The axe bow is a
wave-piercing
A wave-piercing boat hull has a very fine bow, with reduced buoyancy in the forward portions. When a wave is encountered, the lack of buoyancy means the hull pierces through the water rather than riding over the top, resulting in a smoother ri ...
type of a ship's
bow, characterised by a vertical
stem
Stem or STEM may refer to:
Plant structures
* Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang
* Stipe (botany), a stalk to support some other structure
* Stipe (mycology), the stem of a mushro ...
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 in some Latin-speaking countries, is a type of pyrotechnic that produces a bright light or intense heat without an explosion. Flares are used for distress signaling, illumination, ...
, so that the bow profile resembles an
axe
An axe ( sometimes ax in American English; see spelling differences) is an implement that has been used for millennia to shape, split and cut wood, to harvest timber, as a weapon, and as a ceremonial or heraldic symbol. The axe has ma ...
. The bow cuts through the water, and 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
Slamming is the impact of the bottom structure of a ship onto the sea surface. It is mainly observed while sailing in waves, when the bow raises from the water and subsequently impacts on it. Slamming induces extremely high loads to ship structure ...
. The axe bow moves the centre of lateral area forwards and the vessel may need considerably more rudder motion to hold its course, and this increases with the wave steepness.
A vertical prow is not unique; they were common in the early steam era. The innovation of the axe bow is combined with a lengthened bow of the ship. This concept was developed in the
Netherlands
)
, anthem = ( en, "William of Nassau")
, image_map =
, map_caption =
, subdivision_type = Sovereign state
, subdivision_name = Kingdom of the Netherlands
, established_title = Before independence
, established_date = Spanish Netherl ...
by Lex Keuning of
Delft University of Technology
Delft University of Technology ( nl, Technische Universiteit Delft), also known as TU Delft, is the oldest and largest Dutch public technical university, located in Delft, Netherlands. As of 2022 it is ranked by QS World University Rankings among ...
,
[J.A.Keuning, J. Pinkster and F. van Walree: Further Investigation into the Hydrodynamic Performance of the AXE Bow Concept](_blank)
Damen Shipyards Group
The Damen Group is a Dutch defence, shipbuilding, and engineering conglomerate company based in Gorinchem, Netherlands.
Though it is a major international group doing business in 120 countries, it remains a private family-owned company.
Dame ...
, Marin (
Maritime Research Institute Netherlands MARIN, the Maritime Research Institute Netherlands, is one of the leading institutes in the world for hydrodynamic research and maritime technology. The services incorporate a unique combination of simulation, model testing, full-scale measurements ...
), the
Royal Netherlands Sea Rescue Institution
The Royal Netherlands Sea Rescue Institution (Dutch: ''Koninklijke Nederlandse Redding Maatschappij'', abbreviated: ''KNRM'') is the voluntary organization in the Netherlands tasked with saving lives at sea. For that purpose, it maintains 45 lif ...
, the
Royal Netherlands Navy
The Royal Netherlands Navy ( nl, Koninklijke Marine, links=no) is the naval force of the Kingdom of the Netherlands.
During the 17th century, the navy of the Dutch Republic (1581–1795) was one of the most powerful naval forces in the world an ...
,
Damen Schelde Naval Shipbuilding
Damen Naval is a Dutch shipyard, and a continuation of the Koninklijke Maatschappij De Schelde, responsible for a number of ships used by the Royal Netherlands Navy. It is owned by the Damen Group. Damen Naval is situated in Vlissingen.
History
T ...
and the
United States Coast Guard
The United States Coast Guard (USCG) is the maritime security, search and rescue, and law enforcement service branch of the United States Armed Forces and one of the country's eight uniformed services. The service is a maritime, military, mult ...
.
Related energy saving bow designs
Ax-Box
This is a
bulbous bow
A bulbous bow is a protruding bulb at the bow (or front) 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. Large ships ...
with a wave-deflecting axe-shape at the top of the
prow
The bow () is the forward part of the 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 forward-most part ...
. 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
Norwegian, Norwayan, or Norsk may refer to:
*Something of, from, or related to Norway, a country in northwestern Europe
*Norwegians, both a nation and an ethnic group native to Norway
*Demographics of Norway
*The Norwegian language, including the ...
(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 amount over the ordinary bow from incident wave resistance.
See also
*
References
External links
*{{Commonscatinline, Axe bows
Watercraft components
Ship design