Sleipner SX External Stern Thrusters — Installation & User Manual

Using the Thruster

1. Turn on the thruster main power switch (always off when you leave the boat).
2. Turn on the panel by pressing the ON button(s) together; OFF turns it off.
3. Push the button or move the joystick in the direction you want the stern to go.
4. With bow and stern thrusters: same direction on both moves the boat sideways; opposite directions spin her on her axis.
5. Release the control shortly before the boat reaches position – she keeps drifting.

Above about 1-2 kn the thruster has little steering effect. The thruster will not run if two panels give conflicting commands. Never use it near people, animals or objects in the water.

Safety

• Know where the main battery switch is; turn it off before touching any part of the thruster.
• Keep the main engine running while using the thruster to hold battery charge and performance.
• Never run the thruster out of water. Stop it if it stops giving thrust: running without propeller load can severely damage the drive.
• Never store sails, ropes or gear in the thruster compartment: the motor gets hot on long runs, and DC motors shed carbon dust.
• Ignition-protected models: never disassemble the ignition-protected assembly.

Seasonal Service

• In water: cable area inside the boat clean and dry with no sign of leaks; electrical connections clean and firm; batteries in good condition.
• Out of water: propeller and tunnel free of damage; propeller fastened securely; antifouling on propeller and gear leg every season – never on the sealing or propeller shaft, and keep paint out of the gap between propeller and gear leg.
• Checklist: unit and its bolts secure to the hull, antifouling applied, batteries and connections OK.

Key: 1 electro motor, 2 power & control cables, 3 gear leg, 4 propeller, 5 drive pin, 6 washer, 7 lock nut.

Troubleshooting

SX35 / SX50

• Fit as deep on the stern as possible, out of the hull's water flow and clear of drives, trim tabs and props; off-centre is fine, an angle only as a last resort (outflow 5-7 meters per second). It must not protrude past the transom profile.
• Maximum hull thickness 50mm including the optional spacer, or 150mm with the extended-tube model.
• Template 6377 (SX35, <=150mm hull, scale 1:1, A3): support rods Ø8 → drill Ø10; tube Ø30 → drill Ø32. Drill the main hole first, then the two support bolt holes.
• Galvanic isolation on metal hulls or brackets; coat all aluminium parts with epoxy primer before antifouling.
• Antifouling: remove the two anodes, paint the thruster, propeller and both tunnel halves – not the propeller shaft, feed-through bolts or anode screw threads. Anodes 2Nm (one anode uses screws of different lengths).
• Propeller centre nut 19Nm with hand tools only (no impact wrench); hub anode screw 2Nm.
• Tunnel halves: press together evenly with a clamp until all locking tabs engage and the inside is smooth.
• Unit flush on the transom; MS Polymer in the hull holes, on washers and threads and in the main tube recess.
• Control box above the waterline within 0.75 meters of the thruster bolts; motor cables A1/A2 8 NM; battery terminals M10 40 NM, M8 18 NM. Max 70mm2 through the grommet, 50mm2 in the terminal.

SX80 / SX100

• Drill the main Ø140 hole first, then the Ø13 bolt holes; the assembly must sit flush on the transom.
• MS Polymer around the base of the central connector and the 4 threaded rods.
• Tighten the nuts in a cross pattern (1-2-3-4) in three rounds: 5 Nm (3,68 lb/ft), 50 Nm (36,88 lb/ft), 110 Nm (81,13 lb/ft).
• Propeller lock nut 20 Nm (14.75 lb/ft); anode holding screw with Loctite 243 or similar.
• Power lugs on the thruster: M10 nut max 23 Nm (16.96 lb/ft).
• Cowls redirect the outflow around trim tabs, jets or drives and help shallow installations; cowls and grids cannot be combined.

Ohm-meter check with the main switch off: no connection between the motor flange and the positive terminal, nor between the flange and the negative terminal.