Moisture damage is a severe problem in sea transports. Ships and machines corrode, transported goods,
as food must be discarded. Now, there is a remedy to reduce to a great extent cassation and maintenance costs. Several shipping
lines can account for very good results after years of experience.
The product used is a microporous
coating with good insulation capacity and a good capacity to adsorb water. The most important property of the coating is that
water evaporates from the microporous surface considerably quicker than from a metal or painted surface.
An application of 1.5 mm of the coating enables it to store 1 litre of water per square metre, which
then evaporates quickly.
The coating is marketed under the name of GrafoTherm and can now
be found in Norwegian fishing boats, in Australian and Swedish submarines, in Russian ice-breakers, in frigates and cargo
ships and in thousands of sea containers.
Kristian Gerhard Jebsen Skipsrederi uses GrafoTherm in its bulk carriers for pulp transports. At loading and unloading the pulp emits
so much moisture that condensation in the roof of the cargo space can drip down and destroy the cargo.
of 2 mm of GrafoTherm is enough to prevent this. When the ship is loaded and the hatches closed humidifiers can be set to
work and the GrafoTherm layer then evaporates the accumulated water in the form of vapour.
first series of 3 bulk carriers was built in 1990/91 and when a new series was going to be built in 1999 the experience was
so good that it was a matter of course to use GrafoTherm in the new ships.
Lower maintenance costs
Trafikkselskap built a series of ferries in 1992 in Norway. All spaces exposed to moisture and condensation – the entrance
to car decks, the dry tanks, the trust rooms – were treated with GrafoTherm.
At the 5-year-inspection,
none of the treated surfaces had needed repainting or other maintenance. That is still the case after 7 years. Recently three
ferries were delivered from Poland, all with GrafoTherm application. The reduced maintenance cost was the main reason for
- We are not surprised, says Jarl-Erik Rollén, managing director of Kefa
Hightech AB, the producer of GrafoTherm. We have made a very tough test in a salt-mist chamber and that test shows that GrafoTherm
improves the corrosion resistance considerably.
Coffee, cocoa, tea and other groceries
are often damaged by moisture during sea transport. Hapag Lloyd has solved this problem by treating the roofs of
their ventilated containers. This is advantageous to placing hygroscopic material in the container, as
the GrafoTherm treatment is once-for-all. It does not have to be changed or reconditioned after each transport. The container
just needs to be opened for some hours to be ready to be used again. As a rule, it is enough to open the container during
unloading and loading.
shore-containers used by the oil industry in the North Sea are troubled by condensation on the un-insulated steel surfaces.
The weakest areas are the roofs. A leasing company has treated a number of provision- and work shop- containers. The experience
so far is very good. The application job is a very simple operation and GrafoTherm gives a bright and dry surface that will
last as long as the containers are in use.
Improved insulation in fishing-boats
in or near arctic waters have problems with condensation freezing in the insulation material. It has happened that the insulation
has fallen down because of the weight of the ice. Many fishing-boats have solved the problem by applying a GrafoTherm layer
to the hull under the insulation. A layer of 2 mm can keep close to 1.5 litres of water per square metre. GrafoTherm is not
damaged if the water freezes.
During the condensation period GrafoTherm adsorbs the water and
keeps it confined until the surface temperature goes above the dew point. In this way, GrafoTherm is taking over a great deal
of the moisture load from the insulation, which diminishes the risk for damages while retaining the insulating qualities.