I N T R O D U C T I O N
As the technology applied to energy exploration and
p roduction advances to meet the deepwater challenges
beyond the continental shelf, Autonomous Underw a t e r
Vehicles (AUVs) will be increasingly employed. AUV
technology has just reached a milestone as the result of
the first commercial purchase of an AUV by C&C
Technologies, Inc. of
The deep-towed system, the conventional deepwater
mapping tool, suffers from chronic waste and inefficiency.
To rectify this problem, Kongsberg Simrad, in conjunction
with C&C Technologies, is developing the HUGIN
3000. The HUGIN has evolved from an AUV pro g r a m m e
amassing more than one hundred missions since 1995.
The HUGIN will be integrated with an acoustic tether to
monitor data acquisition and optimise system perf o rm a n c e .
D EE P -T OWE D S YS T
The deep-towed system originated as a mapping tool to
accommodate large-scale academic surveying projects
comprising multiple traverses of lengthy, straight lines.
It was later adapted to similar applications, such as pipeline
routes, fibre-optic cable routes, and block hazard
s u rveys. Provided by manufacturers such as
Corporation, Kongsberg Simrad, and Datasonics, Inc.,
the deep-towed system is the true precursor to the
s u rvey AUV and remains the standard deepwater surv e y
tool of today. Typical deep-tow instrumentation packages
include the side scan sonar and sub-bottom profiler.
U n f o rt u n a t e l y, due to the massive amounts of tow cable
re q u i red (10,000 metres is not uncommon), deeptowed
costs are extremely high. Such cable lengths
demand huge handling systems and constitute a substantial
surface area when towed. Survey speeds are there f o re
limited to 2.0 to 2.5 knots and vessel turns often
re q u i re 4 to 6 hours to accomplish, which devour a painful
portion of a survey budget.
Positioning of deep-towed systems embodies the
age-old axiom: accuracy v e r s u s cost. Ranked accord i n g
to cost (highest first), the three primary underwater acoustic
positioning alternatives are:
• Long Base Line (LBL).
• Two-Vessel Ultra Short Base Line (USBL).
• Single-Vessel USBL (for less than 1,000 metres of
water depth).
LBL, the most accurate, is also the most costly,
time-consuming, and dangerous. It involves the placement
of an encompassing grid of acoustic-positioning
transponder beacons, upon the seafloor. An initial,
often tedious, calibration pro c e d u re is re q u i red and each
LBL operation concludes with a transponder retrieval
p ro c e d u re, guaranteed to make any Health, Safety and
Environmental (HSE) auditor shudder.
Tw o - Vessel Ultra Short Base Line (USBL) positioning
re q u i res the addition of a second survey vessel, or chaseboat
(Figure 1). The duty of a chase-boat is to follow
above the towfish, within the acoustic ranging
capability of the USBL, and track the towfish position.
Acoustically derived towfish positions are simultaneously
transmitted via radio to the tow-vessel’s
navigation computer.
S i n g l e - Vessel USBL is, in effect, when the tow vessel
also provides positioning for the deep-towed fish. Deeptowed
systems re q u i re cable lengths of at least 2.5
times the water depth during survey operations and the
acoustic ranging capability of the USBL system is
generally less than 2,500 metres. Consequently, this limits
the utility of Single-Vessel USBL positioning to about
1,000 metres of water for deep-towed operations.
H UGI N 3 0 0 0 A U V
Recognising the need for a more efficient approach to
deepwater surveying, C&C invested one year evaluating
the available vendors of AUV technology. Researc h
included meeting with designers and manufacture r s
and witnessing AUV demonstrations in the
and
The majority of the alternatives were academic in nature ,
p roviding limited depth capabilities and electrical
power sources inadequate for the requisite surv e y
sensors. Kongsberg Simrad’s HUGIN was the only
AUV that had functioned at appreciable depths,
p e rf o rming numerous commercial surveys in hundre d s
of metres of water.
The HUGIN was the only AUV integrated with a
L a u n c h - a n d - R e c o v e ry system. Housed (along with the
AUV vehicle) in an air- t r a n s p o rtable cargo container, the
H U G I N ’s Launch and Recovery system has proven safe
and effective in weather conditions up to sea state 5.
The HUGIN’s survey instrumentation is powered by
a unique aluminium oxygen fuel cell developed in
conjunction with the Norwegian Defence Establishment
(FFI). The HUGIN vehicle is currently in routine use by
the Norwegian Underwater Intervention (NUI) pro v i d i n g
h i g h - p recision mapping to water depths of 600 metre s .1
H U GI N 3 0 0 0 S P E CI FI CAT IO NS
Depth Rating = 3,000 metres
Survey Speed = 4 knots
Line Turn Duration = ~5 minutes
Mission Endurance = >40 hours depending upon
payload power load and vehicle
speed
Length = 5.3 metres
Diameter = 1.0 metres
