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VETUS · tunnel thruster · bow
VETUS Bow Pro 421: specs, price and the boats it fits
It gives 93 lb (42 kgf) of push. VETUS sells it for boats of 26 to 37 ft. It runs on 12 V.
- Haul-out to install
- DIY 2 of 5: wiring prep only
- 3-year warranty
Quick stats
- Thrust 93 lb 42 kgf, VETUS's rating
- Boat length 26 to 37 ft VETUS's own range
- Price per lb of thrust $35.03 Unit only. $114 to $139 installed
- Voltage 12 V As sold
- Battery at 12 V 145 Ah One battery, near the thruster
- Run limit 10 min At a stretch, the user manual's S2 rating
- To install it Haul-out The boat comes out of the water
- Anodes $76.29 A change. More than twice another maker's
About the VETUS Bow Pro 421
The Bow Pro 421 puts 93 lb of push under VETUS’s variable-speed joystick, for boats of about 26 to 37 ft. You decide how hard it pushes, from a gentle correction to full power, and the brushless motor has no brushes to wear.
It sells for $3,258, against $1,734 for the push-button Bow 45 that suits the same size of boat. The tube, panel, main switch and fuses come to about $465 to $1,013 more, and a battery of its own at the bow with cable and charging runs about $1,156 to $1,247. See the list.
Read more
That extra buys a 10-minute run rating where the Bow 45 gets 4, plus control fine enough to tuck the bow in by inches. VETUS says battery charge is the real limit on how long it runs. Yearly care is just the zinc, and dealer servicing keeps the three-year warranty.
The full spec sheet for a yard sits lower down, and the VETUS thruster review covers VETUS’s whole range.
Where this summary comes from (5 sources, read 12 October 2026)
- Fisheries Supply, BOWA0421
- VETUS installation manual for the BOWA0421
- VETUS BOW PRO user manual 020810.04 (thrust not dependent on battery voltage; run time limited by the batteries)
- VETUS Maintenance and Warranty Manual for thrusters, 020901.02
- VETUS warranty policy (three years since 2011, claimed through the dealer)
Will the VETUS Bow Pro 421 steer your boat?
38 FT TRAWLER · BOW · 15 KT WIND
Every knot figure here is wind speed, not boat speed or current.
On a 38 ft trawler the VETUS Bow Pro 421 (93 lb) steers her in a 15 knot breeze. Her bow needs about 98 lb from a tunnel to steer her in a 15 knot breeze. Its 93 lb lands within 15 percent of that figure, which this site counts as enough.
The finder lists it for her.
The VETUS Bow Pro 421 on a trawler, by length
- 25 ft22 kt
- 30 ft19 kt
- 35 ft16 kt
- 40 ft14 kt
- 45 ft12 kt
- 50 ft11 kt
- 55 ft10 kt
- 60 ft9 kt
- 65 ft9 kt
- 70 ft8 kt
- 75 ft7 kt
- 80 ft7 kt
Outlined: the finder does not list it at that length (under 13 kt, far more than she needs, or outside VETUS’s own length range).
- Under 10 kt
- 10 to 15 kt
- 15 to 20 kt: the sweet spot
- Over 20 kt: more than she needs
Prices are the low end of the installed total, from our estimate. For your own boat, drive and installer, the finder prices each unit.
Is it right for your boat?
Every kind of boat it fits, by length
| 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 | 27 to 39 ft | 40 ft onlyfull thrust to about 14 knots at 40 ft |
| Houseboat | None | 30 to 33 ftfull thrust to about 13 knots at 33 ft |
| Catamaran | 31 to 40 ft | None |
| Trawler | 27 to 38 ft | 39 to 40 ftfull thrust to about 14 knots at 40 ft |
| Motor yacht | 35 to 38 ft | 39 to 40 ftfull thrust to about 14 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 | 34 to 40 ft | None |
| Center console | 38 to 40 ft | None |
The VETUS Bow Pro 421 against each kind of boat, in a 15 knot wind. Our sizing, from the finder’s own rules.
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 steers her in a 13 or 14 knot wind, within 15 percent of the 15 knot breeze this site sizes for. On a boat shorter than the first column’s shortest length, the unit is more than the boat needs.
How we size it
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 trawler gets full thrust to 38 ft, and a catamaran to 40 ft. The maker gives one range for every boat.
The table tries the VETUS Bow Pro 421 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).
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 installing. The compare page sets this unit beside others.
What it costs installed
A yard job, everything in. Our estimate.
| Boat | Total installed |
|---|---|
| 27 ft | $10,479 to $12,578$113 to $135 a lb of thrust |
| 35 ft | $10,619 to $12,968$114 to $139 a lb of thrust |
| 40 ft | $10,709 to $16,088$115 to $173 a lb of thrust |
From the shortest to the longest boat it is sized for.
What is in each total
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 $480 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. The cost page builds the same figures line by line.
| Boat length | The unit | Yard labor | Haul-out | Batteries, cable, charger | Other parts |
|---|---|---|---|---|---|
| 27 ft | $3,258 | $5,120 to $5,760about 32 hours | $480 to $1,300 | $1,156 to $1,247 | $465 to $1,013 |
| 35 ft | $3,258 | $5,120 to $5,760about 32 hours | $620 to $1,690 | $1,156 to $1,247 | $465 to $1,013 |
| 40 ft | $3,258 | $5,120 to $8,64032 to 48 hours | $710 to $1,930 | $1,156 to $1,247 | $465 to $1,013 |
For every length in the table above.
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 26 October 2026.
- At 12 V: one 12 V battery, at least 145 Ah (VETUS’s minimum), $930 for the battery; VETUS’s cable table gives 1 to 1/0 AWG: $80 to $171 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.
DIY breakdown
DIY levels
- Level 5: Owner install. No yard, no electrician.
- Level 4: You install 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 installs 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 hours Yard: 32 to 70 hours Electrician: 2 to 4 hours Plus a haul-out.
Your part needs:Heavy battery cableCrimping big lugs
Every step, and who does it
- Cut, bond and fair the tunnel; fit the gear leg, motor and propeller Yard 32 to 70 hours 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 hours 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 hours Our estimate. Nobody publishes a time for the final connections and test on their own.
A qualified marine electrician should make the final connections and test them before first use. Hours are labor only.
Related videos
Two from VETUS’s own channel and one from other channels. Each one is labeled. They play from YouTube only when you tap. Take any claim in a video back to the figures on this page, which are the ones we checked.
Know before you buy
What sets this model apart, what it costs to keep, and what to weigh.
Price per pound of thrust
$35.03 a lb The unit’s price over its published thrust. The bars are VETUS’s next sizes and the nearest other makers.Controls
Proportional: the joystick sets how hard it pushes. The thruster fuse sits in the connection unit.
- VETUS Bow Pro proportional thruster panel (BPPPA), $643.67 at Fisheries Supply.
- VETUS BPCAB1HF / BPCAB5HF / BPCAB10HF / BPCAB15HF / BPCAB20HF / BPCAB25HF, no US price found.
Pricey wear part: anodes
$76.29 a change- Zinc anode (SET0149): $76.29 at Fisheries Supply.
A change costs $76.29. That is over eight times the $9.00 for Sleipner’s anode on the same 125 mm tunnel (SM31180A, Defender). An anode is a plain block of metal that wears away by design, so you will buy it again.
They sit below the waterline, so a change means a haul-out or a diver.
Service and 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.
See VETUS’s warranty VETUS's warranty policy.Special mentions
Battery: at 12 V it wants one battery of 145 Ah or more, VETUS's figure. The cheapest that meets it is the Mastervolt 8D AGM start / deep cycle, $930.00. Check your own bank.
Charger: a NOCO GEN5X2 two-bank shore charger, $146.41. It is the one our estimate prices.
Dealer prices at Fisheries Supply, read 26 October 2026.What to weigh
The boat comes out of the water to install it: it needs a tunnel bore below the waterline.
Short pushes only: VETUS rates the motor for 10 min at a stretch.
Parts for the VETUS Bow Pro 421
See the VETUS Bow Pro 421 manualSearch for the number as printed here, with no spaces. Prices are each dealer’s on the day shown, before shipping and tax. Check the plate on your motor before you order: some parts change with the tunnel size, the voltage or the year.
For the install what the box leaves you to buy
The manual button above opens it on the maker's site. It has the hull, wiring and fuse figures for this model.
From VETUS’s BOW PRO 125 mm installation manual 020803.06 r9, April 2026, read 25 October 2026.
- In the box
- The manual prints no box list. It says the thruster is supplied with a zinc anode and has you drill with the template that comes with it. The thruster fuse sits 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
- The manual wants the thruster on its own battery or batteries, close by so the power cables stay short, and sealed batteries if they share its compartment. Its wiring diagram shows an alternator and a battery separator, and it says nothing more about charging.
The manual’s words, page 22: “We also recommend that each bow thruster is powered by its own separate battery or batteries.”
The “other parts” line in the estimate above covers these parts as a range, $465 to $1,013 at Fisheries Supply’s prices on 30 September 2026 and 26 October 2026, because the exact items depend on your boat. The batteries, cable and charger have a line of their own. The cost page has what every maker says about each part.
Tunnel tube
Fisheries Supply lists it as “Sleipner fiberglass tunnel tube, 125 mm bore, 600 mm”.
Sold in lengths from about 24 to 35 in. This is the shortest: the yard cuts the tube to the width of your hull at the thruster. No VETUS tube is listed at this bore. This one is another maker's.
Control panel
Fisheries Supply lists it as “VETUS Bow Pro proportional thruster panel”.
Control cable, panel to thruster
Ask for VETUS BPCAB1HF / BPCAB5HF / BPCAB10HF / BPCAB15HF / BPCAB20HF / BPCAB25HF.
Not sold at Fisheries Supply. Ask the panel dealer.
Main fuse
Ask for 355 A (VETUS ZE355).
A VETUS strip fuse in its own holder (VETUS ZEHC100). Not listed at Fisheries Supply; ask a VETUS dealer.
Fuse holder
Ask for VETUS ZEHC100 strip fuse holder.
Ask a VETUS dealer.
Battery switch
Fisheries Supply lists it as “HD-Series 600 A battery switch, on/off”.
Rated at or above the 355 A main fuse. If your manual names its own switch, use that one.
Control-circuit fuse holder
Fisheries Supply lists it as “Waterproof in-line ATO/ATC fuse holder”.
The maker asks for a 5 A fuse on the control supply.
Batteries
Ask for 1 at 145 Ah or more.
No listing at Fisheries Supply meets this in stock.
Battery cable, red and black
Defender lists it as “Ancor tinned battery cable 1 AWG, cut to length, red or black”.
This is the short run. A longer run takes heavier cable: the wiring calculator sizes yours. You need 5 ft of each color. For about 10 ft of cable in all, out and back. Measure your run and check it against the cable table in the manual: never go smaller than it asks for.
Cable lugs
Fisheries Supply lists it as “Tin-plated starter lugs, 1 AWG, bag of 10”.
This is the short run. A longer run takes heavier cable: the wiring calculator sizes yours. The listing runs $20.52 to $22.06 by stud size. Eight ends on one run, with two spare.
Charger
Fisheries Supply lists it as “GEN5X2 on-board charger, 10 A, 2 banks”.
Or a DC-to-DC charger from the house system: ask the electrician.
Outside the hull replacement parts in the water
Zinc anode
The metal that wears away in the water so the drive does not. VETUS calls it “Zinc anode (guide column)”.
From VETUS's 2022 spare parts guide, which gives the BOW PRO the same anode as the standard unit of its tunnel size.
Propeller
The propeller on the drive. VETUS calls it “6-blade propeller, 125mm diameter., blue, for 36/42kgf BOW PRO thruster”.
The maker lists this part by a name that covers this model, not by the model itself. Check it against your serial number before you order.
Inside the boat replacement parts on board
Motor controller
The electronics that run the motor when you press the panel. VETUS calls it “Motor controler for BOWA0421”.
The maker lists this part by a name that covers this model, not by the model itself. Check it against your serial number before you order.
No part matches. Try the number without spaces, or the part’s name.
The install parts are matched to VETUS’s own figures and priced at Fisheries Supply, with the battery cable at Defender, cut to length.
Spare part numbers come from VETUS’s parts pages and manuals. A dealer may sell a part we have not priced. Search for the number.
Other sizes and close alternatives
- Size down VETUS Bow Pro 401 88 lb
- Size up VETUS Bow Pro 571 126 lb · $3,794
- Other maker Lewmar 140TT Gen 2 Package 92 lb · $2,754
- Other maker Sleipner SE30/125S DC 88 lb · $1,755
- Other maker Max Power CT45-IP 88 lb · $2,456
The other makers listed are the nearest match each makes, of the same style and for the same end, within a quarter of its thrust. The compare page lists every model, and the thruster index lists every model with a page here.
For the yard and the installer
Every published figure, with its source.
Full spec sheet
| Thrust and motor | |
|---|---|
| Thrust | 93 lb (42 kgf) As printed: Rated thrust: 420 N (42 kgf, 93 lbf) (VETUS Owner's Manual 020810.01) |
| Motor | 3.1 kW |
| Voltage | 12 V |
| Run limit | 10 min at a stretch, the user manual's S2 rating |
| Installation | |
| 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 install it | Yes |
| Maker’s boat length | 26 to 37 ft |
| Price and ordering | |
| Price | $3,258 equipment only, a dealer's price, fisheriessupply.com, 26 October 2026 |
| Part number | BOWA042112 V |
| Documents | |
| Manual | Installation manual (PDF)on the maker's site |
| The site’s review | VETUS thruster review |
Every published figure the site holds for the VETUS Bow Pro 421, with where each came from.
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 | 218 Anominal draw | 1 AWG for up to 15 ft of cable counted out and back. Longer runs take heavier cableinstallation manual 020803.06, r09, April 2026 | 355 A, and 300 A (ZE300) in the controllerinstallation manual 020803.06, r09, April 2026 | 1 x 145 Ah - 12 V, in amp-hoursVETUS installation manual 020803.06, r09, April 2026 | 10 min at a stretch, the user manual's S2 ratingBOW PRO user manual |
The VETUS Bow Pro 421’s draw, cable, fuse, battery and run limit, as the maker publishes them.
- At 12 V: size the cable for your run, or check the battery you have.
Our notes from the manual and listings
In the box: Proportional: the joystick sets how hard it pushes. The thruster fuse sits in the connection unit.
Our note
A 12 V unit in a 125 mm tunnel. It is brushless and proportional, so the joystick sets how hard it pushes instead of switching it on and off. The installation manual rates it at 10 minutes (S2). The user manual says run time is mainly limited by the battery. The US press release's "unlimited runtime" appears in neither.
The manual gives 218 A at 12 V (250 at 10.5) and an example battery of one 145 Ah 12 V battery. It calls for a 355 A main fuse and a 300 A fuse in the controller that must stay in place. It gives 2 AWG cable to 15.7 ft of total run. The same manual prints more current for the smaller BOWA0361.
The manual writes its AWG sizes as zeros (00 for 2/0). 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.
Where each point above comes from
- The boat comes out of the water to install it: it needs a tunnel bore below the waterline.The mounting: a bore through the hull, or a housing recessed into it
Not sure this is the one? The thruster finder asks about your boat and prices every unit that fits.