. A relatively expensive metal used only very occasionally in boatbuilding is cupronickel . Arguably the ideal metal for boat hulls, cupronickel is reasonably tough, highly resistant to corrosion in seawater, and is (because of its copper content)

1525-1094: Is most significant economically to the shipping industries , since fouling on a ship's hull significantly increases drag , reducing the overall hydrodynamic performance of the vessel, and increases the fuel consumption. Biofouling is also found in almost all circumstances where water-based liquids are in contact with other materials. Industrially important impacts are on the maintenance of mariculture , membrane systems ( e.g. , membrane bioreactors and reverse osmosis spiral wound membranes) and cooling water cycles of large industrial equipment and power stations . Biofouling can occur in oil pipelines carrying oils with entrained water, especially those carrying used oils, cutting oils , oils rendered water-soluble through emulsification , and hydraulic oils . Other mechanisms impacted by biofouling include microelectrochemical drug delivery devices, papermaking and pulp industry machines, underwater instruments, fire protection system piping, and sprinkler system nozzles. In groundwater wells, biofouling buildup can limit recovery flow rates, as

1586-493: Is not impervious to diatom and algae fouling. Some studies indicate that copper may also present an unacceptable environmental impact. Study of biofouling began in the early 19th century with Davy's experiments linking the effectiveness of copper to its solute rate. In the 1930s microbiologist Claude ZoBell showed that the attachment of organisms is preceded by the adsorption of organic compounds now referred to as extracellular polymeric substances . One trend of research

1647-436: Is referred to as epibiosis when the host surface is another organism and the relationship is not parasitic. Since biofouling can occur almost anywhere water is present, biofouling poses risks to a wide variety of objects such as boat hulls and equipment, medical devices and membranes, as well as to entire industries, such as paper manufacturing, food processing , underwater construction, and desalination plants. Anti-fouling

1708-409: Is strong in tension but often needs to be either laid up with many heavy layers of resin-saturated fiberglass or reinforced with wood or foam in order to provide stiffness. GRP hulls are largely free of corrosion though not normally fireproof. These can be solid fiberglass or of the sandwich (cored) type, in which a core of balsa , foam or similar material is applied after the outer layer of fiberglass

1769-548: Is the ability of specifically designed materials (such as toxic biocide paints, or non-toxic paints ) to remove or prevent biofouling. The buildup of biofouling on marine vessels poses a significant problem. In some instances, the hull structure and propulsion systems can be damaged. The accumulation of biofoulers on hulls can increase both the hydrodynamic volume of a vessel and the hydrodynamic friction, leading to increased drag of up to 60%. The drag increase has been seen to decrease speeds by up to 10%, which can require up to

1830-489: Is the case in the exterior and interior of ocean-laying pipes where fouling is often removed with a tube cleaning process . Besides interfering with mechanisms, biofouling also occurs on the surfaces of living marine organisms, when it is known as epibiosis. Medical devices often include fan-cooled heat sinks, to cool their electronic components. While these systems sometimes include HEPA filters to collect microbes, some pathogens do pass through these filters, collect inside

1891-407: Is the lightest material for building large boats (being 15–20% lighter than polyester and 30% lighter than steel). Aluminium is relatively cheap in comparison with wood or steel in most countries. In addition it is relatively easy to cut, bend and weld. Galvanic corrosion below the waterline in salt water is a serious concern, particularly in marinas where there are other conflicting metals. Aluminium

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1952-513: Is the study of the relationship between wettability and anti-fouling effectiveness. Another trend is the study of living organisms as the inspiration for new functional materials. For example, the mechanisms used by marine animals to inhibit biofouling on their skin. Materials research into superior antifouling surfaces for fluidized bed reactors suggest that low wettability plastics such as polyvinyl chloride (PVC), high-density polyethylene and polymethylmethacrylate ("plexiglas") demonstrate

2013-405: Is the traditional boat building material used for hull and spar construction. It is buoyant, widely available and easily worked. It is a popular material for small boats (of e.g. 6-metre (20 ft) length; such as dinghies and sailboats). Its abrasion resistance varies according to the hardness and density of the wood and it can deteriorate if fresh water or marine organisms are allowed to penetrate

2074-456: The D-Day Mulberry harbours . After a buzz of excitement among homebuilders in the 1960s, ferro building has since declined. Ferrocement is a relatively cheap method to produce a hull, although unsuitable for commercial mass production. A steel and iron "armature" is built to the exact shape of the hull, ultimately being covered in galvanised chicken netting. Then, on a single day, the cement

2135-497: The Phoenicians and Carthaginians (1500–300 BC). Wax, tar and asphaltum have been used since early times. An Aramaic record dating from 412 BC tells of a ship's bottom being coated with a mixture of arsenic, oil and sulphur. In Deipnosophistae , Athenaeus described the anti-fouling efforts taken in the construction of the great ship of Hieron of Syracuse (died 467 BC). A recorded explanation by Plutarch of

2196-410: The "shell-first" method (also called "planking first") and the "frame first" method. With "shell first", the form of the hull is determined by joining shaped planks that are fastened together, followed by reinforcing the structure with the frames (or ribs) that are fitted to the inside. With "frame first", the hull shape is established by setting up the frames on the keel and then fastening the planking on

2257-456: The 19th century, copper sheathing could no longer be used due to its galvanic corrosive interaction with iron. Anti-fouling paints were tried, and in 1860, the first practical paint to gain widespread use was introduced in Liverpool and was referred to as "McIness" hot plastic paint. These treatments had a short service life, were expensive, and relatively ineffective by modern standards. By

2318-669: The UV range when excited. At UV-range wavelengths, such fluorescence arises from three aromatic amino acids—tyrosine, phenylalanine, and tryptophan. The easiest to detect is tryptophan, which radiates at 350 nm when irradiated at 280 nm. Antifouling is the process of preventing accumulations from forming. In industrial processes , biodispersants can be used to control biofouling. In less controlled environments, organisms are killed or repelled with coatings using biocides, thermal treatments, or pulses of energy. Nontoxic mechanical strategies that prevent organisms from attaching include choosing

2379-742: The attachment of barnacles and seaweeds. According to some estimates, over 1,700 species comprising over 4,000 organisms are responsible for biofouling. Biofouling is divided into microfouling — biofilm formation and bacterial adhesion—and macrofouling —attachment of larger organisms. Due to the distinct chemistry and biology that determine what prevents them from settling, organisms are also classified as hard- or soft-fouling types. Calcareous (hard) fouling organisms include barnacles , encrusting bryozoans , mollusks such as zebra mussels , and polychaete and other tube worms . Examples of non-calcareous (soft) fouling organisms are seaweed , hydroids , algae, and biofilm "slime". Together, these organisms form

2440-440: The bottom. Poled craft include: Other types of human-powered watercraft include: Antifouling Biofouling or biological fouling is the accumulation of microorganisms , plants , algae , or small animals where it is not wanted on surfaces such as ship and submarine hulls, devices such as water inlets, pipework, grates, ponds, and rivers that cause degradation to the primary purpose of that item. Such accumulation

2501-424: The device and are eventually blown out and infect other patients. Devices used in operating rooms rarely include fans, so as to minimize the chance of transmission. Also, medical equipment, HVAC units, high-end computers, swimming pools, drinking-water systems and other products that utilize liquid lines run the risk of biofouling as biological growth occurs inside them. Historically, the focus of attention has been

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2562-476: The energetic penalty of removing water for proteins and microorganisms to attach. The most common examples of these coatings are based on highly hydrated zwitterions , such as glycine betaine and sulfobetaine . These coatings are also low-friction, but are considered by some to be superior to hydrophobic surfaces because they prevent bacteria attachment, preventing biofilm formation. These coatings are not yet commercially available and are being designed as part of

2623-581: The entire hull. It is applied after sandblasting (which is required to have a cleaned surface) and before painting. The painting is usually done with lead paint (Pb 3 O 4 ). Optionally, the covering with the zinc layer may be left out, but it is generally not recommended. Zinc anodes also need to be placed on the ship's hull. Until the mid-1900s, steel sheets were riveted together. Aluminum and aluminum alloys are used both in sheet form for all-metal hulls or for isolated structural members. Many sailing spars are frequently made of aluminium after 1960. It

2684-443: The fibres are laid out and resin is pulled into the mould by atmospheric pressure. This can produce stronger parts with more glass and less resin, but takes special materials and more technical knowledge. Older fibreglass boats before 1990 were often not constructed in controlled temperature buildings leading to the widespread problem of fibreglass pox, where seawater seeped through small holes and caused delamination. The name comes from

2745-470: The first experiments were not made until 1761 with the sheathing of HMS Alarm , after which the bottoms and sides of several ships' keels and false keels were sheathed with copper plates. The copper performed well in protecting the hull from invasion by worm, and in preventing the growth of weed, for when in contact with water, the copper produced a poisonous film, composed mainly of oxychloride , that deterred these marine creatures. Furthermore, as this film

2806-410: The form of a thermosetting plastic (usually epoxy , polyester, or vinylester) and some kind of fiber cloth ( fiberglass , kevlar , dynel , carbon fiber , etc.). These methods can give strength-to-weight ratios approaching that of aluminum, while requiring less specialized tools and construction skills. First developed in the mid-19th century in both France and Holland, ferrocement was also used for

2867-595: The formation of a biofilm . By the end of the first week, the rich nutrients and ease of attachment into the biofilm allow secondary colonizers of spores of macroalgae (e.g. Enteromorpha intestinalis , Ulothrix ) and protozoans (e.g. Vorticella , Zoothamnium sp.) to attach themselves. Within two to three weeks, the tertiary colonizers—the macrofoulers—have attached. These include tunicates , mollusks, and sessile cnidarians . Governments and industry spend more than US$ 5.7 billion annually to prevent and control marine biofouling. Biofouling occurs everywhere but

2928-522: The hull of small to medium-sized boats. Research has shown these systems can help reduce fouling, by initiating bursts of ultrasonic waves through the hull medium to the surrounding water, killing or denaturing the algae and other microorganisms that form the beginning of the fouling sequence. The systems cannot work on wooden-hulled boats, or boats with a soft-cored composite material, such as wood or foam. The systems have been loosely based on technology proven to control algae blooms. Pulsed laser irradiation

2989-414: The impact fouling had on ship speed goes as follows: "when weeds, ooze, and filth stick upon its sides, the stroke of the ship is more obtuse and weak; and the water, coming upon this clammy matter, doth not so easily part from it; and this is the reason why they usually calk their ships." Before the 18th century, various anti-fouling techniques were used, with three main substances employed: "White stuff",

3050-406: The instrument and eventually rendering it inoperable. Biofouling, especially of ships, has been a problem for as long as humans have been sailing the oceans. The earliest attestations of attempts to counter fouling, and thus also the earliest attestation of knowledge if it, is the use of pitch and copper plating as anti-fouling solutions that were attributed to ancient seafaring nations, such as

3111-408: The mid-twentieth century, copper oxide-based paints could keep a ship out of drydock for as much as 18 months, or as little as 12 in tropical waters. The shorter service life was due to rapid leaching of the toxicant, and chemical conversion into less toxic salts, which accumulated as a crust that would inhibit further leaching of active cuprous oxide from the layer under the crust. The 1960s brought

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3172-430: The most toxic pollutant ever deliberately released in the ocean. As an alternative to organotin toxins, there has been renewed interest in copper as the active agent in ablative or self polishing paints, with reported service lives up to 5 years; yet also other methods that do not involve coatings. Modern adhesives permit application of copper alloys to steel hulls without creating galvanic corrosion. However, copper alone

3233-446: The multitude of surface pits in the outer gelcoat layer which resembles smallpox. Sometimes the problem was caused by atmospheric moisture being trapped in the layup during construction in humid weather. "Composite construction" involves a variety of composite materials and methods: an early example was a timber carvel skin attached to a frame and deck beams made of iron. Sheet copper anti-fouling ("copper=bottomed") could be attached to

3294-419: The outside. Some types of wood construction include: Either used in sheet or alternatively, plate for all-metal hulls or for isolated structural members. It is strong, but heavy (despite the fact that the thickness of the hull can be less). It is generally about 30% heavier than aluminium and somewhat more heavy than polyester . The material rusts unless protected from water (this is usually done by means of

3355-531: The procurement of food and oxygen by reducing water flow around shellfish, or interfere with the operational opening of their valves. Consequently, stock affected by biofouling can experience reduced growth, condition and survival, with subsequent negative impacts on farm productivity. Although many methods of removal exist, they often impact the cultured species, sometimes more so than the fouling organisms themselves. Shipping companies have historically relied on scheduled biofouler removal to keep such accretions to

3416-531: The rooms, maintain strict cleaning protocols, require equipment with no fans, and often drape equipment in protective plastic. UVC irradiation is a noncontact, nonchemical solution that can be used across a range of instruments. Radiation in the UVC range prevents biofilm formation by deactivating the DNA in bacteria, viruses, and other microbes. Preventing biofilm formation prevents larger organisms from attaching themselves to

3477-513: The severe impact due to biofouling on the speed of marine vessels. In some instances the hull structure and propulsion systems can become damaged. Over time, the accumulation of biofoulers on hulls increases both the hydrodynamic volume of a vessel and the frictional effects leading to increased drag of up to 60% The additional drag can decrease speeds up to 10%, which can require up to a 40% increase in fuel to compensate. With fuel typically comprising up to half of marine transport costs, biofouling

3538-453: The so-called tributyltin (TBT) compounds were used as biocides (and thus anti-fouling agents). TBTs are toxic to both microorganisms and larger aquatic organisms. The international maritime community has phased out the use of organotin-based coatings. Replacing organotin compounds is dichlorooctylisothiazolinone . This compound, however, also suffers from broad toxicity to marine organisms. Ultrasonic transducers may be mounted in or around

3599-469: The surface of the water, a few, such as human-powered hydrofoils and human-powered submarines , use hydrofoils , either alone or in addition to buoyancy. Oars are held at one end, have a blade on the other end, and pivot in between in oarlocks . Oared craft include: Using oars in pairs, with one hand on each oar, is two-oar sculling . The oars may also be called sculls. Two-oared sculled craft include: Using oars individually, with both hands on

3660-480: The wood. Woods such as teak , totara and some cedars have natural chemicals which prevent rot whereas other woods, such as Pinus radiata , will rot very quickly. The hull of a wooden boat usually consists of planking fastened to frames and a keel. Keel and frames are traditionally made of hardwoods such as oak while planking can be oak but is more often softwood such as pine , larch or cedar . Traditional wood construction techniques can be classified into

3721-459: Was slightly soluble, it gradually washed away, leaving no way for marine life to attach itself to the ship. From about 1770, the Royal Navy set about coppering the bottoms of the entire fleet and continued to the end of the use of wooden ships. The process was so successful that the term copper-bottomed came to mean something that was highly dependable or risk free. With the rise of iron hulls in

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