User Report User Seatight GmbH D-26789 Leer, Germany ...
Transcript of User Report User Seatight GmbH D-26789 Leer, Germany ...
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User Report Topics Seaworthy securing of valuable maritime cargo such as the components of wind-power installations; mechanical loading and securing; parameters for welding the holder-fixtures; welding processes and systems; higher quality and economy in ‘rack’ mode User Seatight GmbH Königstrasse 1 a D-26789 Leer, Germany Tel.: +49 491 976999-55, Fax: + 49 491 976999-65 www.seatight.eu Dialogue partners Angelo Pennacchia, Managing Director Roland M. Barow Research, photos, copy Gerd Trommer, Dipl.-Ing. rgt redaktionsbüro gerd trommer, Johannishofweg 7, D 64579 Gernsheim, Germany Tel. +49 6258 9320-30, Fax -32 [email protected] Client Fronius International GmbH Froniusplatz 1, A 4600 Wels, Austria Tel. +43 7242 241-0, Fax +43 7242 241-267 www.fronius.com Sources Interview with Angelo Pennacchia and Roland M. Barow on 14.11.2011 in Leer, Germany; internal documents from Fronius; online sources _____________________________________________________________
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On-deck joints
Securing cargo using welding systems
Offshore wind-power installations (WPI) and their individual
components have to be safely transported to the installation sites by
ocean freight. The cargo has to be fixed to the ship’s deck solidly and
reliably, as any errors risk serious injury and damage, not to mention
considerable financial losses. Based at Leer, in Northwest Germany,
Seatight is a specialist company that uses its practical, ‘hands-on’
know-how to control and manage these risks. The work carried out by
the welders, and the equipment they use, is of very great significance
here.
Business focus: the high seas Angelo Pennacchia first trained as a ship’s mechanic, then qualified as
a navigational watchkeeping officer before going on to found Seatight,
of which he is now a Managing Director. His company provides advisory
and practical services related to cargo-securing and transportation
safety to a clientele that includes shipping companies, charterers,
logistics firms, shipping agencies and manufacturers of wind-power
installations.
From Pennacchia’s explanations, it soon becomes clear that mastery of
the forces exerted by the ocean requires wide-ranging knowledge of
nautical science and physics: he explains the motions of a ship’s hull in
terms such as roll, heave, pitch, sway and yaw, summing it up by noting
that “The greater the amplitude or the frequency of the motions, the
greater the accelerations that they produce. The further away the
centres of gravity of the cargo items are from the centreline of the
vessel, the greater the acceleration stresses become, and the greater
the precautions needed to secure the cargo. On deck, the wind
pressure and wave-impact forces need to be taken into account as
well.”
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Welding – the preferred solution The cargo has to be secured in such a way as to create a durable
connection between the ship and the cargo item. This connection will be
made either of tensioned flexible elements or welded stoppers. Lugs in
the walls of the cargo hold are used for attaching the tensioned
elements such as chains, steel cables and textile lifting slings, whereas
on the smooth ship’s deck, D-rings (lashing eyes) or lashing plates are
welded onto the deck. Stoppers made from flat-bar steel or double-T
sections secure items against slippage, while clamps fabricated from
shaped steel plates prevent slippage, tipover and lift-up.
“Welding is normally faster and can cost up to six times less than
lashing”, explains Roland Barow, the second Managing Director of
Seatight. Fastening-welding on ships’ decks is governed by rules and
regulations laid down by the International Maritime Organisation (IMO).
An ‘a’ dimension of 6 mm is stipulated for fastening-welds. For a 1 cm
length of seam, this corresponds to a load capacity of around 1.2 t and
a failure load (including safety margin) of 1 t. The ‘Maximum Securing
Load’ (MSL) is specified as 50 % of these loads. Accordingly, a stopper
with a 20 cm long seam reaches an MSL of 10 t, while a double-T
section with a 20 cm long welded join on both sides has an MSL of 20 t.
WPI cargoes To explain the welded joints needed, Angelo Pennacchia takes a WPI
(wind-power installation) as an example. Its approx. 400 t weight is
distributed between the nacelle (approx. 130 t) containing the gearbox
and generator, the rotor hub (40 t), three rotor blades (13 t apiece) and
three tower elements weighing 65 t each. Cargo space and deck space
are expensive, and so are used as densely and efficiently as possible.
On the decks, the gaps between cargo items – and thus the workspace
for the welders – can be very narrow. Before the joining operations
begin, all paint, rust and water must be removed from the join location.
To secure the nacelles, the technicians weld 30 clamps totalling 8 m of
seam-length. These clamps sustain a total MSL of 400 t. 12 clamps are
sufficient to secure the rotor hub; they comprise 2.4 m of seam-length,
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equating to an 120 t MSL. For each rotor blade, fastened in a support
frame, the fixing-points comprise 10 clamps and 5 D-rings; and for each
tower element, 12 clamps and 16 D-rings. All in all, the resulting length
of welded seam totals approx. 50 m. A team of 6 Seatight employees
accomplishes this in an average of one workday.
Criteria, welding processes & systems The deep-see freighter ‘Dynamogracht’ has space for 70 components
for 14 WPI. The client needs to keep loading-times as short as possible,
a requirement that Seatight fulfils by fielding two teams of three
certified, tested welders. In addition to their professional qualifications,
they also bring other vital knowledge and skills into play. The quality of
their welding-results is checked by a neutral expert. The criteria here
are compliance with the parameters specified in the stowage plan,
weld-seam appearance and – in special cases – dye-penetrant and
magnetic-particle inspection testing. The inspectors also look out for
welding spatter that could damage the valuable components. The great
care taken with electrode stubs is just one expression of the
conscientious work ethic at Seatight, as these can cause fires on decks
below the welding site.
On-board welding means manual-electrode (MMA) welding. Wind and
weather, the distance between the power source and the workplace,
and of course rugged, powerful and portable welding systems are the
main factors affecting working practices here. In view of the distances of
75 m to 150 m that are usual between the power source and the
electrode holders at the workplace location, a stable arc is absolutely
critical. This is why Angelo Pennacchia set out in search of high-quality
welding systems – and found just what he was looking for at Fronius:
“They provided test systems for us at very short notice, which really
impressed us – as did the extremely positive results that we got. It didn’t
take long for the investment to pay off. When we set 180 amps on the
TransPocket 2500 Comfort, that’s the value that we get – practically
unchanged – at the other end of the cable a hundred metres away.”
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This is thanks to a technology called ‘Resonant Intelligence’, in which
continuous automatic feedback from the arc responds instantly to every
change, keeping the power parameters in line with those of the ideal
characteristic. This ensures maximum arc stability at all times, even
with long mains supply leads or voltage fluctuations.
More plus-points Unlike conventional remote-control units, the lightweight (only 120 g)
TP09 remote-control is cable-less. It allows the six welding systems to
be regulated separately from one another using only a single TP09.
With the TP09, every welder can respond individually as the situation
demands. Among the other advantages: ‘Hot Start’ facilitates ignition of
cellulose and rutile electrodes; the ignition means that less post-weld
machining is needed; the anti-stick function detects any sticking of the
electrodes in a short circuit; the welders can call up just the right job for
e.g. vertical-up or vertical-down welds, as and when the situation
requires.
Twenty TransPocket 2500 Comfort machines form the ‘backbone’ of
Seatight’s fleet of welding systems. For special cases requiring
extremely high power, there is a TransPocket 4000 unit, including a
remote-control unit.
Says a satisfied Angelo Pennacchia: “Using electrodes from four
millimetres’ diameter upward, and working at between 180 and 220
amps, we can get a 100 percent duty cycle. Our old system used to cut
out every quarter of an hour! This meant that in practice it was much
more expensive, even though the initial investment costs were lower.
And with the TransPocket 2500, a good welder achieves top-grade
seams.”
Rack mode On the pier, six TransPocket 2500 Comfort units are aglow in a special
device known as a ‘rack’. Seatight owns the first serial-production rack
from the Automation Department at Fronius. Among its advantages are
shorter set-up times, as it is simply lifted out of the delivery van by fork-
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lift and set down on the pier, and the fact that it can be wheeled along
the quayside to be close to the workplace. Being run on centrally
connected – and much cheaper – onshore power, the welding systems
are subjected to fewer current fluctuations, and there is less wear-and-
tear on their mains filters. This operating mode also reduces the length
of the individual cables, thanks to the central connector, and the safety
and availability of the welding systems are enhanced by the equipment
being housed in the rack. The IP54 power distributor, with 6
weatherproof outlet sockets and a primary external mains socket, has
125A of fuse protection.
The practical benefit is so great that in the medium term, Seatight is
aiming to deploy further racks of TransPocket 2500 Comfort appliances
at five European ports, in addition to its main facility in Leer.
Box 1:
Seatight: Sustainability-oriented and dynamic In July 2009, the 29-year-old Roland M. Barow joined with 28-year-old Angelo Pennacchia to found Seatight GmbH Port & Cargo Securing Service in Leer, NW Germany. Barow is a captain with an engineering degree; Pennacchia a technician and nautical officer. With their combined technical and nautical expertise, they aim to make a professional and lasting impact on the field of securing high-value maritime cargoes. This philosophy has helped the young company to make it to the top of this market niche in a very short time. After less than two and a half years in business, they had boosted their headcount from 3 to around 20. Their stock of transport vehicles, container storage space and technical equipment has increased several times over – starting with just 6 welding systems, for example, they now have over 20. As well as its own workshop building in Leer, Seatight now has a subsidiary in Spain. In an average week, Seatight now secures the cargo of two ships. After over a hundred and fifty sailings, not one single accident or damage incident has occurred. Thanks to offshore wind-power installations, Barow sees continued growth-potential in the market niche of securing high-value maritime cargo.
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Box 2:
Data on the welds for ‘holding-fixtures for high-value cargo items on ships’ decks’
Workpiece Clamp for fixing tower-element Lashing point for D-ring
Steel grade S235 S235
Wall thickness (mm) 20 15
Weld process Manual electrode (MMA) Manual electrode (MMA)
Seam-length (mm) 400 650; 6 passes of 100 mm
each + overhang
‘a’ dimension (mm) 6 8
Weld passes 1 on each side 3 on each side
Electrodes (rutile),
diam. (mm)
4 4
MSL (t) 20 20 - 25
Seam and position Fillet weld PB Vertical-up weld PF
Process n° 111 111
Torch tilt angle Trailing Trailing
Welding systems
TransPocket 2500 Comfort
Remote-control unit TP09
Mains voltage (V) 380...460
Amperage, range (A) 15...250
Cos phi 0.99
Efficiency (%) 90
Duty cycle (%)
at 10 min/40°, 175A
100
IEC Ingress Protection rating
Dimensions: L x W x H (mm)
Weight (kg)
IP23
430 x 180 x 320
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Pictures/illustrations
1: The wind-power installation (WPI) components are transported and loaded right round the clock. The managers and staff of Seatight specialise in securing non-standardised maritime cargoes.
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2 (selection): The valuable cargo being gently lifted into the hold.
3: The ‘light’ rotor blades (weighing ‘only’ 13t) are stored on the quayside until the heavy WPI components have been stowed.
4: Manual welders join the fixing-elements to the ‘best-fit’ locations on the deck.
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5: The cargo-securing experts weld the holders for the D-rings or lashing eyes directly onto the deck
6: Here, ‘narrow-gap’ refers to the welders’ workspace rather than to the welding groove!
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7 (selection): As well as paying attention to the quality of the welded joints, the welders also have to make sure that the surface of the valuable cargo is not damaged.
8: To reduce the ‘cycle times’, three welders work on the holding fixtures for the heavy (130t) nacelle at the same time.
9: The 6 welding systems are run on low-cost onshore power with low voltage fluctuations, minimising the wear-and-tear on their mains filters.
10: Using electrodes with a 4 mm diameter, Seatight’s welders benefit from a 100 % duty cycle.
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11: The Seatight specialists (at left: Managing Director Angelo Pennacchia) are very satisfied with the rack, and with the enhanced welding-system availability that it brings.
12 (selection): The cargo-securing experts weld the holders for the D-rings or lashing eyes directly onto the deck. (Source: Seatight).
13: Product picture Rack