Download - Hydrex Underwater Technology

Underwater bow thruster repair/replacement
Applying Ecospeed Ship Hull Performance
Technology: A discussion with three experts
on underwater ship hull coatings
Hydrex around the world An interview with Willem White Papers from
Hopmans, Hydrex Senior
Diver
Hydrex
Number 171

EASY AND EFFECTIVE
UNDERWATER HULL CLEANING
AROUND THE WORLD
Throughout the years
Hydrex has invested in
the development of underwater
hull cleaning equipment
and now offers an international
service that can give ships
back their efficiency. This
quick and effective service is
offered on a worldwide basis
through a network of underwater
hull cleaning stations
strategically located around
the planet.
All Hydrex underwater hull
cleaning units are carefully
constructed to minimize the
occurrence of damage on the
underlying paint layers while
still removing all types of
fouling. This restores a vessel’s
performance as close to its
optimum condition as possible
and offers ship owners a considerably
saving in fuel.
2
All Hydrex offices and service
stations are equipped with
multiple sets of these hull
cleaning units which can be
mobilized rapidly to any port.
All divers are trained to
achieve the fastest possible
cleaning rates without losing
the high quality Hydrex is
known for.

Table of contents
3
Underwater bow thruster
repair/replacement 5 - 9
Applying Ecospeed Ship Hull Performance
Technology: A discussion with three experts
on underwater ship hull coatings 10 - 17
Hydrex around the world 18 - 21
An interview with Willem Hopmans,
Hydrex Senior Diver 23 - 25
White Papers from Hydrex 25 - 26

Message from Hydrex
founder Boud van Rompay
I
sincerely hope you had a wonderful
Holiday Season and a good
start of the new year and I would
like to wish you all the best for 2011.
The past year was a very productive
one for Hydrex with our diving
teams almost constantly on the road
to assist ships around the world.
2011 promises to be equally busy
with several big jobs already in the
pipeline.
It’s not only our diving-technician
teams and our technical departments
that have been working hard in 2010.
We have also combined our Hydrex
and Ecospeed magazines and expanded
the content to provide you with a
more comprehensive account of the
activities of the Hydrex group. This
gives us the opportunity to write about
more of the smaller but interesting
operations as well as publishing
longer feature articles on specific
topics of interest.
The first feature in this magazine
deals with underwater thruster operations.
In 2010 Hydrex carried out
many bow thruster and azimuth thruster
operations, a short summary of
which you can find in the article. By
carrying out these operations underwater,
Hydrex gives its customers the
opportunity to have a defected thruster
unit removed, overhauled and reinstalled
without having to take the
vessel to drydock. With our unique
flexible mobdock technique, both
sides of the thruster tunnel can be
closed off. This enables us to create
a dry environment underwater in
which our diver-technicians can also
reinstall the propeller blades of
an overhauled thruster or perform
repair work on a specific part without
removing the unit. Not having to
drydock is a distinct advantage since
the repair can be carried out wherever
the ship is with minimal interruption
to operations.
In the second feature we take a closer
look at the benefits that an Ecospeed
application can offer during drydocking
to everyone involved. We
spoke to three experts and have tried
to offer our readers a broader view of
what makes the Ecospeed underwater
hull coating stand out from other
systems.
Together with the publication of our
revamped magazine we have also
begun publication of a series of white
papers related to underwater hull
protection, maintenance and repair.
A short abstract of the second of
these white papers can be found in
this magazine. The full version of
each of these papers can be downloaded
from both our websites
(www.hydrex.be and www.ecospeed.be).
This magazine also includes Hydrex
operations from around the world and
an interview with Hydrex Senior
Diver Willem Hopmans who started
his career salvaging lost munitions
from World War II.
I hope you enjoy reading this magazine
and if you have any questions
about any of the articles or one of our
services, please do not hesitate to contact
us.
Best regards
Boud van Rompay
4
Underwater bow thruster repair/replacement.
ISO 9001 certified
To receive a free copy, fax to:
Hydrex N.V. +32 3 213 53 21
or e-mail to hydrex@hydrex.be

Underwater bow thruster
repair/replacement
Hydrex was the first company to
show that it was possible to
remove and then replace thrusters
by creating a dry environment underwater.
Using the Hydrex-developed
steel mobdocks to seal off the
thruster tunnel, with an access shaft
protruding above the water, work
teams accessed the thruster tunnel
and removed or repaired the thruster
within the tunnel in complete
safety. This was done in conditions
similar to above water.
Hydrex has since then developed this
technology further using lightweight
flexible mobdocks. These modernized
mobdocks, which are designed to be
easily transported around the world,
are used to close off the thruster tunnel
on both sides. This allows divers to
work in a dry environment around the
unit and enables them to reinstall the
propeller blades of an overhauled
thruster inside the thruster tunnel after
the unit has been secured. They can
also replace the blades or seals and
perform repair work on a specific part
without removing the unit. These operations
are carried out in partnership
with Dutch thruster specialist AEGIR-
Marine Propulsion Service.
“Hydrex divers can replace the blades or seals and
perform repair work on a specific part of the bow thruster
without removing the unit.”
Work on thruster unit inside closed off
thruster tunnel.
There is no need to send the vessel
to drydock as all operations can be
carried out in port or while the vessel
is stationary at sea. Normal commercial
activities can therefore continue
without disruption.
In the last few years Hydrex divers have
5
used the flexible mobdock technique on
numerous occasions for bow thruster
operations around the world, thus
winning for Hydrex the prestigious
Ship Repair and Conversion Award at
Lloyd’s List Global Awards 2009.
Some cases in point from the past
year.
Underwater azimuth thruster
operations in Gabon and Spain
Large tailor made mobdock used during
azimuth thruster operation in Gabon.
When one of the four 40 ton swing-up
azimuth thrusters of an offshore crane
barge which was servicing rigs on an
oil field off the coast of Gabon malfunctioned,
Hydrex was called in to
40 ton thruster lowered onto support unit.

Spare thruster unit brought onto work barge.
remove the thruster and perform the
necessary repair work while the unit
remained at anchor just outside the
field.
While it is possible to maintain location
with three thrusters, the fourth
needed to be repaired straight away.
This had to be done in the short timeframe
in between two scheduled operations,
which was the only time the
barge could leave the oil field. All
repairs and other servicing work need-
ed therefore to be carried out before
the start of the next operation.
A similar operation had been planned
and carried out by Hydrex three years
ago. Just as with the recent operation,
going to drydock had not been an
option as the nearest suitable location
"The operation was carried out in a safe, professional and
time efficient manner, which is not less than what we have
grown to expect from Hydrex.”
Bolts secured to complete thruster repair.
was South Africa and this would
extend the repairs far beyond the
available timeframe. For this reason a
large mobdock (measuring 9 x 6 x 2
meters and weighing over 25 tons by
itself) was constructed under Hydrex
supervision in Belgium after which
it was transported to Gabon. There it
was stored after the repair to be used
at short notice whenever future repairs
were required on the thrusters. This
allowed for a very fast mobilization
and execution of the operation carried
out at the beginning of 2010.
It was an extremely precise operation
requiring a great deal of coordination
6
and organization to ensure that all
went smoothly. There were detailed
safety and technical procedures that
had to be met in order to access the
thruster from within the engine room
as the thruster was located outside the
vessel under the water line. Despite
this, all technical work was performed
smoothly by qualified Hydrex divertechnicians.
They worked in shifts to
finish the operation as soon as possible
and without any loss of quality.
More recently Hydrex mobilized
equipment and a diver-technician
Overhauled azimuth thruster lowered back
into the water.
team to perform a class approved
operation on the heavy-lift semi-sub
crane vessel Saipem 7000. The inspection
and the underwater removal
and reinstallation of one of its 60
ton azimuth thrusters were performed
in Cartagena, Spain.
By taking advantage of one of our
workboats stationed at the Algeciras
office, all necessary equipment was
mobilized to Cartagena where the
semi-sub vessel was given a full maintenance
service as part of the prepara-
Overhauled azimuth thruster guided
under water with wires.

Hydrex diver-technician guiding azimuth thruster during removal.
tions for an operation in the Gulf of
Mexico.
The operation started with a class
approved UWILD inspection of the
two hulls and all twelve of the vessel’s
azimuth thrusters.
Cold straightening of severely bent
propeller blades
In its quest to provide cost effective
services to customers,
Hydrex developed procedures
to address different kinds of
damage to propellers. This research
led to the design of the
Hydrex cold straightening machines
first used in 2002.
By taking advantage of this technique
damaged blades can be
straightened underwater, allowing
the ship to return to commercial
operations without the need to
drydock. Blades can be brought
back close to their original form,
restoring the propeller’s optimum
efficiency.
The cold straightening machines
have been in use for quite some
time now but the Hydrex research
department has been looking into
ways to expand the technique even
further to improve our services.
A new version of the straightening
thrusters had suffered damage on the
leading edges. Hydrex was asked to
perform repair work on these blades
in addition to the thruster renewal.
Both operations were successfully
performed under the supervision of
the factory representative and the
classification surveyors.
Hydrex had performed maintenance
and repair work for this customer
before. Familiar with our procedures,
he asked us to send an experienced
and fully certified diver-technician
team to carry out a detailed and high
"During the operation the team worked in shifts to make
sure that the repair would be finished before the vessel
had to depart."
The inspection revealed that two of
the propeller blades of one of the
7
quality underwater inspection and
azimuth thruster removal. According
machine was recently put into
practice. It is compatible with
the existing models and is used
to restore more severely bent
propeller blades to their original
condition.

Hydrex diver-technicians preparing the
engine room for removal of a bow thruster
unit in Singapore.
to Mr. Maarten Heitling, the customer’s
Manager Lifting Fleet, “the
work went very well. The team and
equipment was readily available for
the task and the operation was carried
out in a safe, professional and timeefficient
manner, which is not less
than what we have grown to expect
from Hydrex.”
Underwater bow thruster replacements
in harsh conditions
When a 300 metre container vessel
lost the blades of its bow thruster,
Bow thruster unit brought to surface in
Singapore.
Hydrex was asked to remove the
damaged thruster and replace it with a
spare one. The operation was carried
out while the vessel was at anchor in
Singapore.
Because of the tight schedule of the
ship, the entire operation was planned
and launched as rapidly as possible.
Just days after the order was confirmed,
the equipment and eight
Hydrex diver-technicians arrived in
Singapore where the team was completed
with an additional work force
supplied by our local support.
The old bow thruster unit was removed
from the tunnel and brought
onto a work barge. From there it was
transported to the workshop to be
thoroughly examined to determine
what had gone wrong. In the meantime
the spare thruster had been prepared
and was subsequently brought
inside the thruster tunnel and secured.
The Hydrex team then installed the
propeller blades.
During this operation the diver-technician
teams worked in shifts to make
sure that the repair would be finished
before the vessel had to depart and
this despite the unavoidable loss of
Overhauled bow thruster prior to
reinstallation.
"Hydrex’s flexibility allowed the company’s technical
department to adapt the repair to the vessel's sailing
schedule."
8
time that the poor weather conditions
brought about. The vessel could once
again use its thruster to maneuver
inside ports without depending on
external assistance.
Last October Hydrex diver-technicians
carried out another bow thruster
operation on a container vessel in
Hydrex team members manoeuvring thruster unit.

Singapore, this time on a 380 meter
ship that only needed the removal
of its bow thruster unit. The superintendent
of the ship was very satisfied
with the operation. He said that
“the job was completed well within
the time frame of 40 hours thanks to
good team work of the Hydrex divers,
the ship staff and the floating crane
operator.”
Closer to home and in better weather
circumstances, Hydrex carried out
the removal, transportation and reinstallation
of a bow thruster unit in
stages in several locations to allow
the vessel to keep to its sailing schedule.
A 334 metre container vessel had
to use the services of a tug boat
for port maneuvering due to a malfunctioning
thruster unit and its
owners commissioned Hydrex to take
care of the entire overhaul.
After the bow thruster unit had been
removed it was transported to the
Hydrex Fast Response Center and sent
on to Norway for repairs. As soon as
the overhauled gearbox returned to the
Hydrex headquarters it was mobilized
to the container vessel’s next port of
call for reinstallation.
The vessel can now maneuver inside
ports again without the need of a
tugboat. Hydrex’s flexibility allowed
the company’s technical department
to adapt the different parts of the
repair to the sailing schedule. The
operation was carried out in Rotterdam,
Southampton, Le Havre, Dunkirk,
Hamburg and finally Rotterdam
and Southampton again. Despite these
multiple locations, the delay for the
customer was reduced to the absolute
minimum. The removal and reinstallation
of the bow thruster unit under
water made it unnecessary for the
vessel to go into drydock.
HYDREX OFFICE FULLY
OPERATIONAL
AT THE STRAIT OF
GIBRALTAR
Our Hydrex office in
Algeciras, Spain offers a
large variety of maintenance
programs and repair works for
ship owners and the offshore
industry, both underwater and
above water.
Underwater maintenance services
include hull cleanings, propeller
polishings, class accepted surveys
and tail-shaft wear down readings.
Underwater repair work consists of
propeller repairs, shell plating
crack repairs, mobdock repairs,
rudder pintle repairs and any type
of welding work.
Hydrex Spain
Poligono Industrial Palmones II
Calle Dragaminas Nave N29
11370 Algeciras • Spain
9
Hydrex Spain also offers a wide
range of above water operations
including accomodation ladder
repairs, anchor and chain work,
cell guide repairs, crane repairs,
hatch cover repairs and mechanical
and engine works.
Hydrex Spain is fully geared to
carry out repairs at anchorage
and in port. All operations are
certified by the classification
societies and are carried out by
highly qualified divers and technicians
all of which have extensive
experience.
Phone: +34 956 675 049 (24/7)
Fax: +34 956 921 914
E-mail: info@hydrex.es

Applying Ecospeed Ship Hull Performance
Technology: A discussion with three experts
on underwater ship hull coatings
Alot has been written on the
advantages of the Ecospeed
underwater ship hull coating system.
The coating offers many long term
benefits to ship owners, ship managers
and operators and this both
from an economical and ecological
point of view. The more practical
and direct advantages of Ecospeed
have been tackled much less. In this
article we take a closer look at how
applying Ecospeed to a vessel can
save a lot of worries, time and hassle
during dockings for superintendents
and shipyards, as well as saving
expenses for the owner.
The experts
To get a clear idea of how exactly
Ecospeed compares to other paint
systems during application and future
drydockings, we talked to Mr. Mike
Novak, a marine consultant in Fort
Lauderdale who has been providing
services for Hydrex, Mr. Gunnar
Ackx, co-owner and managing
director of SCICON Worldwide, an
Mr. Mike Novak, a marine consultant who
has been involved in the marine industry
for more than three decades.
The flexibility of the Ecospeed system allows for application during the block phase.
independent coating inspection and
consulting office, and Mr. Pieter Gysel
who has been working as an Ecospeed
inspector with Hydrex since 2005.
Over three decades of evolution
in the ship coating industry
Mike Novak has been involved in the
marine industry for more than three
decades. He has seen an enormous
evolution in underwater ship hull
paint and coating systems over the
years. “When I was involved with
commercial ships in the Seventies and
Eighties,” he explains “I was always
looking for new technologies to
improve ship hull performance. I was
10
one of the first operators to use a
hydrophilic co-polymer coating. It
was applied directly over what was
then the standard copper anti-foulant.”
These hydrophilic coatings looked
like a cataract film over the copper
according to him. “It was the first time
I’d seen a hull stay clean for five years
without drydocking. However, the
ship was mostly at anchor in tropical
waters, where the delicate nature of
the coating wasn’t an issue because it
didn’t suffer damage from abrasion,
“Despite some supplier claims to the contrary, most
coatings did not provide for the most basic objective:
to protect the steel from corrosion and prevent the hull
from ‘roughening’ with age.”
contact with a pier, tugs, etc. Today
that coating wouldn’t survive, given
the nature of operations.”

Over the course of his career Mike
Novak has worked with commercial,
military and cruise ships and has seen
at least a hundred ships in drydock, all
of which had underwater hull coating
systems. “Of course, seeing the hulls
in the course of over three decades,
I usually saw the latest developments
in applied coatings. With the exception
of the newest technologies, which
have emerged since 2000, they usually
consisted of a number of layers of
different types of paint: a primer, then
one or two layers of an anti-corrosive,
then a tie coat (a single coat that provides
adhesion between two different
coats of paint), and finally one or
more layers of an anti-foulant containing
biocides.”
Mr. Novak told us that despite some
supplier claims to the contrary, almost
none of those coatings provided
for the most basic objective of the
hull coating which was to protect the
steel from corrosion and prevent the
hull from ‘roughening’ with age.
“When ships came into drydock, it
was not uncommon to observe delamination
of different paint layers,” he
continues. “We’d also see evidence of
corrosion and hull roughening.
Repairs of the underwater hull coating
systems greater than five percent of
the underwater area, and up to and
including complete replacement of the
hull coating, were not uncommon.
This resulted in significant cost to the
ship owners, both in terms of cost of
materials and labor, and in fuel costs
due to the roughened conditions of the
hulls. So it’s easy to see that the total
ownership cost (TOC) of a vessel
would drop for a ship operating with
hull that is effectively protected.”
When Novak became aware of
Ecospeed in 2009 he was intrigued
with its claims and characteristics.
“This was the first coating for which a
10-year guarantee was possible,” he
says. “Ecospeed’s producer also
claimed that it was an extremely hard
coating with optimized hydrodynamics
that could be easily maintained
in service. When the company
approached me in my capacity as a
marine consultant I remembered how
curious and interested I’d been in exa-
Mr. Pieter Gysel, a Nace certified Ecospeed inspector during the recent drydocking of a cruise
vessel in the Bahamas.
11
Ecospeed inspector during thruster tunnel
application.
mining this new technology. It has a
huge potential for reducing total cost
of ownership with the vessel, I
thought, but I wanted to learn more.”
Since then Mr. Novak read the reports
of ships in service and their experience
with the product in harsh
”Recently, I’ve observed three ships with 2- to 3-year-old
coatings of Ecospeed. There was no separation of the
coating from the hull and there were no rust blisters that
would be indicative of anti-corrosive failure.”
environments, such as ice-going and
icebreaking operations. He learned
about the technology, the coating’s
composition, the process of coating
development, and the inventor’s
objectives. “I’m also attracted greatly
to the environmentally friendly aspects
of the product. Studies done
in the EU, by the Netherlands in particular,
have determined that in-water
cleaning the hull with Ecospeed produced
no materials that were toxic to
the marine environment. Recently,
I’ve observed three ships with 2- to 3year-old
coatings of Ecospeed. The
ships came out of the water with
clean hulls. There was no separation
of the coating from the hull, there
were no rust blisters that would be
indicative of anti-corrosive failure,
and the overall hull was smooth.”

High quality application – the
secret of long term durability
The reason for the pristine condition
of the Ecospeed coating after several
service years is very simple according
to Mr. Gunnar Ackx, managing director
of SCICON Worldwide. Flexibility
as well as their highly trained, experienced
and certified coating inspectors
are some of the key reasons why
SCICON is sought after internationally
for paint inspections on underwater
hull coating projects. SCICON
provides clients with various inspection
and consulting services in the field
of corrosion protection of steel, concrete,
and other surfaces in just about
any industry. SCICON's main focus is
Europe, but they have clients in several
countries around the world.
As a coating inspector and consultant,
Ecospeed is easily applied in only two layers.
Gunnar Ackx has had the opportunity
to inspect and assist the very first
Ecospeed application, eight years ago.
“When I first saw the ship come out of
the water and noticed how banged up
the hull was, my first reaction was:
‘This is never going to work.’ But that
best value for money in the corrosion
protection business, irrespective of the
type of coating project,” he says. “We
always advocate that surface preparation
is the foundation of any coating
system. So as soon as you start tampering
with the quality of the surface
“There are very substantial benefits in stripping away all
the old paint; immediate fuel savings of up to 8-10% are
very realistic numbers.”
job certainly did prove me wrong.
I have been amazed at Ecospeed’s performance
ever since.”
To Mr. Ackx it is clear that the high
quality of an Ecospeed application is
key to the excellent results obtained
with the coating. “An SSPC-SP10 /
ISO Sa 2.5 blast cleanliness is still the
12
preparation, you will tamper with the
total quality, hence service life of
ANY coating. A proverb that we often
use during our inspection assignments
is: ‘If you fail to prepare, prepare to
fail’ which says a lot about the above.
Of course an SSPC-SP10 / ISO Sa 2.5
blast cleanliness is not the cheapest of
surface preparations you can get and
can sometimes be somewhat challenging
in a drydocking situation. However,
you will only have to do it once!
Because once you have applied the
2-coat Ecospeed hull coating, you’ll
never have to reblast again, throughout
the entire service life of the ship.”
Ecospeed inspector Pieter Gysel,
who is a certified NACE inspector,
confirms the importance of a quality
standard during application. “We have
had access to very extensive research
in this field and especially regarding
the decay or degradation of paint
systems over drydocking intervals,”
he explains. “Most of the time the
effect of this degradation of the paint
system and the build up of paint layers
on the fuel efficiency of the ship has
been largely underestimated. Ideally,
during a second special survey of
a ship in drydock there are very
substantial benefits in stripping away
all the old paint; immediate fuel
savings of up to 8-10% are very realistic
numbers.”
If the Ecospeed coating is applied correctly
this build up of paint layers can

Worldwide network of offices
and service stations
Fully trained and certified diver-technicians
Ship hull cleaning equipment designed
specifically for offshore operations
Offshore repair and
maintenance services
Turnkey underwater solutions for the offshore industry
13
Underwater solutions
avoid drydocking
Fast response centers with
instant mobilizable equipment
Phone: +32 3 213 5300 (24/7)
Fax: +32 3 213 5321
E-mail: hydrex@hydrex.be
www.hydrex.be

Mr. Gunnar Ackx, co-owner and managing
director of SCICON Worldwide bvba.
be avoided. “We pride ourselves on
the durability of Ecospeed and any
paint system is only as good as it is
applied,” says Mr. Gysel. “We therefore
insist that one of our paint engineers
is present and available for
the painters on every job, not only
to check the conditions during the
painting process, but also to work
closely with them and to make sure
that we have a very easy and smooth
application. This, I learned, is very
different from industry standards.
Because we are closely involved with
the application, we know exactly what
has happened during the painting
process. We offer a ten year warranty,
not only on the quality of the paint
material itself but also on the surface
preparation, on the application itself
and on any underwater maintenance
that needs to be carried out. This is a
very extensive guarantee we offer.”
Hydrex works with a team of highly
certified, highly qualified paint inspectors.
“These inspectors have been
working with Ecospeed for years,”
says Pieter Gysel. “They are not only
familiar with Ecospeed, but with a
wide variety of paint systems. They
are also very important in terms of
cooperation with the shipyard, making
sure that the product is applied according
to our standards and thus that the
results will be there for the shipowner
for the next ten years and beyond.”
Cost of application and maintenance
in relation to total
ownership cost
If an owner really has problems with
the cost of such surface preparation,
Gunnar usually sits down with them
to do the math on the alternatives.
“If you reapply 2, 3 to 4 layers of antifouling
coating on the entire hull and
are re-doing the above every 3 to 5
years, you inevitably come to a point
where there are too many layers of
coating on the ship’s hull.” Gunnar
then tells them that, “This will degrade
the quality of the coating even more
easily and rapidly because of the internal
stresses being built up in the
coating, resulting in a required full
reblast, probably every 10 years or
so.” He recalls a recent drydocking
of a large cruise vessel where some
2.0 to 2.5 mm thick old coating
system was removed completely. “It
probably consisted of up to 15 or
more layers, which were continuously
flaking off here and there and were
patch-repaired for a number of years.
If you make such a calculation over,
say, a 25-year service life and compare
that with the initial cost of
the Ecospeed application combined
with the very minimal maintenance
it requires, it doesn’t take a rocket
scientist to figure out which is more
economical. And that is not even
taking into account possible reduced
drydocking times and fuel savings
because of some other characteristics
of the Ecospeed hull coating.”
14
Flexible and easy to learn
application process
The high standard that Hydrex
demands for an Ecospeed application
does not mean that learning to work
with the coating is a difficult process
nor that the application itself is hard to
schedule or carry out.
According to Mr. Gysel, applying
Ecospeed is quite straightforward.
“Common sense needs to be used with
every single paint application,” he
explains. “We are stricter on the pot
life and the thorough cleaning of
equipment, but in general it paints
like any other paint. We’re very happy
to see that most applicators are quite
familiar with hard solid paints and
they know the tricks of the trade. It’s
interesting for us to learn from them
and vice versa. In general I see very
good teamwork on all sides.” Mr.
Ackx has had similar experiences.
“In the last couple of years our inspectors
have probably inspected close
to 100 Ecospeed jobs and every time
the specifications were followed by
the coating contractor, the application
went very well and smoothly.”
The Ecospeed coating also offers a
tremendous flexibility to the shipyard.
The minimum overcoating time is
three to four hours, which means that,
for smaller surfaces such as rudders,
propellers or bow thrusters, the two
coats required can often be applied in
“Because Ecospeed consists of only 2 coats and has quick
and flexible overcoating times, the application can easily
be scheduled around other work taking place.”
one single day. “If blasting is done
overnight and approved after morning
inspection, the object to be coated
can be ready by nightfall.” Mr. Ackx
tell us. “As the coating inspector, you
rarely come in at the exact right
time when the yard is ready to start
blasting and/or coating. Especially

during drydockings, there is a lot
more going on than just the hull
coating, which can easily interfere
with the planning of your project.
Because of the fact that Ecospeed
consists of only 2 coats and has quick
and flexible overcoating times, this
often allows the Ecospeed job to be
scheduled around other work taking
place, resulting in minimal interference
between various activities.” He recalls
a drydocking in Malaysia, where the
weather is notoriously unpredictable:
“They were applying Ecospeed onto
the vertical sides of a ship with steel
temperatures up to 39°C because of
the sun when five minutes later a
thunderstorm passed by and chased
everyone underneath the ship. After
the storm had passed, I expected
the coating to have sustained quite
some rain impact damage, but to my
surprise the coating was curing so
rapidly on the hot steel surface that
absolutely no rain damage was visible
at all. There were also no signs of ‘solvent-entrapment’
whatsoever, which
sometimes occurs when solvent based
coatings are applied onto too hot of a
surface. Twenty minutes later the hull
had dried up and we could continue
spraying again.”
Ecospeed only requires two layers of
500 µm each. This is also a major
“With Ecospeed only minor touch ups need to be carried
out. These can easily be done during a short drydock visit.”
advantage compared with other hull
coatings. “Whether you’re looking at
classic antifouling coating systems
which easily have five coating layers
to be applied, or when comparing
Ecospeed to some of the newer silicone
based hull coatings, which also
consist of four to five layers of coating
to be applied, a two coat application is
always going to be quicker, cheaper
and more flexible,” explains Gunnar
Ackx.
FULLY OPERATIONAL IN NORTH AMERICA
Hydrex US is prepared to
mobilize immediately and
is capable of efficiently servicing
offshore units and ships calling
ports in Canada, North, Central
and South America as well as
the Caribbean.
Saving significant amounts of
time, trouble and expense through
its on-site work, Hydrex services
range from a complete review of a
vessel’s external condition all the
way through to highly technical
major repairs or replacements of a
ship’s external underwater equipment
and machinery. Repairs to
thrusters, propellers, rudders, stern
tube seals, damaged or corroded hulls
and all other underwater services are
done by professional teams trained
Hydrex US
604 Druid Rd,
Clearwater, FL 33756
15
Pieter Gysel also praises the flexibility
of an Ecospeed application: “We
can adapt the coating schedule to that
of the yard and it does not have to be
the other way around. Traditionally a
paint application schedule is defined
first by surface preparation and second
by the weather conditions, which
are very difficult to predict. In this
respect the application of Ecospeed is
easier to adapt to the application
windows that become available. You
can apply the coating quite rapidly on
a prepared surface and the possible
overcoat time goes from three hours
to very extended periods of time.
Depending on what the shipyard likes
to see, we can just adapt the schedule.
We can immediately apply the second
(final) coat or wait a few weeks to
complete the job.”
Easier to plan drydockings for
the rest of the vessel’s service
life
The durability of Ecospeed makes
the planning of future drydockings
far easier for the shipowner and the
shipyard. Mr. Gysel has witnessed that
and qualified to carry out complex
technical tasks underwater while
the vessel is in-situ.
Phone: +1 727 443-3900 (24/7)
Fax: +1 727 443 3990
info@hydrex.us • www.hydrex.us

An Ecospeed application is adapted to the shipyard’s schedule and not the other way around.
shipowners will not have to do any
repainting beyond minor touch ups, if
needed. “These can easily be done
during a short drydock visit,” he says.
“This is in contrast to the full renewal
of paint layers that is needed with
other paint systems. We make sure that
we have a good application from the
start because the result in terms of
durability and long term performance
of the paint system is defined by the
initial application. We have a coating
system that lasts the lifetime of the
vessel; the initial application is therefore
critical for the success of the coating.”
Mr. Ackx confirms that if a ship
coated with Ecospeed comes into drydock
after some years of service, the
planning of this docking is so much
simpler than with vessels coated with
other underwater hull paint systems.
“I have had the opportunity of witnessing
the drydocking of a number of
vessels, with different types of hull
spot blasting and touch up as well.
After a couple of recoating cycles,
the total coating system becomes
increasingly weaker, resulting in more
repairs and maintenance that needs to
be done with every drydocking and
this up to the point where the entire
underwater hull needs to be fully
reblasted.”
Mr. Ackx says that the newer hull coatings
such as silicone based coatings
provide for better performance in
that department, but also come with
a higher initial installation cost.
“Having seen a silicone based antifouling
on a ship that was drydocked
after some three years of service,
I must admit that the hull looked very
good and could be cleaned quite
easily. The problem is that such a
coating is soft and has relatively limited
thickness. Hence there were quite
some mechanical damages all the way
through the coating, down to the steel,
resulting in hull corrosion.” He compares
this to an Ecospeed hull coating
coming in for drydocking. “You see
that the damage is so limited on
an Ecospeed hull coating that it can
easily be seen, which makes it easier
to repair and to maintain. During the
recent drydocking of a large, Ecospeed
coated cruise vessel which
had run aground, resulting in the
buckling of some 40 meters of bottom
plate, only a very limited number
of scratches down to the substrate
“When repainting the underwater hull can be taken out
of the equation for the choice of location and season for
drydocking, the story becomes a lot easier for everybody
involved.”
coatings. With classic antifoulings,
most people in the shipping industry
know what’s happening: the antifouling
has to be renewed every three
to five years, maximum, during which
there will also easily be five, ten or
more percent of corrosion present on
the underwater hull, which requires
16
were observed. On 90% of the 40 m 2
affected, Ecospeed only showed
superficial scratches and still adhered
perfectly to the steel.”
Mike Novak was also present during
this drydocking. “When I saw this
cruise vessel my first thought was,

‘Now there’s a ship that is saving
fuel.’ To see a hull in such clean and
sound condition convinced me that
Ecospeed has tremendous potential
for reducing operating costs – in particular
fuel – as well as hull coating
maintenance costs. This was the first
ship, commercial, military or cruise,
that I’d seen come to a normal drydocking
cycle with such a clean and
smooth hull.”
“For quite a number of ships the
amount of time they spend in drydock
is directly related to painting the
underwater hull,” says Mr. Gysel.
“When repainting the underwater hull
can be taken out of the equation for
the choice of location and season for
drydocking, then the story becomes a
lot easier for superintendents, for the
shipyards, for everybody involved.”
Easy and environmentally
friendly fouling removal
The standard procedure for ship-
yards when a ship enters drydock is
a general wash of the ship hull to
clear away any fouling and residues,
especially salt residues that may
adhere to the paint system. “What
we see with Ecospeed,” explains
Mr. Gysel, “is that after the high
pressure washing the coating is always
in a brand new, excellent condition.
The surface texture is very
smooth. The high pressure washing
reveals without exception that Ecospeed
does not need any additional
paint layers. We also see a very big
difference between cleaning Ecospeed
and other paints,” he continues.
“When washing an antifouling paint
in drydock, everything on the bottom
of the drydock is discolored with a
dirty red water filled with toxins, and
the antifouling paint spreads everywhere
on the bottom of the drydock.
With Ecospeed, none of the paint
material is lost. It’s clean water that
you see. Only the fouling is removed.
The coating stays on the ship instead
17
of dispersing in the water and contaminating
the shipyard and the
surrounding waters.”
Summary
We hope that the words of the experts
have helped communicate the practical
aspects of applying Ecospeed,
the differences between Ecospeed and
other underwater hull coatings, and
the low cost-to-savings ratio that
can be obtained by using Ecospeed to
protect the underwater hull of any
vessel afloat today.
If you have any questions about Ecospeed,
its application and use, please
contact us at info@ecospeed.be.
We will get your questions answered
and, if of general interest, will publish
your question with the answer in
a future edition of The Hydrex
Magazine.

Hydrex around the world
Inspection and hull repair on a
semi-submersible vessel in Malaysia
Last month a Hydrex diver-technician
team performed a full
inspection and repair of the damaged
area of the hull of a drilling
vessel during its stay at Labuan,
which is the main island of the
Malaysian Federation.
Doubler plate covering cavitation hole.
During the inspection the team located
a cavitation hole which they blanked
with a temporary wooden plug to keep
the water out while they prepared to
area around the hole for installation of
Within a couple of weeks two
container vessels had their
rudders coated with Ecospeed in
the same shipyard in Dubai.
Earlier several other vessels of the
same owner were also given the same
treatment. The decision to use Ecospeed
was made by the shipowner
after cavitation damage had appeared
on the rudders of several of his container
vessels. These rudders are given
lasting protection by Ecospeed against
rudder cavitation which will prevent
similar damage from occurring again.
a doubler plate. This doubler plate,
measuring 300 mm x 300 mm, was
then positioned over the in-water side
of the damage area and secured with
full penetration weld. The hole was
then also closed on the onboard side
with clad welding and a doubler plate.
Ecospeed rudder application
on container vessels in Dubai
Ecospeed will remain intact for the
lifetime of the vessel and is guaranteed
for ten years. The rudder will not
have to be repainted during future
drydockings and extensive repairs
will not be needed. Planning the
maintenance of the vessel’s stern area
therefore becomes much easier. The
smoothness attained by the coating
also provides optimum hydrodynamic
conditions for rudders to operate at
maximum efficiency. The ship's performance
remains stable and the
owner's investment is secured.
18
Semi submersible vessel during its stay in Malaysia.
An ABS inspector was present during
the entire operation to give his approval.
The repair was carried out to
the satisfaction of the customer’s operations
managers who congratulated
the team for the excellent job they
performed.
Container vessel’s rudder given lasting
protection with Ecospeed.

Pipe repair in Algeciras in the wake
of big storm
AHydrex diver-technician team
mobilized with one of the
workboats from our office in Algeciras
to carry out a pipe repair on a
LPG Tanker during the vessel’s stop
in Algeciras.
When the team arrived at the ship’s
location the current was extremely
heavy and the operation had to be
postponed until the storm had passed
and the safety of the divers could be
guaranteed again.
The operation started with preparations
for the welding work inside the
engine room. At the same time a cofferdam
was installed and secured
underwater over the location of the
pipe. The team could then disconnect
the inside piping and remove the old
pipe. The new pipe was then fitted,
secured and welded according to the
Hydrex class approved welding procedures.
The attending ABS surveyor,
the owner of the vessel and the ship’s
19
Preparation of new pipe at the Hydrex fast response centre.
superintendent were all very satisfied
with the way the team performed the
operation.
IN-SITU BOW THRUSTER OPERATIONS
The Hydrex lightweight flexible mobdocks are
designed to be easily transported around the
world and are used to close off the thruster tunnel
on both sides, allowing divers to perform repairs
and other operations in a dry environment around
the bow thruster unit.
This technique enables them to reinstall the propeller
blades of an overhauled thruster inside the thruster tunnel
after the unit has been secured or replace the blades or
seals and perform repair work on a specific part without
removing the unit.
Since the development of this flexible mobdock technique,
numerous thruster repairs have been carried out by
Hydrex diver-technicians around the world.
There is no need to send the vessel to drydock as all
operations can be carried out in port or while the vessel
is stationary at sea. Normal commercial activities can
therefore continue without disruption.
Phone: + 32 3 213 5300 (24/7) hydrex@hydrex.be
Fax: + 32 3 213 5321 www.hydrex.be

HYDREX
OFFICES IN
INDIA
READY TO
MOBILIZE
Hydrex has two fully staffed
offices in India. One in
Mumbai and one on Visakhapatnam,
covering the East and
the West Coast of India.
Equipped with a complete array
of Hydrex diving and repair
equipment, both offices are ready
to carry out any necessary repair
and maintenance work and provide
preventive as well as problem
solving services.
All operations will be carried out
by professional Hydrex teams,
trained and qualified to perform
complex technical tasks underwater.
All procedures are fully
approved by all major classification
societies.
Hydrex Mumbai
Phone/Fax:
+91 222 2046 988 (24/7)
E-mail:
mumbai@hydrex.be
Hydrex Vishakhapatnam
Phone/Fax:
+91 891 2711 863 (24/7)
E-mail:
vishakhapatnam@hydrex.be
Transducer renewal on
crude oil tanker at anchorage
in Benin
Hydrex divers and technicians
worked together with a local
support base to renew the transducer
of a 333 meter crude oil tanker
at anchorage in Cotonou, Benin.
The necessary equipment was arranged
by the local support base in close
communication with the Hydrex technical
department. When the Hydrex
team and the equipment arrived with
the vessel, the operation started with
the blanking of the housing of the
transducer from the outside. The
transducer could then be replaced
Recently the rudder of a 210
meter container vessel was coated
with Ecospeed during its drydocking
in Bremerhaven. The rudder
had suffered cavitation damage
and the owner wanted to make sure
that the damage would not recur.
A great deal of effort goes into the design
and manufacturing of rudders
because they are obviously a key part
of a vessel. Therefore they ought to be
protected properly. Ecospeed’s durability
provides this protection because
the coating will remain intact for the
lifetime of the vessel. Tests in a flow
channel have confirmed that Ecospeed
performs extremely well under severe
cavitation. These tests were divided
into six stages during which the coating
was exposed to an increasing pressure
drop, leading to a growing cavita-
20
Transducer replacement in Benin performed
in cooperation with local support base.
from the inside without water coming
in. After the new transducer was in
place, the plug was removed, concluding
the operation very successfully.
Rudder given lasting
protection with Ecospeed in
Bremerhaven
tion force. Even after the last stage no
erosion occurred on the test patch
coated with Ecospeed. The tests were
sponsored by the French MOD/DGA
and were carried out by DCNS at LEGI
in Grenoble. More and more shipowners
are finding that Ecospeed coating
is the most effective guarantee of
a trouble-free rudder on their vessels.
Ecospeed is applied in two layers after grit
blasting.

Ship hull performance improved even
further after conditioning
One year after its entire underwater
hull was coated using
the Ecospeed hull performance
technology at Swansea drydocks in
Wales, the cruise vessel Saga Pearl
II’s hull was conditioned underwater
in Ghent, Belgium.
The conditioning was carried out
together with a quick and simple
cleaning which removed the small
amount of marine fouling that had
attached to the hull, consisting mainly
of a thin layer of slime. The entire
operation was performed underwater
without interfering with the ship’s
schedule.
This conditioning is what makes
Ecospeed unique. It is carried out with
specially designed tools and brings the
Hydrex West Africa is situated
in Port Gentil, Gabon
right next to Cape Lopez Bay.
Working closely together with
the headquarters in Antwerp the
office can benefit from Hydrex’ s
long tradition in the ship repair
and offshore industry.
Port Gentil is a general and bulk
cargo port. It is the only port on the
Gabon coast with a bunkering service.
The sheltered bay is ideally
suited for in-water work. This
combined with its central location
on the African West coast makes
it the ideal place to have repair
or maintenance work carried out
on a ship, barge or rig in optimal
circumstances.
Hydrex West Africa can mobilize
teams immediately to service vessels
and offshore units in Port
smoothness of the coating’s surface
to an optimum condition by aligning
the glass platelets inside the vinyl ester
matrix. This allows for an improvement
of Ecospeed’s surface charac-
Gentil or any other suitable location
in West Africa. A good example of
this is the recent removal, repair and
reinstallation of a 40 ton swing-up
azimuth thruster of an offshore crane
21
Ecospeed conditioning is carried out with specially designed tools.
teristics with each further hull cleaning
throughout the service life of the
vessel. It sets Ecospeed entirely apart
from antifouling and foul-release
paints that deteriorate over time.
HYDREX WEST AFRICA IN PORT GENTIL, GABON
barge that was servicing rigs in an
oil field off the coast of Gabon.
The entire operation was performed
while the unit stayed at anchorage
just outside the oil field.
Hydrex West Africa
Sis TLC/ Cité Shell
BP 2160 Port Gentil - Gabon
Phone : +241 04 16 49 48 (24/7)
E-mail: westafrica@hydrex.be

SHIP HULL PERFORMANCE TECHNOLOGY
Ecospeed ship hull performance
technology lasts
the lifetime of the vessel. The
need for full repaints during
future drydockings is eliminated.
An impermeable and extremely
tough coating is combined with
an underwater cleaning system
keeping the hull roughness at an
optimum level and resulting in a
major saving in fuel.
a
Phone: +32 3 213 5318
Fax: +32 3 213 5321
22
Ecospeed is a 100% non-toxic
technology and is guaranteed
for 10 years. Its surface texture
will improve over time with regular
inwater hull maintenance.
info@ecospeed.be
www.ecospeed.be

From lost World War II munitions
to performing underwater repairs
all around the world
An interview with Willem Hopmans, Hydrex Senior Diver
Willem Hopmans has been
with Hydrex for seven years
and has seen the organization grow
from a company with only one
office to a constantly expanding
international group with fullyequipped
offices in Antwerp, Spain,
U.S.A., Gabon and India. While he
rose through the ranks, the number
of divers working for Hydrex full
time has grown from less than twenty
to over fifty.
On a cold and snowy afternoon we sat
together with Willem to talk about
how he went from working in his
father’s car repair shop in Tilburg, the
Netherlands, to being a Senior Diver
with Hydrex.
Hydrex: You are almost thirty three
and have been working with Hydrex
for seven years. Can you briefly tell
us what you did in between high
school and starting with us?
Willem Hopmans: After graduation I
started working in my father’s auto
repair shop. The plan was to take over
the business from him but it soon
became clear that there was no long
term future for the shop. Our biggest
customers were large car-leasing
companies who signed contracts for
500-600 cars at a time. They realized
that they could save a lot of money
by hiring people to do the repairs inhouse.
Hydrex Senior Diver Willem Hopmans.
H: What did you do next?
WH: I got a letter informing me that I
needed to sign up for Military Service.
This was right in the period when they
abolished conscription in the Netherlands.
Sometime later I got a second
letter which said that I didn’t need to
go to the Army after all, but by then I
had already decided that I wanted to
go, so I signed up with the Marines for
four years. I started as a student diver
and then got promoted to Mine
Counter Measure Diver, which is the
highest available rank for divers. The
“I had seen the big helmet on the side of the depot, so I
knew about Hydrex. When I started looking for a new job,
I applied for a job as diver.”
main part of our job was salvage:
retrieving lost and abandoned explosives
and munitions from World War II.
There is quite a bit left under water, so
this was almost a full time job. And
23
that was exactly what made me decide
to leave. On the few occasions when
there was underwater damage to
one of our vessels, an external diving
company was contacted to perform
the repairs. I felt that there was no
opportunity for me to develop my
career any further. I wanted to keep
on working in the diving sector so I
started working for a diving company.
I only stayed with them for one year,
because I still didn’t feel that I was
given enough opportunity to expand
my diving knowledge and skills.
H: And then you discovered Hydrex?
WH: Yes. I lived, and still live, in the
most Southern part of the Netherlands
and we often came to Antwerp. I had
seen the big helmet on the side of
the depot, so I knew about Hydrex.
When I started looking for work
again, I applied for a job as diver with
Hydrex and also with another company.
To be honest, the decision to

Senior Diver Willem Hopmans is the diver performing the cleaning operation in one of Hydrex’s
most well known pictures.
join Hydrex was purely a geographical
one. Both companies offered me
a similar package, but working in
Antwerp would save me a lot of traveling
time. Since then Hydrex has
given me the opportunity to develop
myself in so many ways that I have
never regretted this decision.
H: Did you start your career with
Hydrex as student diver?
WH: Yes. I did have the required
diving certificates, but I had no familiarity
with the shipping business. I
also had no welding experience and
had never carried out underwater
repairs. They did however assure me
that I would be able to climb the ranks
pretty fast because of my diving experience.
This turned out to be true.
Hydrex was still a relatively small
company back when I started here in
2003 and it wasn’t long before I was
appointed as team leader and also put
in charge of handling the paper work
on the job. A lot has changed in seven
years and Hydrex has grown considerably.
With so many more divers
working for us, new student divers
are given the opportunity to climb the
ladder in their own time and learn
the trade while working with more
experienced divers. It also gives our
technical department more options
and breathing space when assembling
teams for a job.
H: You just arrived back from the
Gulf of Mexico where you spent six
months on board several drilling vessels
as team leader of a large offshore
cleaning operation. How do you
cope with being away from home so
long?
WH: I have been away for long periods
since I was very young. During
my time with the Marines we often
were on a mission for months and
when we weren’t we slept in the
barracks during the week and only
went home on weekends. It’s been
probably harder on my family and
friends. Six months is also exceptional.
Most jobs only take a couple of
days up to one or two weeks and can
be more easily planned in advance.
This gives you and your relatives a
much better idea of what to expect.
H: Having a good line of communication
with the Hydrex technical
department is probably really important
during a large and extensive
operation like the one in the Gulf of
Mexico?
WH: Indeed. They’re your link with
the outside world. They also help you
when you need any new equipment.
When you’re on a job for so long
supplies run out. However, one phone
call was enough. When we required
something they immediately provided
it for us. I remember asking our
technical department for the strangest
things, thinking they would never be
able to send it or not in time, but they
did, much to our amazement.
H: The last 10 to 15 years Hydrex
has been constantly expanding the
possibilities of in-situ repairs to the
point where we can now perform
almost any repair underwater. When
you started working for us in 2003,
however, the Hydrex flexible mobdock
technique had just been developed.
How did you experience this
evolution?
WH: In 2005 I was part of the Hydrex
team that performed the first dry
underwater stern tube seal repair. I
really feel like I have been part of it
from the very beginning and have also
helped in perfecting the technique.
When we come back from an operation
the guys in our research department
listen to what you have to
say. They know that your on-the-job
“When we come back from an operation the guys in our
research department listen to what you have to say and
they take the time to write down your suggestions.”
24
experience is very important and they
take the time to write down your
suggestions and comments. I feel
that this is a big part of what helps
Hydrex to stay at the cutting edge:
understanding that the combination
between technical knowhow and

on-the-job experience helps you
create the best products.
H: A final question, from your experience
with diving companies and
operations, what sets Hydrex apart
from the rest?
WH: The equipment available for
Hydrex diving teams is very up to
date, which is very pleasant to work
Abstract
All ship hulls and other submerged
surfaces begin to acquire aquatic
microorganisms almost as soon as
they enter the water, despite any kind
of antifouling or foul-release or other
paint or coating.
This aquatic life continues to build up
over time if not removed. The degree
of build-up depends on a variety of
factors including the surface itself, the
type of paint on the hull and its condition,
the water in which the vessel
is operating (e.g tropical, arctic, etc.),
the motion or lack of motion of the
hull and its speed if it is in motion.
The build-up of marine fouling goes
through stages as it increases over time.
This build-up of marine life on the
hulls of ships, even in its early stages
such as light slime, has a significant
effect on the performance of the hull,
increasing skin friction or drag. This,
in turn, demands greater shaft power
to achieve a particular speed or, con-
with. If changes or improvements
need to be done to the equipment our
technical department listens to the
divers and make it happen. Another
important aspect for me is that as
a diver your skills are constantly
tested because of the high quality
and technologically advanced operations
that Hydrex carries out. During
these operations you are given respon-
White Papers from Hydrex
HYDREX UNDERWATER HULL WHITE PAPER No. 2
The Slime Factor
How to save 25% or more through advanced underwater hull maintenance technology
Figure 1. Build-up of marine biofouling
(source: Davis and Williamson, 1995).
versely, causes a reduction in speed
for a particular shaft power.
The consequences are an immediate
impact on the fuel consumption of
vessel and on the CO2 and other emissions
for a given trip.
These increases are significant for an
individual vessel. Multiplied over a fleet
they can add up to an increase of millions
of dollars a day in fuel alone. The
CO2 emissions are similarly affected.
25
sibility and are allowed to think. In
cooperation with our technical department,
you can work out solutions
for unexpected circumstances or constantly
changing conditions.
H: Thanks for this interview and
enjoy some well-deserved time with
your family and friends.
Antifouling paints not immune
This fouling occurs even on so-called
antifouling paints which leach biocides
in an attempt to kill the marine life
and thus prevent fouling build-up, and
on so-called “foul-release” coatings
which are designed to be unsuitable
for marine life to adhere to.
The solution to this problem is to
remove the fouling regularly so that it
does not build up.
Routine hull cleaning requires the
right kind of underwater hull coating.
If biocide leaching antifoulants are
cleaned in the water they produce a
sudden and marked increase in pollution
of the marine environment. In
fact, in-water cleaning of such paints
has been forbidden by many port
authorities for that reason. Their lifespan
is also reduced which means
more frequent drydocking for repainting.
Coatings such as silicone based
foul-release paints are easily damaged
by in-water cleaning.

Since regular drydocking (say every
60 days) is simply not feasible, the
underwater hull cleaning should be
carried out in the water when needed.
How to reap the benefits of
effectively dealing with slime
Since the rate at which the fouling
builds up is not regular, depending on
a number of variables, this brings us to
the best approach using the best available
technology:
1.Apply a hard coating to the underwater
hull which does not pollute
the environment when cleaned in
the water and which is not damaged
by in-water cleaning methods.
2.Monitor the build-up of fouling
on the hull and propeller. Use the
ship’s speed with constant settings
as the main indicator of a fouling
problem.
3.When the speed of the ship drops
by half a knot or a knot, all other
factors being fairly constant,
inspect the hull for slime.
4.Clean the hull in the water routinely
to prevent the build-up even
of slime.
5.Watch the fuel consumption for
your ship or fleet reduce dramatically
saving you far more than
the cost of the monitoring and
cleaning program.
6.Watch the CO2 emissions of your
vessel or fleet reduce dramatically.
ISO 9001 certified
So you see that what we can term “the
slime factor” and therefore the choice
of hull coating and the implementation
of a program for monitoring
and inspecting the state of the hull
as far as biofouling is concerned is
not just a matter for the engineering
department. It is of vital interest to
the owner, the operator, the charterer
26
and anyone else responsible for keeping
the operating costs of the ship
down.
This white paper will help such people
make the right decisions which will
result in tremendous financial savings
while at the same time ensuring that
the ship or fleet’s impact on the environment
is minimal. It is a fresh look at
a problem which has existed for the
longest time without ever being satisfactorily
solved. This white paper outlines
the most advanced technology
available to deal with The Slime Factor.
To download the entire White
Paper visit
www.hydrex.be
or
www.ecospeed.be

Permanent rudder repairs now
possible without drydocking
Hydrex has developed an
entirely new method enabling
permanent repairs of
rudders without drydocking
the ship. Permanent repairs
were hitherto not possible and
ships had to drydock in case a
major defect was found. The
newly designed equipment is
lightweight and can be mobilized
very rapidly in our
special flight containers. Therefore
this new service is now
available worldwide.
Major defects on rudders very
often cause unscheduled drydocking
of ships. The new
method designed by our technical
department allows engineers,
welders and inspectors to perform
their tasks in dry conditions.
Class approved permanent
repairs in-situ, without moving
the ship, are now possible
and commercial operations
can continue. Steel repairs and
replacements can be performed
and pintle and bushing defects
27
can be solved without the loss of
time and money associated with
drydocking.
The equipment can be mobilized
within hours to any port in the
world and is available for rapid
mobilization from the Hydrex
headquarters in Antwerp.

Keeping ships in business
Hydrex underwater technology
and services provide
high quality solutions
to the repair and replacement
problems encountered
by ships and offshore vessels.
We deliver a complete line of
Headquarters Hydrex N.V. - Antwerp
Phone: + 32 3 213 5300 (24/7)
E-mail: hydrex@hydrex.be
Hydrex Spain - Algeciras
Phone: + 34 (956) 675 049 (24/7)
E-mail: info@hydrex.es
services that may reduce or
avoid off-hire time entirely.
From major projects to simple
inspections, Hydrex has the
worldwide facilities and capability
to meet your demands.
Drydocking is not necessary
so time, trouble and expense
Hydrex LLC - Tampa, U.S.A.
Phone: + 1 727 443 3900 (24/7)
E-mail: info@hydrex.us
Hydrex West Africa – Port Gentil, Gabon
Phone: + 241 04 16 49 48 (24/7)
E-mail: westafrica@hydrex.be
www.hydrex.be
are saved by doing work
in-situ. Hydrex services cover
highly technical major repairs
or replacements of a ship’s
external underwater equipment
such as thrusters, propellers,
rudders, stern tube
seals and damaged or corroded
hulls.
Hydrex India - Mumbai
Phone: + 91 222 2046 988 (24/7)
E-mail: mumbai@hydrex.be
Hydrex India -Vishakhaptnam
Phone: + 91 891 2711 863 (24/7)
E-mail: vishakhapatnam@hydrex.be