Sleipner SAC AC Electric Thrusters — Installation & User Manual

Product Specifications

Further models in the SAC750–SAC1400 installation manual

• Supply: 3-phase 208-240/380-440V (SAC240 to SAC520), 380-440V from SAC750 up. All models: proportional speed, twin counter-rotating propellers, no galvanic separation (galvanic separation kit available as option on the large models). SAC240 and SAC320 have sealed gear legs; the others are gravity fed from an oil tank, with optional on-water oil change from SAC750.
• Max thrust is available until the motor winding exceeds 130°C, then thrust is gradually limited to the continuous rating. Motor output is @ 230/400V supply; current draw values are the max set in the VFD.
• Generator load is the maximum at standard setup, not the required generator capacity: Sleipner's indicative recommendation is 2 x the listed generator load, selected with the generator supplier. Low harmonic drives (THD <5%) on request.

Figures are from the 2026 user manual. The 2025 installation manuals print slightly different current draw and generator load for some models (e.g. SAC450, SAC520, SAC700, SAC750): check the manual for your exact model.

Tunnel and Motor Dimensions

• Propeller or anode must never extend out of the tunnel: respect the minimum tunnel length.
• Weight of the complete assembly: SAC700 215 kg; SAC750 330 kg, SAC900/513-I 450 kg, SAC900/513-C and SAC1100/513-I 465 kg, SAC1100/513-C 575 kg, SAC950/610 490 kg, SAC1100/610 580 kg, SAC1200 and SAC1400 740 kg, SAC1300 680 kg.
• Gear centre to motor flange (vertical) and to first mounting point (horizontal), motor footprint and VFD dimensions per variant (-2 = 208-240V, -4 = 380-480V, -4L = low harmonic, -H horizontal, -V vertical) are tabulated in each installation manual. The ACS580-01 VFDs are IP21.

Gear Leg, Propeller and Coupling

• Mark tunnel and boat centrelines, use the gasket or template, drill the centre hole first; all holes in line with the tunnel centreline (blade clearance is minimal). Smooth the tunnel surface under the bracket.
• Gear leg with P-mark to port and S-mark to starboard. Dry-fit with the propeller to check equal blade clearance and shaft height, then fit with MS Polymer sealant on both sides of the gasket (not in the bolt holes). Oil or grease the O-rings in the motor bracket.
• Twin counter-rotating propellers: LH on the port shaft, RH on the starboard shaft (marking on the back of the propeller). Keyed propellers: approx. 1mm gap to the gear leg; tighten the nut once without washer, remove, grease the washer face, refit and fold the tab washer.
• Anti-foul gear leg and propeller – never the anode, rubber parts or sealing surfaces.

Flexible coupling (Centa)

Bolts come with factory-applied glue (hardens in 4-5 hours at 20°C): no extra Loctite, no oil or grease on the bolts. Fit radial bolts first, then axial, with a torque wrench; the rubber elements must not be twisted or axially loaded. Shim the motor so it is in line – misalignment can break the motor bracket. The coupling is maintenance free; keep oil off the natural rubber.

Power, PDC-301 and Commissioning

General recommendation only: VFD and power wiring by certified electricians to the VFD manual, with shielded VFD motor cable, and allowing for regulations, temperature and cable length.

Operation and Load Sharing

• Turn on the thruster main power, then the panel (both "ON" buttons together). Push or move the joystick the way you want the bow/stern to go; proportional thrust follows joystick travel. Always switch off the main power when leaving the boat.
• Bow and stern together: both the same way to go sideways, opposite ways to spin on the spot. Release shortly before the boat reaches position – it keeps moving. Above about 1-2 kn the thruster has little steering effect.
• Stop at once on abnormal noise, vibration or loss of thrust; never operate with people or animals in the water near the thruster.

PDC-301 load sharing

• Limits combined generator load when bow and stern run together: set "Load share limit" for each PDC-301 in SETUP on any PJC2xx/PJC4xx panel.
• Read each thruster's maximum power under SETUP→INFO→THRUSTER INFO while running 100% thrust.
• Example from the manual: bow 40kW limited to 60% = 24kW, stern 30kW limited to 80% = 24kW, total 48kW with both joysticks at full.

Gear Oil and Seasonal Service

• Gear oil API GL-5, SAE 80W-90. Drain after the first 50 hours, then every 500 hours, and change at least every second year; check oil quality whenever the boat is out of the water.
• Oil tank above the waterline by at least 20% of the waterline-to-tunnel-centre distance; no loops in the oil tube. There must always be oil in the reservoir.
• Draining: remove the reservoir cap, open the lower drain plug and let it run until the reservoir is empty (SAC450/520 have one drain plug; others got three drain ports from medio 2021). Filling: pump in through the lower drain hole until the reservoir level is right, refit the plug and cap.
• Every season: check the compartment is clean and dry with no leaks, connections tight, propeller and components secure; clean growth off tunnel and gear leg; anti-foul propeller and gear leg (never the anode, seals or shaft); replace the anode (or at half eroded) with thread glue on the screw.
• The VFD comes pre-configured for the thruster: do not change its settings.

Before calling for help

S-Link panels show fault codes; Sleipner's online Fault Code Navigator explains each code.

Key: 1 motor, 2 mounting feet, 3 cardan shaft with flexible coupling, 4 gear leg support bracket, 5 gear leg, 6 propeller, 7 anode, 8 drive pin, 9 washer, 10 lock nut, 11 anode fastening screw, 12 oil drain screw with washer, 13 holding key, 14 pin bolts.