Technical details Finnpusku

1 technical details

1.1 combination
1.2 pushers

1.2.1 rautaruukki , steel
1.2.2 herakles


1.3 barges

1.3.1 hull , machinery
1.3.2 cargo space

technical details
combination

pusher rautaruukki barge botnia outside raahe, finland, raahe steel works in background.

a finnpusku pusher-barge combination consists of 1 pusher vessel , 1 barge. overall length of combination 166.6 metres (546.6 ft) , breadth , draft @ summer load line of barge, 27.2 metres (89.2 ft) , 6.7 metres (22.0 ft), respectively. however, in brackish water of baltic sea can loaded maximum draught of 6.85 metres (22.5 ft). during ballast legs pusher maintains normal draught while barge ballasted draught of 5.6 metres (18.4 ft) reduce displacement 20,930 tons 17,630 tons. in such loading condition main deck of barge @ same level pusher s gunwale. tonnage of combination of pusher , barge combined, 10,620 gt, 3,184 nt , 14,447 dwt.

the combination classified det norske veritas class notation of +1a1, pusher/barge unit, ice ia+. has highest finnish-swedish ice class, 1a super, means designed operate in difficult ice conditions without icebreaker assistance. icebreaker bow , sloping sides, combination operate independently in level ice. when finnpusku system entered service in mid-1980s, icegoing capability superior conventional bulk carriers.

finnpusku uses unique rigid coupling system, wärtsilä marine locomotive, consists of 2 hydraulic locking pins, 1 on each side of pusher, , 1 fixed pin in bow. when connected, hydraulic pins exert transverse force of 450 tons sockets, forcing jaws of barge apart 45 millimetres (1.8 in), , angled faces of coupling pins push pusher forwards, resulting in longitudinal force, of 450 tons, @ bow pin. three-point connection removes degrees of freedom , results in combination behaving hydrodynamically single ship, allowing unrestricted service , independent operation in severe ice conditions of gulf of bothnia. pusher can connected barge @ 3 different levels, removing need ballast barge same draught pusher when not carrying cargo. in addition mechanical coupling pusher connected barge several electrical cables on starboard side , flexible pipes on port side. latter allow pusher s fuel , freshwater tanks topped larger storage tanks of barge.

the combination of pusher , barge referred using names of both vessels, e.g. rautaruukki-board.

pushers

initially there 2 pushers in finnpusku system, rautaruukki , finn, built hollming in 1986 , 1987, respectively. after capsizing in 1990 finn rebuilt , returned service steel in 1991.

in 1991 herakles, salvage tug built in 1967 , owned finnish towing , marine salvage company alfons håkans, converted pusher , chartered rautaruukki third pusher of finnpusku system. after conversion herakles chartered rautaruukki , continued operate part of transport system until demise on 3 march 2004, when sank barge bulk near swedish grundkallen lighthouse in bothnian sea.

rautaruukki , steel

pusher steel without barge in port of raahe. wärtsilä marine locomotive coupling devices visible in hull behind superstructure.



main articles: steel (pusher) , rautaruukki (pusher)

the pushers of finnpusku system 41.7 metres (136.8 ft) long , have breadth of 14.37 metres (47.1 ft) @ waterline , 15.5 metres (50.9 ft) @ bridge wings. draught , depth upper deck, 6.7 metres (22.0 ft) , 10 metres (32.8 ft) respectively, same of laden barge.

one of prominent features of pushers high superstructure rising 22 metres (72 ft) waterline. in addition accommodation, mess , dayroom crew of nine, housed 2 bridges @ different levels. lower bridge on third deck intended used when pusher operating on own without barge, allowing more comfortable conditions crew — chairs in upper bridge on seventh deck equipped seatbelts due large motions of vessel when operating independently. however, lower bridge used , space later rebuilt other use in both pushers. upper bridge, bridge wings extending beyond pusher s breadth, equipped allow 1 man bridge operation.

propulsion power provided 2 six-cylinder sulzer 6zal40 4-stroke medium-speed diesel engines running on heavy fuel oil, manufactured under licence wärtsilä, each maximum continuous output of 3,840 kw (5,150 hp) @ 380 rpm, giving combination service speed of 13.4 knots (24.8 km/h; 15.4 mph). lohmann & stolterfoht reduction gearbox connects main engines propeller shaft driving 4.7-metre (15.4 ft) four-bladed rauma-repola liaaen controllable-pitch propeller , 900 kva strömberg shaft generator used power bow thruster. main engines equipped steam-generating exhaust boilers improve overall efficiency of power plant. electricity provided 2 wärtsilä-vasa 4r22hf diesel engines, each producing 590 kw (791 hp) @ 1,000 rpm, connected 710 kva strömberg alternators. auxiliary generating sets mounted side side above propeller shaft due narrow hull. 158 kw volvo penta tmd102a emergency generator located on main deck level in smoke stack.

while connected barge, pushers capable of operating independently. however, low metacentric height of vessels, 0.5–0.6 m (1.6–2.0 ft), results in large roll amplitudes , pitching, making pushers uncomfortable in severe weather. reason short transit journeys without barge done when absolutely necessary.

herakles

when salvage tug herakles converted pusher, new wheelhouse installed on top of cylindrical pillar 14.2 m (46.59 ft) above old superstructure, hull modified accept coupling devices, additional diesel generator installed power bow thruster of barge , propulsion , steering gear upgraded. conversion included refitting existing barges new coupling devices since herakles, having considerably smaller breadth original finnpusku pushers , different hull shape, incompatible original rigid three-point wärtsilä marine locomotive coupling. herakles , barges fitted japanese articouple k articulated coupling system allowed free pitching of tug relative barge.

being considerably less powerful rautaruukki , steel, herakles received new main engines , propellers in 1995. while engine output doubled 4060 kw, remained underpowered in comparison original finnpusku pushers. had lower finnish-swedish ice class, 1b.

barges

the barges of finnpusku system built in 2 series, kalla , tasku in 1986 , baltic, board , bulk in 1987. hulls constructed portuguese shipyard estaleiros navais de setubal , towed hollming in rauma outfitting. of these baltic renamed botnia after capsizing , bulk sank along pusher herakles in 2004.

hull , machinery

as finnpusku system designed operate independently in severe ice conditions of bothnian sea, special attention has been paid hull form. spoon-shaped bow has low stem angle reduce icebreaking resistance , sides of barge flared prevent combination becoming immobilized ice ridges , compressive ice fields. when pusher coupled barge, deep stern notch forms streamlined aftship seakeeping characteristics similar of conventional ships.

when coupled, power ramps, pumps, floodlights , other equipment on board barge taken pusher. when power cables on starboard side of pusher s superstructure disconnected, 200 kva volvo penta td100crc generating set starts automatically , provides power operate equipment when barge left alone loading or unloading. increase maneuverability in ports barges equipped 680 kw controllable-pitch bow thruster powered pusher s shaft generator.

cargo space

the barges of finnpusku system of so-called deck cargo type, meaning cargo carried on main deck in open cargo space instead of closed holds in conventional bulk carriers. cargo space, surrounded coamings 7.5 to 9.0 metres (24.6–29.5 ft) high, has free area of 2,650 square metres (28,500 sq ft) , total volume of 20,000 cubic metres (710,000 cu ft). total cargo carrying capacity 13,400 tons. bulk cargo loaded either shiploaders or bulk-handling cranes, while cargo deck strengthened grab discharging, barges equipped 2 side ramps facilitate faster discharging wheel loaders , dump trucks. more efficient method removes need invest in discharging equipment in unloading port. ramps 14.5 metres (48 ft) long, have free driving width of 7.6 metres (25 ft) , strengthened axle loads 52 metric tons (51 long tons; 57 short tons).

there differences between first , second series of barges. first 2 built lower side coamings due limited clearance under loader @ port of luleå. when finnpusku system developed, volume enclosed fixed coamings included in tonnage of barge rules regarding ship measurement, minimize side coamings in kalla , tasku consisted of removable cassettes held in place vertical supports. however, rules later changed none of open deck included in tonnage assessment, last 3 barges had cassettes welded in place. second series designed higher coamings around increase capacity cargo low stowage factor, such coal, restrictions placed cargo handling equipment of ports resulted in compromise lower coamings forward of side ramps , higher towards aft.

since cargo open elements, there 4 drainage pipes , 6 storm shutters, gravity-closed hatches opened internal water pressure, on both sides of barge remove water cargo space. these covered cargo, forward part of barge bulk equipped retractable, air-filled cloth cover protect cargo water splashing on bow in heavy weather. due problems during winter months later removed , not installed on other barges.

as cargo carried on main deck, barges have considerable tank capacity belowdecks. in addition 12,413.75 m of ballast water in side tanks , 12,304 m of void space in middle of barge there tanks 592.66 m of heavy fuel oil can used replenish fuel tanks of pusher, 82.05 m of marine diesel oil pusher s auxiliary engines , barge s own generator , 82.05 m of freshwater.