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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 trommer.gerd@rgt-gg.de 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

12.5

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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