Boat Thruster Guide

What to buy, what it costs, what it takes to fit

We may earn a referral commission from some links on this page. It doesn't change your price or our recommendations.

Thruster specs

Lewmar 110TT 1.5 Complete Package: specs, price and boat fit

This is the 110TT in a box with most of what the job needs: the thruster, a simple joystick, 10 m of cable, the fuse and its holder, and a short length of tube. It gives 62 lb of push on 12 V from one propeller, sized for small boats that only need a nudge at the dock.

Defender’s price for the package is $1,339, against $936 for the thruster kit on its own. What it leaves out is the battery switch Lewmar requires, about $35 to $107, and a starting battery close to the bow. That battery, its cable and a charger come to about $498 to $574 by our pricing. See the parts list.

Pushing one way for more than three minutes puts the system in fault mode, so use short bursts. Its composite hub carries no zinc anode, so there is none to replace. On paper the warranty is three years, yet Lewmar limits motors and electronic controls to one, and claims go back through the store that sold it.

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 (5 sources, read 13 October 2026)

Key facts

  • DIY level 2 of 5 Wiring prep only
  • Thrust 62 lb 28 kgf, Lewmar's rating
  • Boat length Not published See our sizing below
  • Price $1,339 full kit, defender.com, 13 October 2026
  • Fitted by a yard $7,612 to $9,470 Our estimate at 35 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 2 of 5: Wiring prep only. The yard fits the unit and does the hull work; you do the wiring prep.

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 DIY

You: 4 to 16 h Yard: 32 to 70 h Electrician: 2 to 4 h Plus a haul-out.

  1. 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.
  2. 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.
  3. 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?

What Lewmar says No boat length Our sizing is the guide here
What our sizing says 26 to 37 ft Full thrust in 15 knots. The longest boat of each kind is in the table.

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 26 ft, and a center console to 37 ft.

The table below tries the Lewmar 110TT 1.5 Bow Thruster Complete Package 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.

The Lewmar 110TT 1.5 Bow Thruster Complete Package against each kind of boat, in a 15 knot wind. Our sizing, from the finder’s own rules.
Boat Full thrust at 15 knotsStill 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 23 to 26 ft 27 to 39 ftfull thrust to about 10 knots at 39 ft
Houseboat No length. Short of the thrust the boat needs.
Catamaran 30 ft only 31 to 44 ftfull thrust to about 10 knots at 44 ft
Trawler 23 to 26 ft 27 to 38 ftfull thrust to about 10 knots at 38 ft
Motor yacht None 35 to 38 ftfull thrust to about 10 knots at 38 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 28 to 33 ft 34 to 49 ftfull thrust to about 10 knots at 49 ft
Center console 32 to 37 ft 38 to 40 ftfull thrust to about 14 knots at 40 ft

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.

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 $410 to $2,360 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.

The Lewmar 110TT 1.5 Bow Thruster Complete Package fitted by a yard, from the shortest to the longest boat it is sized for. Our estimate.
Boat length The unit Yard labor Haul-out Batteries, cable, charger Other parts Total
23 ft $1,339 $5,120 to $5,760about 32 hours $410 to $1,110 $498 to $574 $35 to $107 $7,402 to $8,890
35 ft $1,339 $5,120 to $5,760about 32 hours $620 to $1,690 $498 to $574 $35 to $107 $7,612 to $9,470
49 ft $1,339 $5,120 to $12,60032 to 70 hours $970 to $2,360 $498 to $574 $35 to $107 $7,962 to $16,980

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 215 CCA (Lewmar’s minimum), $257 for the battery; Lewmar’s cable table gives 1/0 AWG: $95 to $171 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
A simple joystick, 10 m of cable, the fuse holder, a 200 A ANL fuse and a 0.75 m tunnel, 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, $35 to $107 at Fisheries Supply’s prices on 30 September 2026. The batteries, cable and charger have a line of their own.

Parts the Lewmar 110TT 1.5 Bow Thruster Complete Package’s box leaves to you, from the makers’ manuals read 30 September 2026. “What to ask for” is Lewmar’s own part or model where its manual names one, otherwise the dealer’s item.
Part What it is What to ask for Dealer price
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.

The Lewmar 110TT 1.5 Bow Thruster Complete Package, every published figure the site holds, with where each came from.
Thrust and motor
Thrust 62 lb (28 kgf) As printed: 62 lbs
Motor1.5 kW
Voltage12 V
Fitting
TypeTunnel, fixed mount
End of the boatNot stated
Tunnel diameter110 mm
What it does to the hullTunnel bore below the waterline
Haul-out to fit itYes
Maker’s boat lengthNot published
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 $1,339 full kit, a dealer's price, defender.com, 13 October 2026
Part number 591102Complete Package w/ Tube/Joystick/Cable, 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 reviewLewmar 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.

The Lewmar 110TT 1.5 Bow Thruster Complete Package’s draw, cable, fuse, battery and run limit, as the maker publishes them.
Voltage Draw Maker’s cable Fuse Battery Run limit
12 V 215 Anominal draw 1/0 AWG, the one size Lewmar gives for this model, for any run up to 39 ft of cable counted out and backGen 2 installation manual, Iss.3 200 AGen 2 installation manual, Iss.3 Crank capacity at least the 215 A draw, Lewmar's ruleLewmar Gen 2 installation manual 3 min in one direction, then fault modeGen 2 installation manual

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 publishes no boat length for it. The boat table is our sizing alone.The maker's documents, as the database records them

What the manual and listings say

This is the note we keep on the Lewmar 110TT 1.5 Bow Thruster Complete Package, written from the maker’s manual, its product pages and the dealer’s listing.

In the box: This package adds a simple joystick, 10 m of cable, the fuse holder, a 200 A ANL fuse and a 0.75 m tunnel.

Our note

The 110TT as a complete package: the thruster, a simple joystick, 10 m of cable, a 200 A ANL fuse holder and a 0.75 m tunnel section. The Gen 2 manual rates it 28 kgf (62 lb), with a composite gearbox, 10 kg and a 200 A fuse.

It gives 215 A at 12 V on at least 50 mm² cable to 12 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.

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.

Lewmar’s own video, on Lewmar’s YouTube channel. The picture is a still from it.

Other sizes and close alternatives

These are Lewmar’s next sizes in the same line, by thrust.

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.

Compare them side by side

Every model with a page here is listed, maker by maker, on the thruster index.

Where to go next

The specs are the maker’s and the dealers’, on the dates shown. The sizing and the costs are our arithmetic, done without seeing your boat.