1. Design & Operation of Wind Farm Support Vessels, 29-30 January 2014, London, UK
© 2014: The Royal Institution of Naval Architects
OWTIS™ SHIP DEVELOPMENT - REDUCING OFFSHORE INSTALLATION COSTS
AND IMPROVING SAFETY
A West, M Dziedzicka and G Olafsson, W3G Marine Ltd, UK
SUMMARY
The subject of this paper outlines the methodology adopted to develop the arrangement for the OWTIS™ - Offshore
Wind Turbine Installation Ship, a floating ship with a 1500t crane, large clear deck space and the ability to work in deep
water and harsh environments. The design is focused on: safe operations, vessel efficiency and reducing overall
installation costs. The result is a ship providing a high level of safety, operability and capacity at a low cost per unit
installed
In addition, analysis and design work is currently ongoing to enable the loading, transportation and installation of fully
assembled wind turbines onto pre-installed foundations. The ship will offer offshore wind Developers a flexible solution
for offshore wind farm foundation installation, allowing components to be collected efficiently and cost effectively from
a number of ports at a considerable distance from the offshore site.
NOMENCLATURE
DP Dynamic Positioning
FTP Fire Test Procedures
GBP Pounds Sterling
Hs Significant wave height (m)
HSE Health and Safety Executive
ILO International Labour Organisation
IMCA International Marine Contractors
Association
m metres
MW Mega Watt
GW Giga Watt
NM Nautical Miles
OWTIS™ Offshore Wind Turbine Installation
Ship
P Pressure (N m-2
)
PUWER Provision and Use of Work Equipment
Regulations 1998
ROV Remotely Operated Vehicle
SPS Special Purpose Ships
t metric tonne
W3GM W3G Marine Ltd
1. INTRODUCTION
The announcement of the UK Round 3 licences, Scottish
Territorial Waters licences and the German government’s
objectives for offshore wind farm developments in 2010
encouraged a number of companies to look at this new
market as an area that would require support vessels that
are specifically designed for the offshore construction
activities.
1.1 OIL AND GAS RELEVANCE
W3GM has vast experience in offshore construction in
all areas of the world, primarily related to oil and gas,
over the full range of water depths and activities. W3GM
also have extensive experience in defining and building
offshore construction ships and their associated
equipment.
Offshore construction is a mature market in the oil and
gas industry. This market is forecast to continue to grow
rapidly for at least the coming 20 years, increasing in size
by at least a factor of three [1].
The offshore wind industry has different challenges to
that of the oil and gas industry. There are a number of
offshore construction contractors that are solely focused
on offshore wind farm construction. The methodologies
they have developed differ from those traditionally
employed for construction in the oil and gas industry –
namely the use of jack-up vessels. Some of these are
large and can also operate using DP while floating and
when jacked-up offering stable platforms, which meet
the current delicate assembly requirements of the
turbines. These larger jack-ups have had success with
near shore and coastal wind farm construction but are not
suitable for deeper water installation due to the limited
leg length and the high weather downtime which will be
experienced during offshore construction.
It is the view of the authors that significant safety and
cost advancements are available by applying the tried-
and-tested methods of oil and gas construction industry
to the wind industry, but also recognising that there are a
number of different challenges which must also be taken
account of in the development of the construction assets.
1.2 UNIQUE CHALLENGES
The offshore wind industry does present unique
challenges which must be considered when determining
the safest and most cost effective solution. In order to
illustrate the differences, approximately 500 subsea
structures have been installed in the UK sector of the
North Sea since the oil and gas developments
commenced in the 1970’s. The offshore wind industry is

2. Design & Operation of Wind Farm Support Vessels, 29-30 January 2014, London, UK
© 2014: The Royal Institution of Naval Architects
planning to install in excess of 500 structures every year
from 2017 onwards. The oil and gas projects are focused
around the characteristics of the product being extracted.
This is in contrast to the offshore wind industry where
standardisation is a key factor to the economic success of
the industry. The assets used for offshore construction in
the oil and gas industry are therefore not ideally
configured for the series installation.
Looking forward to the UK and German Bight projects
installation will take place further offshore, in deeper
waters and in harsher environments. Should the offshore
wind industry continue with the current approach, there
will be significant increases in costs and safety incidents
as contractors tackle more complex work with unsuitable
vessels and equipment. To counter this, offshore wind
farm developers need to adopt installation plans and
strategies involving the right equipment to meet future
wind farm demands beyond 2017.
1.3 PROPOSED SOLUTION
W3GM was formed to address the challenges described
in 1.2 above. The objective was to understand the
particular challenges of offshore wind farm construction
and develop a solution that would be safe and cost
effective for the industry. This involved taking a step by
step approach through a process with the following
stages:
- Define the problem and create a Basis of Design
- Establish the functional requirements
- Define load out and operational scenarios for
OWTIS™
- Develop an interactive economic model
- Carry out basic naval architecture
- Compare with existing and anticipated market
solutions
- Carry out project case studies
These steps have all been carried out by W3GM over the
last 4 years. This has been an enormous effort for a small
company, which has been supported by IHC Merwede,
the offshore wind farm developers at all levels and also
from turbine manufacturers.
2. RELATED WORK
A number of other concepts of a similar philosophy have
been proposed by other contractors. A2SEA along with
Teekay had a concept based on a converted DP Aframax
tanker. Jumbo shipping and Fred Olsen have presented
concepts based on floating vessels. Norwind and Ulstein
have also presented their concepts. W3GM does not have
access to sufficient information about these ships to carry
out a proper evaluation and comparison.
W3GM has carried out extensive searches of all existing
heavy lift and jack-up vessels, which would theoretically
have the capacity to carry out offshore installation work.
The conclusion reached is that there are currently few
existing potential competitors that can match the safety
and cost objectives and none of which are purpose built
or specifically configured to address the needs of the
offshore wind industry.
W3GM considered the approach of converting an
existing ship. However, the conclusion was that a
conversion would not be a good approach for the
following reasons:
- Donor vessels that were identified required
significant structural modifications
- Donor vessels did not meet the draught
requirements (too deep a draught) – thereby
restricting the number of ports that could be
used
- Donor vessels required additional
accommodation, and associated services
- When older vessels are subjected to ‘major
conversions’ they often have to meet current
requirements that would apply to new vessels
- Donor vessels do not optimise the load carrying
capacity of the ship
- Primary machinery and propulsion needed to be
changed or upgraded in the conversion
- The area for the crane needed significant
strengthening
- Ballasting for crane operations needed to be
upgraded
The conclusion was that a conversion would always be a
significant compromise in capacity, safety and cost.
Furthermore, the converted ship would require to be
depreciated over a shorter period thereby reducing any
possible cost advantage. The only possible reason for
considering a conversion instead of a new build could be
that it may be available sooner although even this should
be questioned as historically conversions have had
significant cost and schedule variations and always
detrimental on both counts.
3. PROBLEM DEFINITION
3.1 OFFSHORE WIND SITES
As the offshore wind industry has developed,
installations have progressively shifted further from land
to take advantage of the stronger and more consistent
winds found offshore. Installations are increasingly sited
in deeper waters. Projects to date, such as the SSE
Greater Gabbard field are in the region of 24-34m water
depth [2], whereas future projects such as the Forewind
Dogger Bank will be at depths of up to 63m [3]. The
harsher environmental conditions further from shore lead
to smaller weather windows where it is feasible for the
installation to work and perform tasks safely. Increasing
water depth renders many jack-up assets obsolete,
necessitating the development of larger more expensive
vessels. The variation of seabed also precludes the use of
jack-ups where uncertain levels of soft soil and mud are
present necessitating the use of floating solutions for
carrying out the construction work.

3. Design & Operation of Wind Farm Support Vessels, 29-30 January 2014, London, UK
© 2014: The Royal Institution of Naval Architects
3.2 SIZE OF THE TURBINES AND
FOUNDATIONS
In addition to moving away from shore, wind turbines
have become larger. As a function of both developments
in the manufacture of turbines and the higher quality
wind available offshore, the size and capacity of turbines
is increasing significantly. A 6MW turbine is currently
being tested by Siemens; a 7MW turbine is currently
being tested by Mitsubishi, both in preparation for
offshore deployment, (for SSE in Hunterston). Samsung
are testing a 7MW turbine at Methil. This coupled with
the increase in water depth results in large, heavy
structures which require a large crane capacity for
construction activities. Existing installations typically use
a monopile type foundation in shallow water. With
increasing turbine size, weight and environmental loads
as well as increasing water depth, jacket type structures
are becoming increasingly attractive. Jackets are for
example installed on three or four piles and can be suited
to any depth and designs easily scaled up. Current vessel
crane capacities are in many cases insufficient to manage
such lifts efficiently, due to crane height, payload or
weight restrictions.
3.3 MAGNITUDE OF THE CHALLENGE
The overall size of the sites are also becoming larger.
The Dogger Bank site, representative of the Round 3
developments, will occupy an area equivalent to the size
of North Yorkshire (8660 km2
) with an installed capacity
of 9GW [3], making it significantly larger than the
London Array (680MW) which is currently the world’s
largest offshore wind farm.
4. KEY CONSIDERATION IN DESIGN
During the development of the design a large number of
inter-related parameters were identified. Choices had to
be made to reach the safety and cost effectiveness
objectives for the OWTIS™.
4.1 OPERATIONAL EFFICIENCY
Measured as the output from the system compared to the
work input, operational efficiency in terms of the
installation offshore can be improved through the
following factors:
- Minimisation of man-hours offshore
- Autonomous operation (no dependence on other
ships
- No requirement for expensive diving operations
- Maximise the number of operations that can be
completed and monitored without underwater
intervention
- Minimise critical path activities
4.2 WEATHER DEPENDENCY
North Sea waters are some of the harshest work
environments in the world. In order to achieve the most
efficient operation the following should be assured:
- Ability to work in a minimum of 2.5m Hs
(typically for the central North Sea this means
that there will on average be 20% weather
downtime during a year, while if the capability
is 1.8 to 2.0 m Hs then the weather downtime
will be of the order of 40%)
- Short duration activities so that all short breaks
in the weather can be used (less exposure to
alpha factor [5])
- Operations planned to avoid the use of small,
supporting boats
- Unrestricted sailing with cargo on deck, as
capable of being at sea in 9m significant wave
height.
- All equipment (e.g. ROV’s) to be capable of
operating at the vessel operating limits.
4.3 VESSEL CONSTRAINTS
To face the ever-growing turbine, foundation and site
size, the ship has to be large enough to load, transport
and install the required quantity of cargo.
On the other hand length, breadth and draught should
allow access to the strategic load-out ports.
4.4 SCALE
The OWTIS™ offers realistic and reliable installation
rates meeting the forecasted industry demand during the
expected service life of the vessel.
4.5 ENVIRONMENTAL IMPACT
The following challenges have been considered:
- Minimise the impact on the seabed (the
OWTIS™ is a floating installation vessel that
does not touch the seabed)
- One efficient ship instead of two or three less
effective ships
- Ability to work in harsh weather means that the
ship will incur less standby
- Minimise the carbon footprint for each
installation
4.6 LOGISTIC CHAIN/ SUPPLY BASES
The logistic and supply chain for offshore wind is on the
critical path of the cost reduction. Installation vessels
should be built to support it and to provide:
- Predictable load-out rates which will cause less
congestion in the upstream supply chain
- Larger load-outs requiring fewer port calls
- Ability to lift structure from barges at sea if
conditions permit
- Ability to transit to a number of different ports
so that the upstream fabrication supply chain

4. Design & Operation of Wind Farm Support Vessels, 29-30 January 2014, London, UK
© 2014: The Royal Institution of Naval Architects
can be managed more flexibly than if only one
port is used for all load outs
The main limiting factors for port entry are draught and
beam. A ports study was carried out and the OWTIS™
can enter all potential load-out locations in the UK,
Germany, Holland and Denmark.
4.7 SIZE OF STRUCTURES TO BE INSTALLED
It is anticipated that the majority of wind turbine
foundations will be steel structures and will either be
some form of space frame or monopiles. The weights are
expected to be up to 1200t. The footprint for steel space
frames are expected to range between 17 and 28m centre
to centre. The heights are expected to be up to 80m,
including suction buckets or leg stick-outs for installing
into pre-installed piles.
The OWTIS™ is also capable of loading and
transporting fully assembled wind turbines. The sizes and
weights considered were 80m hub height, 70m blades
and a weight of 720t. The allowable accelerations due to
ship motions at the turbine hub are 0.38g longitudinal,
2.0g vertical and 0.74 transverse.
These requirements defined the minimum lifting capacity
and geometry of the crane to be capable of an offshore
lift in a significant wave height of 2.5m 30m from the
crane centre.
4.8 CRANE LOCATION
The crane has been located over the transverse midships
offset to port, in order to minimise the crane tip motions.
The traditional approach of locating the crane at the stern
increases the crane tip motions significantly such that
lifting is generally limited to a significant wave height
less than 2.5m. The positioning of the crane near the
longitudinal centreline and to port means that the boom
can be stored facing forward on a rest located on the
accommodation block increasing vertical space above the
deck is maximised allowing the transportation of the
maximum number of tall structures. W3GM have studied
existing ships and jack-ups and have found that the
OWTIS™ arrangement provides the greatest amount of
uncluttered deck space, including vertical clearance,
when compared to other heavy lift vessels.
Another critical factor for the economics of the ship is
that the OWTIS™ is designed to load in port, transport
and install the foundations. Other solutions may need
other means such as barges to transport the structures to
the site which will result in a significant reduction in the
allowable weather window for lifting as a lift off a barge
is a more onerous lift than an off the deck lift which is
the planned operating model for the OWTIS™.
OWTIS™ can lift structures from a barge in benign
conditions so there is no loss in flexibility by choosing
the crane location arrangement.
4.9 OTHER FUNCTIONAL REQUIREMENTS
Once the crane location, size, geometry and
environmental conditions for lifting were defined then
further work was carried out to establish the functional
requirements. The functional requirements addressed
issues such as design rules, particular safety issues, codes
and standards, speed, DP capability, deck systems, deck
capacity, accommodation size and load out scenarios.
The load out scenarios were related to the economics of
the vessel – a target was set that the ship should be on
site at least 80% of the time. This means that the ship
spends less than 20% of its operational time in port
loading, transiting or waiting in port for the necessary
environment conditions to sail.
In order to meet the required 80% of operational time on
site, definition of the minimum payload of piles or
number of foundations to be transported in each load is
required, and a minimum loaded transit speed and
weather criteria for sea fastening structures on the deck.
The conclusions were as follows:
- Speed loaded requires to be at least 13 knots
- The sea fastenings for foundations should be
suitable for 9m significant waves
- The deck should be capable of carrying 6 x 650t
jackets or 5 x 820t jackets in the vertical
orientation. The ship should be capable of
carrying and deploying jackets up to 1500t but
will be able to transport fewer than 5
Once these functional requirements were defined some
initial naval architecture was carried out to identify a
feasible design. The design had to meet the above
parameters plus such scenarios as losing the load off the
crane. The basic vessel outline was created with the
following primary dimensions: (see Figure 1)
- Length 194.5m
- Beam 38m
- Depth 14m
- Draught 8.1m (maximum, normally <
7.3m)
- Deck space 5200m2
- Main crane 1500t at 30m in Hs 2.5m
(100000 tm crane)

5. Design & Operation of Wind Farm Support Vessels, 29-30 January 2014, London, UK
© 2014: The Royal Institution of Naval Architects
Figure 1 – OWTIS™
4.10 AUTONOMY
The OWTIS™ has been designed to carry out the
complete works for foundation installation. No further
support ships are required and no small boat transfers are
needed. The work that will be completed by the ship
typically for a pre-piled jacket will be:
1. Piling Campaign
- Load the structures and piles in port using the
vessel crane
- Sea fasten the components on the deck
- Transit to the site
- Initial visual survey of the seabed using ROV
- Installation of a piling template
- Installation of piles
2. Jacket Installation Campaign
- Load jackets and seafasten to deck
- Transit to site
- Installation of the jacket
- Grouting of the jacket to the piles
- As-installed ROV survey
In order to achieve this, the ship will be fitted with two
ROVs, telescopic manned access systems and grout
storage and a dry air system for transferring the grout.
Two access systems will be fitted, one as 100% backup –
see Figure 2.
Figure 2 – Access gangway deployed from OWTIS™ to
jacket
There will be no interdependence on vessels, and
therefore no potential for knock on delay. All the
equipment on board the OWTIS™ is capable of being
used in at least 2.5m Hs.
5. TYPICAL PROJECT EXECUTION
The following outlines a typical project execution. This
is not the only scenario that can be handled by the
OWTIS™ but has been used to validate the design. This
validation is one of a number of case studies which have
been analysed during the design development, using real
data and constraints, provided by developers.
The use of case studies is essential in the development of
a design like the OWTIS™. It tests all the steps in the
installation phase from load out using the vessel crane in
port, re-fuelling, loading grout, port turn around, transit,
site arrival, survey and installation work.
In this case study the ship will be required to carry out
the following activities:
- Load out in port, including piles, jackets, piling
equipment, grouting equipment, turbines (in the
future) and all ship supplies of fuel and stores
- Transport of the permanent equipment offshore
- Carry out the installation work
5.1 LOAD-OUT IN PORT- GENERAL POINTS
Efficient load-out operation in port requires the
following:
- The ship is to be moored port side along a quay
in such a way that there is at least 50 m of quay
either side of the vessel’s crane

6. Design & Operation of Wind Farm Support Vessels, 29-30 January 2014, London, UK
© 2014: The Royal Institution of Naval Architects
- Components are delivered to the crane from
onshore which can alternatively load materials
to the fore and after parts of the clear working
deck
- The deck has a rail and carriage system to which
the cargo is to be sea fastened and using the
carriages the cargo is moved away from the
crane to allow the loading of more cargo
- The crane boom rest is located on the
accommodation block resulting in a large clear
working deck
The proposed equipment layout in the port during load-
out has been illustrated in Figure 3.
Figure 3 – Port load out
5.2 PILING CAMPAIGN LOAD-OUT IN PORT
Efficient load-out of the piles includes following
assumptions: (See Figure 4)
- Piles will be lifted in sets of 4 (~600t total) by
the ship’s crane and stored in two areas along
the starboard side of the vessel (12 lifts for
7200t)
- The piling and pile handling equipment will be
stored in the area forward and aft of the crane
- The ship will be able to refuel simultaneously as
the objective is to have no planned welding on
deck during loading
- Ship stores can be loaded simultaneously using
one of the two forward 30t cranes located on the
aft part of the accommodation
Figure 4 – OWTIS™ loaded for piling campaign
5.3 JACKET INSTALLATION CAMPAIGN
LOAD-OUT IN PORT
Efficient load-out of the jackets includes following
assumptions: (see Figure 5)
- The jackets are to be delivered to the ship in two
lines approaching either side of the crane
- The crane will lift each jacket in turn and locate
it onto one of the deck rail carriages which will
be adapted to sea fasten the jackets without
welding resulting in an increased operability
- The carriage will then be moved away from the
crane in order to clear room for the next jacket
to be loaded
- The grouting spread will be stored forward of
the crane
Figure 5 – OWTIS™ loaded for jacket installation
campaign
5.4 FIELD OPERATIONS- GENERAL POINTS
Efficient field operation will involve the following:
- Operations will be performed with DP
- For jacket installation the base case is for pre-
piling to be carried out using a template which

7. Design & Operation of Wind Farm Support Vessels, 29-30 January 2014, London, UK
© 2014: The Royal Institution of Naval Architects
will be deployed and recovered using the main
crane.
- Offshore operations will be predominantly
carried out over the port side of the ship
- Where possible all movements of equipment
and materials on deck while at sea will be by
mechanical handling, not swinging on the crane
- Deck operations will be remotely controlled
where possible to minimise the number of
personnel on deck. This will reduce the number
of hazards to personnel.
- Access to the crane, ROV’s and control room
area (located around the base of the crane) will
be from a below deck passage from the
accommodation block (minimising personnel on
deck).
- There will be two ROV’s located beside the
crane for subsea intervention work.
- There will be two motion compensated
personnel access systems located at 20m above
the waterline either side of the crane
5.5 FIELD OPERATIONS- PILING
The steps for the piling will be as follows
- Locate the site
- Set-up on DP
- Survey the seabed
- Deploy the piling template
- Pile each pile to depth
- Carry out relative height metrology
- Survey the site
- Recover the template
- Move to next site
5.6 FIELD OPERATIONS- JACKETS
The following steps are for jacket installation
- Deployments can be carried out both forward
and aft of the crane
- The ship will locate to the deployment site
- The ROV will be launched to survey the piles,
including checking that there is no build up of
material inside the pile
- Any material inside the pile will be dredged out
and the pile re-surveyed
- Once the seabed site is ready the jacket will be
connected to the crane
- The jacket will be released (mechanically) from
its sea fastenings and lifted and deployed by the
crane (constraints will be used to prevent any
swinging of the load)
- The jacket will be deployed into the water and
the first (longer) leg will be located into the first
pile
- The jacket will then be manoeuvred into
position so that the other legs are lined up and it
will be lowered until the load is transferred
- The motion compensated access system
gangways will be deployed and the grouting
hoses connected to a manifold at the top of the
jacket
- The personnel will be withdrawn and the
grouting operation will be carried out from the
ship
- Once the grouting operation is complete and the
work is surveyed the ship will move to the next
site
5.6 SAFETY
Safety is built into the vessel and its operating model. By
using the vessel, the components will be handled the
minimum number of times (i.e. no intermediate
transportation is required). Also, as far as possible all
materials are handled mechanically on the deck reducing
the risks of swinging loads. The need for personnel on
the deck has been kept to a minimum and even deck
handling operations will be by facilities that will be
controlled some distance away from the moving
materials.
There are many other safety aspects that have been
incorporated that add to the security of the operation.
There is no operational requirement for small boat
transfers. The crane will have independent power
supplies from each switchboard. There are two motion
compensated access system, 100% backup. There is a
below deck corridor between the accommodation and the
operational centre around the crane reducing the need for
personnel to be on deck.
6. BASIC NAVAL ARCHITECTURE
The general requirements for the design considered and
evaluated a floating ship with crane offset to one side and
rail and carriage system to move cargo in and out of
crane radius over a clear, large high load capacity deck.
The ship will operate on DP. The following design work
has been carried out:
- Ship, including load out cases, stability, tank
capacities, tank plan, lightweight breakdown,
load balance, KG curves
- Deck rail system preliminary design
- Motion results for jackets and piles on deck
- DP plots
- Load Balance
- Electrical distribution
- Pile and jacket installation motion analysis
- Pile up-ending and installation procedures
- Fuel consumption study
- Speed and power
- Crane manufacturer confirmation of feasibility
6.1 CODES AND STANDARDS
The ship and crane will be classed by one of the leading
Class Societies in accordance with their rules.

8. Design & Operation of Wind Farm Support Vessels, 29-30 January 2014, London, UK
© 2014: The Royal Institution of Naval Architects
In addition other standards and guidelines that are to be
complied with (e.g. IMCA, SPS code, PUWER, ILO,
HSE, FTP and Flag State)
7. ECONOMIC MODEL
The objective of the OWTIS™ design was to develop a
vessel which would efficiently perform offshore
construction work to the highest safety standards at a
lower cost per unit installed in comparison to current
installation methods.
The main drivers for the economics are as follows:
- Load carrying capacity
- Ability to operate in 2.5m Hs as a minimum
- Transit speed, loaded
- Minimise restrictions on sailing with regard to
sea fastening capability
- Flexible operations, there are no tasks that
require longer than 6 hours meaning that all
short weather windows can be used
- Minimise the number of critical path activities
The typical project execution outlined in 5. above was
used as the basis of a cost study. The criteria were as
follows:
- Load out, transport and install 4 piles for each
jacket (pre-installed piles)
- Piles 60m long, 140t
- Five jackets 820t each
- Load out, transport and install jackets, including
the grouting
- Distance from port 100NM
- Location, North Sea, waves < 2.5m Hs for 80%
of the year
The result is that in excess of 100 foundations can
comfortably be installed in a year, and it could be up to
130. This requires no intervention from any other
vessels. The OWTIS™ can collect components from a
number of different ports; thereby bring flexibility to the
upstream supply chain which may offer developers
further economies and opportunities.
The following are included in the cost model:
- Project management
- Quality, Safety, Health, Environment and
Security management
- Installation engineering (from quayside lifting
to completion offshore
- Procurement of all non-permanent works
- Sub-contracting of all services to carry out the
work (e.g. grouting and piling)
- Managing offshore personnel
- Project support services for planning,
administration cost control and reporting
This is a full installation service costing exercise. No
costs for any part of the permanent works are included.
The resulting cost is around 1-1.1MGBP per foundation.
This compares a cost of 2.2MGBP in [4].
8. CONCLUSIONS
The process which has been used to develop the
OWTIS™ has resulted in a design that provides a
significant improvement in the safety and cost
effectiveness for the offshore installation of wind turbine
foundations. The industry is still at a stage where
dramatic cost savings are possible.
The industry predicted costs for the installation of
foundations will be less than half if the OWTIS™ is used
for the work. This applies to materials picked up from a
number of different ports for the same project, with the
ports at significant distances from the offshore worksite.
This provides developers with potential upstream savings
in their supply chain as it provides flexibility as to where
the components are manufactured.
The key steps that have been followed are to:
- Define the problem and create a Basis of Design
- Establish the functional requirements
- Define load out and operational scenarios for
OWTIS™
- Develop an interactive economic model
- Carry out basic naval architecture
- Compare with existing and anticipated market
solutions
- Carry out project case studies
It should be noted that the final step is crucial and
W3GM have spent over one and a half years dedicated to
this step in conjunction with major offshore wind
developers.
The OWTIS™ will be developed further to carry out the
load out, transportation and installation of fully
assembled turbines and initial economic analysis shows
that further significant cost savings are possible.
9. ACKNOWLEDGEMENTS
The development of OWTIS™ would not have been
possible without the input and vision of certain
individuals. Stewart Willis was one of the founders of
W3GM and had 10 years experience in the offshore wind
industry. Stewart brought a wealth of experience in the
offshore construction industry and was instrumental in
determining the problem which required to be solved.
Martin Welsh of Reflex Technical Solutions Ltd also
made a significant contribution by taking the functional
requirements and carrying out the basic naval
architecture that was to define the size and capacities of
the ship in order to meet the codes and standards.
IHC Merwede carried out the basic design of the ship
based on the functional specifications and the naval
architecture.
Many of the developers supported W3GM in carrying
out the case studies which are crucial in the development
of an offshore construction asset.

9. Design & Operation of Wind Farm Support Vessels, 29-30 January 2014, London, UK
© 2014: The Royal Institution of Naval Architects
Furthermore we have had support and suggestions from
the turbine installation manufacturers which has been
essential input for the work.
Scottish Enterprise and the Business Gateway have
engaged and helped W3GM, assisting with contacts and
business support.
Many other people, too many to name, have patiently
helped W3GM with discussions and as a sounding board
during the development of the OWTIS™ for which
W3GM are grateful and again we needed this industry
feedback to ensure that we have the best solution.
10. REFERENCES
1. Ivy Fang, Professor Fai Cheng, Professor Atilla
Inceik, Patrick Carnie, Global Marine
Trends 2030, ISBN: 978-0-957904-0-3
2. Fluor website
http://www.fluor.com/uk/projects/Pages/pro
jectinfopage.aspx?prjid=64#projectTitle
3. Forewind website
http://www.forewind.co.uk/dogger-
bank/overview.html
4. The Crown Estate, ‘Offshore Wind Cost
Reduction – Pathways Study’, May 2012.
5. DNV – Rules for Planning and Execution of
Marine Operations – January 1996, Pt.1
Ch.2 3.OPERATIONAL
REQUIREMENTS Table 3.1
11. AUTHORS BIOGRAPHY
Alan West holds the position of CEO at W3GM. A
Senior Executive with a significant worldwide
Management record of over 31 years in the offshore
subsea contracting industry, working on multiple
projects, asset and offshore personnel management and
asset development and building.
Marzena Dziedzicka holds the position of a Project
Engineer for W3GM. Marzena has a Masters Degree in
Mechanical Engineering has been involved in the project
for two years.
Geir Olafsson holds the position of a Project Engineer
for W3GM. Geir has a Masters Degree in Mechanical
Engineering has been involved in the project for two
years.