Lewmar 125 VRTT Pontoon Thruster Owner's Manual (PDF)

OWNER'S MANUAL

Hull mounting box, fitting and limit adjustment, ICU and battery wiring, cable sizing, operation and LED codes, servicing, fault finding and the spare kits for the Lewmar 125 VRTT retractable pontoon thruster.

DocumentLewmar 125 VRTT Pontoon Thruster Owner's Manual

FormatPDF · 24 pages · 5.3 MB

LanguageEnglish

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Specifications Installation Electrical Operation Servicing Spares Products

Lewmar 125 VRTT Pontoon Thruster — Owner's Manual

Specifications

The 125 VRTT must not be used at speeds greater than 5 kts.

Model	Voltage	Stated current draw	Circuit breaker	Cable section	Cable length
125 VRTT 2.0 kW	12 V	280 A	200 A	70 mm²	14 m

Cable length is the total run from battery to thruster and back. The worked example in the text says 20 m (66 ft) of cable needs 70 mm² (000 AWG), while the table row reads 14 m (as printed). Cable sizes are guidelines only: use 90°C-rated insulation and check with a marine electrician.

Placement & Mounting Box

Bow installation: as far forward as possible. Deployed, the hub centre line must be at least 1.5 × propeller diameter below the waterline and clear of the hull.
Keep the compartment dry and ventilated, clear of loose items (fit a cover or barrier if it doubles as storage), with room for cables and service access.
The thruster needs a watertight compartment whose top is the seat for the base plate, built to take the thruster weight and the thrust; a naval architect should design it.
Recommended welded mounting box: part 55110251, material 5083. Cut the hull opening, keep the flange as level as possible, flange height +-5 mm.
Lower flange minimum cut for the 125 model: height (A) 190 mm, minimum width (B) 220 mm.

Fitting the Thruster

Supplied with the leg raised. Lift with proper strops, never by the actuator or the propeller shroud; protect the micro switches and control box.
Lower the leg, remove the tunnel (held by only 2 bolts in transit) and the securing ring, then post the assembly down through the box.
Lower it through the mounting box with its 2 O-rings in place (grease to hold them) and line up the bolt holes.
Push the securing ring on from below with its 3 O-rings greased, and secure it with 6 bolts from above.
Refit the tunnel with its O-ring, turning the prop if the motor shaft does not line up, and secure with 6 × norlock washers (as printed) and M6 bolts.
Limit adjustment: raise the top cone to raise the retracted position, lower the bottom cone to lower the extended position; tighten the nuts either side to 10 Nm with blue Loctite 243.

ICU & Electrical Installation

ICU & Motor

Mount the ICU dry, vertical (arrow on the lid), within 5 metres of the motor but not on it. It has its own battery supply and a 5A circuit breaker; its power cable must be rated 5 amps minimum.
Plug the VRTT flying lead into the ICU THRUSTER port. The AUX cable is only needed with an automatic battery switch.
The motor needs its own battery supply with a supply switch, circuit breaker and in-line fuse; battery crank capacity at least equal to thruster current.
Motor studs: two 13 mm spanners (hold the inner nut), 20 Nm (15 lbs.ft), do not overtighten; fit the supplied boots so no bare metal shows.
Minimum voltage at the motor while running: 10V on 12V units. Fit a battery switch and switch it off whenever the thruster is not in use or the boat is unattended.

Electrolytic Test & Control Panel

The motor body must stay isolated from supply and ground. Test 1: negative off, positive connected but switched off – no continuity from either stud to the motor body.
Test 2: power on – if supply voltage (12V) shows between the –VE stud and the motor body, disconnect at once and inspect.
Control panel: 63.5 mm (2 1/2") hole saw; integral seal; clamp from the rear or with the bezel. Use Y connectors for two or more panels.
Final checks: tight boots-on connections, correct fuse, switch wires correct, then connect the batteries. Never run it out of the water.

Operation & Safety Features

On: press and hold ON for 1 second; the LED flashes green while the leg deploys and turns solid when deployed. Off: press ON once; it flashes green while retracting, then switches off.
Running one way for more than 3 minutes, or a PORT/STBD signal at switch-on, puts the system in fault mode (solid red). PORT and STBD together stop thrusting.
Auto power-down after 1 minutes of inactivity (as printed). A short delay is built in when reversing direction.
The motor thermal switch stops operation when hot (flashing red) until it cools. Low battery shows amber, for information only.
Hitting a hard object while deploying trips the ICU breaker; on reset the VRTT retracts home. If the limit switch is not reached within 15s, deployment stops with a red fault.

LED colour	Status
Green (flashing)	Thruster extending / retracting
Green	System ON
Amber	Low voltage
Red (flashing)	Motor high temperature
Red	Fault
Black	Off / no power source / circuit breaker blown

Annual Service

Switch off at the battery switch or remove the fuse first.
Clear debris from tunnel, propeller and hub; replace a damaged or heavily contaminated propeller.
Grease the exposed seal and shaft; top up the hub grease through the grease nipple. Replace the tunnel gasket whenever the hub is removed.
Check motor leads, bolt torques, that the motor is dry and the compartment watertight; clean it out.
Brush carbon dust off the top of the motor, especially on aluminium boats.
Drive pin: cut the cable tie, punch out the pin parts, tap in a new pin and secure with a new cable tie.

Fault Finding

Will not turn on: ICU health LED – if not flashing, replace the ICU fuse / reset the breaker; check ICU battery cables.
Green flash then solid red: actuator did not complete in time – check the down switch, actuator wiring and UP/DOWN switch adjustment.
Wrong direction: swap the contactor wires on the motor solenoid.
Fuse/breaker keeps blowing: wrong fuse; water too shallow overloading the raise/lower motor; obstacle stopping retraction.
Poor or one-way thrust: batteries or cables too small (10V minimum at the motor), debris, propeller washers wrong, brush springs, D1/D2 terminals.
Motor turns, no drive: stop – shear pin broken (remove the 4 motor bolts, replace the pin) or blades broken.
Noise/vibration: propeller touching the tunnel; hub height. Lowers then raises (red): stop – tunnel blocked or lower limit cone mis-set.

Spare Kits & Accessories

Lewmar 125 VRTT thruster spares view, items 1 to 36

Lewmar 125 VRTT thruster spares view, items 26 to 47

Part no.	Description	Items included (qty)
581110	125 VRTT 2.0 kW 12V	1(1)	Ask us to source it →
589455	125 spare prop	20(1)	Ask us to source it →
589894	125 VRTT Gen 2 ICU	23(1)	View part →
589808	Gen2 RT motor loom 2 m	(1)	View part →
589809	Gen2 RT motor loom 5 m	(0)	Ask us to source it →
56110037	125 VRTT drive shaft kit	7(1), 5(1), 8(1), 9(4), 6(2)	Ask us to source it →
56110038	125 VRTT upper bushing kit	10(2), 11(2), 12(1), 13(1)	Ask us to source it →
56110039	125 VRTT leg fixing kit	15(1), 18(1), 19(1), 24(1)	Ask us to source it →
56110040	125 VRTT lower leg sealing kit	27(1), 28(1), 29(1), 30(2), 31(2), 35(1), 36(1)	Ask us to source it →

Part no.	Accessory
589222	Controller, dual pad	View part →
589223	Controller, single pad	View part →
589267	Controller, dual joystick	View part →
589268	Controller, single joystick	View part →
589845	Controller, single, hyd	Ask us to source it →
589846	Controller, dual, hyd	Ask us to source it →
589809	5 m RT motor loom MX	Ask us to source it →
589800	Gen2 Y loom MX	View part →
589801	Gen2 AUX 2 m loom MX	View part →
589802	Gen2 AUX 7 m loom MX	View part →
589803	Gen2 AUX 10 m loom MX	View part →
589804	Gen2 AUX 18 m loom MX	View part →
589805	Gen2 AUX 22 m loom MX	View part →
589006	Fuse holder	Ask us to source it →
589010	T2 fuse holder	Ask us to source it →
589861	3-button remote (Gen2 system)	Ask us to source it →
589862	5-button remote (Gen2 system)	Ask us to source it →
589810	Automatic battery switch 12V (shown in the wiring layout)	View part →