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HEMPASIL 77100 silicone-based fouling releaseThe fast track for surface coating

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ContentsThe new dimension in surface contact • Fouling release

Copper-free advantage • Environmental advantage

Business as usual • Meeting the challenge • Specifications

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The new dimension in

surface contactHEMPASIL silicone-based fouling release systems open up a new

dimension in fouling control. HEMPASIL systems feature a “non-

stick” surface that is flexible and smooth, with exceptionally low

surface tension.

HEMPASIL technology is biocide-free and copper-free. This provides

an environmentally sound fouling release solution because the

effect is due to the water-repellent physical properties of the

surface, instead of the coating exerting a chemical effect on the

surroundings.

This provides two breakthrough advantages. Fouling organisms

find it extremely difficult to adhere to a HEMPASIL-treated surface,

and the smoothness of such surfaces cuts down on drag, thus

reducing fuel costs.

HEMPASIL 77100 is specially designed for high-speed vessels

that normally operate at speeds higher than 25 knots.

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Fouling release systems are basically designed to hinder a

wide variety of organisms from adhering to coated surfaces.

Early fouling release coatings incorporated polytetra fluoro-

ethylene (PTFE) and other fluorocarbon resins. The idea of

using Teflon® -coated surfaces – familiar from cookware –

seemed ideal because these are both hard and “non-stick”.

However, despite having low surface energy, Teflon® is

actually porous and still allowed fouling organisms to

establish a mechanical interlock.

Silicone-based elastomeric coatings are an important new

way of achieving this “non-stick” effect, exploiting all the

advantages of the latest research. Their effect is due to a

balanced combination of flexibility and smoothness, along

with water-repellent properties related to reduced surface

tension.

When such surfaces are stationary, fouling organisms may

settle on them. However, the flexibility, smoothness and

low surface tension of a silicone-based topcoat means

these organisms tend to get scoured away simply by

forceful water movement or the scrubbing effect caused by

a vessel’s motion.

This also means that if there is sufficiently forceful water

movement around a vessel’s hull – as with high-speed

vessels – there is normally a natural self-cleaning effect.

For the same reasons, vessels where the hull is treated with

a silicone-based fouling release system, but which encounter

less forceful water movement, only need cleaning at longer

than normal intervals. This is because fouling organisms

have difficulty adhering to the surface – which also makes

cleaning relatively easy.

How does silicone-based fouling release work?

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Smoothness countsOne of the most unique advantages of a silicone-based

fouling release system is that it reduces drag when the hull

passes through the water.

Any reduction in drag as a result of greater smoothness

and lower surface tension cuts down on fuel consumption.

Even though the difference may be tiny, it will represent a

substantial saving on operating costs over the service life of

the coating. It is currently estimated that overall fuel savings

can amount to approx. 1–2% compared with self-polishing

antifoulings.

Keep it cleanA HEMPASIL 77100 fouling release system doubles the hull

coating service life, at less than half the weight.

The self-cleaning effect provided by a HEMPASIL 77100

“non-stick” topcoat reinforces this service life. As a result, a

vessel treated with a HEMPASIL system is able to maintain

the same high speeds and operating efficiency as the day

it left the shipyard – and will continue to do so throughout

its service time.

Future potentialThe HEMPASIL 77100 fouling release system is specially

designed for economical use with relatively fast vessels

such as:

fast ferries

patrol vessels, police and coastguard craft

high-speed monohulls

wave piercers

hydrofoils

4,000

3,000

2,000

1,000

0

Saving 1% fuel

After year1 2 3 4 5

MT = Metric Tonnes

MT fuel savings

*Calculation based on fuel price USD 200/MT

800,000

600,000

400,000

200,000

0

USD savings*

Consumption 200 MT/day

150 MT/day

100 MT/day

50 MT/day

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The HEMPASIL 77100 fouling release system was specially

developed for use on a wide range of high-speed vessels.

Vessels of this type often feature aluminium hulls in order to

save weight.

Because of its composition and the silicone-based technology

behind it, HEMPASIL 77100 is inherently copper-free. This is a

major benefit for aluminium-hulled vessels because it means

there is no risk of galvanic corrosion of the hull on account of

the fouling release system.

Lightweight and fastFuel consumption and weight are critical for profitable high-speed

operations – and the HEMPASIL 77100 fouling release system

provides an extremely smooth surface with less friction and

reduced drag, as well as weighing approximately 50% less than

conventional antifouling.

The copper-free advantageWeight countsA conventional 30-month antifouling system

weighs approximately 900 kg per 1,000 m2

of hull area.

A corresponding 60-month HEMPASIL 77100

fouling release system, however, only

weighs approximately 500 kg for the same

surface coverage.

HEMPASIL 77100 reduces the weight of

underwater paint by approximately 40%

compared with traditional antifouling

systems. This saving in weight is particularly

important for high-speed vessels, which tend

to have relatively high fuel consumption.

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Simple physicsThe basic idea behind HEMPASIL fouling release systems

makes them environmentally sound in a manner that

conventional antifouling systems can never match.

The antifouling effect is simply the result of the water

repellent physical properties of the surface, rather than

being due to the coating exerting a chemical effect on the

surroundings.

Biocide-freeThe biocide-free HEMPASIL specifications are a clear

environmental advantage. Users are free of having to deal

with the practical consequences of legislation relating to

biocides.

This also means there are no problems of the kinds

encountered with conventional antifouling, such as the

need to deal with waste water from washing down during

construction or when in dry dock.

Copper-freeHEMPASIL fouling release systems are also copper-free. In

addition to doing away with any risk of galvanic corrosion

on aluminium hulls and structures, this ensures there is no

leaching of copper during operation.

Low VOC contentUsers of all HEMPASIL fouling release systems also benefit

from their low VOC (volatile organic compounds) content.

This cuts down on emissions of organic compounds during

application.

The environmental advantages

Kg VOC per m2 for 5-year specifications

Volume solids in paint

Kg VOC1.0

0.8

0.6

0.4

0.2

0.040% VS

antifouling50% VS

antifouling60% VS

antifouling70% VS

HEMPASIL

All figures include a consumption factor of 1.4

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Coating as normalDespite all the many advantages of HEMPASIL fouling release

systems, the application procedures and requirements are

on a par with conventional antifouling systems.

With due care, applying a silicone-based system such as

HEMPASIL is just as straightforward as working with any

other multi-component coating system.

However, the quality of the completed coating is important

for its effectiveness. This means that full blasting of the

hull is recommended prior to application. The sprayers

must be skilled and experienced, and all equipment in good

condition.

A HEMPASIL fouling release system can also be applied on

top of existing coatings, using a sealer.

The renewal advantageThe surface properties of such coatings normally need to be

renewed after 5–8 years, depending on the stress to which

the coating has been exposed. With a HEMPASIL topcoat

solution, renewal is simple and only requires application of

a new layer of HEMPASIL on top of the old surface.

Smaller quantities neededFouling release coatings involve using less paint than

traditional antifouling solutions.

HEMPASIL fouling release systems are notable for only requiring

3 full coats over a 10-year service period, whereas conventional

antifouling requires as many as 4–6 full coats over the same

time interval. This easily balances out any initial purchase price

differences, and is an important part of the overall cost/benefit

advantages of a HEMPASIL fouling release system.

Business as usual

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The technology behind silicone-based fouling release coatings

and their properties is well known, but has proved difficult to

implement in practice.

This is because there are major challenges involved in

getting the non-stick surface of a fouling release system to

adhere to the anticorrosive coating applied to the hull. This

has hindered wide-scale use of fouling release technology to

date, and is a well-known weak point in many silicone-based

fouling release systems.

More than the sum of the partsHempel has solved this by developing a new tiecoat that

combines some of the chemical properties from the

anticorrosive coating and some of the chemical properties

from the fouling release topcoat.

This new Hempel tiecoat makes it possible to achieve a

reliable link between the highly adhesive anticorrosive layers

and the non-stick topcoat. We have therefore named it NEXUS,

the Latin word for connection between two equal parts.

NEXUS is a key component in all HEMPASIL fouling release

systems, and the feature that makes them uniquely effective.

HEMPASIL NEXUS ensures perfect adhesion between all the

coats used in the HEMPASIL fouling release system.

Large application windowA key advantage of HEMPASIL in relation to other silicone-

based fouling release systems is that HEMPASIL NEXUS

provides a relatively large overcoating window. It is normally

possible to choose between applying the NEXUS tiecoat and

the HEMPASIL topcoat the same day or waiting until the next

day, using a one-coat/one-day schedule.

Meeting the challenge

Topcoat

NEXUS

Anticorrosive

NEXUS

Anticorrosive

Anticorrosive

NEXUS

NEXUS has chemical properties that are

similar to the anticorrosive layer.

Adhesion between NEXUS and the

anticorrosive layer is ensured by

chemical bonding.

NEXUS also has chemical properties that

are similar to the topcoat. Here, too,

adhesion is ensured by chemical bonding.

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Typical application schemeMaintenance and newbuilding*

HEMPASIL 77100 150 µm

HEMPASIL NEXUS 120 µm

Anticorrosive 2 150 µm

Anticorrosive 1 150 µm

*Specification for newbuilding where all coatings

are applied on a fully assembled vessel.

Hempel supplies several different types of fouling

release coatings, each designed to withstand the

specific types of stress characteristics for different

surfaces and different types of vessels.

HEMPASIL specifications

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1. An anticorrosive coating,

normally applied in two coats.

2. A HEMPASIL NEXUS tiecoat

that adheres to both the

anticorrosive system and the

silicone-based topcoat.

3. A HEMPASIL silicone-based

topcoat that helps prevent

fouling organisms from adhering

to the hull.

A complete systemA typical HEMPASIL silicone-based

fouling release system consists

of three types of coating, normally

applied in four layers.

Hempel worldwideMost large construction projects today involve companies from more than one country. Often,

different sections are constructed in different countries before final assembly on site. Delays in the

construction of any of these sections will mean costly delays for the entire construction project.

This is why the rapid, efficient supply of paint is an important key to our customers’ success.

The Hempel Group is a leader in the production and sales of protective coatings

within the marine, container, yacht, decorative and protective market segments.

Hempel is currently represented in 82 countries. The Hempel Group of companies

currently comprises 18 production sites, 7 R&D centres and more than 130 stock

points around the world.

We operate with a worldwide product assortment so that our products are rapidly

available wherever and whenever they are needed. The HEMPASIL silicone-based

fouling release system is part of this range, adding yet another high-quality

product to the Hempel range, available worldwide.

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Comprehensive information about other Hempel products and services is always available at www.hempel.com

Comprehensive information about other Hempel products and services is always available at www.hempel.com

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The Hempel Group Head OfficeHempel A/S Lundtoftevej 150DK-2800 Kgs. Lyngby DenmarkPhone: +45 45 93 38 00 E-mail: marine@dk.hempel.comwww.hempel.com

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