Brødrene Aa has been working with sandwich
composites and Diab for nearly 40
years. The yard has delivered around 200
vessels with Divinycell FRP sandwich constructions,
and for more than a decade it
has excelled in working with carbon fiber.
The company won the prestigious JEC
Composite Awards in 2005 for its vacuum
infusion molding process involving skins of
carbon/vinylester.
Compared to traditional construction,
the use of carbon-fiber sandwich composites
reduces structural weight by 40%, giving
boats from Brødrene Aa lower fuel consumption
and CO2 emissions. At the same
time, it makes them both stronger and more
rigid, since the composites have 2-3 times the
tensile strength and four times the rigidity of
fiberglass.
The latest boat to leave the Brødrene Aa
yard is the ambulance boat Rygervakt, which
is 30th in the line of carbon-fiber vessels produced
by the company. While part of a long
tradition, the Rygervakt is also a major step forward, since it is the very first ambulance boat constructed with twin hulls.
As a catamaran, the 21 m Rygervakt offers
not only greater stability than single-hull
ambulance boats, but also a great deal more
space. In addition to accommodating up to
twelve people, the boat has ample room for
sophisticated medical equipment, as well as
room for two stretchers and an extra stretcher
stowed below deck. Next to the shower there
is even a bath for use in treating burn injuries.
Of course, the Rygervakt does share
characteristics with its predecessors. From
keel to mast if features an optimized combination
of several Divinycell H grades delivered
by Diab in sheets and blocks that were
adapted for core infusion with Toray T700
FOE carbon fiber and Reichold vinylester
resin. In addition, it was delivered to the
same customer as Brødrene Aa’s very first
carbon-fiber vessel, a single-hull ambulance
boat for L. Rødne & Sønner.
L. Rødne & Sønner, which provides ferry
services along with charter and ambulance
contracts, will be operating the Rygervakt as
an ambulance in the Norwegian county of
Austevoll. Since the boat is equipped with a
water cannon that sprays seawater up to 40
meters, it will also be a resource for the local
fire department, offering assistance when
fires prove inaccessible from land.
For Brødrene Aa as well, the Rygervakt
provides a flexible platform that can be
adapted to other applications. The basic design,
which incorporates a new and highly
efficient propulsion system, would require
only a two-meter extension to increase passenger
capacity by half and enable use as a
50-seat ferry.
www.braa.no