The four tugs are typical ASD tugs with rudder propellers beneath the stern. The tug has a
double chine hull with the chines proceeding into the stern. The hull is built on transverse frame 500mm apart and is divided in
5 watertight compartments. A bilge keel is fitted between the chines. A second smaller bilge keel follows the upper chine over
almost the complete length. The hull and machinery are ice strengthened according to Bureau Veritas ice class 1C which is adequate
to Germanischer Lloyd class E1. The rudder propellers are mounted approx. 3.5m from the stern. They are tilted backwards 3.5° to
minimise the angles in the universal joints and provide a better performance. The rudder propellers are Schottel type SRP 1515 FP
with fixed pitch propellers of 2.70m diameter running in nozzles. The Schottels protrude approx. 0.80m beneath the hull’s bottom.
The skegs are different within the two tug series. The skeg begins behind the curvature of the bow and ends approx. 6m from the
stern in the first series. The second series has kind of a flat bulbous bow and the skeg ends approx. 8m from the stern. At the
end of the skeg the draught is 15cm larger as at the propulsion units to provide some protection in the case of a grounding. Two
four-stroke diesel motors make ABC type 8MDZC provide 1,850kW (2,516bhp) at 1,000rpm. The power is transferred by Marine Control
Drive clutches and cardan shafts to the Schottels. The clutches were provided by Twin Disc Inc, USA. The tugs have a maximum
bollard pull of 70t and a speed of 12kts. The bunker capacity is 164m3 Marine Diesel Oil giving the tugs cruising
ranges of approx. 12 days. Their accommodations are completely air-conditioned. The tugs are classified by German See-Berufsgenossenschaft
and Bureau Veritas and got the class notation BV + HULL + MACH, TUG, AUT UMS, ICE 1C, UNRESTRICTED SERVICE.
Tank top deck:
the forepeak shelters water tanks, a store area and two chain lockers. In addition to
the main engines two generators with an electrical output of 180kVA and driven by Scania type D 9 95M 10-40 diesel motors with
196kW are located on the ship’s centerline in the engine room. The forward gen-set is enclosed in a soundproof hood for harbor use.
A special harbor gen-set was saved this way. Two hydraulic pumps for the towing winch are mounted at the forward end of the engine room.
Behind the engine room follow a store with workbench, the rudder propeller room with the steering/gear units of the azimuth thrusters, and
the aft peak with again water tank.
A hydraulically operated combined anchor and towing winch is mounted in front of the superstructure. It is a Brusselle Marine
Industries type SLH150.20/2-2-2 winch with two drums, two chain lifters, and two warping heads. One drum carries 90m synthetic
fibre rope and 15m steel pennant for harbour use, the second drum is fitted out with conventional harbour gear consisting of 90m
steel wire with 52mm diameter, synthetic fibre ‘spring’, and a steel wire pennant. Alternatively the second drum can be equipped
with a sea towing wire of greater length. The drums provide pulling powers of 44t at 0-10m/min, 8.5t at up to 44m/min, and 6t at
up to 50m/min. The brake power is 180t in dry and 160t in wet conditions. The winch is of the constant tension type where the
towline is automatically paid out or recovered depending on the measured tension to keep the tension within preset limits. Chain
stoppers are fitted in front of the winch. A double towing fairlead is integrated into the bulwark in front of each drum. As the
winch is the only on board, it is used when towing over the stern too. In this case the towline is led through a tunnel beneath
the accommodation onto the aft deck
The approx. 1m high deck at both sides of the tunnel accommodates parts of the air-conditioning unit, a paint store, a battery
room, and a second store. Above is the accommodation deck with mess and galley at port and three two-berth cabins at starboard
at front. As none of the cabins has en-suite sanitary facilities a large sanitary space is located in the middle. The exhaust
pipes are fitted at both aft corners. Ventilation shafts are placed on both sides behind the superstructure. They accommodate small
stores additionally. The towing fairlead is mounted between these shafts.
This fairlead is right in front of the tunnel and carries a Palfinger Marine hydraulic knuckle boom crane. The crane is type
PK 10000M and has a safe working load of 0.39t at 12.3m reach. With the exception of the customary bollards, ventilators, and
an emergency exit the aft deck is completely void.
The wheelhouse is fitted approx. in the middle of the bridge deck. Its floor is raised
1.0m above the bridge deck. The space between is used for parts of the air-conditioning plant, the switch gear of the bridge
electronics and stores. Beside the wheelhouse front two 6-persons inflatable life rafts from DSB are mounted in cradles at both
outside edges of the deck. Inside the wheelhouse two control consoles are arranged to left and right of the ship’s centerline.
They carry all necessary controls for rudder propellers, winch, main engines, and navigation lights. A Transas multifunctional
screen with electronic charting is placed at the front end between the consoles. Gauges with the main motor data and indicators
for the orientation of the rudder propellers are arranged vertically along the window posts in front aft of the control consoles.
The captain’s chair is freely movable in the wheelhouse. A desktop is fixed to the handrails above the aft stairs. The navigational
equipment contains among others magnet compass, autopilot, two radars for sailing forward and astern, electronic chart system, GPS,
echo sounder, log, and AIS. The communications equipment is state-of-the-art according to GDMSS area A1 standard. This restricts
the vessel to service within the VHF range of Coast Stations fitted with DSC (30-40nm). The two funnels are placed in the aft
corner of the bridge deck. A Narwhal rigid inflatable boat (RIB) is used as M.O.B. and work boat. It is supported by a bracket
cantilevering from the aft edge of the bridge deck. The boat is handled by the Palfinger crane.
It carries the magnet compass and a Seematz searchlight in the forward part of the deck and
the mast and a second searchlight in the aft part. The mast carries two radar antennas and the navigation lights.
The tugs are run by a crew of three while ship-handling in harbour.