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Sleipner · tunnel thruster · bow or stern
Sleipner SE100/185T: specs, price and the boats it fits
It gives 256 lb (116 kgf) of push. Sleipner sells it for boats of 35 to 55 ft. It runs on 12 V or 24 V.
- Haul-out to install
- DIY 2 of 5: wiring prep only
- 2-year warranty
Quick stats
- Thrust 256 lb 116 kgf, Sleipner's rating
- Boat length 35 to 55 ft Sleipner's own range
- Price per lb of thrust $17.40 Unit only. $46 to $81 installed
- Voltage 12 V or 24 V As sold
- Battery at 12 V 713 CCA Two batteries, near the thruster
- Run limit 2 to 3 min Duty cycle at 20 C ambient
- Weight 68 lb 31 kg, Sleipner's page
- Anodes $28.80 A change, at Defender
About the Sleipner SE100/185T
The SE100 is a strong twin-prop thruster for cruisers of about 35 to 55 ft, with 256 lb of push from a 185 mm tube. It is also the model Sleipner uses to explain its ratings: the lower figure is what it pushes at the 10.5 volts a working battery delivers, the higher one at a full 12 V.
Defender has it at $4,455. Add about $541 to $1,369 for the tube, a panel, the main switch and a fuse. On 12 V it draws a very heavy current, so it takes a pair of batteries and generous cables; we estimate $961 to $1,180 for the batteries, cable and charging. The 24 V version draws less than half the current, so its cables are far lighter. See the parts list.
Read more
Owners report these units running for years, though one with a converted 24 V SE100 lost propeller blades to fish, a cheap part by design. On an older unit, a corroded shaft is replaced as a whole lower leg. Keep pushes inside 2 to 3 minutes. Two-year warranty, transferable.
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 (6 sources, read 12 October 2026)
- Sleipner product page
- Sleipner SE80 to SE150 installation guide, document 2687 rev 30
- Sleipner FAQ (rated voltage, the Sleipner name since 2021, batteries and lithium, tunnel depth)
- Sleipner warranty statement, effective 1 April 2022
- Trawler Forum, "Bow thruster manufacturer opinions", Dec 2021 (ten years on two Side-Power units; the prop built to break)
- Trawler Forum, "Side Power bow thruster corrosion", Dec 2020 (shaft sold as the whole lower leg)
Will the Sleipner SE100/185T steer your boat?
60 FT TRAWLER · BOW · 15 KT WIND
Every knot figure here is wind speed, not boat speed or current.
On a 60 ft trawler the Sleipner SE100/185T (256 lb) steers her in a 15 knot breeze. Her bow needs about 240 lb from a tunnel to steer her in a 15 knot breeze.
The finder lists it for her.
The Sleipner SE100/185T on a trawler, by length
- 25 ft37 kt
- 30 ft31 kt
- 35 ft26 kt
- 40 ft23 kt
- 45 ft21 kt
- 50 ft19 kt
- 55 ft17 kt
- 60 ft15 kt
- 65 ft14 kt
- 70 ft13 kt
- 75 ft12 kt
- 80 ft12 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?
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 | 45 to 60 ft | None |
| Houseboat | 34 to 48 ft | 49 to 54 ftfull thrust to about 13 knots at 54 ft |
| Catamaran | 51 to 60 ft | None |
| Trawler | 45 to 60 ft | None |
| Motor yacht | 45 to 60 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 | 57 to 60 ft | None |
| Center console | No length. More thrust than the boat needs. | |
The Sleipner SE100/185T 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 48 ft, and a sailboat to 60 ft. The maker gives one range for every boat.
The table tries the Sleipner SE100/185T 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 down to 34 ft and up to 60 ft, just past Sleipner’s own range (35 to 55 ft).
It is sized for six 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 |
|---|---|
| 34 ft | $11,687 to $14,404$46 to $56 a lb of thrust |
| 45 ft | $11,877 to $20,694$46 to $81 a lb of thrust |
| 60 ft | $12,237 to $22,504$48 to $88 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 $610 to $2,900 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 |
|---|---|---|---|---|---|
| 34 ft | $4,455 | $5,120 to $5,760about 32 hours | $610 to $1,640 | $961 to $1,180 | $541 to $1,369 |
| 45 ft | $4,455 | $5,120 to $11,52032 to 64 hours | $800 to $2,170 | $961 to $1,180 | $541 to $1,369 |
| 60 ft | $4,455 | $5,120 to $12,60032 to 70 hours | $1,160 to $2,900 | $961 to $1,180 | $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: two 12 V batteries side by side (in parallel), at least 713 CCA each (Sleipner’s minimum), $720 for both; Sleipner’s cable table gives 3/0 AWG, priced on 4/0 AWG, the nearest size cut to length: $180 to $314 for the red and black cable and the lugs; a GEN5X2 charger, $146.
- At 24 V: two 12 V batteries in series, at least 760 CCA each (Sleipner’s minimum), $720 for both; Sleipner’s cable table gives 1/0 AWG: $95 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 Sleipner’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
$17.40 a lb The unit’s price over its published thrust. The bars are Sleipner’s next sizes and the nearest other makers.Controls
Gasket, bolts and anode with the unit. The panel, its cable, the fuse and main switch are bought.
- Control panel, on/off dual joystick (bow and stern) (SM8940G), $574.81 at Fisheries Supply.
- Control panel, on/off single joystick (SM8960G), $350.73 at Fisheries Supply.
- Control panel, on/off touch panel (SM8950G), $202.50 at Defender.
Want push you can dial in? The proportional Sleipner SEP100/185T has the same thrust. It costs $6,975, which is $2,520 more.
Anodes
$28.80 a change- Anode (SM71190A): $14.40 at Defender, $18.01 at Fisheries Supply, and it takes two.
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 two batteries of 713 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 SE100/185T-IP, $6,300.
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.
At 12 V it draws 740 A, so the battery cable is heavy and the battery sits close to it.
Parts for the Sleipner SE100/185T
See the Sleipner SE100/185T manualThe 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
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 SE80 to SE150 installation guide, document 2687 rev 30, 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.
- Bought separately
- The ANL fuse and a main switch ("must include"), the control panel with its own guide, the panel cable, the tunnel and the 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.
The manual’s words, 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.
Outside the hull replacement parts in the water
Anode (takes two)
The metal that wears away in the water so the drive does not. Sleipner calls it “Anode, aluminium SE60/80/100”.
Propeller (185 mm)
The propeller on the drive. Sleipner calls it “Propeller SE80/100 5bl Q-Prop™”.
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)”.
Gear leg gasket
The leg under the motor that turns the propeller. Sleipner calls it “Gasket kit for gearleg/tunnel”.
Gear leg, complete
The leg under the motor that turns the propeller. Sleipner calls it “Gearleg SE80/100”.
Sleipner describes it as the complete gearbox.
Controller
The electronics that run the motor when you press the panel. Sleipner calls it “Controller SE40-80 (12V & 24V) / SE100-130 (24V)”.
Inside the boat replacement parts on board
Motor brush kit
Carbon brushes inside the motor. They wear down with use. Sleipner calls it “Brush kit SP95 + SE100 12V”. This one is for the 12 V version.
Sleipner asks for the thruster's serial number with every brush kit order. More than one kit is in print for this model, and the serial number decides which.
Motor brush kit
Carbon brushes inside the motor. They wear down with use. Sleipner calls it “Brush kit SP95/125 + SE100/130 12V”. This one is for the 12 V version.
Sleipner asks for the thruster's serial number with every brush kit order. More than one kit is in print for this model, and the serial number decides which.
Motor brush kit
Carbon brushes inside the motor. They wear down with use. Sleipner calls it “Brush kit SP95 + SE100/120 24V”. This one is for the 24 V version.
Sleipner asks for the thruster's serial number with every brush kit order. More than one kit is in print for this model, and the serial number decides which.
Motor brush kit
Carbon brushes inside the motor. They wear down with use. Sleipner calls it “Brush kit SP95/125 + SE100/130 24V”. This one is for the 24 V version.
Sleipner asks for the thruster's serial number with every brush kit order. More than one kit is in print for this model, and the serial number decides which.
Controller (the relay box on the motor)
A small switch in the motor’s control circuit. Sleipner calls it “Controller SE100-130 12V + SE150-250 24V”.
On the SE100 it is listed for the 12 V motor only.
Solenoid (the motor switch)
The heavy switch that sends battery power to the motor. Sleipner calls it “Solenoid SE100/130 12V”. This one is for the 12 V version.
Listed on the SE100 12 V motor page (8 0101 12).
Solenoid (the motor switch)
The heavy switch that sends battery power to the motor. Sleipner calls it “Solenoid SE100/170 24V”. This one is for the 24 V version.
Listed on the SE100 24 V, SE120 and SE130 24 V motor pages.
Main fuse
The main fuse at the battery, in the rating the maker gives. Sleipner calls it “Recommended fuse A”. This one is for the 12 V version.
The rating on Sleipner's product page for this model.
Main fuse
The main fuse at the battery, in the rating the maker gives. Sleipner calls it “Recommended fuse A”. This one is for the 24 V version.
The rating on Sleipner's product page for this model.
Control panel, on/off dual joystick (bow and stern)
The control at the helm. Sleipner calls it “Dual joystick, 12/24 V”.
Runs a bow and a stern thruster.
Control panel, on/off single joystick
The control at the helm. Sleipner calls it “Single joystick, 12/24 V”.
For one on/off thruster.
Control panel, on/off touch panel
The control at the helm. Sleipner calls it “Touch panel, 12/24 V, 5-wire, round cut-out”.
For one on/off thruster.
Replacement motor
The electric motor that turns the propeller. Sleipner calls it “Electric motor SE100 12V”. This one is for the 12 V version.
Replacement motor
The electric motor that turns the propeller. Sleipner calls it “Electric motor SE100 24V”. This one is for the 24 V version.
No part matches. Try the number without spaces, or the part’s name.
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
- Size down Sleipner SE80/185T 212 lb · $3,285
- Size up Sleipner SE130/250T 352 lb · $5,670
- Ignition-protected Sleipner SE100/185T-IP 256 lb · $6,300
- Proportional (SEP) Sleipner SEP100/185T 256 lb · $6,975
- Proportional (SEP), ignition-protected Sleipner SEP100/185T-IP 256 lb · $8,190
- Other maker Max Power CT125 (24 V) 254 lb · $2,947
- Other maker VETUS BOW PRO Boosted 110 243 lb · $6,106
- Other maker Quick BTQ 185 DP six sizes, 143 to 231 lb · $4,201 to $8,752
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 | 256 lb (116 kgf) As printed: 256 lbs (116 kg) at 12VDC / 24VDC |
| Thrust under load | 220 lb at 10.5 V |
| Motor | 6.3 kW |
| Voltage | 12 V or 24 V |
| Run limit | 2 to 3 min duty cycle at 20 C ambient |
| Installation | |
| Type | Tunnel, fixed mount |
| End of the boat | Bow or stern |
| Tunnel diameter | 185 mm |
| What it does to the hull | Tunnel bore below the waterline |
| Haul-out to install it | Yes |
| Weight | 31 kg (68 lb)Sleipner’s product page |
| Maker’s boat length | 35 to 55 ft |
| Price and ordering | |
| Price | $4,455 equipment only, a dealer's price, defender.com, 26 October 2026 |
| Part number | 88342712 V/24 V |
| Documents | |
| Manual | Installation manualon the maker's product page |
| The site’s review | Sleipner (Side-Power) review |
Every published figure the site holds for the Sleipner SE100/185T, 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 | 740 Anominal draw | 3/0 AWG for up to 22 ft of cable counted out and back. Longer runs take heavier cableinstallation guide | ANL 500installation guide | 750 CCA DIN minimumSleipner installation manual, SE100/185T | 2 to 3 min duty cycle at 20 C ambientproduct page, "Motor cycle duty" |
| 24 V | 340 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 | 400 CCA DIN minimumSleipner installation manual, SE100/185T | 2 to 3 min duty cycle at 20 C ambientproduct page, "Motor cycle duty" |
The Sleipner SE100/185T’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.
- At 24 V: size the cable for your run, or check the battery you have.
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: Gasket, bolts and anode with the unit. The panel, its cable, the fuse and main switch are bought.
Our note
Twin props in a 185 mm tunnel, 31 kg, for boats of 35 to 55 ft, sold at 12 or 24 V. Sleipner's FAQ uses this unit to explain its two thrust figures: 100 kg at 10.5 V and 116 at 12 V.
At 12 V the manual gives 740 A, a minimum battery of 750 cold cranking amps DIN (1,425 SAE) and 3/0 cable to 7 m of total run. At 24 V it gives 340 A, 400 DIN and 1 AWG to 7 m. The page's fuse is ANL 500. 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. Defender's price sits below Imtra's list. Since the 2025 tariffs, that list carries a separate tariff line.
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: 220 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.