Thrusterpedia

Which boat thruster, what it costs, how to get it installed

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Drawing of a tunnel thruster: a tube through the bow below the waterline, the hull cut away to show the motor on top.
Our drawing of a tunnel thruster, the same for every maker. It is not Sleipner’s own design.

Sleipner · tunnel thruster · bow or stern

Sleipner SEP60/185S-IP: specs, price and the boats it fits

It gives 161 lb (73 kgf) of push. Sleipner sells it for boats of 29 to 38 ft. It runs on 12 V or 24 V.

The unit$5,895 to $6,210Equipment only, Defender, read 26 October 2026
Installed by a yard, 35 ft boat$12,777 to $15,829Our estimate: the unit, labor, haul-out, battery and parts
  • Haul-out to install
  • DIY 2 of 5: wiring prep only
  • 2-year warranty

Quick stats

  • Thrust 161 lb 73 kgf, Sleipner's rating
  • Boat length 29 to 38 ft Sleipner's own range
  • Price per lb of thrust $36.61 Unit only. $79 to $98 installed
  • Voltage 12 V or 24 V As sold
  • Battery at 12 V 665 CCA One battery, near the thruster
  • Run limit 2 to 3 min Duty cycle at 20 C ambient
  • To install it Haul-out The boat comes out of the water
  • Anodes $28.80 A change, at Defender

About the Sleipner SEP60/185S-IP

For a gas-engined boat of about 29 to 38 ft that wants a thruster it can feather, this is the one. The SEP60-IP has an ignition-protected motor, safe around fuel vapors, and the same 161 lb top push as the standard SEP60, with the speed set by the joystick. Order it for 12 V or 24 V.

Defender lists it from $6,210; the standard SEP60 starts at $5,085. You add the tube, a panel, a main switch and a fuse, about $541 to $1,369, and a starting battery close to the thruster with its cable and charging, about $601 to $800. See what else to buy.

Read more

Its controller watches heat and current and trims power before the motor overheats, so gentle use can go on for a long while. Pushed hard, it is a 2 to 3 minute motor like the rest of the range. Sleipner’s warranty is two years and stays with the boat.

The full spec sheet for a yard sits lower down, and the Sleipner (Side-Power) review covers Sleipner’s whole range.

Sleipner sold its thrusters under the Side-Power name until 2021, and many dealers and owners still call them that. It is the same company and the same thrusters.

Where this summary comes from (4 sources, read 12 October 2026)

Will the Sleipner SEP60/185S-IP steer your boat?

41 FT TRAWLER · BOW · 15 KT WIND

Size forThis page always opens on Steering.

Every knot figure here is wind speed, not boat speed or current.

Steers her at 18 kt

On a 41 ft trawler the Sleipner SEP60/185S-IP (161 lb) steers her in an 18 knot breeze. Her bow needs about 113 lb from a tunnel to steer her in a 15 knot breeze.

The finder lists it for her.

14.3 FT LEVER Sleipner SEP60/185S-IP pivot

A tunnel at the bow of a 41 ft trawler 113 lb ★ this unit · 1 to 3: the three cheapest others that steer her at 13 kt or more, installed

  1. ★ Sleipner SEP60/185S-IP this unit 161 lb · tunnel from $12,887 Steers her at 18 kt
  2. 1 Lewmar 140TT Tunnel Thruster 82 lb · tunnel from $8,468 Steers her at 13 kt
  3. 2 Lewmar 140TT Tunnel Thruster Kit 82 lb · tunnel from $8,655 Steers her at 13 kt
  4. 3 Max Power CT60 (12 V) 154 lb · tunnel from $8,796 Steers her at 18 kt

The Sleipner SEP60/185S-IP on a trawler, by length

  1. 25 ft29 kt
  2. 30 ft25 kt
  3. 35 ft21 kt
  4. 40 ft19 kt
  5. 45 ft16 kt
  6. 50 ft15 kt
  7. 55 ft13 kt
  8. 60 ft12 kt
  9. 65 ft11 kt
  10. 70 ft11 kt
  11. 75 ft10 kt
  12. 80 ft9 kt

Outlined: the finder does not list it at that length (under 13 kt, far more than she needs, or outside Sleipner’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?

What Sleipner says 29 to 38 ft The maker's own range, from its listing
What our sizing says 37 to 41 ft Full thrust in 15 knots, across the kinds of boat it fits
Every kind of boat it fits, by length ten boat types
Which boats it fits, by length
Boat Full thrust at 15 knotsStill 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 36 to 41 ft None
Houseboat 30 to 37 ft 38 to 41 ftfull thrust to about 13 knots at 41 ft
Catamaran 40 to 41 ft None
Trawler 35 to 41 ft None
Motor yacht 35 to 41 ft None
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 No length. More thrust than the boat needs.
Center console No length. More thrust than the boat needs.

The Sleipner SEP60/185S-IP 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 houseboat gets full thrust to 37 ft, and a sailboat to 41 ft. The maker gives one range for every boat.

The table tries the Sleipner SEP60/185S-IP 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 41 ft, just past Sleipner’s own range (29 to 38 ft).

It is sized for five 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.

Installed by a yard
Boat Total installed
30 ft $12,697 to $15,589$79 to $97 a lb of thrust
35 ft $12,777 to $15,829$79 to $98 a lb of thrust
41 ft $12,887 to $19,539$80 to $121 a lb of thrust

From the shortest to the longest boat it is sized for.

What is in each total five lines

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 $540 to $1,980 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.

Each line of the estimate
Boat length The unit Yard labor Haul-out Batteries, cable, charger Other parts
30 ft $5,895 to $6,210 $5,120 to $5,760about 32 hours $540 to $1,450 $601 to $800 $541 to $1,369
35 ft $5,895 to $6,210 $5,120 to $5,760about 32 hours $620 to $1,690 $601 to $800 $541 to $1,369
41 ft $5,895 to $6,210 $5,120 to $9,18032 to 51 hours $730 to $1,980 $601 to $800 $541 to $1,369

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 665 CCA (Sleipner’s minimum), $360 for the battery; Sleipner’s cable table gives 1/0 AWG: $95 to $171 for the red and black cable and the lugs; a GEN5X2 charger, $146.
  • At 24 V: two 12 V batteries in series, at least 332 CCA each (Sleipner’s minimum), $513 for both; Sleipner’s cable table gives 3 AWG, priced on 1 AWG, the nearest size cut to length: $80 to $141 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 2 of 5: Wiring prep only. The yard installs the unit and does the hull work; you do the wiring prep.

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 DIY

You: 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 three steps
  1. 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.
  2. 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.
  3. 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 Sleipner’s own channel and two 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.

How to Change the Anode & Prop on a Sleipner (Side-Power) SE60 ThrusterService how-to Imtra, Sleipner’s US distributor, February 2018
Sleipner (Side-Power) Proportional Thrusters 101Magazine Yachting Magazine, December 2022
Sleipner / Side-Power thruster systems - the importance of correct tunnel installation!Maker Sleipner’s own channel
eVision: Sleipner e-series thrustersMaker Sleipner’s own channel

Know before you buy

What sets this model apart, what it costs to keep, and what to weigh.

Price per pound of thrust

$36.61 a lb The unit’s price over its published thrust. The bars are Sleipner’s next sizes and the nearest other makers.

Controls

Proportional: the joystick sets how hard it pushes. The power controller (PPC) is included.

Anodes

$28.80 a change

They sit below the waterline, so a change means a haul-out or a diver.

Service and warranty

Sleipner gives 2 years for leisure use and 1 for commercial use. It transfers to the next owner, and it starts no later than 18 months after the boat's first launch.

See Sleipner’s warranty Sleipner's warranty statement, effective 1 April 2022.

Special mentions

Battery: at 12 V it wants one battery of 665 CCA or more, Sleipner's figure. The cheapest that meets it is the Optima BlueTop SC27DM Group 27 AGM, $359.99. Check your own bank.

Charger: a NOCO GEN5X2 two-bank shore charger, $146.41. It is the one our estimate prices.

Gas engine room? Buy the ignition-protected Sleipner SE60/185S, $2,295.

Sleipner sells it for either end, so it can go at the bow or the stern.

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: Sleipner rates the motor for 2 to 3 min at a stretch.

Parts for the Sleipner SEP60/185S-IP

See the Sleipner SEP60/185S-IP manual

The US dealer number comes first, then Sleipner’s own. 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

21 parts

The manual button above opens it on the maker's product page. It has the hull, wiring and fuse figures for this model.

From Sleipner’s SEP60 IP installation guide, document 4354 rev 19, 2025, read 25 October 2026.

In the box
The guide prints no box list. It has you install the unit with the gasket and the bolts provided. It treats the PPC power controller as part of the unit, and the PPC has its own installation guide. Imtra, Sleipner's US distributor, sells each PRO unit as the thruster and a PPC together.
Bought separately
The ANL fuse and a main switch ("must include"), an S-Link control panel with its own guide, the S-Link cables, the tunnel and the battery cable. Imtra, Sleipner's US distributor, lists the same items to buy with a new thruster.
Charging
The word "charging" is not in any of the Sleipner guides we read. The battery is sized by cold cranking amps, and a battery near the thruster is suggested. How it gets charged is left to you and your installer.

In Sleipner’s words, from its SE80 to SE150 installation guide, document 2687 rev 30, page 19: “For installations on large vessels with bow and stern thrusters or catamarans a dedicated battery for each thruster should be considered.”

The “other parts” line in the estimate above covers these parts as a range, $541 to $1,369 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, 185 mm bore, 750 mm”.

Sold in lengths from about 30 to 59 in. This is the shortest: the yard cuts the tube to the width of your hull at the thruster.

Part number SM8001

Control panel

Fisheries Supply lists it as “Side-Power PJC211 S-Link LCD panel and joystick, one thruster”.

Part number SMPJC211

S-Link backbone cable

Fisheries Supply lists it as “S-Link backbone cable, 0.2 m”.

Sold in lengths from 0.2 to 20 m. This is the shortest: measure the run from the helm to the thruster and buy the length that reaches.

Part number SM61320-0.2M

S-Link spur cables

Fisheries Supply lists it as “S-Link spur cable, 0.4 m”.

Sold in lengths from 0.4 to 5 m. This is the shortest: measure the run from the helm to the thruster and buy the length that reaches. You need 2.

Part number SM61321-0.4M

S-Link T-connector

Fisheries Supply lists it as “S-Link T-connector”.

You need 3.

Part number SM61326

S-Link end terminator

Fisheries Supply lists it as “S-Link end terminator”.

You need 2.

Part number SM61327

S-Link power cable, 8 ft

Fisheries Supply lists it as “S-Link power cable, 8 ft”.

Part number SM61328

Main fuse

Fisheries Supply lists it as “Side-Power ANL fuse 325 A”. This one is for the 12 V version.

The maker's figure: ANL 325.

Part number SMANL325

Main fuse

Fisheries Supply lists it as “Side-Power ANL fuse 150 A”. This one is for the 24 V version.

The maker's figure: ANL 150.

Part number SMANL150

Fuse holder

Fisheries Supply lists it as “ANL fuse block, 35 to 750 A, cable up to 4/0, with cover”. This one is for the 12 V version.

Part number 3903

Fuse holder

Fisheries Supply lists it as “ANL compact fuse block, 35 to 300 A, cable up to 2/0, with cover”. This one is for the 24 V version.

Part number 3803

Battery switch

Fisheries Supply lists it as “e-Series 350 A battery switch, on/off”. This one is for the 12 V version.

Rated at or above the 325 A main fuse. If your manual names its own switch, use that one.

Part number 9003E

Battery switch

Fisheries Supply lists it as “m-Series 300 A battery switch, on/off”. This one is for the 24 V version.

Rated at or above the 150 A main fuse. If your manual names its own switch, use that one.

Part number 2306

Control-circuit fuse holder

Fisheries Supply lists it as “Waterproof in-line ATO/ATC fuse holder”.

The maker asks for a 2 A fuse on the control supply.

Part number 5065

Batteries

Fisheries Supply lists it as “Optima BlueTop SC27DM Group 27 AGM”. This one is for the 12 V version.

One at 665 CCA or more. The cheapest listing that meets it.

Part number BAT SC27DM

Batteries

Fisheries Supply lists it as “Lifeline GPL-1400T AGM starting”. This one is for the 24 V version.

You need 2, each at 332 CCA or more, in series for 24 V. The cheapest listing that meets it.

Part number LFL GPL-1400T

Battery cable, red and black

Defender lists it as “Ancor tinned battery cable 1/0 AWG, cut to length, red or black”. This one is for the 12 V version.

You need 10 ft of each color. For about 20 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.

Part number None on the listing. Order it by name.

Battery cable, red and black

Defender lists it as “Ancor tinned battery cable 1 AWG, cut to length, red or black”. This one is for the 24 V version.

You need 10 ft of each color. For about 20 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.

Part number None on the listing. Order it by name.

Cable lugs

Fisheries Supply lists it as “Tin-plated starter lugs, 1/0 AWG, bag of 10”. This one is for the 12 V version.

The listing runs $23.74 to $28.04 by stud size. Eight ends on one run, with two spare.

Part number 91066-P10

Cable lugs

Fisheries Supply lists it as “Tin-plated starter lugs, 1 AWG, bag of 10”. This one is for the 24 V version.

The listing runs $20.52 to $22.06 by stud size. Eight ends on one run, with two spare.

Part number 91066-P10

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.

Part number GEN5X2

Outside the hull replacement parts in the water

6 parts

Anode (takes two)

The metal that wears away in the water so the drive does not. Sleipner calls it “Anode, aluminium SE60/80/100”. It fits the 12V size on this page.

Part number SM71190A Sleipner 71190A
See it at Defender$14.40 Price read 29 Oct 2026

Propeller

The propeller on the drive. Sleipner calls it “Propeller Ø185/5bl Q-Prop™”. It fits the 12V size on this page.

Part number SM41261 Sleipner 41261
See it at Defender$103.50 Price read 29 Oct 2026

Drive pin (the pin that drives the propeller)

The pin that locks the propeller to its shaft. Sleipner calls it “Drive pin propeller SE60/80/100 (4/6/7HP)”. It fits the 12V size on this page.

Part number SM61241 Sleipner 61241
See it at Defender$6.70 Price read 29 Oct 2026

Gear leg gasket, 1 mm

The leg under the motor that turns the propeller. Sleipner calls it “Gasket for gearleg/tunnel SE60 1mm”. It fits the 12V size on this page.

The SE60 gear leg takes this 1 mm gasket and the 1.5 mm gasket 6 1311 15. Sleipner also sells both as kit 4 0610.

Part number 6131110
See it at Sleipner No US price found

Gear leg gasket, 1.5 mm

The leg under the motor that turns the propeller. Sleipner calls it “Gasket for gearleg/tunnel SE60 1,5mm”. It fits the 12V size on this page.

Fitted together with the 1 mm gasket 6 1311 10.

Part number 6131115
See it at Sleipner No US price found

Gear leg, with propeller

The leg under the motor that turns the propeller. Sleipner calls it “Gearleg SE60”. It fits the 12V size on this page.

Part number 40602
See it at Sleipner No US price found

Inside the boat replacement parts on board

4 parts

Main fuse

The main fuse at the battery, in the rating the maker gives. Sleipner calls it “Recommended fuse A”. It fits the 12V size on this page.

The rating on Sleipner's product page for this model.

Part number ANL325
See it at Sleipner No US price found

Control panel, proportional dual joystick with display

The control at the helm. Sleipner calls it “Dual joystick speed control panel with display, S-Link”.

Runs a bow and a stern proportional thruster.

Part number SMPJC212 Sleipner PJC212
See it at Defender$990.00 Price read 29 Oct 2026

Control panel, proportional joystick with display

The control at the helm. Sleipner calls it “Single speed control panel with display, S-Link”.

For one proportional thruster on S-Link.

Part number SMPJC211 Sleipner PJC211
See it at Imtra$1,000.00 Price read 29 Oct 2026

Replacement motor

The electric motor that turns the propeller. Sleipner calls it “Electric motor SEP60 12V IP”. It fits the 12V size on this page.

Part number 4010712
See it at Sleipner No US price found

The install parts are matched to Sleipner’s own figures and priced at Fisheries Supply, with the battery cable at Defender, cut to length.

Spare part numbers come from Sleipner’s parts pages and manuals. A dealer may sell a part we have not priced. Search for the number.

Other sizes and close alternatives

Compare them side by side

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, motor, mounting, price, part number, documents
Full spec sheet
Thrust and motor
Thrust 161 lb (73 kgf) As printed: 161 lbs (73 kg) @ 12V
Thrust under load132 lb at 10.5 V
Motor3.1 kW
Voltage12 V or 24 V
Run limit2 to 3 min duty cycle at 20 C ambient
Installation
TypeTunnel, fixed mount
End of the boatBow or stern
Tunnel diameter185 mm
What it does to the hullTunnel bore below the waterline
Haul-out to install itYes
Maker’s boat length29 to 38 ft
Price and ordering
Price $5,895 to $6,210 equipment only, a dealer's price, defender.com, 26 October 2026
Part number 88348212 V
88348224 V
Documents
Manual Installation manualon the maker's product page
The site’s reviewSleipner (Side-Power) review

Every published figure the site holds for the Sleipner SEP60/185S-IP, with where each came from.

Draw, cable, fuse and battery at each voltage 12 V and 24 V

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.

Draw, cable, fuse and battery
Voltage Draw Maker’s cable Fuse Battery Run limit
12 V 370 Anominal draw 1/0 AWG for up to 22 ft of cable counted out and back. Longer runs take heavier cableinstallation guide ANL 325installation guide 350 CCA DIN minimumSleipner installation guide, SEP-IP60, document 4354 rev 19 (2025) 2 to 3 min duty cycle at 20 C ambientproduct page, "Motor cycle duty"
24 V 170 Anominal draw 3 AWG for up to 22 ft of cable counted out and back. Longer runs take heavier cableinstallation guide ANL 150installation guide 175 CCA DIN minimumSleipner installation guide, SEP-IP60, document 4354 rev 19 (2025) 2 to 3 min duty cycle at 20 C ambientproduct page, "Motor cycle duty"

The Sleipner SEP60/185S-IP’s draw, cable, fuse, battery and run limit, as the maker publishes them.

The tunnel: length and depth rules

Tunnel length. Avoid a tunnel longer than four times its diameter. Friction inside a long tube slows the water and cuts thrust. Too short, and the flow reaches the propeller before it has straightened, which the manual says causes cavitation and noise. The propeller must sit entirely inside the tube. Sleipner’s installation manual.

Depth below the waterline. As deep as possible under the waterline, and as far forward as possible. The depth for a given model is in that model’s own measurements. Deeper prevents air being sucked in from the surface and raises the water pressure at the propeller. SE20 to SE40 installation guide, 5611 rev 25 (2025).

Our notes from the manual and listings

In the box: Proportional: the joystick sets how hard it pushes. The power controller (PPC) is included.

12 V

The ignition-protected build, for a boat with gasoline engines or tanks in the same space. PRO means proportional: the joystick sets how hard it pushes. The 2026 catalog says to expect close to continuous run time at half power or less. This unit has the same 185 mm tunnel and 73 kg rating as the SEP60, for boats of 29 to 38 ft.

Defender's page spans both voltages and prints only the 12 V figures. The page rates the brushed motor for two to three minutes' running at 20 C. The control panel switches itself off after about six minutes unused. Sleipner's FAQ wants the tunnel at least three quarters of its diameter below the surface, never less than half. This row is the 12 V version; Defender prices it separately, read 12 October.

24 V

This row is the 24 V version; Defender prices it separately, read 12 October.

Where each point above comes from
  • Sleipner sells it for either end, so it can go at the bow or the stern.The maker's listing
  • It is sold at 12 V and at 24 V.The maker's and dealers' listings
  • Sleipner also prints a second, lower thrust figure for when the battery sags under load: 132 lb at 10.5 V.The maker's published rating
  • 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.

Where to go next

The specs are the maker’s and the dealers’, on the dates shown. The sizing and the costs are our arithmetic, done without seeing your boat.