Boat Thruster Guide

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

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Thruster specs

Max Power CT125 (24 V): specs, price and the boats it fits

The CT125 is the 24 V partner to the CT100: twin propellers in a 185 mm tube give 254 lb of push for motor boats and sailboats of about 35 to 60 ft. On 24 V it pulls far less current than the 12 V CT100, which keeps the cable to the bow manageable.

Marinedeal’s price is $2,947. Expect about $541 to $1,369 for the tube, a helm panel, a main switch and a fuse. Max Power’s current manual asks for a strong 24 V bank, two pairs of batteries by our pricing; with cable and a charger, about $2,013 to $2,668. See the parts list.

It shares the CT100’s sealed composite leg, so there is no zinc to change. Owners of Max Power units most often report the heat sensor and the relay. Push in short spells within the manual’s 2 to 3 minutes. A replacement leg is about $699. Warranty: two years, three if registered.

The full spec sheet for a yard sits lower down, and the Max Power thruster review covers Max Power’s whole range.

Where this summary comes from (7 sources, read 12 October 2026)

Key facts

  • DIY level 2 of 5 Wiring prep only
  • Thrust 254 lb 115 kgf, Max Power's rating
  • Boat length 35 to 60 ft Max Power's product page
  • Price $2,947 equipment only, marinedeal.com, 15 September 2026
  • Fitted by a yard $11,701 to $22,234 Our estimate at 55 ft, unit and job
  • Voltage 24 V As sold
  • Mounts Tunnel Fixed mount, end not stated
  • To fit it Haul-out The boat comes out of the water
  • Run limit 2 to 3 min At a stretch, depending on the air temperature. The motor's S2 rating is 3 min

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 Max Power says 35 to 60 ft From Max Power's product page. The listing prints none
What our sizing says 39 to 65 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 houseboat gets full thrust to 39 ft, and an express cruiser to 65 ft.

The table below tries the Max Power CT125 (24 V) 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. Max Power's own figures are in the opening lines.

The Max Power CT125 (24 V) 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 44 to 53 ft 54 to 80 ftfull thrust to about 10 knots at 80 ft
Houseboat 33 to 39 ft 40 to 59 ftfull thrust to about 10 knots at 59 ft
Catamaran 50 to 61 ft 62 to 80 ftfull thrust to about 12 knots at 80 ft
Trawler 44 to 53 ft 54 to 79 ftfull thrust to about 10 knots at 79 ft
Motor yacht 44 to 53 ft 54 to 79 ftfull thrust to about 10 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 56 to 65 ft None
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.

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 $590 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. Your own yard will have its own opinion. The cost page builds the same figures line by line.

The Max Power CT125 (24 V) 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
33 ft $2,947 $5,120 to $5,760about 32 hours $590 to $1,590 $2,013 to $2,668 $541 to $1,369 $11,211 to $14,334
55 ft $2,947 $5,120 to $12,60032 to 70 hours $1,080 to $2,650 $2,013 to $2,668 $541 to $1,369 $11,701 to $22,234
80 ft $2,947 $5,120 to $12,60032 to 70 hours $1,490 to $3,860 $2,013 to $2,668 $541 to $1,369 $12,111 to $23,444

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 24 V: four 12 V batteries, two strings of two in series, at least 1,000 CCA each (Max Power’s minimum), $1,772 to $2,208 for all four; Max Power’s cable table gives 1/0 to 3/0 AWG, priced on 1/0 to 4/0 AWG, the nearest size cut to length: $95 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 Max Power’s CT100 and CT125 installation manual, July 2024, read 30 September 2026.

In the box
The motor with its relay, the electronic controller, the composite leg with screws and gasket, two propellers. "The thruster is delivered without accessories (fuse, fuse holder, control panel)."
Bought separately
The fuse and holder, a manual battery isolator and an electric one, the control panel, an 8 A control fuse, a breaker on the DC panel, the cable, the tunnel. No anode on the composite leg.
Charging
Max Power is the one maker that asks for both: the engine's alternator and a charger. A dedicated bank is optional and goes "as close as possible to the thruster". It wants starting-type batteries with high cold cranking amps.

The manual’s words, page 3: “The batteries used by the thruster must be charged by both the main engine's alternator and an appropriate battery charger.”

The “other parts” line in the estimate above is the priced parts below, $541 to $1,369 at Fisheries Supply’s prices on 30 September 2026. The batteries, cable and charger have a line of their own.

Parts the Max Power CT125 (24 V)’s box leaves to you, from the makers’ manuals read 30 September 2026. “What to ask for” is Max Power’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
Tunnel tube The fiberglass, aluminum or steel pipe the thruster sits in, bonded through the bow. Max Power names none $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.
Control panel The buttons or joystick at the helm. One helm, one panel: a second steering station needs a panel of its own. A Max Power control panel, sold with its own guide $219–$374Side-Power touch panel and single joystick, VETUS push-button panel, Lewmar single joystick, at Fisheries Supply.
Control cable, panel to motor The thin cable from the helm to the motor. Sold by length. Max Power names none $29–$173Side-Power control cables, VETUS panel cables, Lewmar Gen 2 connecting cables, at Fisheries Supply.
Main fuse A slow-blow fuse of the ANL type at the battery, in the size the maker prints for the model. Ceramic or ANL, the rating in the manual's table $18–$57Side-Power ANL fuses, Blue Sea ANL fuses, at Fisheries Supply, read 16 October 2026.
Fuse holder The block the ANL fuse bolts into, with a cover. Holder T1 OPTI3119 or T2 $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. A manual isolator, plus the electric isolator OPTI3160/3 (12 V) or OPTI3170/3 (24 V) $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.
Control-circuit fuse and switch A small fuse, and often a switch, on the thin wire that powers the panel or control box. An 8 A fuse on the control box feed $8–$12Blue Sea in-line ATO fuse holders, 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. Max Power 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. Max Power 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. Max Power 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. Max Power 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 Max Power CT125 (24 V), every published figure the site holds, with where each came from.
Thrust and motor
Thrust 254 lb (115 kgf) As printed: 115 kg / 253 lbs
Motor8.58 kW
Voltage24 V
Fitting
TypeTunnel, fixed mount
End of the boatNot stated
Tunnel diameter185 mm
What it does to the hullTunnel bore below the waterline
Haul-out to fit itYes
Maker’s boat length35 to 60 ftMax Power's product page; the listing prints none
The tunnel
Depth below the waterline The minimum acceptable position is 139 mm below the waterline. Ideally the top of the installed tunnel sits 185 mm below it. Shallower than the ideal, the manual says, performance falls off progressively. CT100 and CT125 installation manual (July 2024)
Price and ordering
Price $2,947 equipment only, a dealer's price, marinedeal.com, 15 September 2026
Part number 42535Duo propeller, composite drive leg, 24 V
Documents
Manual Installation manual (PDF)on the maker's site
Warranty Max Power's website gives 3 years. Its manual gives 2, and 1 more if the warranty is registered within 3 months of installation. Outside pleasure craft it is 6 months. It transfers to the next owner, and the first year covers up to 2 hours of labor in the field. Max Power's warranty conditions
The site’s reviewMax Power 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 Max Power CT125 (24 V)’s draw, cable, fuse, battery and run limit, as the maker publishes them.
Voltage Draw Maker’s cable Fuse Battery Run limit
24 V 430 Ameasured draw 1/0 AWG for up to 16 ft of cable counted out and back. Longer runs take heavier cableCT100/CT125 installation manual 200 A ceramic or 225 A ANLCT100 / CT125 manual 2,000 CCA minimum, as maintenance-free "starting" type batteries, with high CCA outputs; the manual's example is the Exide Maxxima 900, 800 CCA and 55 Ah, with 2000 CCA total outputMax Power installation manual CT100 / CT125, serials from 83338, July 2024 2 to 3 min at a stretch, depending on the air temperature. The motor's S2 rating is 3 minCT100 / CT125 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
  • Max Power's product page puts it on boats of 35 to 60 ft. Its selection chart puts it on 35 to 46 ft boats with heavy displacement and high windage, and out to 60 ft on light ones. The listing the price comes from prints no range. The boat table is our sizing alone.Max Power's product page and selection chart, read 15 September 2026

What the manual and listings say

This is the note we keep on the Max Power CT125 (24 V), written from the maker’s manual, its product pages and the dealer’s listing.

In the box: Delivered without accessories: the fuse, holder and control panel are bought.

Our note

Twin props in a 185 mm tunnel. Max Power's selection chart puts it on 35 to 46 ft boats with heavy displacement and high windage, and out to 60 ft on light ones. The July 2024 manual rates the motor at two to three minutes' running, depending on the air temperature. It measures 430 A at 22 V against its own fuse-table maximum of 330 A.

It wants the tunnel at least 139 mm below the waterline. The manual's warranty is two years, three if registered within three months of purchase. The website says three. Hauling the boat is excluded either way. Standard on/off units are made for lead-acid, AGM or gel batteries. Max Power's FAQ says lithium will damage them unless specified correctly. Max Power publishes no price and sells through dealers.

The figure here is one US dealer's listing for the unit alone. The same dealer's package with a control panel and 25 m of control cable costs more.

Videos

One of Max Power’s own videos, from its YouTube channel: a short reel of the range. 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.

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

Other sizes and close alternatives

Max Power also sells this thrust built another way. Each has its own page:

These are Max Power’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.