We may earn a referral commission from some links on this page. It doesn't change your price or our recommendations.
Stern thruster cost: what owners paid, and what to expect today
Lift the cockpit hatch and you can see why a stern quote is a different animal from a bow quote: there is already a lot going on down there. This page shows what owners have paid for a stern thruster, with every figure dated, and our own estimate at today's prices by boat length. It also explains why a stern tunnel is hard to fit and an external unit is not, so you can tell a fair quote from a guess.
The short answer
Owners reporting professional stern installs paid roughly $7,500 to $10,000. Every figure is listed below with who said it and when.
Owners doing their own labor reported $4,000 to $6,000 in parts.
The newest report we could find is June 2022. US yard labor roughly doubled between 2021 and 2025, and the bow thruster cost page has the rate cards. Today's figure is probably well above them.
Our own estimate at today's prices is set out by boat length, for the external units built for the stern.
The stern is where the machinery lives, and moving it adds hours that a yard can only quote after looking. An external unit bolts to the transom above the waterline and moves none of it. Of the 15 stern reports we collected, 5 name an external unit.
Pricing the other end? The bow thruster cost page has the same by-length table for the bow. If you want control at both ends, bow and stern thrusters together covers fitting one at each end.
How the stern job differs from the bow job
On most boats the bow is close to empty: a chain locker and maybe a berth. The stern is where the machinery lives. That means fuel, batteries, the generator, the water heater, steering gear, and the hoses connecting all of it.
One owner on Trawler Forum described a stern A tube bored straight through the hull below the waterline, with a propeller in the middle of it. It is the conventional thruster. Fitting one is mostly a labor job rather than a hardware one. install. The job required moving the water heater, the generator muffler and about six hoses. The result made any future maintenance in that space impractical.
Those are hours the bow job does not have. The lost access is also a cost to the boat, and it never appears on the invoice. You pay it the first time you need to reach that water heater.
Ask the yard what has to come out before it can quote. A stern quote given without someone physically looking at what is behind the The flat surface across the very back of the boat. is a guess. Two stern quotes on boats of the same length can differ by exactly what one yard looked at and the other did not.
What it costs, by boat length
This is our estimate at today's prices. It is worked out the same way as the bow thruster cost table: the thruster at its published price, a boatyard's hours to fit it, the batteries and wiring, the other parts the box does not hold, and the haul-out where the unit needs the boat out of the water.
Each row counts only thrusters that steer a trawler-weight boat of that length at 13 knots or more, no more than 15 percent under a 15 knot breeze. A thruster at the stern has a longer The distance from the point the boat turns about to the place the push is applied. Double the distance and the same push turns the boat twice as hard. than one at the bow, so it needs less push. On small boats even the smallest external unit sold is more than enough.
Why there is no tunnel column. A stern tunnel is a tube bored through the hull right where the fuel, the generator, the water heater and their hoses usually sit, so most of the job is moving them first, and a yard can only price that after looking. Most boats cannot take one without it. A retractable is the same story: it needs a hatch cut into the bottom under the same machinery.
An external unit bolts to the transom, or mounts on an outboard or a sterndrive, and moves none of it. So for the stern, this table and the thruster finder price the units built for that end: pods, bolt-on units, and the kits for outboards and sterndrives.
| Boat length | External |
|---|---|
| Under 25 ft | All bigger than needed External thrusters at the stern for a boat under 25 ft Every one we list is more thruster than this boat needs. Fitted by a boatyard, least expensive first:
And one more model, up to $10,800 for the Sleipner Side-Power SX50. The thruster itself, before fitting: $3,300–$4,700. One of these can be fitted with the boat in the water. Find the right one for your boat |
| 25–30 ft | All bigger than needed External thrusters at the stern for a boat of 25–30 ft Every one we list is more thruster than this boat needs. Fitted by a boatyard, least expensive first:
And 9 more models, up to $19,400 for the Sleipner Side-Power SXP100 PRO. The thruster itself, before fitting: $3,300–$12,500. One of these can be fitted with the boat in the water. Find the right one for your boat |
| 30–35 ft | All bigger than needed External thrusters at the stern for a boat of 30–35 ft Every one we list is more thruster than this boat needs. Fitted by a boatyard, least expensive first:
And 10 more models, up to $19,400 for the Sleipner Side-Power SXP100 PRO. The thruster itself, before fitting: $3,300–$12,500. Two of these can be fitted with the boat in the water. Find the right one for your boat |
| 35–40 ft | External thrusters at the stern for a boat of 35–40 ft Fitted by a boatyard, least expensive first:
And 4 more models, up to $16,600 for the Sleipner Side-Power EX70C. The top of this range is lower than the 30–35 ft row’s because the Sleipner Side-Power SXP100 PRO leaves the set at this length. The thruster itself, before fitting: $3,300–$9,600. Two of these can be fitted with the boat in the water. Find the right one for your boat |
| 40–50 ft | External thrusters at the stern for a boat of 40–50 ft Fitted by a boatyard, least expensive first:
And 9 more models, up to $25,300 for the Sleipner Side-Power EX180D. The thruster itself, before fitting: $3,700–$17,800. Three of these can be fitted with the boat in the water. Find the right one for your boat |
| 50–55 ft | External thrusters at the stern for a boat of 50–55 ft Fitted by a boatyard, least expensive first:
And 11 more models, up to $25,500 for the Sleipner Side-Power EX180D. The thruster itself, before fitting: $3,700–$17,800. Three of these can be fitted with the boat in the water. Find the right one for your boat |
| 55–60 ft | External thrusters at the stern for a boat of 55–60 ft Fitted by a boatyard, least expensive first:
And 5 more models, up to $25,700 for the Sleipner Side-Power EX180D. The thruster itself, before fitting: $4,900–$17,800. Two of these can be fitted with the boat in the water. Find the right one for your boat |
| 60 ft and up | External thrusters at the stern for a boat of 60 ft or more Fitted by a boatyard, least expensive first:
And 4 more models, up to $25,900 for the Sleipner Side-Power EX180D. The thruster itself, before fitting: $4,900–$17,800. One of these can be fitted with the boat in the water. Find the right one for your boat |
Want a price for your own boat? Answer a few quick questions and the thruster finder shows which thrusters fit it, and what each one costs fitted.
What owners reported
The table below holds 15 figures from two Trawler Forum threads, February 2018 and June 2022.
Read the Covers column first. A parts-only number and a whole-job number are different kinds of figure, and the ranges below keep them apart.
| Owner | When | What | Reported | Covers |
|---|---|---|---|---|
| Comodave | Feb 2018 | Thruster and materials, own labor | $4,000 | Parts only |
| boathealer | Feb 2018 | All own labor, new battery and rewiring | $6,000 | Parts only |
| GracieGene | Feb 2018 | 24 volt stern thruster, quoted | $8,000 | Quoted |
| Tamrow | Feb 2018 | Quoted complete with battery and controller | $8,000 | Quoted |
| Arthurc | Feb 2018 | 54 ft, full tube, integrated hydraulic controls | $20,000 | Installed |
| Comodave | Jun 2022 | Side-Power parts (2016), self-installed | $5,000 | Parts only |
| Comodave | Jun 2022 | Sideshift parts, self-installed External | $4,500 | Parts only |
| ScottC | Jun 2022 | Side-Power SR80/185T retractable (2012), yard fitted | $7,500 | Installed |
| Spinner | Jun 2022 | 42 ft Nordic Tug, Side-Power, yard fitted early 2018, Seattle | $9,000–$10,000 | Installed |
| Bellakins | Jun 2022 | Heritage East 36, Side-Power, yard fitted | $10,000 | Installed |
| Rpoconnor | Jun 2022 | Mainship 390, Sideshift External | $6,909 | Unclear |
| Bryant | Jun 2022 | Grand Banks 36 Classic, what he says the job goes for External | $9,000 | Unclear |
| Cartouche | Jun 2022 | Side-Power external unit, Canada External | C $3,200 | Parts only |
| UrsusMaritimus | Jun 2022 | Sideshift, per unit, Canada External | C $4,900 | Parts only |
| UrsusMaritimus | Jun 2022 | Bow AND stern together, Canada | C $14,000–$15,000 | Installed |
Professionally installed, US dollars: $7,500–$20,000 across 4 reports. That top figure is one 54 ft boat with a full tube and integrated hydraulic controls, which is a different job. Set it aside and the remaining three run $7,500–$10,000.
Parts only, owner's own labor: $4,000–$6,000 across 4 reports.
Quoted but not bought: 2 owners were quoted, and both were quoted $8,000 almost exactly. Two quotes is too few to read much into.
Confidence: weak, and the reason is the dates. Nothing here is newer than June 2022. Every professional figure predates most of the labor-rate rise this site documents elsewhere.
Treat the installed range as the bottom of what a yard will say in 2026. Expect the parts side to have moved much less. Hardware prices have risen at an ordinary rate, while labor rates roughly doubled.
How many owners went external
Of the 15 reports, 5 name an external unit: SideShift or a Side-Power external pod. At the bow, the same forums are dominated by tunnels.
One owner said plainly why he chose it. It mounts above the waterline, so he avoided cutting a hole below it.
Those 15 posts are a small sample. People who post on a forum are not a random slice of owners, and people who fit something unusual are more likely to write about it. One owner also appears three times in this set.
That choice does fit the access problem above. Where the machinery is in the way, owners more often choose a unit that goes on the outside of the boat.
Fitting both ends at once
Doing bow and stern in one visit shares the 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. and the yard’s set-up for the job. So it costs less than two separate jobs.
The owner reports give no figure for the saving. Nobody in them priced the same job at both ends of the same boat in the same year. Our own table above counts the haul-out once in its one-at-each-end line, and that is the only line you clearly pay once instead of twice.
A single boatyard-installed tunnel at one end of a 35 ft boat runs $10,100–$14,200 in the by-length table. The quote-checker takes that job apart line by line.
Why you cannot just look the price up
Part of the reason there is no straight answer is that retailers are not always allowed to give one. Binnacle's listing for the VETUS STERN150P tunnel withholds the price.
A notice on the listing says the manufacturer does not permit the price to be shown until the item is in your cart. That is a Minimum Advertised Price policy.
Not every retailer does this. Fawcett lists a VETUS stern thruster extension kit openly at $406.87: same brand, price on the page.
So some of this hardware is priced in public and some is not.
If you already have a bow thruster
Maybe your boat already has a bow thruster and what you are missing is stern control. You do not necessarily need a second tunnel.
The bow-or-stern page says which end each docking problem points at. A single external unit on the transom is a real option, and here the price gap is wide.
A single DockStar unit with a standard stern hull track comes to $4,270 at their published per-item prices, captured 23 September 2026. Set that against $7,500 at the bottom of what owners reported paying a yard.
That owner figure is a Side-Power A thruster that lives inside the hull and drops down through a hatch when you press the button, then pulls back up. It leaves no permanent hole in the water flow., yard-fitted, and the job dates from 2012. June 2022 is only when it was posted. None of the yard-fitted reports inside that band is described as a tunnel. Two name Side-Power and nothing more.
The two are not like for like, and on cost alone the gap at this end of the boat is wide. The quote checker sets out what you give up with a DockStar against a tunnel. Their configurator is here.
The wider comparison is on the retrofit page. It covers what each external product genuinely drills, and what you give up.
What this means for your quote
If you already have a bow thruster and the stern is the problem, you do not necessarily need a second tunnel. A single external unit on the transom is a real option.
If the space behind your transom is full of machinery, expect the yard to need a look before it can quote. That is also where owners most often chose an external unit.
If you want control at both ends, do both in one visit. You pay for the haul-out once, though no owner has published what that saved them.
If you are holding a forum figure up against a quote, check its date first. Nothing in the stern reports is newer than June 2022.
Owner reports collected 26 August 2026 from public Trawler Forum threads dated February 2018 and June 2022. Retailer listings checked the same day.