Future Boat Developments
Encyclopedia
Rising oil prices and environmental concerns are driving boat development towards better fuel efficiency and reduced pollution. Global warming impact of shipping also begins to be of concern. According to Professor James J. Corbett of the University of Delaware
, 20-30% GHG-emissions reduction for shipping is possible as well as economical and health benefits
Possible ways to achieve this include reducing drag losses and augmenting fossil fuels by more environmentally friendly sources of energy.
Bulbous bow
is a protruding bulb at the bow (or front) of a ship just below the waterline that modifies the way the water flows around the hull
. Large ships with bulbous bows generally have a twelve to fifteen percent better fuel efficiency than similar vessels without them.
Surface effect ship
reduce drag by reducing wetted area of the hull. In Skjold class patrol boat
s this is achieved by augementing buoyancy by a fan-blown skirted compartment between the two rigid catamaran-type hulls. This permits to lower displacement and hence reduce drag at high speed.
A related concept is Air Cavity System
(also available as upgrade for existing vessels). By creating an air cavity on the underside of the hull it claims to reduce drag by up to 15%.
Wind power as a free, clean and renewable source of energy has been used to propel watercraft since prehistoric times. Classic sail
s are however poorly suited for modern economic conditions not only because of inherent dependence on weather, but also because of large crew requirements with associated costs. Some designs try to overcome this issue through the use of modern technologies.
An example for straightforward approach is the windmill ship
that captures wind energy with rotor to drive a conventional propeller.
The commercially offered SkySails
propulsion system consists of a large foil kite
, an electronic control system for the kite and an automatic system to retract it. The kites, having an area of around 320 square meters (3,400 sq ft), can be flown at altitudes of 100–300 meters (330–980 ft). Because of the stronger winds at these heights, they receive a substantially higher thrust per unit area than conventional mast-mounted sails. A ship equipped with the current SkySails could consume from 10 to 35% less fuel.
A number of designs and proposals for Flettner ship
s exist, however it never demonstrated efficiency to be economically viable. Improvement has been attempted by Jacques Cousteau who designed Turbosail
. Unlike simple Flettner rotors, it is able to produce thrust in the direction of travel, regardless of wind direction. The first turbosail-equipped ship, Alcyone
, reported a 1/3 fuel savings. The efficiency of the system has however not been subjected to sufficient comparative engineering research. There have been only two turbosail-equipped vessels on which active research has been performed.
Solar panels have been also suggested for powering primary and secondary ship systems .
Solar powered boats have mainly been limited to rivers and canals, but in 2007 an experimental 14m catamaran, the Sun21 sailed the Atlantic from Seville
to Miami, and from there to New York.
University of Delaware
The university is organized into seven colleges:* College of Agriculture and Natural Resources* College of Arts and Sciences* Alfred Lerner College of Business and Economics* College of Earth, Ocean and Environment* College of Education and Human Development...
, 20-30% GHG-emissions reduction for shipping is possible as well as economical and health benefits
Possible ways to achieve this include reducing drag losses and augmenting fossil fuels by more environmentally friendly sources of energy.
Drag reduction
New technologies can offer significant advantage in fuel efficiency by reducing drag. For instance modern materials like aluminum alloys or carbon-fiber composites reduce hull weight and hence displacement and drag for a given payload.Bulbous bow
Bulbous bow
A bulbous bow is a protruding bulb at the bow of a ship just below the waterline. The bulb modifies the way the water flows around the hull, reducing drag and thus increasing speed, range, fuel efficiency, and stability...
is a protruding bulb at the bow (or front) of a ship just below the waterline that modifies the way the water flows around the hull
Hull (watercraft)
A hull is the watertight body of a ship or boat. Above the hull is the superstructure and/or deckhouse, where present. The line where the hull meets the water surface is called the waterline.The structure of the hull varies depending on the vessel type...
. Large ships with bulbous bows generally have a twelve to fifteen percent better fuel efficiency than similar vessels without them.
Surface effect ship
Surface effect ship
A Surface Effect Ship or Sidewall Hovercraft is a watercraft that has both an air cushion, like a hovercraft, and twin hulls, like a catamaran. When the air cushion is in use, a small portion of the twin hulls remain in the water...
reduce drag by reducing wetted area of the hull. In Skjold class patrol boat
Skjold class patrol boat
The Skjold class patrol boats is a new class of superfast, large stealth missile craft, formerly known as MTBs . From 2009, the Royal Norwegian Navy officially label them as coastal corvettes because their seaworthiness is seen as comparable to corvettes. They are built at the Umoe Mandal yard...
s this is achieved by augementing buoyancy by a fan-blown skirted compartment between the two rigid catamaran-type hulls. This permits to lower displacement and hence reduce drag at high speed.
A related concept is Air Cavity System
Air Cavity System
Air Cavity System is a commercially offered technology for reducing drag of ships.- Principle of operation :The idea behind ACS is to trap air beneath hull recesses and thus reduce wetted area with associated viscous drag. Since some air will be inevitably carried away by water stream, a pump...
(also available as upgrade for existing vessels). By creating an air cavity on the underside of the hull it claims to reduce drag by up to 15%.
Wind power
Sail
A sail is any type of surface intended to move a vessel, vehicle or rotor by being placed in a wind—in essence a propulsion wing. Sails are used in sailing.-History of sails:...
s are however poorly suited for modern economic conditions not only because of inherent dependence on weather, but also because of large crew requirements with associated costs. Some designs try to overcome this issue through the use of modern technologies.
An example for straightforward approach is the windmill ship
Windmill ship
A windmill ship, wind energy conversion system ship or wind energy harvester ship propels itself by use of a windmill to drive a propeller.They use wind power through a mechanical or electrical transmission to the propeller...
that captures wind energy with rotor to drive a conventional propeller.
The commercially offered SkySails
SkySails
SkySails GmbH & Co. KG is a Hamburg-based company that sells equipment to propel cargo ships, large yachts and fishing vessels by the use of wind energy. The company was founded in 2001 by engineers Stephan Wrage and Thomas Meyer...
propulsion system consists of a large foil kite
Kite
A kite is a tethered aircraft. The necessary lift that makes the kite wing fly is generated when air flows over and under the kite's wing, producing low pressure above the wing and high pressure below it. This deflection also generates horizontal drag along the direction of the wind...
, an electronic control system for the kite and an automatic system to retract it. The kites, having an area of around 320 square meters (3,400 sq ft), can be flown at altitudes of 100–300 meters (330–980 ft). Because of the stronger winds at these heights, they receive a substantially higher thrust per unit area than conventional mast-mounted sails. A ship equipped with the current SkySails could consume from 10 to 35% less fuel.
A number of designs and proposals for Flettner ship
Flettner ship
A rotor ship, or Flettner ship, is a ship designed to use the Magnus effect for propulsion. To take advantage of this effect, it uses rotorsails which are powered by an engine. The Magnus effect is a force acting on a spinning body in a moving airstream, which acts perpendicularly to the direction...
s exist, however it never demonstrated efficiency to be economically viable. Improvement has been attempted by Jacques Cousteau who designed Turbosail
Turbosail
-Concept:In 1980, Jacques Cousteau dreamed of creating a ship with a modern engine that would be powered, at least in part, by the wind, a clean, free, renewable energy source...
. Unlike simple Flettner rotors, it is able to produce thrust in the direction of travel, regardless of wind direction. The first turbosail-equipped ship, Alcyone
Alcyone (ship)
The Alcyone is a ship operated by the Cousteau Society. It was created as an expedition ship and to test the operation of a new kind of marine propulsion system, the turbosail. The Alcyone is equipped with two of these unusual sails, which are used to augment its diesel engines...
, reported a 1/3 fuel savings. The efficiency of the system has however not been subjected to sufficient comparative engineering research. There have been only two turbosail-equipped vessels on which active research has been performed.
Alternative energy sources
Fuel cell powered boats might benefit from higher thermodynamic efficiency of fuel cells compared to internal combustion engines (40-60% vs 20-25%). Greatest impediment is currently high cost of fuel cells. In 2009, the Department of Energy reported that 80-kW automotive fuel cell system costs in volume production (projected to 500,000 units per year) are US$61 per kilowatt.Solar panels have been also suggested for powering primary and secondary ship systems .
Solar powered boats have mainly been limited to rivers and canals, but in 2007 an experimental 14m catamaran, the Sun21 sailed the Atlantic from Seville
Seville
Seville is the artistic, historic, cultural, and financial capital of southern Spain. It is the capital of the autonomous community of Andalusia and of the province of Seville. It is situated on the plain of the River Guadalquivir, with an average elevation of above sea level...
to Miami, and from there to New York.