JEC COMPOSITES MAGAZINE - Issue #96 - April 2015 - 20

trimaran
Preparing to
infuse
To ensure the
infusion process
was as efficient
and successful as
possible, Sicomin
assisted with a
series of infusion
tests completed on
a large glass table
to ensure all the
cored laminates
would infuse completely without
issue.

Main hull before infusion

crease a little (as the laminate
is exposed to high temperatures and humidity levels)
and this is referred to as the
"wet Tg" - however, it must
remain above 80°C. Sicomin
requested that H2X make
small samples for every batch
of mixed resin during the
actual infusion, which were
then cured with the same
history as the boat. These
samples were subsequently
tested using DSC and DMA
to verify the Tg and ensure
the mix ratio was respected.
This process also provided
complete traceability for the
moulding process.

Key facts

* 4000kg of Sicomin's SR8100
resin were needed to infuse each
main hull
* The Ocean Eagle 43 is capable
of a top speed of 30 knots yet
can also maintain an economical
20-knot cruise for a 4,828-km
range
* Each trimaran composite structure weighs less than 30 MT

The results of the
laminate schedule tests proved
invaluable. With
the designer and
naval architect's
approval, Sicomin and H2X
subsequently made numerous changes to maximise
the infusion process such as
altering the laminate plan and
switching the direction of the
fibre to achieve the best flow
and wet-out possible.
Sicomin also developed
150mm- and 300mm-wide
unidirectional tape for the
infusion of the critical arm
structures. Stitching was designed to leave open paths to
encourage resin flow but was
balanced to achieve sufficient
fibre volume for the required
mechanical parts. H2X used
ten layers of these tapes in
the arms.

A resin specified for
large-scale infusions
Sicomin recommended
SR8100, a two-component
epoxy system specifically formulated for large-scale resin
infusion projects, and offered
H2X a robust and cost-effective solution. The product

20 jec composites magazine / No96 April 2015

delivers reduced viscosity at
ambient temperatures and is
compatible with a selection
of hardeners, making it versatile and easy to work with.
With Sicomin's support, H2X
ran numerous tests to ensure
they had the precise viscosity
levels and gel times to ensure
the SR8100 resin flowed
through the reinforcements
quickly without leaving dry
spots. " You don't want a gel
time so long that there is too
much time between completion of wet-out and beginning
of gel", Pierre Lallemand of
H2X remarks. "This wastes
time and money and increases
risk."
To achieve full mechanical
properties, the epoxy infused
structures also had to be
post- cured. A post-cure temperature of 60°C was selected
as the most effective.
Throughout these crucial
trials, the French certification company, Bureau Veritas
(BV), visited H2X on a
weekly basis to inspect the
construction quality of the
laminates and the work being
undertaken.

Infusing in one shot
To keep construction time to
a minimum, the hull, amas,
arms and deck parts were
laid up and infused in parallel. This was a technical and
logistical challenge but one
that H2X and Sicomin were
fully prepared for.
The main hull took 5 hours
in total to infuse and a
vacuum was maintained for a
further 4 hours until gel was
completed. This was followed
by a 16-hour post-cure in a
43m-long oven at 60°C. The
11-metre amas were infused

in two halves and then joined
along the centreline. The
additional large structures
included the main deck, the
6x9m helicopter deck, the
pilothouse and the 5m-wide
x 15m-long arms that connect
the amas.

Assembling the lightweight superstructure
Following the infusion and
cure of the first boat, the assembly of the Ocean Eagle's
106 parts could commence.
It took several weeks to build
the structure inside the main
hull; this included the stringers, bulkheads, floors and
decks. The parts were joined
by conventional wet lay-up
tabbing, using glass reinforcements supplied by Sicomin
and the SR8500 hand
laminating resin for tabbing.
Sicomin's Isobond SR1170
was used for enhanced bonding strength in high-stress
areas.
The first fully assembled boat
took 3 months in total to
complete and Sicomin and
H2X's overall attention to
process control and material
selection paid dividends. "The
weight of the first and second
boats' main hulls differed by
less than 5kg - impressive for
such a large structure," comments Lallemand of H2X.
CMN is so pleased with the
design concept of the Ocean
Eagle 43 that the company
is developing a mine-hunter
version. Sicomin continues
to work collaboratively with
H2X on the remaining two
boats. n
More information:
www.sicomin.com
http://www.sicomin.com
JEC COMPOSITES MAGAZINE - Issue #96 - April 2015

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