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Thruster specs
VETUS Bow 45: specs, price and the boats it fits
The Bow 45 is VETUS’s small-cruiser workhorse for boats of about 26 to 37 ft. With 99 lb of push from a simple on/off button, it swings the bow where you want it while the engine does the driving. VETUS has been building this kind of thruster since 1982.
At $1,927 it’s one of the least expensive ways into a VETUS bow thruster, though that buys the unit only. The tube, panel, switch and fuse add about $465 to $1,013. A starting (cranking) battery of its own near the bow, with cable and charging, comes to roughly $586 to $820 on our estimate. See the parts list.
Owners of the brushed VETUS units name brush dust as the thing to watch: one cleared his with a shop vac and compressed air and got it working again. A yearly brush and zinc check heads that off. The rating is 4 minutes of running, or 4 in an hour. Have an authorized VETUS dealer do the servicing, or the three-year warranty can lapse.
Installers will find the wiring figures and dimensions further down. For the rest of VETUS’s line, read the VETUS thruster review.
Where this summary comes from (6 sources, read 12 October 2026)
- Defender, BOW4512D
- VETUS installation manual for the BOW4512D
- VETUS Maintenance and Warranty Manual for thrusters, 020901.02
- VETUS warranty policy (three years since 2011, claimed through the dealer)
- VETUS, Our Legacy (founded 1964, first bow thruster 1982, Yanmar Group 2013, BOW PRO 2018)
- Trawler Forum, "Vetus bow thruster troubleshooting" (brush dust)
Key facts
- DIY level 2 of 5 Wiring prep only
- Thrust 99 lb 45 kgf, VETUS's rating
- Boat length 26 to 37 ft VETUS's own range
- Price $1,927 equipment only, defender.com, 28 August 2026
- Fitted by a yard $8,718 to $11,210 Our estimate at 35 ft, unit and job
- Voltage 12 V As sold
- Mounts Tunnel Fixed mount, bow
- To fit it Haul-out The boat comes out of the water
- Run limit 4 min Of continuous use at 12 V
Every figure here is the maker’s or a dealer’s, except the fitted cost, which is our estimate. The full spec sheet is further down.
How much of the install is yours
DIY levels
- Level 5: Owner install. No yard, no electrician.
- Level 4: You fit it, electrician connects. You mount and wire it; a marine electrician makes the final connections.
- Level 3: Split with the yard. The yard does the below-waterline part; you do the wiring.
- Level 2: Wiring prep only. The yard fits the unit and does the hull work; you do the wiring prep.
- Level 1: Yard job. A qualified professional does all of it.
You Yard Electrician. The bar is labor hours; a haul-out is a note.
How we rate DIYYou: 4 to 16 h Yard: 32 to 70 h Electrician: 2 to 4 h Plus a haul-out.
- Cut, bond and fair the tunnel; fit the gear leg, motor and propeller Yard 32 to 70 h The low end is two crew over two days, the job as owners describe it on the forums. The high end rises with boat length between two real billed figures: 32 hours at 35 ft, and the largest invoice we hold, 70 hours at 47 ft.
- Mount the battery box, switch and fuse holder; run and secure the cables You 4 to 16 h Our estimate. No maker times this step, and a first-time owner is slower than a yard, so the range is wide.
- Final connections at the battery and the motor, load test Electrician 2 to 4 h Our estimate. Nobody publishes a time for the final connections and test on their own.
Your part needs:Heavy battery cableCrimping big lugs
A qualified marine electrician should make the final connections and test them before first use. Hours are labor only.
Is it right for your boat?
Our figure is the longest boat one unit can steer in a 15 knot wind. It is a range because each kind of boat catches the wind differently. Here a sailboat gets full thrust to 33 ft, and an express cruiser to 40 ft. The maker gives one range for every boat.
The table below tries the VETUS Bow 45 on each kind of boat, at every length that kind of boat is built in. The wind is 15 knots and the rules are the finder’s own. A length counts as a fit when the unit gives the thrust that boat needs at the bow and the maker lists it for that length.
A boat up to 10 percent past the maker’s range still counts here, as it does in the finder. So the table runs up to 40 ft, just past VETUS’s own range (26 to 37 ft).
| Boat | Full thrust at 15 knots | Still a fit, in lighter wind |
|---|---|---|
| Pontoon & tritoon | Not listed. A pontoon has no hull body between the logs to bore a tunnel through, and nobody sells one for these boats. | |
| Sailboat | 28 to 33 ft | 34 to 40 ftfull thrust to about 13 knots at 40 ft |
| Houseboat | None | 30 to 37 ftfull thrust to about 10 knots at 37 ft |
| Catamaran | 32 to 38 ft | 39 to 40 ftfull thrust to about 14 knots at 40 ft |
| Trawler | 28 to 33 ft | 34 to 40 ftfull thrust to about 13 knots at 40 ft |
| Motor yacht | None | 35 to 40 ftfull thrust to about 13 knots at 40 ft |
| Bass & flats | Not listed. Nobody sells a tunnel kit for these hulls, and a bass boat’s shallow planing bow has almost no depth to hold one. | |
| Wake & ski boats | Not listed. Nobody sells a tunnel kit for these hulls. | |
| Express cruiser | 36 to 40 ft | None |
| Center console | 40 ft only | None |
Reading the two length columns. The first column is where one unit gives all the thrust the boat needs in 15 knots. The second is where the finder still lists it: the unit falls short of what the boat needs by no more than 10 percent, and gives the whole figure only in the lighter wind named. On a boat shorter than the first column’s shortest length, the unit is more than the boat needs.
It is sized for seven kinds of boat here. For your own boat, the finder gives an answer that also counts your drive and who does the fitting. The compare page sets this unit beside others.
What it costs fitted
These totals are our estimate of a yard job: the unit’s price, plus a yard’s hours at $160 to $180 an hour, plus the batteries, cable and charger, plus the other parts the box does not hold. A Lifting the boat out of the water on a travel lift or a trailer so work can be done below the waterline. It is billed separately from the job itself. adds $500 to $1,930 at these lengths, with 5 to 7 days out of the water, worked from eight yards’ own rate cards. The hours come from what owners and yards report. Your own yard will have its own opinion. The cost page builds the same figures line by line.
| Boat length | The unit | Yard labor | Haul-out | Batteries, cable, charger | Other parts | Total |
|---|---|---|---|---|---|---|
| 28 ft | $1,927 | $5,120 to $5,760about 32 hours | $500 to $1,350 | $586 to $820 | $465 to $1,013 | $8,598 to $10,870 |
| 35 ft | $1,927 | $5,120 to $5,760about 32 hours | $620 to $1,690 | $586 to $820 | $465 to $1,013 | $8,718 to $11,210 |
| 40 ft | $1,927 | $5,120 to $8,64032 to 48 hours | $710 to $1,930 | $586 to $820 | $465 to $1,013 | $8,808 to $14,330 |
How the batteries, cable and charger add up. We price a battery bank close to the thruster, as the makers recommend, with 10 to 20 ft of cable out and back: red for the positive, black for the negative, cut to length. The low end is the cheapest battery that meets the figure and the shorter run; the high end is a sealed (AGM) battery and the longer run. The charger is a NOCO GEN5X2 two-bank shore charger.
Batteries and lugs are priced at Fisheries Supply and the cable and charger at Defender, read 12 October 2026.
- At 12 V: one 12 V battery, at least 625 CCA (VETUS’s minimum), $360 for the battery; VETUS’s cable table gives 1 to 3/0 AWG, priced on 1 to 4/0 AWG, the nearest size cut to length: $80 to $314 for the red and black cable and the lugs; a GEN5X2 charger, $146.
The sizing and the costs on this page are estimates, for guidance only and without warranty. They are no quote, and nobody has inspected your boat. Check them against the maker’s manual and your yard before you rely on them. Terms of use.
What else you buy
What follows comes from VETUS’s BOW55D installation manual 020522.11 r08 and the BOW PRO Boosted manual 020808.04 r09, May 2026 and February 2026, read 30 September 2026.
- In the box
- The unit assembled or in parts, the zinc anode, insulated gaskets, the drill template, the solenoid switches and the 5 A control fuse on the motor. BOW PRO: the thruster fuse in the connection unit.
- Bought separately
- The tunnel, the main switch (BATSW250 or BATSW600), the main fuse (ZE) and holder (ZEHC100), the cable, the control panel and its cable.
- Charging
- Every VETUS manual wants "its own separate battery or batteries" near the thruster, sealed if it shares the motor's compartment. The BOW PRO Boosted units carry a charger (12 V, 80 A) fed from the boat's bank, with a fused feed cable. The other manuals show an alternator and a battery separator on the wiring diagram and say nothing more.
The manual’s words, page 22 of the Boosted manual: “By connecting the 24 Volt battery bank to the MCVB boosted charge connection, the 48 Volt, battery bank is charged. An additional charging facility is not required.”
The “other parts” line in the estimate above is the priced parts below, $465 to $1,013 at Fisheries Supply’s prices on 30 September 2026. The batteries, cable and charger have a line of their own.
| Part | What it is | What to ask for | Dealer price |
|---|---|---|---|
| Tunnel tube | The fiberglass, aluminum or steel pipe the thruster sits in, bonded through the bow. | VETUS names none | $136–$209125 mm fiberglass tunnel tubes up to 60 in (1.5 m) long (Sleipner Side-Power), at Fisheries Supply, read 16 October 2026. |
| Control panel | The buttons or joystick at the helm. One helm, one panel: a second steering station needs a panel of its own. | BPSE2 push buttons, BPJSTA joystick, BPJE2 or EZDOCK2 | $219–$374Side-Power touch panel and single joystick, VETUS push-button panel, Lewmar single joystick, at Fisheries Supply. |
| Control cable, panel to motor | The thin cable from the helm to the motor. Sold by length. | VETUS panel cable, by length | $29–$173Side-Power control cables, VETUS panel cables, Lewmar Gen 2 connecting cables, at Fisheries Supply. |
| Main fuse | A slow-blow fuse of the ANL type at the battery, in the size the maker prints for the model. | ZE series slow-blow, the rating in the yard table below | $18–$57Side-Power ANL fuses, Blue Sea ANL fuses, at Fisheries Supply, read 16 October 2026. |
| Fuse holder | The block the ANL fuse bolts into, with a cover. | ZEHC100 | $27–$93Egis and Blue Sea ANL fuse blocks, Side-Power ANL fuse holders, at Fisheries Supply, read 16 October 2026. |
| Main battery switch | The switch that cuts the thruster off from its battery when you leave the boat. | BATSW250 (BATSW600 on the bigger units), or BPMAIN12/24 for a remote switch | $35–$107Egis m-Series 300 A, Blue Sea e-Series 350 A and HD-Series 600 A on/off switches, at Fisheries Supply, read 16 October 2026. |
| Battery cable and lugs | The two heavy cables from the battery to the motor, sized to the length of the run. The wiring calculator sizes them. | VETUS names none | In the electrical line |
| Battery bank | A cranking-type bank near the motor, sized by the maker's cold cranking amps. The battery calculator checks it. | VETUS names none | In the electrical line |
| Charger or charge feed | How the thruster bank gets charged: a shore charger of its own, a DC-to-DC charger or charging relay from the boat's system, or a charger built into the unit. | VETUS names none | $146–$305NOCO GEN5X2 shore charger, Victron Orion-Tr Smart DC-DC charger, Blue Sea ML-ACR charging relay, at Fisheries Supply. |
| Glass, resin, filler and sealant | What bonds the tube or housing into the hull and seals the gear leg. | VETUS names none | Not priced |
The cost page has the whole list with what every maker says about each part.
For the yard and the installer
The full spec sheet, grouped the way a yard reads it. Every figure is the maker’s or a dealer’s, with its source.
| Thrust and motor | |
|---|---|
| Thrust | 99 lb (45 kgf) As printed: 99 lbf |
| Motor | 3 kW |
| Voltage | 12 V |
| Fitting | |
| Type | Tunnel, fixed mount |
| End of the boat | Bow |
| Tunnel diameter | 125 mm |
| What it does to the hull | Tunnel bore below the waterline |
| Haul-out to fit it | Yes |
| Maker’s boat length | 26 to 37 ft |
| Price and ordering | |
| Price | $1,927 equipment only, a dealer's price, defender.com, 28 August 2026 |
| Part number | BOW4512D12 V |
| Documents | |
| Manual | Installation manual (PDF)on the maker's site |
| Warranty | VETUS gives 3 years, or 1 for professional use, and it transfers to the next owner. Claims go through the dealer only. It is void unless an authorized VETUS dealer does the periodic maintenance, and transport, labor and lifting are excluded. VETUS's warranty policy |
| The site’s review | VETUS thruster review |
Draw, cable, fuse and battery, at each voltage
These are the maker’s own figures, at each voltage it is sold at. The cable is the size for the shortest run in the maker’s table. A longer run may need heavier cable, and the wiring calculator works that out for your own boat.
| Voltage | Draw | Maker’s cable | Fuse | Battery | Run limit |
|---|---|---|---|---|---|
| 12 V | 375 Anominal draw | 2 AWG for up to 7 ft of cable counted out and back. Longer runs take heavier cableinstallation manual 020573.03, r06, January 2025 | 250 Ainstallation manual 020573.03, r06, January 2025 | 625 CCA minimum, 1,250 CCA maximumVETUS installation manual 020573.03, r06, January 2025 | 4 min of continuous use at 12 Vinstallation manual 020573.03, r06, January 2025 |
- At 12 V: size the cable for your run, or check the battery you have.
What to weigh
Each point names the fact it rests on.
What to weigh
- The boat comes out of the water to fit it: it needs a tunnel bore below the waterline.The mounting: a bore through the hull, or a housing recessed into it
What the manual and listings say
This is the note we keep on the VETUS Bow 45, written from the maker’s manual, its product pages and the dealer’s listing.
In the box: The solenoid switches and the 5 A control fuse are on the motor. The panel, its cable, the main fuse and switch are bought.
Our note
A 125 mm tunnel. The manual gives 375 A, a battery of 625 to 1250 cold cranking amps and a 250 A fuse. For cable it gives 4 AWG to 7.5 ft of total run (positive plus negative), and 4/0 to 36.1 ft. The motor is brushed. The manual rates it for 4 minutes at a time, or 4 per hour, at 375 A.
Brushes and anode are checked yearly, and no copper-based antifouling goes on the unit. The motor wants at least 9.5 V while running. The warranty runs three years and is claimed through the dealer only. It is void unless an authorized VETUS dealer does the periodic maintenance, and labor, transport and lifting are excluded.
Videos
Two of VETUS’s own videos, from its YouTube channel: how VETUS picks a size, a battery bank and a panel, and the first of its service videos for a tunnel unit. They are the maker’s pitch. Watch them for what the unit looks like and how it goes in, and take any claim back to the figures above.
Other sizes and close alternatives
VETUS also sells this thrust built another way. Each has its own page:
- Ignition-protected: VETUS Bow 45 Ignition Protected, $2,399.
These are VETUS’s next sizes in the same line, by thrust.
- One size down: VETUS Bow 40, 88 lb.
- One size up: VETUS Bow 55, two sizes, 121 to 132 lb, $2,137.
These are other makers’ units of the same style, for the same end, within a quarter of its published thrust. Each is that maker’s nearest match.
- Max Power CT45, 99 lb, $1,473.
- Sleipner SE40/125S, 105 lb, $1,845.
- Lewmar 140TT Gen 2 Thruster Package with Joystick and Tunnel, 92 lb, $2,754.
Every model with a page here is listed, maker by maker, on the thruster index.