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Thruster specs
Lewmar 185TT GEN 2 Package: specs, price and the boats it fits
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.
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
Key facts
- DIY level 2 of 5 Wiring prep only
- Thrust 128 lb 58 kgf, Lewmar's rating
- Boat length 36 to 45 ft Lewmar's chart, by windage. See below
- Price $2,239 equipment only, defender.com, 13 October 2026
- Fitted by a yard $9,199 to $18,720 Our estimate at 50 ft, unit and job
- Voltage 12 V As sold
- Mounts Tunnel Fixed mount, end not stated
- To fit it Haul-out The boat comes out of the water
- Run limit 3 min In one direction, then fault mode
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: 4 to 16 h Yard: 32 to 70 h Electrician: 2 to 4 h Plus a haul-out.
- Cut, bond and fair the tunnel; fit the gear leg, motor and propeller Yard 32 to 70 h 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 h 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 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?
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 trawler gets full thrust to 37 ft, and an express cruiser to 48 ft.
The table below 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.
| 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 38 ft | 39 to 57 ftfull thrust to about 10 knots at 57 ft | 41 to 45 ftas the 185TT 3.0, class B |
| Houseboat | None | 30 to 42 ftfull thrust to about 10 knots at 42 ft | 36 to 40 ftas the 185TT 3.0, class C |
| Catamaran | 37 to 43 ft | 44 to 64 ftfull thrust to about 10 knots at 64 ft | 36 to 40 ftas the 185TT 3.0, class C |
| Trawler | 32 to 37 ft | 38 to 56 ftfull thrust to about 10 knots at 56 ft | 36 to 40 ftas the 185TT 3.0, class C |
| Motor yacht | 35 to 37 ft | 38 to 56 ftfull thrust to about 10 knots at 56 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 48 ft | 49 to 65 ftfull thrust to about 11 knots at 65 ft | 41 to 45 ftas the 185TT 3.0, class B |
| 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.
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 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 $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. Your own yard will have its own opinion. The cost page builds the same figures line by line.
| Boat length | The unit | Yard labor | Haul-out | Batteries, cable, charger | Other parts | Total |
|---|---|---|---|---|---|---|
| 30 ft | $2,239 | $5,120 to $5,760about 32 hours | $540 to $1,450 | $583 to $717 | $267 to $754 | $8,749 to $10,920 |
| 50 ft | $2,239 | $5,120 to $12,60032 to 70 hours | $990 to $2,410 | $583 to $717 | $267 to $754 | $9,199 to $18,720 |
| 65 ft | $2,239 | $5,120 to $12,60032 to 70 hours | $1,240 to $3,140 | $583 to $717 | $267 to $754 | $9,449 to $19,450 |
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 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.
What else you buy
What follows comes 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 table 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 is the priced parts below, $267 to $754 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 |
|---|---|---|---|
| Tunnel tube | The fiberglass, aluminum or steel pipe the thruster sits in, bonded through the bow. | 589301, 589302 (39 in, 59 in) | $205–$554185 mm fiberglass tunnel tubes up to 60 in (1.5 m) long (VETUS, Sleipner Side-Power, Lewmar), at Fisheries Supply, read 16 October 2026. |
| Fuse holder | The block the ANL fuse bolts into, with a cover. | 589006 (589010 for the T2 fuse) | $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. | Gen 2 ABS 589810 (12 V) or 589830 (24 V), or any manual battery switch | $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. |
| 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. | Lewmar 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. | Lewmar 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. | Lewmar 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. | Lewmar 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.
| Thrust and motor | |
|---|---|
| Thrust | 128 lb (58 kgf) As printed: Thrust: 128 lbs |
| Motor | 3 kW |
| Voltage | 12 V |
| Fitting | |
| Type | Tunnel, fixed mount |
| End of the boat | Not stated |
| Tunnel diameter | 185 mm |
| What it does to the hull | Tunnel bore below the waterline |
| Haul-out to fit it | Yes |
| Maker’s boat length | 36 to 45 ftLewmar's selection chart, by windage; the listing prints none |
| The tunnel | |
| 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) |
| Price and ordering | |
| Price | $2,239 equipment only, a dealer's price, defender.com, 13 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) |
| 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. Lewmar's Gen 2 installation manual |
| The site’s review | Lewmar 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 |
|---|---|---|---|---|---|
| 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 |
- At 12 V: size the cable for your run, or check the battery you have.
What to weigh
Each point names the fact it rests on.
What to weigh
- The boat comes out of the water to fit 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
What the manual and listings say
This is the note we keep on the Lewmar 185TT GEN 2 Tunnel Thruster Package with Joystick, written from the maker’s manual, its product pages and the dealer’s listing.
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 refitting are not covered. Lewmar publishes no boat length. Fisheries Supply's listing for the bare unit says 35 to 45 ft.
Videos
One of Lewmar’s own videos, from its YouTube channel: what changed in the Gen 2 tunnel units. It is the maker’s pitch. Watch it 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 Lewmar’s next sizes in the same line, by thrust.
- One size down: Lewmar 140TT Gen 2 Thruster Package with Joystick and Tunnel, 92 lb, $2,754.
- One size up: Lewmar 185TT GEN 2 Tunnel Thruster, five sizes, 128 to 214 lb, $1,912 to $4,825.
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.
- VETUS Bow Pro 571, 126 lb, $3,794.
- Sleipner SE50/140S, 136 lb, $2,160 to $3,375.
- Max Power CT60 (12 V), 154 lb, $1,719.
Every model with a page here is listed, maker by maker, on the thruster index.