10.2.1 Feasibility workshop - The effectiveness and efficiency of any ALS will
heavily depend on the operational profile and conditions of the vessel. To fully
understand and categorise vessel operations, LR can host a feasibility workshop with
fleet managers and Operators, in order to identify vessels for which ALS would be
beneficial in their actual use. In addition to operational aspects, the workshop can
discuss initial structural and hydrodynamic considerations, thereby assessing the
feasibility of ALS implementation on specific vessels.
10.2.2 HAZID and roadmap - Once suitable candidate vessels are selected, a HAZID
study can be conducted to identify all the required steps in the installation
process and how each of these steps will impact the current ship operations. Based
on the results of this study, an implementation roadmap can be produced with draft
timelines and required lead times, giving Owners and Operators clear guidelines on
when decisions need to be made for a project to continue smoothly.
10.2.3 Scoping and tendering - LR Marine Consulting can provide valuable assistance
with the preparation and scoping of tendering documents, giving clients the
confidence that tenders will meet their requirements. In addition, assistance can be
provided with the selection of suitable manufacturers, based on their track records,
technical expertise and where appropriate by interviews with the technical staff
from the manufacturers.
10.2.4 Impact study of proposed system - Due to heavy weather conditions
and unforeseen system outages, the ALS might not be able to operate all the time. As
the air cavities themselves create an additional drag on the hull, a non-operational
system will result in an increase in fuel consumption. LR’s validated full-scale
computational fluid dynamics (CFD) methodology can accurately assess this additional
drag, thereby providing clients insight into the financial risk taken with regards
to fuel consumption.
10.2.5 Location of air release units - Using the LR’s validated full-scale CFD
methodology, the variation in streamlines along the hull under different draught and
trim conditions can be assessed in detail, allowing the ALS manufacturer to select
the ideal locations for the air release units in the double bottom. The proposed
locations can then be compared by LR consultants against the structural arrangement
in the double bottom, allowing for a perfect compromise between hydrodynamic and
structural performance.
10.2.6 Structural modelling - The air release units will inevitably interrupt the
longitudinal stiffness continuity in the double bottom structure, requiring support
brackets to be engineered in detail. For this, LR’s structural consultants can
perform a full Structural Design Assessment on the interaction of the air release
units with the double bottom stiffeners. During their assessment, the consultants
can liaise upon the Owner’s instructions with Class and address any concerns.
10.2.7 Noise and vibration - The majority of the ALS will rely on
compressors to force air underneath the double bottom of the hull. Especially for
passenger vessels, the emitted noise and vibrations can impede on passenger comfort.
It is therefore recommended to have a noise specialist pre-assess the proposed
installation, thereby reducing the risk of noise and vibration issues arising. If
special comfort requirements need to be met, LR’s dedicated noise specialist can
carry out verification on board the vessel upon delivery.
10.2.8 Class submission support - LR Marine Consultancy can support the Owners with
the submission of the relevant documents to any Class Society and assist in
understanding and answering any questions that may arise. Having a thorough
understanding of the Rules for Ships, as well as in-depth subject matter expertise,
their support will assure a smooth Class approval process.
10.2.9 Factory acceptance testing - To ensure all components of the ALS
are produced within acceptable tolerances and are fit for purpose, LR consultants
can witness the factory acceptance test on behalf of the Owner. Naturally, the
integration of the air release units with the double bottom structure will be
witnessed by the relevant Class Surveyors, as part of the normal Class approval
process.
10.2.10 Sea trials performance verification - Upon installation of the system, it is
highly recommended performing dedicated sea trials to verify the system’s
performance. LR’s years of experience with performing and witnessing sea trials will
ensure that these trials are conducted to the highest standard, providing Owners
with the certainty that the system performs as designed.
10.2.11 Long-term performance monitoring - To fully understand the long-term impact of
the ALS on the vessel’s fuel consumption, long-term performance monitoring can be
conducted on board. LR’s digital solutions allow Shipowners to collect vessel
performance data 24/7, wherever their vessels sail in the world. The system can be
installed even before the ALS is fitted to the hull, allowing for a relative
comparison before and after retrofitting.
10.2.12 Underwater Radiated Noise Class Notation (UWM-M and UWM-L) - As part of LR’s
mission to protect the environment, the Owner can use LR’s capability with
underwater noise measurement to verify whether the vessel has a reduced underwater
noise signature. The results of which could be used by the Operator to show that,
when using the system in sensitive areas, they have a reduced effect on the aquatic
environment.