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Lewmar · tunnel thruster · bow or stern
Lewmar 185TT GEN 2 Package: specs, price and the boats it fits
It gives 128 lb (58 kgf) of push. Lewmar's own chart puts it on boats of 36 to 45 ft. It runs on 12 V.
- Haul-out to install
- DIY 2 of 5: wiring prep only
- 3-year warranty
Quick stats
- Thrust 128 lb 58 kgf, Lewmar's rating
- Boat length 36 to 45 ft Lewmar's chart, by windage. See below
- Price per lb of thrust $17.49 Unit only. $72 to $146 installed
- Voltage 12 V As sold
- Battery at 12 V 330 CCA One battery, near the thruster
- Run limit 3 min In one direction, then fault mode
- To install it Haul-out The boat comes out of the water
- Anodes $20.89 A change, at Fisheries Supply
About the Lewmar 185TT GEN 2 Package
This package is the 3 kW 185TT Gen 2 with its controls in the box: the Blue Box control unit, the control box, a joystick, the cables and two fuses. It gives 128 lb of push on 12 V, and Lewmar’s chart sizes it for boats of about 36 to 45 ft. The Blue Box also lets an older Lewmar take the new controls without rewiring.
Defender’s price is $2,239, against $1,912 for the bare 3 kW thruster. The tube, a fuse holder and the battery switch Lewmar requires are about $267 to $754 more. One starting battery near the bow runs it; that battery, its cable and a charger come to about $583 to $717. See what else to buy.
Read more
The gearbox is sealed, with no reservoir, but look at it each haul-out: one 185TT owner found his full of water and short of oil in 2025, and Lewmar replaced it under warranty, as a part only. Keep each push under three minutes one way. Parts can be slow, by owner accounts, so carry a spare propeller.
Installers will find the wiring figures and dimensions further down. For the rest of Lewmar’s line, read the Lewmar thruster review.
Where this summary comes from (9 sources, read 13 October 2026)
- Defender listing (the database’s price)
- Defender, 185TT Gen 2 listing (in the box; sealed, no reservoir)
- Lewmar Gen 2 control manual 559232 (the Blue Box converter for older installations)
- Lewmar Thruster Selection Guide (boat length by windage)
- Great Grady forum, 2025: a 185TT gearbox replaced under warranty
- Tugnuts, 2020: a Ranger Tug’s gear leg hub, and slow parts
- Lewmar Gen 2 TT installation manual 559231 Iss.3 (three minutes one way, then fault mode; warranty one year on motors and controls)
- Lewmar, About (making boat hardware in Havant, England, since 1946)
- Lippert Components acquires Lewmar Marine Limited, 1 August 2019
Will the Lewmar 185TT GEN 2 Tunnel Thruster Package with Joystick steer your boat?
45 FT TRAWLER · BOW · 15 KT WIND
Every knot figure here is wind speed, not boat speed or current.
On a 45 ft trawler the Lewmar 185TT GEN 2 Tunnel Thruster Package with Joystick (128 lb) steers her in a 15 knot breeze. Her bow needs about 135 lb from a tunnel to steer her in a 15 knot breeze. Its 128 lb lands within 15 percent of that figure, which this site counts as enough.
The finder lists it for her.
The Lewmar 185TT GEN 2 Tunnel Thruster Package with Joystick on a trawler, by length
- 25 ft26 kt
- 30 ft22 kt
- 35 ft19 kt
- 40 ft17 kt
- 45 ft15 kt
- 50 ft13 kt
- 55 ft12 kt
- 60 ft11 kt
- 65 ft10 kt
- 70 ft9 kt
- 75 ft9 kt
- 80 ft8 kt
Outlined: the finder does not list it at that length (under 13 kt, far more than she needs, or outside Lewmar’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 | Lewmar’s chart |
|---|---|---|---|
| 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 | 32 to 45 ft | 46 to 51 ftfull thrust to about 13 knots at 51 ft | 41 to 45 ftas the 185TT 3.0, class B |
| Houseboat | 30 to 33 ft | 34 to 38 ftfull thrust to about 13 knots at 38 ft | 36 to 40 ftas the 185TT 3.0, class C |
| Catamaran | 37 to 52 ft | 53 to 59 ftfull thrust to about 13 knots at 59 ft | 36 to 40 ftas the 185TT 3.0, class C |
| Trawler | 32 to 45 ft | 46 to 51 ftfull thrust to about 13 knots at 51 ft | 36 to 40 ftas the 185TT 3.0, class C |
| Motor yacht | 35 to 45 ft | 46 to 51 ftfull thrust to about 13 knots at 51 ft | 36 to 40 ftas the 185TT 3.0, class C |
| 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 | 41 to 57 ft | 58 to 65 ftfull thrust to about 13 knots at 65 ft | 41 to 45 ftas the 185TT 3.0, class B |
| Center console | No length. More thrust than the boat needs. | ||
The Lewmar 185TT GEN 2 Tunnel Thruster Package with Joystick against each kind of boat, in a 15 knot wind. Our sizing, from the finder’s own rules, beside Lewmar's chart.
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 33 ft, and an express cruiser to 57 ft.
The table tries the Lewmar 185TT GEN 2 Tunnel Thruster Package with Joystick 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. The listing prints no boat length, so thrust alone decides. Lewmar's own figures are in the opening lines.
Reading Lewmar’s chart. Lewmar publishes a selection guide, checked 15 September 2026, on a dealer’s copy. It names a model by boat length, from 30 to 90 ft, for a The area of the boat the wind can push on: the hull sides, the cabin, the mast and rigging, or the canopy. A tall, boxy boat has a lot of it, and wind force does not care how slowly you are moving. class and a wind band. Our 15 knots falls in its lightest band, 11 to 16 knots.
The Lewmar 185TT GEN 2 Tunnel Thruster Package with Joystick is not on the chart by name. Lewmar rates it at the same 128 lb (58 kgf) as the 185TT 3.0. That tunnel unit is on the chart, so the column shows what the chart says for it. Which class a kind of boat falls in is our reading of its windage. The chart starts at 30 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 |
|---|---|
| 30 ft | $8,749 to $10,920$68 to $85 a lb of thrust |
| 50 ft | $9,199 to $18,720$72 to $146 a lb of thrust |
| 65 ft | $9,449 to $19,450$74 to $152 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 $540 to $3,140 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 |
|---|---|---|---|---|---|
| 30 ft | $2,239 | $5,120 to $5,760about 32 hours | $540 to $1,450 | $583 to $717 | $267 to $754 |
| 50 ft | $2,239 | $5,120 to $12,60032 to 70 hours | $990 to $2,410 | $583 to $717 | $267 to $754 |
| 65 ft | $2,239 | $5,120 to $12,60032 to 70 hours | $1,240 to $3,140 | $583 to $717 | $267 to $754 |
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 330 CCA (Lewmar’s minimum), $257 for the battery; Lewmar’s cable table gives 4/0 AWG: $180 to $314 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
One from Lewmar’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
$17.49 a lb The unit’s price over its published thrust. The bars are Lewmar’s next sizes and the nearest other makers.Controls
This package adds the blue control box, the joystick (589268), a 2 m motor cable, a 10 m auxiliary cable and two 250 A fuses (589008).
- Lewmar Gen 2 AUX control loom, 7 m (589802), $69.10 at Fisheries Supply.
Anodes
$20.89 a change- Anode kit (589350): $20.89 at Fisheries Supply.
They sit below the waterline, so a change means a haul-out or a diver.
Service and warranty
Lewmar gives 3 years, but 1 on electric motors and their electrical equipment and on electronic controls. Service by anyone but an authorized Lewmar representative can void it. Removal, transport and installation costs are not covered.
See Lewmar’s warranty Lewmar's Gen 2 installation manual.Special mentions
Battery: at 12 V it wants one battery of 330 CCA or more, Lewmar's figure. The cheapest that meets it is the Lifeline GPL-1400T AGM starting, $256.72. Check your own bank.
Charger: a NOCO GEN5X2 two-bank shore charger, $146.41. It is the one our estimate prices.
Lewmar 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.
Lewmar prints no single length band for it. Its selection chart gives one by windage: 36 to 45 ft at 15 knots, across the kinds of boat in the table. The boat table is our sizing alone.
Short pushes only: Lewmar rates the motor for 3 min at a stretch.
Parts for the Lewmar 185TT GEN 2 Tunnel Thruster Package with Joystick
See the Lewmar 185TT GEN 2 Package manualSearch for the number as printed here, with no spaces. 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 a dealer's copy (the maker publishes none we could find). It has the hull, wiring and fuse figures for this model.
From Lewmar’s Gen 2 TT installation manual 559231 and the RT manual 55110070, Iss.3 and Iss.4, read 30 September 2026.
- In the box
- The motor, the solenoid and its loom, the ICU control box, a 2 m motor loom, the saddle, gasket, hub, propeller, anode kit and fixings. The RT ships with its own housing and actuator.
- This package adds
- The blue control box, the joystick (589268), a 2 m motor cable, a 10 m auxiliary cable and two 250 A fuses (589008), by the dealer’s listing, read 13 October 2026. Those parts are not in the cards below or in the estimate’s “other parts” line.
- Bought separately
- Under Accessories: the control panels, the panel looms, the fuse holders and ANL fuses, the automatic battery switch. "The installation MUST have a battery switch". The tunnel fits a Lewmar saddle.
- Charging
- The manual sizes the battery by cranking amps and says to "ensure batteries are fully charged before switching on the main power". It gives no rule on a charger, a feed or a bank of its own.
The manual’s words, page 12: “Battery crank capacity should be at least equal to the thruster current.”
The “other parts” line in the estimate above covers these parts as a range, $267 to $754 at Fisheries Supply’s prices on 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.
Tunnel tube
Fisheries Supply lists it as “Lewmar fiberglass tunnel tube, 185 mm bore, 1000 mm”.
Sold in lengths from about 39 to 59 in. This is the shortest: the yard cuts the tube to the width of your hull at the thruster.
Control cable, panel to thruster
Fisheries Supply lists it as “Lewmar Gen 2 AUX control loom, 7 m”.
Sold in lengths from 7 to 18 m. This is the shortest: measure the run from the helm to the thruster and buy the length that reaches.
Fuse holder
Ask for The holder for the fuse type your manual names.
Match it to the fuse.
Battery switch
Ask for A manual battery switch rated for this circuit.
Rate it at or above the main fuse your manual names. 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”.
Lewmar's control unit (ICU) draws 8 A and has a slow-blow fuse inside; fuse its own supply to suit the wire, and use cable rated for 8 A.
Batteries
Fisheries Supply lists it as “Lifeline GPL-1400T AGM starting”.
One at 330 CCA or more. The cheapest listing that meets it.
Battery cable, red and black
Defender lists it as “Ancor tinned battery cable 4/0 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, 4/0 AWG, bag of 10”.
The listing runs $47.52 to $49.44 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
Anode kit
The metal that wears away in the water so the drive does not. Lewmar calls it “ANODE KIT”.
Propeller
The propeller on the drive. Lewmar calls it “PROPELLER AND WASHER”.
One propeller on the 185TT tunnel thruster.
Drive pin (breaks to protect the drive)
The pin that locks the propeller to its shaft. Lewmar calls it “DRIVE PIN”.
Defender sells a two-pack of this pin as 559017A.
Tunnel gasket
It keeps water out of the joint it sits in. Lewmar calls it “TUNNEL GASKET”.
Inside the boat replacement parts on board
Solenoid (the motor switch)
The heavy switch that sends battery power to the motor. Lewmar calls it “SOLENOID 2.2 / SOLENOID 3.0 12V”. This one is for the 140TT 2.2 kW; 185TT 3.0 kW 12 V version.
The 140TT 2.0 kW takes B12526. On the 185TT this one is for the 3.0 kW 12 V only.
Controller box (the ICU)
The electronics that run the motor when you press the panel. Lewmar calls it “GEN2 TT ICU”.
The 250TT parts list prints its ICU as 589834, the same number as its solenoid loom, so we list no ICU number for the 250TT.
Main fuse, 250 A
The main fuse at the battery, in the rating the maker gives. Lewmar calls it “250 A ANL TYPE FUSE”.
The rating the manual gives for each model it fits. Lewmar sells it as an ANL fuse.
Control panel, dual joystick (bow and stern)
The control at the helm. Lewmar calls it “Controller, Dual Joystick”.
Control panel, dual pad (bow and stern)
The control at the helm. Lewmar calls it “Controller, Dual Pad”.
Control panel, single joystick
The control at the helm. Lewmar calls it “Controller, Single Joystick”.
Control panel, single pad
The control at the helm. Lewmar calls it “Controller, Single Pad”.
Replacement motor
The electric motor that turns the propeller. Lewmar calls it “MOTOR ASSY 3.0KW 12V MX”. This one is for the 3.0 kW 12 V version.
The standard motor. The manual lists a separate IP (ignition protected) motor.
No part matches. Try the number without spaces, or the part’s name.
The install parts are matched to Lewmar’s own figures and priced at Fisheries Supply, with the battery cable at Defender, cut to length.
Spare part numbers come from Lewmar’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 Lewmar 140TT Gen 2 Package 92 lb · $2,754
- Size up Lewmar 185TT GEN 2 five sizes, 128 to 214 lb · $1,912 to $4,825
- Other maker VETUS Bow Pro 571 126 lb · $3,794
- Other maker Sleipner SE50/140S 136 lb · $2,160 to $3,375
- Other maker Max Power CT60 (12 V) 154 lb · $1,719
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 | 128 lb (58 kgf) As printed: Thrust: 128 lbs |
| Motor | 3 kW |
| Voltage | 12 V |
| Run limit | 3 min in one direction, then fault mode |
| 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 |
| Maker’s boat length | 36 to 45 ftLewmar's selection chart, by windage; the listing prints none |
| Price and ordering | |
| Price | $2,239 equipment only, a dealer's price, defender.com, 26 October 2026 |
| Part number | 590091LEW3.0kW Package w/ Joystick, 12 V DC |
| Documents | |
| Manual | Installation manual (PDF)a dealer's copy (the maker publishes none we could find) |
| The site’s review | Lewmar thruster review |
Every published figure the site holds for the Lewmar 185TT GEN 2 Tunnel Thruster Package with Joystick, 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 | 330 Anominal draw | 4/0 AWG, the one size Lewmar gives for this model, for any run up to 49 ft of cable counted out and backGen 2 installation manual, Iss.3 | 250 AGen 2 installation manual, Iss.3 | Crank capacity at least the 330 A draw, Lewmar's ruleLewmar Gen 2 installation manual | 3 min in one direction, then fault modeGen 2 installation manual |
The Lewmar 185TT GEN 2 Tunnel Thruster Package with Joystick’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.
The tunnel: length and depth rules
Tunnel length. A minimum suggested tunnel length of twice the diameter. Lewmar’s installation manual.
Depth below the waterline. One tunnel diameter below the waterline to keep air out of the tunnel, with 0.75 of a diameter the minimum. Gen 2 TT installation manual, 559231 Iss.3 (2018).
Our notes from the manual and listings
In the box: This package adds the blue control box, the joystick (589268), a 2 m motor cable, a 10 m auxiliary cable and two 250 A fuses (589008).
Our note
The 3.0 kW 185TT Gen 2 as a package: the thruster with its Blue Box control unit, the blue control box, a joystick with 2 m of motor cable, 10 m of auxiliary cable and two 250 A fuses. The 185 mm tunnel is sold separately. The Gen 2 manual rates it 58 kgf (128 lb), with a stainless gearbox, 20 kg and a 250 A fuse.
It gives 330 A at 12 V on at least 95 mm² cable to 15 m of total run, battery to thruster and back. That fuse sits below the stated draw, as on every row of the manual's table. Lewmar's whole battery rule is that crank capacity should at least equal the thruster current. Run it in one direction for more than three minutes and the system enters fault mode.
A thermal switch stops a hot motor, and the manual says wait 20 minutes. The panel powers itself down after 15 minutes idle. Three years' warranty on paper, but one year on electric motors, associated electrical equipment and electronic controls. Service by anyone but an authorized Lewmar representative voids the warranty, and removal and reinstalling are not covered. Lewmar publishes no boat length. Fisheries Supply's listing for the bare unit says 35 to 45 ft.
Where each point above comes from
- Lewmar sells it for either end, so it can go at the bow or the stern.The maker's listing
- 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
- Lewmar prints no single length band for it. Its selection chart gives one by windage: 36 to 45 ft at 15 knots, across the kinds of boat in the table. The boat table is our sizing alone.Lewmar's Thruster Selection Guide, checked 15 September 2026
Not sure this is the one? The thruster finder asks about your boat and prices every unit that fits.