We may earn a referral commission from some links on this page. It doesn't change your price or our recommendations.
Lewmar · tunnel thruster · bow or stern
Lewmar 250TT GEN 2: specs, price and the boats it fits
It gives 308 lb (140 kgf) of push. It runs on 24 V.
- Haul-out to install
- DIY 2 of 5: wiring prep only
- 3-year warranty
Quick stats
- Thrust 308 lb 140 kgf, Lewmar's rating
- Boat length Not published See our sizing below
- Price per lb of thrust $16.07 Unit only. $42 to $76 installed
- Voltage 24 V As sold
- Battery at 24 V 500 CCA Two batteries, 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 $52.32 A change, at Fisheries Supply
About the Lewmar 250TT GEN 2
The 250TT Gen 2 is the first Lewmar tunnel with twin counter-rotating propellers, built for big cruisers and trawlers. This is the 8.0 kW motor on 24 V with the bronze gearbox. The Gen 2 manual rates it at 308 lb of push and 46 kg, and gives it a 400 A fuse.
Defender, Fisheries and Lippert’s own store list no Gen 2 250TT, so the price here is Marinedeal’s, $4,949. Its listing prints 353 lb, more than the manual’s figure, so we follow the manual. The tube, the controls, the fuse and the battery switch are about $635 to $1,634 more, and a 24 V bank near the bow is the larger cost. See every part.
Read more
Lewmar also makes this motor with an aluminum gearbox, and a 48 V build at 9.6 kW; Marinedeal does not list them. The run rule is the same as the smaller units: three minutes one way and it goes into fault mode. Motors and controls carry one year of warranty inside the three.
The full spec sheet for a yard sits lower down, and the Lewmar thruster review covers Lewmar’s whole range.
Where this summary comes from (4 sources, read 15 October 2026)
- Marinedeal, Lewmar 250TT 8 kW 24 V Gen 2 (590024) listing
- 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 250TT GEN 2 Tunnel Thruster steer your boat?
70 FT TRAWLER · BOW · 15 KT WIND
Every knot figure here is wind speed, not boat speed or current.
On a 70 ft trawler the Lewmar 250TT GEN 2 Tunnel Thruster (308 lb) steers her in a 15 knot breeze. Her bow needs about 328 lb from a tunnel to steer her in a 15 knot breeze. Its 308 lb lands within 15 percent of that figure, which this site counts as enough.
The finder lists it for her.
The Lewmar 250TT GEN 2 Tunnel Thruster on a trawler, by length
- 25 ft40 kt
- 30 ft34 kt
- 35 ft29 kt
- 40 ft26 kt
- 45 ft23 kt
- 50 ft20 kt
- 55 ft18 kt
- 60 ft17 kt
- 65 ft16 kt
- 70 ft15 kt
- 75 ft14 kt
- 80 ft12.7 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 |
|---|---|---|
| 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 | 49 to 70 ft | 71 to 80 ftfull thrust to about 13 knots at 80 ft |
| Houseboat | 37 to 52 ft | 53 to 59 ftfull thrust to about 13 knots at 59 ft |
| Catamaran | 56 to 80 ft | None |
| Trawler | 49 to 70 ft | 71 to 79 ftfull thrust to about 13 knots at 79 ft |
| Motor yacht | 49 to 70 ft | 71 to 79 ftfull thrust to about 13 knots at 79 ft |
| 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 | 62 to 65 ft | None |
| Center console | No length. More thrust than the boat needs. | |
The Lewmar 250TT GEN 2 Tunnel Thruster against each kind of boat, in a 15 knot wind. Our sizing, from the finder’s own rules.
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 52 ft, and a catamaran to 80 ft.
The table tries the Lewmar 250TT GEN 2 Tunnel 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 at the bow. Lewmar publishes no boat length, so thrust alone decides.
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 |
|---|---|
| 37 ft | $12,383 to $16,501$40 to $54 a lb of thrust |
| 60 ft | $12,883 to $23,371$42 to $76 a lb of thrust |
| 80 ft | $13,213 to $24,331$43 to $79 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 $660 to $3,860 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 |
|---|---|---|---|---|---|
| 37 ft | $4,949 | $5,120 to $6,84032 to 38 hours | $660 to $1,790 | $1,019 to $1,288 | $635 to $1,634 |
| 60 ft | $4,949 | $5,120 to $12,60032 to 70 hours | $1,160 to $2,900 | $1,019 to $1,288 | $635 to $1,634 |
| 80 ft | $4,949 | $5,120 to $12,60032 to 70 hours | $1,490 to $3,860 | $1,019 to $1,288 | $635 to $1,634 |
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 24 V: two 12 V batteries in series, at least 500 CCA each (Lewmar’s minimum), $513 for both; Lewmar’s cable table gives 2 x 4/0 AWG: $360 to $629 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 one 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
$16.07 a lb The unit’s price over its published thrust. The bars are Lewmar’s next sizes and the nearest other makers.Controls
The solenoid, the ICU control box and a 2 m motor loom are in the box. The panel, its loom, the fuse and holder are bought.
- Lewmar Gen 2 single joystick control (589268), $373.53 at Fisheries Supply.
- Lewmar Gen 2 AUX control loom, 7 m (589802), $69.10 at Fisheries Supply.
Anodes
$52.32 a change- Anode kit (589550): $52.32 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 24 V it wants two batteries of 500 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 publishes no boat length for it. The boat table is our sizing alone.
Short pushes only: Lewmar rates the motor for 3 min at a stretch.
Parts for the Lewmar 250TT GEN 2 Tunnel Thruster
See the Lewmar 250TT GEN 2 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.
- 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, $635 to $1,634 at Fisheries Supply’s prices on 30 September 2026 and 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, 250 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 panel
Fisheries Supply lists it as “Lewmar Gen 2 single joystick control”.
Check the listing or the box before you buy: the maker does not say whether one is included.
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.
Main fuse
Ask for 400 A (Lewmar 589010).
Lewmar's figure for the 590024, TT 250 8.0 24v (bronze) (Gen 2 installation manual, Iss.3). Not listed at Fisheries Supply; ask a Lewmar dealer.
Fuse holder
Ask for Lewmar fuse holder 589013 (T2).
Ask the dealer who sells the fuse.
Battery switch
Fisheries Supply lists it as “HD-Series 600 A battery switch, on/off”.
Rated at or above the 400 A main fuse. 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”.
You need 2, each at 500 CCA or more, in series for 24 V. 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, twice over (20 ft of each). 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”.
You need 2 bags. 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, 250TT and 300TT”.
Fisheries Supply lists it as a pair.
Propeller washer
The propeller on the drive. Lewmar calls it “PLASTIC WASHER”.
Propeller, left hand
The propeller on the drive. Lewmar calls it “LH PROPELLER & WASHER”.
The 250TT runs two counter-rotating propellers. Order the right and left hand separately.
Propeller, right hand
The propeller on the drive. Lewmar calls it “RH PROPELLER & WASHER”.
The 250TT runs two counter-rotating propellers. Order the right and left hand separately.
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 4/5/6.0 24V; SOLENOID 8.0”. This one is for the 24 V version.
For the 24 V units only. The 12 V 185TT units take a different solenoid.
Main fuse, 400 A
The main fuse at the battery, in the rating the maker gives. Lewmar calls it “400 A ANL TYPE FUSE”.
The manual gives 400 A for the 300TT 15.0 kW 48 V (590035) and for the aluminum 300TT 10.8 kW, but 500 A for the bronze 10.8 kW (590034).
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 8.0KW 24V”.
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 185TT GEN 2 five sizes, 128 to 214 lb · $1,912 to $4,825
- Size up Lewmar 300TT GEN 2 two sizes, 550 to 616 lb · $7,339 to $10,499
- Other maker VETUS Bow 125 two sizes, 275 to 308 lb · $4,130
- Other maker Sleipner SE120/215T-24V 306 lb · $4,905
- Other maker Max Power CT125 (24 V) 254 lb · $2,947
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 | 308 lb (140 kgf) As printed: "590024 TT 250 8.0 24v 250 8.0 10.8 24v Bronze Twin CR 5 Blade 140 308 46 101 400A 589010" - Lewmar Gen 2 TT manual 559231 Iss.3, section 6 |
| Motor | 8 kW |
| Voltage | 24 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 | 250 mm |
| What it does to the hull | Tunnel bore below the waterline |
| Haul-out to install it | Yes |
| Maker’s boat length | Not published |
| Price and ordering | |
| Price | $4,949 equipment only, a dealer's price, marinedeal.com, 26 October 2026 |
| Part number | 5900248.0kW 24 V, bronze gearbox, 24 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 250TT GEN 2 Tunnel Thruster, 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 |
|---|---|---|---|---|---|
| 24 V | 500 Anominal draw | 2 x 4/0 AWG per leg, the one size Lewmar gives for this model, for any run up to 65 ft of cable counted out and backGen 2 installation manual, Iss.3 | 400 AGen 2 installation manual, Iss.3 | Crank capacity at least the 500 A draw, Lewmar's ruleLewmar Gen 2 installation manual | 3 min in one direction, then fault modeGen 2 installation manual |
The Lewmar 250TT GEN 2 Tunnel Thruster’s draw, cable, fuse, battery and run limit, as the maker publishes them.
- At 24 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: The solenoid, the ICU control box and a 2 m motor loom are in the box. The panel, its loom, the fuse and holder are bought.
Our note
The 250TT Gen 2 at 8.0 kW and 24 V: twin counter-rotating propellers in a 250 mm tunnel. The Gen 2 manual rates it 140 kgf (308 lb), 46 kg, with a 400 A fuse.
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 publishes no boat length for it. The boat table is our sizing alone.The maker's documents, as the database records them
Not sure this is the one? The thruster finder asks about your boat and prices every unit that fits.