AdvAnCEd hullformS
Navatek explores Bow Lifting Bodies
navatek ltd in hawaii, one of the four
companies that participated in Phase
1 of the T-Craft project, has recently
turned its attention to the development
of Bow lifting Bodies (BlBs), which it
has recently tested successfully on a
technology demonstration craft.
As Steven loui, a director at
navatek explained, lifting body
technology has been demonstrated
using Computational fluid dynamics
(Cfd), scale-model tests and, most
recently, full-scale at-sea trials, which
have shown that it provides reduced
motions at zero and loiter speeds while
providing dynamic lift at high speeds to
reduce hull drag and to provide active
ride control.
lifting bodies are underwater
appendages with cambered foil cross
sections that generate dynamic lift
at speed. hybrid lifting body ships
combine a parent hullform (usually
A Bow lifting Body (as seen here on the BlB-70 demonstrator) is an underwater
a monohull or a multihull such as a
appendage with cambered foil cross section that generates dynamic lift at speed.
catamaran) with lifting bodies. mr loui
said the potential benefits offered by
innovative hullforms combined with
lifting bodies and active control systems
are numerous, and include enhanced
seakindliness; improved sea-keeping;
higher speed, due to reduced total
drag; and the ability to carry higher
payloads, since for a given parent
hull, lifting bodies provide added
displacement and useable volume.
A 21.3m technology demonstrator,
the BlB-70, was successfully tested at
sea and navatek is currently working An example of one
on a roughly half-scale demonstrator of a number of BlBs
for a 91m design, the 49m BlB-160 tested by navatek.
‘Sea-frame’, which is intended
for use as a multi-role technology
demonstrator, with a possible follow-on arrangement provides a large deck catamarans, or ‘BlB CAT’, that uses
application as a fast offshore supply area while the patented bow lifting BlB bodies in place of a T-foil. The
vessel. body and an aft foil, in concert with company believes that this particular
The BlB-160 is being designed an advanced ride control system, will application of the BlB could be the
to demonstrate the benefits of a significantly reduce motions when first to be commercialised, being
BlB, providing a comfortable ride underway. The BlB-160 is currently in structurally more robust than a T-foil,
for passengers and crew while the preliminary design phase, and without any increase in draught,
maintaining its ability to rapidly and construction could start later in 2008. whilst providing usable volume in
efficiently deliver supplies to offshore more recently, navatek has also an otherwise very fine bow, with no
facilities. The stabilised monohull developed a ride control systems for increase in drag.
16 Warship Technology January 2008
WT Jan - p14+15+16.indd 16 08/01/2008 16:45:55
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