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Thruster specs
Sideshift ST350-D: specs, price and the boats it fits
The ST350-D gives a big boat strong steering at the stern: two complete ST350 stern thrusters, one on each side of the transom, run from one joystick. It’s made for boats of 50 to 70 ft and up to 35 tons. Each half is a full ST350, the Sideshift stern unit with the longest owner record.
Bought as two single ST350 kits, the pair would cost $10,990. The ST350-D is $8,995, which saves you $1,995, and you get one joystick to steer both. Each unit still comes with its own controller and battery switch, so plan on two full installs.
What isn’t in the box is the batteries, because each unit runs on its own 24 V bank. Sideshift’s manual and its FAQ give different battery sizes for this kit, so ask Sideshift to confirm before you buy them. With cable and charging, figure about $1,961 to $2,136 more.
Owners have reported on the ST350 since 2012, and most are happy with it. The complaints that come back are shaft seals failing at around seven years and lines catching on the units. Each push is full on or off. Sideshift’s habit is 3 to 5 seconds, and its ceiling is 20 to 30. A replacement motor is $1,595 per unit, and the warranty is two years on parts.
The full spec sheet for a yard sits lower down, and the Sideshift thruster review covers Sideshift’s whole range.
Where this summary comes from (6 sources, read 11 October 2026)
Key facts
- DIY level 4 of 5 You fit it, electrician connects
- Thrust Not published Our sizing works from the motor's rating
- Boat length 50 to 70 ft Sideshift's own range
- Price $8,995 full kit, sideshift.com, 28 August 2026
- Fitted by a yard $12,244 to $14,743 Our estimate at 45 to 77 ft, unit and job
- Voltage 24 V As sold
- Mounts External Fixed mount, stern
- To fit it Afloat The maker says it goes on in the water
- Run limit Bursts of 3 to 5 seconds Never more than 20 to 30 seconds at a time
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 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 DIYYou: 6 to 8 h Yard: none Electrician: 2 to 4 h No haul-out.
- Mount the thruster; fit the battery, controller and joystick; run the cables You 6 to 8 h Sideshift’s own figure: 6 to 8 hours per thruster, depending on the wire runs. Every mount and connection is above the waterline. Source.
- 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:Drilling above the waterlineHeavy 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?
Sideshift prints no thrust, so our sizing uses an estimate from the motor’s rating. That estimate can say a boat is too big for it. It cannot promise a fit. The maker gives one range for every boat.
The table below tries the Sideshift ST350-D 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 down to 45 ft and up to 77 ft, just past Sideshift’s own range (50 to 70 ft).
| Boat | Lengths it fits, on our estimate |
|---|---|
| Pontoon & tritoon | Not listed. Its maker does not name this kind of hull. |
| Sailboat | 45 to 77 ft |
| 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 | 45 to 77 ft |
| Motor yacht | 45 to 77 ft |
| Bass & flats | No length. Outside the maker's length range. |
| Wake & ski boats | No length. Outside the maker's length range. |
| Express cruiser | 45 to 65 ft |
| Center console | No length. Outside the maker's length range. |
It is sized for four 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. The hours come from what owners and yards report. Your own yard will have its own opinion. The cost page builds the same figures line by line.
- The unit$8,995
- Yard labor$1,280 to $3,6008 to 20 hours
- Batteries, cable, charger$1,961 to $2,136
- Other parts$8 to $12
- Total, 45 to 77 ft$12,244 to $14,743Our estimate
The Sideshift ST350-D Stern Thruster fitted by a yard. It comes to the same at every length it is sized for. Our estimate.
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 for each of the two thrusters: two 12 V batteries in series, at least 850 CCA each (Sideshift’s minimum), $1,440 for all four; Sideshift’s cable table gives 2/0 AWG: $228 to $403 for the red and black cable and the lugs; two GEN5X2 chargers, $293.
Fitting it yourself. Tell the finder you will fit a Sideshift yourself and it takes the yard’s labor off. With that off, the total is $10,964 to $11,143. That is the unit plus the batteries, cable and other parts, which you buy whoever does the fitting.
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 Sideshift’s Monohull installation manual Rev 3.1, November 2025, read 30 September 2026.
- In the box
- The thruster, the motor controller, the wireless joystick and its receiver, a wireless key fob, the wiring harness and mounting hardware, the fuse in a holder with a digital voltage display, and a battery switch. Sideshift lists these on each product page. The manual adds the crimper, anti-seize, Loctite, Sikaflex and heat shrink.
- Bought separately
- The batteries, the 1/0 or 2/0 battery cable and the charger. The joystick is wireless: no wire runs from it to the thruster. It still needs 12 V at the helm for its own power, so plan a small feed there.
- Charging
- The thruster gets a bank of its own: cranking type, 850 cold cranking amps per battery, within 10 ft of the controller. You buy the charger too, either a shore charger or a DC-to-DC charger fed off the bank the alternator charges.
The manual’s words, page 40: “The 2 most popular ways are: AC/DC multi-bank charger such as the NOCO GEN5X2 (available in our online store). ... Using a DC-DC Isolated Charger such as the Victron Orion-Tr DC-DC Converters Isolated.”
The “other parts” line in the estimate above is the priced parts below, $8 to $12 at Fisheries Supply’s prices on 30 September 2026. The batteries, cable and charger have a line of their own.
| Part | What it is | What to ask for | Dealer price |
|---|---|---|---|
| Control-circuit fuse and switch | A small fuse, and often a switch, on the thin wire that powers the panel or control box. | Sideshift 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. | 1/0 AWG (230 series) or 2/0 AWG tinned battery cable | 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. | Sideshift 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. | NOCO GEN5X2, or a Victron Orion-Tr Smart isolated DC-DC charger | $146–$305NOCO GEN5X2 shore charger, Victron Orion-Tr Smart DC-DC charger, Blue Sea ML-ACR charging relay, at Fisheries Supply. |
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.
| Thrust and motor | |
|---|---|
| Thrust | Not published |
| Motor | 11.19 kW |
| Voltage | 24 V |
| Fitting | |
| Type | External, fixed mount |
| End of the boat | Stern |
| What it does to the hull | Three small holes, all above the waterline |
| Haul-out to fit it | No: the maker says it goes on afloat |
| Maker’s boat length | 50 to 70 ft |
| Price and ordering | |
| Price | $8,995 full kit, the maker's own price, sideshift.com, 28 August 2026 |
| Part number | Not held for this listing |
| Documents | |
| Manual | Installation manual (PDF)on the maker's site |
| Warranty | Sideshift gives 2 years against faulty workmanship or materials. Its exclusions include wrong wire size or low voltage, burn-out from overuse, collisions, and tangled line or netting. installation manual, Rev 3.1, p. 68 |
| The site’s review | Sideshift thruster 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.
| Voltage | Draw | Maker’s cable | Fuse | Battery | Run limit |
|---|---|---|---|---|---|
| 24 VEach of the two thrusters | 400 Astart current | 2/0 AWG. The manual keeps the run to 10 ft of cable counted out and back. The FAQ allows the battery up to 50 ft from the controllerinstallation manual, Rev 3.1 | Not published | Each thruster is wired on its own, to its own two 12 V starting batteries of at least 850 CCA each, in series for 24 Vinstallation manual, Rev 3.1, p. 30 | bursts of 3 to 5 seconds, never more than 20 to 30 seconds at a timeinstallation manual, Rev 3.1 |
- At 24 V: size the cable for your run, or check the battery you have.
What holds up and what to weigh
Each point names the fact it rests on.
What holds up
- It goes on with the boat in the water. No haul-out is needed to fit it.Sideshift: "All Sideshift thrusters can be installed in-water since all the mounting locations and cable connections are routed above the waterline."
What to weigh
- Sideshift publishes no thrust figure for it. The boat table uses our estimate from the motor's rating.The maker's published specs
- It runs in bursts of 3 to 5 seconds, never more than 20 to 30 seconds at a time.installation manual, Rev 3.1
What the manual and listings say
This is the note we keep on the Sideshift ST350-D Stern Thruster, written from the maker’s manual, its product pages and the dealer’s listing.
In the box: Two thrusters in the kit, one for each end. The kit has the thruster, the controller, the wireless joystick and key fob, the harness, the fuse and a battery switch. You buy the batteries, the cable and a charger. The joystick is wireless but needs 12 V at the helm for its own power.
Our note
Two ST350 units, one each side of the transom, on one control. Sideshift rates the pair for boats to 35 tons, and it goes on with the boat afloat. The manual's battery line for this kit reads 850 cold cranking amps each, where the FAQ says 850 in total. Ask which before you buy batteries.
Bursts only: the manual asks for pushes of 3 to 5 seconds as normal practice, and never more than 20 to 30 seconds at a time. Its warranty does not cover a motor burned out by overuse. On 17 September 2026 sideshift.com was running an end of summer sale, with ten percent off every thruster. The price here is the list price. The sale was still on when the page was read again on 2 October 2026.
Videos
Two of Sideshift’s own videos, from its YouTube channel: a transom-mounted stern unit going on, and a stern unit docking a small boat, from above. 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.
Other sizes and close alternatives
These are Sideshift’s nearest sizes by thrust, in any of its lines.
- One size down: Sideshift ST350 Stern Thruster, no published thrust, $5,495.
Sideshift prints no thrust, so we name no other maker’s unit as its match. The compare page lists every model.
Every model with a page here is listed, maker by maker, on the thruster index.