Boat Thruster Guide

What to buy, what it costs, what it takes to fit

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Thruster specs

Sleipner ERV170 eVision: specs, price and the boats it fits

The ERV170 gives 375 lb of push from a vertical eVision retractable on a 250 mm unit, for boats of about 49 to 72 ft, at 24 or 48 V.

Imtra lists the 24 V build at $26,455, before a separate tariff line, and no price for the 48 V one. The manual gives 420 A at 24 V and 225 A at 48 V; the page puts the 48 V figure at 220. See the specs.

Like the other ERV units it is brushless with speed control, and the manual gives 2 to 3 minutes at full thrust. It weighs about 84 kg. Warranty: two years.

Installers will find the wiring figures and dimensions further down. For the rest of Sleipner’s line, read the Sleipner (Side-Power) review.

Where this summary comes from (5 sources, read 15 October 2026)

Key facts

  • DIY level 2 of 5 Wiring prep only
  • Thrust 375 lb 170 kgf, Sleipner's rating
  • Boat length 49 to 72 ft Sleipner's own range
  • Price $26,455 equipment only, imtra.com, 15 October 2026
  • Fitted by a yard $35,331 to $47,531 Our estimate at 60 ft, unit and job
  • Voltage 24 V or 48 V As sold
  • Mounts Retractable Drops down, bow or stern
  • To fit it Haul-out The boat comes out of the water
  • Run limit Not published Ask the maker before long use

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 2 of 5: Wiring prep only. The yard fits 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 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 DIY

You: 4 to 16 h Yard: 40 to 88 h Electrician: 2 to 4 h Plus a haul-out.

  1. Cut the hull and fit the housing and mechanism Yard 40 to 88 h Nobody publishes an hours figure. Fisheries Supply says installation is significantly more expensive than a tunnel, and that is too loose to turn into a number. So this is the tunnel’s own banded figure plus a quarter, which keeps it above a tunnel as the distributors describe it.
  2. 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.
  3. 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?

What Sleipner says 49 to 72 ft The maker's own range, from its listing
What our sizing says 48 to 74 ft Full thrust in 15 knots. The longest boat of each kind is in the table.

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 catamaran to 74 ft. The maker gives one range for every boat.

The table below tries the Sleipner ERV170 eVision 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 45 ft and up to 79 ft, just past Sleipner’s own range (49 to 72 ft).

The Sleipner ERV170 eVision against each kind of boat, in a 15 knot wind. Our sizing, from the finder’s own rules.
Boat Full thrust at 15 knotsStill a fit, in lighter wind
Pontoon & tritoon Not listed. A retractable drops down inside the hull, and a pontoon has no hull depth to drop into.
Sailboat 54 to 65 ft 66 to 79 ftfull thrust to about 12 knots at 79 ft
Houseboat 45 to 48 ft 49 to 72 ftfull thrust to about 10 knots at 72 ft
Catamaran 61 to 74 ft 75 to 79 ftfull thrust to about 14 knots at 79 ft
Trawler 53 to 65 ft 66 to 79 ftfull thrust to about 12 knots at 79 ft
Motor yacht 53 to 65 ft 66 to 79 ftfull thrust to about 12 knots at 79 ft
Bass & flats Not listed. A retractable needs hull depth to drop into, and these planing hulls have almost none forward.
Wake & ski boats Not listed. A retractable needs hull depth to drop into, and these planing hulls have almost none forward.
Express cruiser No length. More thrust than the boat needs.
Center console No length. More thrust than the boat needs.

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 five 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 $800 to $3,810 at these lengths, with 5 to 7 days out of the water, worked from eight yards’ own rate cards. The hours are our own estimate. Your own yard will have its own opinion. The cost page builds the same figures line by line.

The Sleipner ERV170 eVision fitted by a yard, from the shortest to the longest boat it is sized for. Our estimate.
Boat length The unit Yard labor Haul-out Batteries, cable, charger Other parts Total
45 ft $26,455 $6,400 to $14,40040 to 80 hours $800 to $2,170 $980 to $1,521 $336 to $815 $34,971 to $45,361
60 ft $26,455 $6,400 to $15,84040 to 88 hours $1,160 to $2,900 $980 to $1,521 $336 to $815 $35,331 to $47,531
79 ft $26,455 $6,400 to $15,84040 to 88 hours $1,480 to $3,810 $980 to $1,521 $336 to $815 $35,651 to $48,441

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 24 V: two 12 V batteries in series, at least 798 CCA each (Sleipner’s minimum), $720 for both; Sleipner’s cable table gives 2/0 AWG: $114 to $201 for the red and black cable and the lugs; a GEN5X2 charger, $146.
  • At 48 V: four 12 V batteries in series, at least 428 CCA each (Sleipner’s minimum), $1,027 for all four; Sleipner’s cable table gives 2/0 AWG: $114 to $201 for the red and black cable and the lugs; two GEN5X2 chargers, $293.

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 Sleipner’s SE80 to SE150 installation guide, document 2687 rev 30, 2025, read 30 September 2026. That manual is written for the tunnel units. A retractable unit brings its own housing, so there is no tunnel to buy.

In the box
The gasket, bolts and anode come with the unit. The SEP guides call the power controller "the included PPC unit".
Bought separately
The ANL fuse and a main switch ("must include"), the control panel with its own guide, the panel cable and the battery 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.

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 is the priced parts below, $336 to $815 at Fisheries Supply’s prices on 30 September 2026. The batteries, cable and charger have a line of their own.

Parts the Sleipner ERV170 eVision’s box leaves to you, from the makers’ manuals read 30 September 2026. “What to ask for” is Sleipner’s own part or model where its manual names one, otherwise the dealer’s item.
Part What it is What to ask for Dealer price
Control panel The buttons or joystick at the helm. One helm, one panel: a second steering station needs a panel of its own. SM8960G single joystick, SM8950G touch panel $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. Side-Power 4-wire control 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. Side-Power ANL fuse, 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. SMANLHOLD (SMANLHOLD-C with a cover) $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. Side-Power manual main switch, 350 or 600 A, or the automatic AMS $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.
Control-circuit fuse and switch A small fuse, and often a switch, on the thin wire that powers the panel or control box. Sleipner names none $8–$12Blue Sea in-line ATO fuse holders, 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. Sleipner 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. Sleipner 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. Sleipner 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. Sleipner 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.

The Sleipner ERV170 eVision, every published figure the site holds, with where each came from.
Thrust and motor
Thrust 375 lb (170 kgf) As printed: 170 kg
Motor7.3 kW
Voltage24 V or 48 V
Fitting
TypeRetractable, drops down
End of the boatBow or stern
Tunnel diameter250 mm
What it does to the hullLarge hull opening below the waterline
Haul-out to fit itYes
Maker’s boat length49 to 72 ft
Price and ordering
Price $26,455 equipment only, a dealer's price, imtra.com, 15 October 2026
Part number ERV170/250TC-24V24 V, 24 V DC (nominal 21 V DC)
ERV170/250TC-48V48 V, 48 V DC (nominal 42 V DC)
Documents
Manual Installation manualon the maker's product page
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. Sleipner's warranty statement, effective 1 April 2022
The site’s reviewSleipner (Side-Power) 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.

The Sleipner ERV170 eVision’s draw, cable, fuse, battery and run limit, as the maker publishes them.
Voltage Draw Maker’s cable Fuse Battery Run limit
24 V 420 Anominal draw 2/0 AWG for up to 22 ft of cable counted out and back. Longer runs take heavier cableinstallation guide ANL 400installation guide 420 CCA DIN minimumSleipner installation guide, ERL and ERV 130 to 210 eVision, document 7241 rev 22 (2025) Not published
48 V 225 Anominal draw 2/0 AWG for up to 22 ft of cable counted out and back. Longer runs take heavier cableinstallation guide ANL 200installation guide 225 CCA DIN minimumSleipner installation guide, ERL and ERV 130 to 210 eVision, document 7241 rev 22 (2025) Not published

What holds up and what to weigh

Each point names the fact it rests on.

What holds up

  • Sleipner sells it for either end, so it can go at the bow or the stern.The maker's listing
  • It is sold at 24 V and at 48 V.The maker's and dealers' listings

What to weigh

  • The boat comes out of the water to fit it: it needs a large hull opening 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 Sleipner ERV170 eVision, written from the maker’s manual, its product pages and the dealer’s listing.

In the box: A brushless eVision motor on S-Link control. The panel, fuse and main switch are bought.

24 V

This retractable lives in a housing let into the hull through a large opening, and drops when used. It is a bigger yard job than a tunnel. It also has a mechanism to keep in order. The brushless eVision 170 kg retractable with its motor standing vertical.

48 V

The product page gives 220 A; the manual gives 225 A.

Videos

Two of Sleipner’s own videos, from its YouTube channel: X-Yachts on the ERV100 retractable in a 47 ft sailboat, and how the SRV and SRL retractables go in. 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.

Sleipner’s own video, on Sleipner’s YouTube channel. The picture is a still from it.
Sleipner’s own video, on Sleipner’s YouTube channel. The picture is a still from it.

Other sizes and close alternatives

Sleipner also sells this thrust built another way. Each has its own page:

These are Sleipner’s next sizes in the same line, by thrust.

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.

Compare them side by side

Every model with a page here is listed, maker by maker, on the thruster index.

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.