The axe bow is a
wave-piercing type of ship's
bow, characterised by a vertical
stem
Stem or STEM most commonly refers to:
* Plant stem, a structural axis of a vascular plant
* Stem group
* Science, technology, engineering, and mathematics
Stem or STEM can also refer to:
Language and writing
* Word stem, part of a word respon ...
and a relatively long and narrow entry (front hull). The forefoot is deep and the freeboard relatively high with little
flare
A flare, also sometimes called a fusée, fusee, or bengala, bengalo in several European countries, is a type of pyrotechnic that produces a bright light or intense heat without an explosion. Flares are used for distress signaling, illuminatio ...
, so the bow profile resembles that of an
axe
An axe (; sometimes spelled ax in American English; American and British English spelling differences#Miscellaneous spelling differences, see spelling differences) is an implement that has been used for thousands of years to shape, split, a ...
. The bow is less affected by passing through waves than a bow with more flare, making this bow type much less susceptible to
pitching. Because the deep forefoot does not generally rise above the water level, it is less susceptible to
slamming. The axe bow moves the centre of lateral area forward and the vessel may need considerably more rudder motion to hold its course, an effect that increases with increasing wave steepness.
A vertical prow is not unique; they were common in the early steam era. The innovation of the axe bow is to combine the shape with a lengthened bow of the ship. This concept was developed in the
Netherlands
, Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...
by Lex Keuning of
Delft University of Technology
The Delft University of Technology (TU Delft; ) is the oldest and largest Dutch public university, public Institute of technology, technical university, located in Delft, Netherlands. It specializes in engineering, technology, computing, design, a ...
,
[J.A.Keuning, J. Pinkster and F. van Walree: Further Investigation into the Hydrodynamic Performance of the AXE Bow Concept](_blank)
Damen Shipyards Group, Marin (
Maritime Research Institute Netherlands MARIN, the Maritime Research Institute Netherlands, is the leading institute in the world for hydrodynamic research and maritime technology. The services incorporate a unique combination of simulation, model testing, full-scale measurements and trai ...
), the
Royal Netherlands Sea Rescue Institution, the
Royal Netherlands Navy
The Royal Netherlands Navy (, ) is the Navy, maritime service branch of the Netherlands Armed Forces. It traces its history to 8 January 1488, making it the List of navies, third-oldest navy in the world.
During the 17th and early 18th centurie ...
,
Damen Schelde Naval Shipbuilding and the
United States Coast Guard
The United States Coast Guard (USCG) is the maritime security, search and rescue, and Admiralty law, law enforcement military branch, service branch of the armed forces of the United States. It is one of the country's eight Uniformed services ...
.
Related energy saving bow designs
Ax-Box
This is a
bulbous bow with a wave-deflecting axe-shape at the top of the
prow
The bow () is the forward part of the hull (watercraft), hull of a ship or boat, the point that is usually most forward when the vessel is underway. The aft end of the boat is the stern.
Prow may be used as a synonym for bow or it may mean the f ...
. It was developed by
NKK of Japan, and first noted in the early 2000s. It offers an advantage of several percent in added resistance by incident waves over the ordinary bow shape.
[Development of Bow Shape to Reduce the Added Resistance due to Waves and Verification on Full Scale Measurement](_blank)
, Hirota, K., Matsumoto, K., Takagishi, K., Yamasaki, K., Orihara, H. & Yoshida, H., 2005, accessed 2016-12-22[Optimization of Bow Shape for Large, Slow Ships](_blank)
S7.3, Daniel E. Nordås, Norwegian University of Science and Technology
The Norwegian University of Science and Technology (NTNU; ) is a public university, public research university in Norway and the largest in terms of enrollment. The university's headquarters is located in Trondheim (city), Trondheim, with region ...
(NTNU), June 2012, accessed 2016-12-22
LEADGE-bow
The LEADGE (or LEAding eDGE) bow is a non-bulbous bow that fills in between the bulb and the Ax to form a straight and vertical bow, slightly higher than normal prow to ensure wave deflection. It was first described by K, Hirota et al. in 2005. It offers an advantage of about 5% over the Ax-box and a further similar advantage over the ordinary bow with respect to incident wave resistance.
See also
*
References
External links
*{{Commonscatinline, Axe bows
Watercraft components
Ship design