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Sleipner · external thruster · stern
Sleipner SX50 Compact: specs, price and the boats it fits
It gives 137 lb (62 kgf) of push. Sleipner sells it for boats of 26 to 36 ft. It runs on 12 V.
- Haul-out to install
- DIY 3 of 5: split with the yard
- 2-year warranty
Quick stats
- Thrust 137 lb 62 kgf, Sleipner's rating
- Boat length 26 to 36 ft Sleipner's own range
- Price per lb of thrust $31.86 Unit only. $53 to $84 installed
- Voltage 12 V As sold
- Battery at 12 V 665 CCA One battery, near the thruster
- Run limit Not clear Sleipner's page prints "4 duty cycle" with no unit
- Weight 34 lb 15.3 kg, Sleipner's page
- Anodes No US price The parts list names them
About the Sleipner SX50 Compact
The SX50 is the stronger of Sleipner’s two external stern units: 137 lb of push from a pod bolted to the outside of the hull, for boats of about 26 to 36 ft. It needs only three small holes below the waterline, so there is no tunnel to cut where the stern has no room for one.
Defender lists it at $4,365 for the version that fits a hull up to 50 mm thick, and a little more for the 150 mm version made for thicker hulls. Plan on about $307 to $642 for the panel, main switch and fuse, and $601 to $677 for a battery near the stern with cable and charging. The parts list.
Read more
Installing it means hauling the boat. Sleipner keeps its external pods to displacement and semi-planing boats under 20 knots, where waves do not slam them, and rates the motor for 2 to 3 minutes of running at a time. The unit weighs about 15 kg. The warranty is two years and passes to the next owner.
Installers will find the wiring figures and dimensions further down. For the rest of Sleipner’s line, read the Sleipner (Side-Power) review.
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 SX50 Compact Stern Thruster steer your boat?
39 FT TRAWLER · STERN · 15 KT WIND
Every knot figure here is wind speed, not boat speed or current.
On a 39 ft trawler the Sleipner SX50 Compact Stern Thruster (137 lb) steers her in a 22 knot breeze. Her stern needs about 70 lb from an external unit on the transom to steer her in a 15 knot breeze.
The finder leaves it off her list. It is far more than she needs.
The Sleipner SX50 Compact Stern Thruster on a trawler, by length
- 25 ft33 kt
- 30 ft28 kt
- 35 ft24 kt
- 40 ft21 kt
- 45 ft18 kt
- 50 ft17 kt
- 55 ft15 kt
- 60 ft14 kt
- 65 ft13 kt
- 70 ft12 kt
- 75 ft11 kt
- 80 ft10 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. Its maker does not name this kind of hull. | |
| Sailboat | 39 ft only | None |
| Houseboat | Not listed. Its maker does not name this kind of hull. | |
| Catamaran | Not listed. An external unit bolts to the side of a single hull at the bow or to its transom, and a cat has two narrow hulls with a bridgedeck between them, so there is nowhere forward to hang one. | |
| Trawler | 39 ft only | None |
| Motor yacht | 39 ft only | None |
| Bass & flats | Not listed. This site does not list it for this kind of boat. | |
| Wake & ski boats | Not listed. This site does not list it for this kind of boat. | |
| Express cruiser | Not listed. This site does not list it for this kind of boat. | |
| Center console | Not listed. This site does not list it for this kind of boat. | |
The Sleipner SX50 Compact Stern Thruster 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 every kind of boat it fits gets full thrust to 39 ft. The maker gives one range for every boat.
The table tries the Sleipner SX50 Compact Stern Thruster 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 where it mounts 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 39 ft, just past Sleipner’s own range (26 to 36 ft).
It is sized for three 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 |
|---|---|
| 39 ft | $7,253 to $11,457$53 to $84 a lb of thrust |
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 $700 to $1,880 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 |
|---|---|---|---|---|---|
| 39 ft | $4,365 to $4,658 | $1,280 to $3,6008 to 20 hours | $700 to $1,880 | $601 to $677 | $307 to $642 |
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.
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: 4 to 8 hours Electrician: 2 to 4 hours Plus a haul-out.
Your part needs:Heavy battery cableCrimping big lugs
Every step, and who does it
- Drill, seal and bolt the unit below the waterline Yard 4 to 8 hours Our estimate. No maker times it; one owner paid his yard about a day of labor to mount two units. Source.
- 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
One 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.
Know before you buy
What sets this model apart, what it costs to keep, and what to weigh.
Price per pound of thrust
$31.86 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.
- Side-Power 8950 G touch panel, one thruster (SM8950G), $219.21 at Fisheries Supply.
- Side-Power 4-lead control cable, 4 m (SM61277-04M), $29.23 at Fisheries Supply.
Anodes
We found its anodes in Sleipner’s parts list, with no US price. The parts below name them.
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.
Dealer prices at Fisheries Supply, read 26 October 2026.What to weigh
The boat comes out of the water to install it: it needs three small holes, below the waterline.
Parts for the Sleipner SX50 Compact Stern Thruster
See the Sleipner SX50 Compact 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 SX35 and SX50 installation manual, document 8086 rev 3, 2026, read 16 October 2026.
- In the box
- The manual prints no box list. It mentions the bolts for the grids or cowls, and the blue hose that goes over the cable harness.
- Bought separately
- The battery, the ANL fuse, a main switch (manual or Sleipner's automatic one), the battery cable, the control panel and its control cable.
- 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, $307 to $642 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.
Control panel
Fisheries Supply lists it as “Side-Power 8950 G touch panel, one thruster”.
Control cable, panel to thruster
Fisheries Supply lists it as “Side-Power 4-lead control cable, 4 m”.
Sold in lengths from 4 to 22 m. This is the shortest: measure the run from the helm to the thruster and buy the length that reaches.
Main fuse
Fisheries Supply lists it as “Side-Power ANL fuse 325 A”.
The maker's figure: ANL 325.
Fuse holder
Fisheries Supply lists it as “ANL fuse block, 35 to 750 A, cable up to 4/0, with cover”.
Battery switch
Fisheries Supply lists it as “e-Series 350 A battery switch, on/off”.
Rated at or above the 325 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”.
Your manual names no value for this: size a small in-line fuse to the wire.
Batteries
Fisheries Supply lists it as “Optima BlueTop SC27DM Group 27 AGM”.
One at 665 CCA or more. The cheapest listing that meets it.
Battery cable, red and black
Defender lists it as “Ancor tinned battery cable 1/0 AWG, cut to length, red or black”.
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.
Cable lugs
Fisheries Supply lists it as “Tin-plated starter lugs, 1/0 AWG, bag of 10”.
The listing runs $23.74 to $28.04 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
Propeller shaft anode
The metal that wears away in the water so the drive does not. Sleipner calls it “Anode kit SX35/50 for propeller shaft”.
Sleipner: for units with a threaded propeller shaft only, made after June 2024.
Side anode retrofit kit
The metal that wears away in the water so the drive does not. Sleipner calls it “Anode retrofit kit for both sides SX35/50”.
Sleipner: the kit upgrades SX35 and SX50 units with side-mounted anodes.
Side anodes, spare pair
The metal that wears away in the water so the drive does not. Sleipner calls it “Anode spare part kit for both sides SX35/50”.
Two anodes with bolts.
Propeller
The propeller on the drive. Sleipner calls it “Propeller SE50/SX35/SX50 5bl Q-Prop™”.
For the 137 mm across. Listed on all four SX35 and SX50 pages.
Replacement tunnel (the pod housing)
Sleipner calls it “SX35/50-140 Replacement tunnel kit”.
Sleipner’s page says it fits all SX35 and SX50 models, PRO included.
Inside the boat replacement parts on board
Controller seal
It keeps water out of the joint it sits in. Sleipner calls it “Seal”.
Also in Sleipner’s SX50 controller parts list.
Delay relay (the motor control interface)
A small switch in the motor’s control circuit. Sleipner calls it “Electronic Interface for thruster motor control”.
On the SX35, SX50 and SX80 24V it sits inside the controller. The EX pages call it the Electronic Control box.
Controller
The electronics that run the motor when you press the panel. Sleipner calls it “Controller SX50/140 12V”.
Sleipner lists it for both the 50 mm and 150 mm hull versions.
Main fuse
The main fuse at the battery, in the rating the maker gives. Sleipner calls it “Recommended fuse A”.
The rating on Sleipner’s page for this model.
No part matches. Try the number without spaces, or the part’s name.
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
- Size down Sleipner SX35 Compact Stern 93 lb · $3,870 to $4,167
- Size up Sleipner EX95S 148 lb · $9,450
- Other maker Max Power CT80 stern pod (12 V) 152 lb · $4,299
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 | 137 lb (62 kgf) As printed: 62 kg (136 lbs) at 12V/24V; 50 kg (110 lbs) at 10.5V/21V |
| Thrust under load | 110 lb at 10.5 V/21 V |
| Motor | 2.8 kW |
| Voltage | 12 V |
| Run limit | "4 duty cycle", as the page prints it |
| Installation | |
| Type | External, fixed mount |
| End of the boat | Stern |
| What it does to the hull | Three small holes, below the waterline |
| Haul-out to install it | Yes |
| Weight | 15.3 kg (34 lb)Sleipner’s product page |
| Maker’s boat length | 26 to 36 ft |
| Price and ordering | |
| Price | $4,365 to $4,658 equipment only, a dealer's price, defender.com, 26 October 2026 |
| Part number | 883351for a hull up to 50 mm (2 in) thick, 12 V 883351for a hull up to 150 mm (6 in) thick, 12 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 SX50 Compact Stern Thruster, 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 | 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, SX35 and SX50 external, document 8086 rev 3 (2026) | "4 duty cycle", as the page prints itproduct page, "Motor cycle duty" |
The Sleipner SX50 Compact Stern Thruster’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: Gasket, bolts and anode with the unit. The panel, its cable, the fuse and main switch are bought.
for a hull up to 50 mm (2 in) thick
It bolts to the outside of the hull through three small holes below the waterline. It comes in a 50 mm and a 150 mm version, the figure being the thickest hull it fits without glass work. Sleipner's external page puts its external units on displacement and semi-planing boats up to 60 ft. The boat comes out of the water to install it.
It is rated 62 kg at 12 or 24 V and 50 at 10.5 or 21. The unit weighs 15.3 kg and draws 370 A at 12 V, with an ANL 325 fuse and a minimum battery of 350 cold cranking amps DIN. It is for boats of 26 to 36 ft. Defender's price is a range across the two versions.
The page prints its duty as "4 duty cycle at 20 C", as written. This row is the 50 mm (2 in) hull-thickness version; Defender prices it separately, read 12 October.
for a hull up to 150 mm (6 in) thick
This row is the 150 mm (6 in) hull-thickness version; Defender prices it separately, read 12 October.
Where each point above comes from
- Sleipner also prints a second, lower thrust figure for when the battery sags under load: 110 lb at 10.5 V/21 V.The maker's published rating
- The boat comes out of the water to install it: it needs three small holes, below the waterline.The mounting style
Not sure this is the one? The thruster finder asks about your boat and prices every unit that fits.