Africa Surveyors November-December issue 2023

INNOVATION
Hydrus:
For Greater Flexibility, Manoeuvrability
and Scalability
Image: NAVIGATION TECHNOLOGIES
By Peter Baker
Subsea pipeline inspection is critical
to the safe transfer of oil and gas
from off-shore rigs to storage and
processing facilities on land. As perhaps
the costliest and most widely installed
component in subsea infrastructure, subsea
pipelines bear a high possibility of suffering
damage. This could be the result of anything
from equipment failure and corrosion to
human error and natural causes.
The timely inspection of subsea pipelines is
key to preventing damage such as oil spills
and leakages. Typically, these inspections
require either sending a well-trained human
diver or using large and heavy work-class
ROVs, however both methods have downsides.
The first puts the diver at risk, which becomes
greater the deeper they travel underwater.
The second method remains suited only
to large-scale operations and at suitable
depth. A common challenge industries face
is when depths and other conditions are
not favourable. For example, as the water
becomes shallower or the environment more
sensitive to larger vessels, complications
arise in getting appropriately sized and
manoeuvrable equipment into place.
Additionally, ROVs are costly to build and
maintain, often requiring large, specialised
crews to deploy and retrieve. They are also
limited by the length of their tethers and
the need for constant human supervision,
impacting the frequency and scale of
inspections.
The demand for greater flexibility,
manoeuvrability and scalability is driving
underwater drones, or micro-AUVs, to become
an increasingly popular tool for inspecting
subsea pipelines. This concept was introduced
to the market when Advanced Navigation
launched Hydrus, a fully autonomous
underwater drone that miniaturised
multiple technologies to enable a drone-like
experience for users underwater.
Weighing in at less than 7kg, Hydrus
is effectively an all-in-one untethered
autonomous solution ready for use directly
out of the box. Capable of being launched
and retrieved by a single person, it alleviates
the need for expensive survey vessels and
highly trained operators. The compactness
and deployability bring simpler logistics,
minimal complexity, reduced downtime
and operational costs. These are important
attributes, given the offshore energy sector
is becoming increasingly aware of the
total carbon emissions of projects and
consequently seeking technologies that can
help reduce footprints.
The traditional approach of sending a
large construction vessel equipped with a
work-class ROV is inefficient, expensive and
labour-intensive. The answer to this challenge
is smaller vessels that burn little to no fuel,
remove humans from dangerous conditions
and can be deployed on a large scale.
Specifically in the offshore energy sector,
scalability is pivotal to the effectiveness of
any kind of operation.
Being fully autonomous, Hydrus can have its
missions pre-planned while on land. Once it
goes underwater, it can repeat missions and
deliver data back without requiring ongoing
human interaction. In the case of a large oil
field, multiple Hydrus units can be deployed
to inspect various sections of the pipeline and
recharge via the docking stations. To assist in
retrieval, the unit has lighting and an onboard
GNSS receiver that can help navigate to the
exact pickup point.
18 November-December issue l 2023 www.africasurveyorsonline.com