Six steps from sizing to sea trial
- 01
Size the thruster
Thrust in kgf from your boat's length, windage and the wind you want to handle. Start with the size calculator.
- 02
Choose the tunnel position
As far forward as practical for leverage, and deep enough to stay submerged at rest and under way.
- 03
Cut and bond the tunnel
Shipwright work: the hull is cut and a GRP, steel or aluminium tunnel is glassed or welded in.
- 04
Fit the thruster
The motor, gearbox and propeller arrive as one assembly that bolts to the tunnel flange.
- 05
Wire the power
Battery bank, main switch, slow-blow fuse and correctly sized cable, all matched to the model.
- 06
Panel, test and trial
Fit the control panel or joystick link, check direction and thrust, then a sea trial.
Position matters as much as diameter
VETUS makes purpose-built tunnels in glassfibre-reinforced polyester (GRP) for fibreglass boats, steel for steel hulls and aluminium for alloy boats. Diameters run 110, 125, 140, 150, 185, 250, 300 and 400 mm, in lengths from 750 to 3,000 mm, and every thruster model maps to one tunnel diameter.
The tunnel goes as far forward as practical, because leverage around the boat's pivot point is what makes a thruster effective. It also has to sit deep enough to stay fully submerged in every trim. A tunnel too close to the surface sucks air and loses a lot of thrust, which is why VETUS insists the installer measures the tunnel's actual outside diameter before cutting the hull.
If your hull can't submerge a tunnel, for example a shallow-draft or cutaway forefoot, the retractable BOW PRO (coming soon) deploys below the hull instead. For full sideways control, a stern thruster mounts on the transom.
Retrofitting an old thruster?
BOW PRO shares tunnel sizes with earlier VETUS thrusters and many other brands, so an upgrade can often reuse the tunnel with no hull work at all.
New build or refit?
Both are routine. On a new build the tunnel goes in before the interior is fitted; on a refit, access to the forward locker or cabin sole usually decides the labour.
Get the power right and the thruster performs
DC thrusters: sized by CCA
DC thrusters draw a big inrush current, so the battery bank is specified by cold cranking amps. Each model has a minimum and a maximum, and bigger isn't better: an oversized bank pushes the thruster outside its operating window, adding wear and heat.
BOW PRO and RIMDRIVE: sized by Ah
Brushless thrusters have no inrush current but run far longer, so their bank is specified by capacity in amp-hours (C20), with no maximum. Extra capacity simply extends runtime. BOW PRO Boosted charges its own bank from the boat's supply.
Main switch and fuse
Every installation has a battery main switch and a slow-blow fuse matched to the thruster model. Both are listed in VETUS's data for each model and included in our kit quotes.
Cable runs
VETUS publishes the maximum total cable length for each model at every cable size. A long run to a bow locker is fine as long as the copper is sized to match.
How much does it cost to fit a bow thruster?
There's no honest single figure, because two boats of the same length can be very different jobs. The total is the kit plus the installation, and these are the things that move it.
Get an itemised quote- Thrust class and type. DC is VETUS's most affordable range; BOW PRO, RIMDRIVE, retractable and hydraulic systems sit above it.
- Tunnel material and length. GRP, steel or aluminium, and how wide the hull is at the tunnel.
- Access. Interior joinery, tanks or a cabin sole in the way adds labour.
- Batteries and cable run. A new dedicated bank and a long cable run to the bow add parts.
- Controls. A single panel, a double joystick, or integration with an engine joystick.
- Haul-out and yard time. Most tunnel work needs the boat out of the water; doing it at your next scheduled haul-out saves a lift.
DIY or professional?
Cutting the hull and bonding or welding the tunnel is shipwright work, and getting the position wrong is expensive to undo. The electrical side is standard marine installation. VETUS thrusters come with clear instructions, and because the thruster arrives assembled, fitting it to the tunnel is straightforward.
Luxfords supplies complete kits (thruster, tunnel, panel, cables, switch and fusing) from our Mornington showroom and can recommend installers in Victoria. If you already have a shipwright or a yard booked, we'll give them everything they need.
Installation FAQ
Where should the bow thruster tunnel go?
As far forward as practical for leverage, and deep enough that it stays submerged in all trim conditions. The installer measures the tunnel's real outside diameter before cutting.
Can a bow thruster be added to an existing boat?
Yes, retrofits are routine. The hull is cut for the tunnel, the thruster bolts to it, and the battery, main switch, fuse and panel are wired in. Replacing an older thruster can often reuse the existing tunnel.
Does the boat need to come out of the water?
For a new tunnel, yes. Swapping a thruster unit in an existing tunnel can sometimes be done afloat, depending on the boat. Planning the job around your next haul-out keeps costs down.
What battery does a bow thruster need?
DC thrusters are matched by cranking amps (CCA), within a minimum and a maximum. BOW PRO and RIMDRIVE are matched by capacity in amp-hours, with no maximum. Each model's minimum is in the specs on our BOW PRO page and in the calculator results.
Planning a thruster install in Victoria?
Tell us the boat, where it's kept and when it's next out of the water. We'll size the kit and put you in touch with an installer if you need one.