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Thruster specs
Lewmar 140TT Kit: specs, price and the boats it fits
This kit pairs the 140TT 2.0 kW thruster with its controls: a locking joystick, 7 m of control cable, a fuse and its holder. The tube is the one big piece left to buy. It gives 82 lb of push on 12 V, and Lewmar’s chart sizes it for boats of about 30 to 35 ft.
Defender charges $1,965 for the kit, against $1,486 for the bare thruster, so the controls cost the difference. Lippert, Lewmar’s owner, asks well over that on its own store. The tube and the battery switch come to about $257 to $526 more, and a starting battery near the bow, with its cable and a charger, about $583 to $717. Here is everything.
Older Lewmar controllers had a bad name: owners told of thrusters that switched on by themselves. The Gen 2 controls in this kit are Lewmar’s answer. The motor brushes are the part that wears, and Lewmar sells the whole motor rather than brushes. Warranty: three years, one on the motor and controls.
Fitting it yourself? The installer section has every spec, and the Lewmar thruster review sets this model against the rest of the Lewmar range.
Where this summary comes from (9 sources, read 13 October 2026)
- Defender listing (the database’s price)
- Lippert store, 140TT kit with joystick (price read 2 Oct 2026)
- Lewmar Thruster Selection Guide (boat length by windage)
- Trawler Forum, 2017 to 2020: older Lewmar controllers running on their own
- Trawler Forum, 2018 to 2020: Lewmar controller failures
- Tugnuts, 2025: a Cutwater C-32’s 140TT motor, sold only as an assembly
- 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 82 lb 37 kgf, Lewmar's rating
- Boat length 30 to 35 ft Lewmar's chart, by windage. See below
- Price $1,965 full kit, defender.com, 13 October 2026
- Fitted by a yard $8,635 to $13,778 Our estimate at 40 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 sailboat gets full thrust to 30 ft, and a center console to 40 ft.
The table below tries the Lewmar 140TT Tunnel Thruster Kit 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 | 25 to 30 ft | 31 to 46 ftfull thrust to about 10 knots at 46 ft | 30 to 35 ftas the 140TT 2.0, class B |
| Houseboat | None | 30 to 34 ftfull thrust to about 10 knots at 34 ft | 30 to 30 ftas the 140TT 2.0, class C |
| Catamaran | 30 to 34 ft | 35 to 52 ftfull thrust to about 10 knots at 52 ft | 30 to 30 ftas the 140TT 2.0, class C |
| Trawler | 25 to 30 ft | 31 to 45 ftfull thrust to about 10 knots at 45 ft | 30 to 30 ftas the 140TT 2.0, class C |
| Motor yacht | None | 35 to 45 ftfull thrust to about 10 knots at 45 ft | Off the chart |
| 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 | 32 to 38 ft | 39 to 58 ftfull thrust to about 10 knots at 58 ft | 30 to 35 ftas the 140TT 2.0, class B |
| Center console | 35 to 40 ft | None | 30 to 35 ftas the 140TT 2.0, class A |
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 140TT Tunnel Thruster Kit is not on the chart by name. Lewmar rates it at the same 82 lb (37 kgf) as the 140TT 2.0. 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 seven 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 $450 to $2,800 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 |
|---|---|---|---|---|---|---|
| 25 ft | $1,965 | $5,120 to $5,760about 32 hours | $450 to $1,210 | $583 to $717 | $257 to $526 | $8,375 to $10,178 |
| 40 ft | $1,965 | $5,120 to $8,64032 to 48 hours | $710 to $1,930 | $583 to $717 | $257 to $526 | $8,635 to $13,778 |
| 58 ft | $1,965 | $5,120 to $12,60032 to 70 hours | $1,130 to $2,800 | $583 to $717 | $257 to $526 | $9,055 to $18,608 |
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 270 CCA (Lewmar’s minimum), $257 for the battery; Lewmar’s cable table gives 3/0 AWG, priced on 4/0 AWG, the nearest size cut to length: $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 fuse and fuse holder, a 7 m control cable and a locking joystick, 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, $257 to $526 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. | 589101, 589102, 589103 (30 in, 39 in, 59 in) | $221–$419140 mm fiberglass tunnel tubes up to 60 in (1.5 m) long (Lewmar), 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 | 82 lb (37 kgf) As printed: 37 kgf |
| Motor | 2 kW |
| Voltage | 12 V |
| Fitting | |
| Type | Tunnel, fixed mount |
| End of the boat | Not stated |
| Tunnel diameter | 140 mm |
| What it does to the hull | Tunnel bore below the waterline |
| Haul-out to fit it | Yes |
| Maker’s boat length | 30 to 35 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 | $1,965 full kit, a dealer's price, defender.com, 13 October 2026 |
| Part number | 591458Kit (unit+joystick+cable; tunnel separate), 12 V |
| 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 | 270 Anominal draw | 3/0 AWG, the one size Lewmar gives for this model, for any run up to 45 ft of cable counted out and backGen 2 installation manual, Iss.3 | 200 AGen 2 installation manual, Iss.3 | Crank capacity at least the 270 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: 30 to 35 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 140TT Tunnel Thruster Kit, written from the maker’s manual, its product pages and the dealer’s listing.
In the box: This package adds the fuse and fuse holder, a 7 m control cable and a locking joystick.
Our note
The 2.0 kW 140TT as a kit: the thruster, fuse and holder, 7 m of control cable and a locking joystick, with the tunnel sold separately. The Gen 2 manual rates it 37 kgf (82 lb), with a composite gearbox, 13 kg and a 200 A fuse.
It gives 270 A at 12 V on at least 70 mm² cable to 14 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 for any unit. The same kit is dearer at Lippert's own store than at Defender.
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
Lewmar also sells this thrust built another way. Each has its own page:
- The unit alone: Lewmar 140TT Tunnel Thruster, $1,486.
These are Lewmar’s nearest sizes by thrust, in any of its lines.
- One size down: Lewmar 125TT Tunnel Thruster, 77 lb, $1,846.
- One size up: Lewmar 140TT Gen 2 Thruster Package with Joystick and Tunnel, 92 lb, $2,754.
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 361, 79 lb, $3,188.
- Max Power CT35, 77 lb, $1,276.
- Sleipner SE30/125S DC, 88 lb, $1,755.
Every model with a page here is listed, maker by maker, on the thruster index.