Lewmar 125 VRTT Quick start guide

125 VRTT Pontoon Thruster
Manual ref 55110293 iss.4
Owner’s Installations, Operation & servicing manual

2
GB
1 - Introduction
Dear Customer,
Thank you for choosing Lewmar. Lewmar products are world renowned for their quality, technical innovation and
proven performance. With a Lewmar product you will be provided with many years of outstanding service.
Product support
Lewmar products are supported by a worldwide network of distributors and Authorised Service Representatives.
If you encounter any difficulties with this product, please contact your national distributor, or your local Lewmar
dealer. Details are available at: www.lewmar.com
CE Approvals
For CE approval certificates contact Lewmar.
Important information about this manual
Throughout this manual, you will see safety and product damage warnings. You must follow these warnings
carefully to avoid possible injury or damage.
 THE 125VRTT MUST NOT BE USED AT SPEEDS
GREATER THAN 5KTS.

Pontoon VRTT Thruster Manual ref 55110293 iss.4 | 3
General
Please ensure that you thoroughly understand the operation and safety requirements of the thruster before
commencing the installation. Only persons who are completely familiar with the controls and those who have
been fully made aware of the correct use of the thruster should be allowed to use it. If there is any doubt of how
to install or operate this unit please seek advice from a suitably qualified engineer.
 Please ensure that you thoroughly understand the operation and safety requirements of the thruster.
 Your thruster should not be operated close to swimmers, as a powerful suction of water is generated when in
use.
The tunnel installation and any hull modifications should only be carried out by a specialist.
 We recommend that a qualified person install the thruster. Faulty installation will place the boat and crew in
danger and make the warranty invalid.
 It is the unavoidable responsibility of the owner or master or other responsible party to assess the risk of any
operation on the vessel.
Thruster supply
 The thruster is securely packed for transit. However all parts should be inspected for signs of damage before
installation. If any parts are found to be damaged please contact lewmar.
Fitting
 This equipment must be installed and operated in accordance with the instructions contained in this manual.
Failure to do so could result in poor product performance, personal injury and/or damage to your boat.
 Electric thrusters must be located in a dry environment.
 Electric bow thrusters use powerful electric motors, it is very important that there is sufficient battery
capacity and large enough cables for safe operation. Using smaller than recommended battery and cables will
cause loss of performance and may cause dangerous overheating.
 Electric motors spark and run hot. Do not place near flammable or sealed areas.
 Main battery must not be connected and power must not be switched on until all covers and terminal
protectors are correctly fitted.
 It is very dangerous to run the thruster out of the water, even for a few seconds, the motor will over speed
by 300%, causing damage to the motor seals etc. And the propeller will cause serious damage to whatever
comes into contact with it. This action will invalidate the warranty.
 Consult the boat manufacturer if you have any doubt about the strength or suitability of the mounting
location.
Electrical
 Make sure you have switched off the power before you start installing this product.
 If in doubt about installing electrical equipment please seek advice from a suitably qualified electrical
engineer.
 For safety RT to only be supplied with Lewmar ICU or control system.
 WARNING!
 This manual forms part of the product and MUST BE RETAINED
along with, OR incorporated into, the Owner’s Manual for the vessel
to which the thruster is fitted.
2 - Safety Notice
To the best of our knowledge, the information in this manual was correct when it went to press.
However, Lewmar cannot accept liability for any inaccuracies or omissions it may contain.
In addition, our policy of continuous product improvement may change specifications without notice. As a result,
Lewmar cannot accept liability for any differences between the product and the manual.

Fig 3.2.1 Fig 3.2.2
4
GB
3.1 Fitting the Thruster
The VRTT Thruster is supplied with the leg raised for ease of installation. Correct installation of the Thruster,
associated equipment and the watertight integrity of the vessel is the responsibility of the installer.
3.2 Placement
For Bow installation the thruster should be installed as far forward as possible. When the VRTT is lowered to
the Thrust position, the centre line of the hub must be a minimum of 1.5 x propeller diameter below the water
line and clear of the hull. The performance of the Thruster is largely due to the power source supplying the
Thruster motor. Adequate space should be allowed inside the hull for electric cables and access for service etc.
It is also important that the area around the thruster be kept clear of any loose items. It is recommended that if
the area is to be used for additional storage that a removable cover or barrier be constructed around the unit to
prevent damage to the unit. This area must also be kept dry to avoid damage.
This area must be kept dry while leaving sufficient room to allow the motor and other electrical to breathe.
Ideally this area should be ventilated.
3 - Installation
 It is important that nothing can cause jamming of the raise/lower
mechanism or damage to the stop switches.
1.5 x propeller diameter
below the water line
Tunnel must be
below hull line

Fig 3.3.1
Fig 3.3.2
REMOVE ALL BURRS AND SHARP EDGES
Unauthorised use, manufacture or reproduction
In whole or in part is prohibited
1 2
A
345
B C D E
678
ORIGINAL SIZE A3
10
REFERENCE SCALE IN MM
9 10
0 20
A
30 40 50
B C D E
GF H I J
12345
GF H
678
I J
9 10
FIRST ANGLE PROJECTION
SHEET 1 OF 2
IF IN DOUBT ASK
R327.5
186.0
126.0
THRO'
25.0° 25.0°
90.0°
100.0°
155.0°
155.0°
7.0
THRO'
20.0°
20.0°
300.0
300.0
220.0
213.0
R20.0
PART No.
55110251
DATEMOD'D BYMOD No.REVISIONISSUE
17-Jun-20AB18014FIRST ISSUEA
PART No.
55110251
MODEL NAME: 55110251
FINISH
TBD
SCALE
1:4
TOLERANCES (UNLESS STATED)
LINEAR 0.2
ANGULAR 0.5
TITLE
PONTOON VRTT MOUNTING BOX
DATE
17-Jun-20
MATERIAL
5083
DRN
AB
ALL DIMENSIONS IN mm
BOAT BOW
BOAT BOW
HULL CUTOUT DIMS
WELD 4 EDGES OF BOX
SCALE 1:5
B
A
Pontoon VRTT Thruster Manual ref 55110293 iss.4 | 5
Map out location and mark door opening,
 See section 13 for setting-out dimension
3.3 - Lower Flange Fitment
Cut the marked up hole in the hull.
 Important!: Keep the flange as level as possible when fitting.
VRTT MODEL
A
HEIGHT
MM
B
MINIMUM WIDTH
MM
MINIMUM DEPTH
MM
125 190 220
Cut opening piece of hull and prepare area for welding mounting box.
 Height of flange should be +-5mm
Note minimum cut Height!
 Note minimum height, width & depth required for each lower flange. (See Fig 3.3.3)
Hull
MountingFlange

REMOVE ALL BURRS AND SHARP EDGES
Unauthorised use, manufacture or reproduction
In whole or in part is prohibited
1 2
A
345
B C D E
678
ORIGINAL SIZE A3
10
REFERENCE SCALE IN MM
9 10
0 20
A
30 40 50
B C D E
GF H I J
12345
GF H
678
I J
9 10
FIRST ANGLE PROJECTION
SHEET 1 OF 2
IF IN DOUBT ASK
R327.5
186.0
126.0
THRO'
25.0° 25.0°
90.0°
100.0°
155.0°
155.0°
7.0
THRO'
20.0°
20.0°
300.0
300.0
220.0
213.0
R20.0
PART No.
55110251
DATEMOD'D BYMOD No.REVISIONISSUE
17-Jun-20AB18014FIRST ISSUEA
PART No.
55110251
MODEL NAME: 55110251
FINISH
TBD
SCALE
1:4
TOLERANCES (UNLESS STATED)
LINEAR 0.2
ANGULAR 0.5
TITLE
PONTOON VRTT MOUNTING BOX
DATE
17-Jun-20
MATERIAL
5083
DRN
AB
ALL DIMENSIONS IN mm
BOAT BOW
BOAT BOW
HULL CUTOUT DIMS
WELD 4 EDGES OF BOX
SCALE 1:5
6
GB
3.4 Liing the unit
The Thruster is heavy so when liing the Thruster unit from its packing case, ensure that adequate liing strops
are used. The thruster should not be lied by its actuator assembly or propeller shroud. Extra caution should be
used to avoid damaging these parts and the micro switches and control box. When moving the Thruster, ensure
that the seating surfaces of the main housing are protected against potential damage.
3.5 Fitting into the hull
The thruster requires a compartment to be constructed within the hull to mount the assembly, with an opening
in the bottom of the hull for thruster to be deployed and retract through.
The top of this watertight compartment is to act as the mounting seat for the thruster base plate. This
watertight compartment must be designed to take the weight of the thruster, the transfer of thrust to the hull
and any additional forces created while the vessel is in motion. It is recommended that this is carried out by a
qualified navel architect.
The VRTT Thruster is supplied in the retracted position for ease of transportation. The thruster will need to
be lowered once located. The tunnel can then be removed to allow the thruster assembly to be posted down
through the top of the hull. The unit is shipped with only 2 bolts holding the tunnel on.
Securing ring should also be removed from the bottom of the thruster.
Recommended mounting box shown above. Other shaped mounting plates can be used, but must be to the cor-
rect height, and also sealed from below.

Fig 4.1.1
Fig 4.1.2
Pontoon VRTT Thruster Manual ref 55110293 iss.4 | 7
4.1 Place upper VRTT
Assembly on to the lower flange.
1. Lower thruster through hole in mounting box. Ensure 2 orings are in place. Use grease to temporarily hold
orings in place while lowering thruster. Line bolt clearance holes.
2. Push on securing ring from underneath, ensuring that 3 orings are used and in place. Apply grease to Oring.
3. Secure retaining ring with 6 bolts from above thruster.
4. Replace tunnel assembly. Ensure oring is in place
5. Rotate prop if motor sha doesnt line up with thruster hub
6. Secure tunnel assembly with 6 x norlock washers and m6 bolts.
4 - Fitting

Fig 5.1
Fig 5.2
8
GB
5 - Adjust Thruster Up-Down Posn
 If the fully up position does not line up with your hull, the limit switch position can be adjusted.
 To raise full retracted position, adjust the top cone upwards
 To lower full extended position, adjust the bottom cone downwards.
 Above and below each cone is a nut. Tighten to 10Nm after adjustment with application of Blue Loctite 243
Fully Retracted
Limit Cone
Fully Extended
Limit Cone

POWER THRUSTER AUX CONTROLLER
SPLITTER SPLITTER
BATTERY SWITCH
OR
AUTOMATIC BATTERY
12v 589810
BATTERY
CONTROL BOX
COVER
REMOVED
THERMAL
SWITCH
* Solenoid
r.
Connector
FUSE
ICU
Aux cable only required
if using the the
ABS and/or PS box
ON
Pontoon VRTT Thruster Manual ref 55110293 iss.4 | 9
6 - Fit ICU and wire to VRTT, power Supply:
Find a suitable location for the ICU. The ICU needs to be in a dry environment and away from the motor, due to
electrical noise. The ICU should be located in the vertical plane, as per the arrow on the lid, and within 5 meters
of the motor. It is recommended that the ICU not is attached directly to the motor.
The ICU requires its own battery supply, follow locate electrical law for the installation.
1. The ICU has a 5A circuit breaker.
2. ICU power cable should be rated for 5-amps minimum.
Connect the VRTTs flying lead into the THRUSTER port of the ICU.
Electrical motor installs
 The motor requires its own battery supply. Battery + is marked on the motor. The motor should be wired to the
battery with a supply switch and circuit breaker.(Hold battery terminal when tightening nuts)

Boot
Fig 7.2.1
Boot
Fig 7.2.2
Boot
Fig 7.2.3
Boot
Fig 7.2.4
Fig 7.1
10
GB
 Terminals must be correctly clamped to motor
studs. Use a pair of spanners - the one nearest
motor to stop rotation of the stud.
 Spanner sizes are 13 mm.
 Tighten the bolts to 20 Nm (15 lbs.ft).
 Correct installation. Supplied cable boots are used
and no bare wires exposed (Fig 7.2.1).
 Live wire exposed! (Fig. 7.2.2). Correct the cable
installation to match (Fig 7.2.1).
 Terminal or motor is damaged. Contact Lewmar
Limited (Fig 7.2.3).
 Crimp inverted and is touching motor! (Fig 7.24).
NOTE: Cable length is total from battery to thruster and back.
 Example: Measure the total cable run from the battery to thruster and back in metres. Grey area on the table
shows a total of 20 m (66 ft) of cable with a model VRTT125 thruster would need 70 mm CSA (000 AWG)
cable.
 Battery crank capacity should be at least equal to the thruster current.
 Main power cables should be run from the batteries and must have an in line fuse fitted.
 The cables should be terminated with a ring terminal corresponding to the motor studs, 8 mm (5/16”) for
RT140. It is important that this termination is secure so that the high current is transferred to the motor
efficiently. The minimum voltage at motor when running should be 10V for 12V units.
 Ensure the insulating boots, supplied with the unit, are correctly fitted.
NOTE: If very large cables are used discard supplied boots and fit appropriate sized ones.
7 - Installation of electric motor
7.2 Battery cable connections
7.3 Correct cable sizes
DO NOT overtighten electric motor
terminal nuts.
 Incorrect installation of battery cables or
damage to connection studs may result in a
short to the thruster body. Use the examples
above to check for a correct installation on both
+V and -V battery connections.
The installation MUST have a battery switch
that is switched off whilst the thruster is not in
use or the boat is unoccupied.
7.1 Motor Terminal connections