Hempasil 77500 Brochure

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HEMPASIL silicone-based fouling releaseThe high-activity approach to surface coating



ContentsThe new dimension in surface contact • Fouling release

Meeting the challenge • Environmental advantage • Fuel savings

Specifications • Business as usual • Roughness or smoothness?



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 smooth and flexible, with

exceptionally low surface tension.

HEMPASIL technology is biocide-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.

The HEMPASIL range include products designed for service

speeds down to 8 knots.



Fouling release systems are basically designed to hinder a

wide variety of organisms from adhering to coated surfaces.

Early fouling release coatings incorporated polytetrafluoro-

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

using Teflon®-coated surfaces – familiar from cookware –

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

However, despite having low surface energy, Teflon® is actually

porous and thus 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 smoothness and flexibility, along with

water-repellent properties related to reduced surface tension.

When such surfaces are stationary, fouling organisms may

settle on them. However, the flexibility and low surface tension

of a silicone-based topcoat means these organisms get

washed away simply by forceful water movement caused by

the vessel’s motion.

This also means that if there is sufficiently forceful water

movement around a vessel’s hull, there is normally a natural

self-cleaning effect.

These properties also mean that hulls treated with a

silicone-based fouling release system, but which sail less

frequently or 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 foulingrelease work?



Container vessels

LNG/LPG carriers

Ferries

Oil tankers

Car carriers

Cruise ships

The technology behind silicone-based fouling release coatingsand 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. Up until now, this

has hindered full-scale exploitation of fouling release technology,

and is known as the weak point in many silicone-based fouling

release systems.

More than the sum of the parts

Hempel has solved this by developing a new tiecoat that combines

chemical properties from the anticorrosive coating with chemical

properties from the fouling release topcoat. This new Hempel

tiecoat is a breakthrough that 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 window

A key advantage of HEMPASIL compared with 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.

Future potential

The HEMPASIL fouling release system is particularly economical

for use on vessels, such as:

Meeting thechallenge

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.

The economical benefit is higher for faster and for larger ships.



Simple physics

The 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-free

The biocide-free HEMPASIL specifications are a clear

environmental advantage. Users are free of having to deal

with the consequences of both current and future 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.

Low VOC content

Users 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

1.0

0.8

0.

0.

0.

0.0

Kg VOC per m for -year specifications

Volume solids in paint

0% VS

antifouling

0% VS

antifouling

0% VS

antifouling

70% VS

HEMPASIL

All figures include aconsumption factor of 1.

Kg VOC

1.0

0.8

0.

0.

0.

0.0



Smoothness counts

One 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 cuts

down on fuel consumption.

Test results from independent towing tank experiments

document that HEMPASIL show a significantly lower skin friction

than a reference self polishing antifouling. The improvement in

skin friction compared to antifouling was up to 5%. For a large

container vessel a skin friction improvement of 5% corresponds

in propulsion efficiency to an improvement of 10.6% or a fuel

saving of up to 2.6 million USD annually.

Keep it clean

The self-cleaning effect provided by a HEMPASIL “non-stick” topcoat

extends the service life of the hull coating. As a result, a vessel

treated with a HEMPASIL system is able to maintain the same

speeds and operating efficiency as the day it left the shipyard – and

will continue to do so throughout its service life.

Fuel savings

HEMPASIL also comes in a

version suitable for vessels

that operate at speeds down

to 8 knots.

A HEMPASIL silicone-based

fouling release system ensures

a smooth surface that results

in fuel savings.

Vessel type Power efficiency

improvement of HEMPASIL

Service speed

(Knots)

ROPAX 7.5% 22

Large container vessel 10,6% 24

Aframax tanker 11.3% 15

Bulk carrier 8.8% 15

Results based on towing tank experiments (FORCE Technology)



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.

The HEMPASIL range include products designed for vessels that operate with high service

speeds like fast aluminium ferries as well as products for vessels with a relative low

speed like VLCC’s and bulk carriers. The example below illustrate a typical specification

with HEMPASIL 77500, a product particularly suitable for use by high-activity operators

that appreciate the fuel economy benefits of an extremely smooth, self cleaning hull

surface.

HEMPASIL specifications

Anticorro

siv e 1Anti

corrosiv e

2HEMPASI

L NEXUSHEM

PASIL 775

00

Steel

Typical application scheme

Typical maintenance specification

HEMPASIL 77500 150 µm

HEMPASIL NEXUS 120 µm

Anticorrosive 2 150 µm

Anticorrosive 1 150 µm

Typical newbuilding specification*

HEMPASIL 77500 150 µm (grey)

HEMPASIL NEXUS 120 µm (black)

Sealer 75 µm (grey)

Sealer 75 µm (bronze)

Anticorrosive 150 µm (grey)

Anticorrosive 150 µm (red)

*Specification for newbuilding where the final

coats are applied on a fully assembled vessel.

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 system

A typical HEMPASIL silicone-based

fouling release system consists of

three types of coating, normally

applied in four layers.

Anticorrosiv e

1 Anticorro

siv e 2 Seale

r

Sealer HEM

PASIL NE

XUS HEMPASI

L 77500

Steel

Last 3 coats in building dock

First 3 coats at block stage



Coating as normal

Despite all the many advantages of HEMPASIL fouling release

systems, the application procedures and requirements are

fully on a par with conventional coatings.

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.

The renewal advantage

The surface properties of silicone-based fouling release

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 topcoat onto

the old surface.

Smaller quantities needed

Fouling 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



Average Hull Roughness (AHR) is crucial for the vessel’s

perfomance. More power and therefore more fuel is required

if AHR is increasing. AHR is being measured by the BMT gauge

and such measuremetns are typically taken after the final

coat has been applied. For a newbuilding vessel applied a

conventional antifouling the AHR is typically 125-150 micron.

The inherent AHR of HEMAPSIL is below 20 micron one of

the reasons why an economical fuel performance can be

achieved.

To achieve the full benefit of HEMPASIL’s very low AHR it is

however, crucial that the surface condition as well as application

of epoxy coats also are of high standards. HEMPASIL may be

applied existing antifoulings after a proper surface preparation.

However, the full benefit of the fuel saving potential is only

achieved when the fouling release system is applied a well

adhering and smooth existing system or after a full blasting.

Roughness or smoothness?HEMPASIL posess an AHR of 0 micron

HEMPASIL topcoat has been applied these two panels. AHR measurements are

significantly different due to difference in roughness of underlying coats.



Hempel worldwide

Most 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



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The Hempel Group Head Office

Hempel A/S

Lundtoftevej 150

DK-2800 Kgs. Lyngby

Denmark

Phone: +45 45 93 38 00

E-mail: [email protected]

www.hempel.com

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