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Max Power · tunnel thruster · bow or stern
Max Power CT325 (24 V): specs, price and the boats it fits
It gives 717 lb (325 kgf) of push. Max Power sells it for boats of 51 to 100 ft. It runs on 24 V.
- Haul-out to install
- DIY 2 of 5: wiring prep only
- 3-year warranty
Quick stats
- Thrust 717 lb 325 kgf, Max Power's rating
- Boat length 51 to 100 ft Max Power's own range
- Price per lb of thrust $9.08 Unit only. $23 to $41 installed
- Voltage 24 V As sold
- Battery at 24 V 1,200 CCA Four batteries, near the thruster
- Run limit 2 to 3 min At a stretch, depending on the air temperature. The motor's S2 rating is 3 min
- To install it Haul-out The boat comes out of the water
- Anodes No US price The parts list names them
About the Max Power CT325 (24 V)
The CT325 is Max Power’s largest DC tunnel thruster: 717 lb of push from twin propellers in a 315 mm tube with a bronze leg, for big motor yachts and deep-keeled sailboats. This is the 24 V version.
Marinedeal lists it at $6,510 for the unit. Add about $1,189 to $2,130 for the tube, a panel, a main switch and a fuse. At 24 V it pulls a lot of current, so the manual asks for a strong bank and very heavy cable; we put batteries, cable and charging at $2,098 to $4,767. See every part.
Read more
Max Power also builds it for 48 V, with roughly half the current. Push in short spells within 2 to 3 minutes. A replacement propeller is about $134. Warranty: two years, three when registered.
Installing it yourself? The installer section has every spec, and the Max Power thruster review sets this model against the rest of the Max Power range.
Where this summary comes from (6 sources, read 12 October 2026)
- Max Power product page
- US dealer listing (price read 12 Oct 2026)
- Max Power CT325 installation manual
- Marinedeal, Max Power thrusters and spare parts (prices read 12 Oct 2026)
- Max Power: founded 1987 in Mandelieu, France; Lalizas Italia
- Max Power Warranty Conditions (three years; transferable; two hours of field labor in year one)
Will the Max Power CT325 (24 V) steer your boat?
80 FT TRAWLER · BOW · 15 KT WIND
Every knot figure here is wind speed, not boat speed or current.
On a 80 ft trawler the Max Power CT325 (24 V) (717 lb) steers her in a 19 knot breeze. Her bow needs about 428 lb from a tunnel to steer her in a 15 knot breeze.
The finder lists it for her.
The Max Power CT325 (24 V) on a trawler, by length
- 25 ft62 kt
- 30 ft52 kt
- 35 ft44 kt
- 40 ft39 kt
- 45 ft35 kt
- 50 ft31 kt
- 55 ft28 kt
- 60 ft26 kt
- 65 ft24 kt
- 70 ft22 kt
- 75 ft21 kt
- 80 ft19 kt
Outlined: the finder does not list it at that length (under 13 kt, far more than she needs, or outside Max Power’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 | 75 to 80 ft | None |
| Houseboat | 55 to 80 ft | None |
| Catamaran | No length. More thrust than the boat needs. | |
| Trawler | 74 to 80 ft | None |
| Motor yacht | 74 to 80 ft | None |
| 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 | No length. More thrust than the boat needs. | |
| Center console | No length. More thrust than the boat needs. | |
The Max Power CT325 (24 V) 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 every kind of boat it fits gets full thrust to 80 ft. The maker gives one range for every boat.
The table tries the Max Power CT325 (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 and the maker lists it for that length.
A boat up to 10 percent past the maker’s range still counts here, as it does in the finder.
It is sized for four 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 |
|---|---|
| 55 ft | $15,997 to $28,657$22 to $40 a lb of thrust |
| 70 ft | $16,247 to $29,387$23 to $41 a lb of thrust |
| 80 ft | $16,407 to $29,867$23 to $42 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 $1,080 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 |
|---|---|---|---|---|---|
| 55 ft | $6,510 | $5,120 to $12,60032 to 70 hours | $1,080 to $2,650 | $2,098 to $4,767 | $1,189 to $2,130 |
| 70 ft | $6,510 | $5,120 to $12,60032 to 70 hours | $1,330 to $3,380 | $2,098 to $4,767 | $1,189 to $2,130 |
| 80 ft | $6,510 | $5,120 to $12,60032 to 70 hours | $1,490 to $3,860 | $2,098 to $4,767 | $1,189 to $2,130 |
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: four 12 V batteries, two strings of two in series, at least 1,200 CCA each (Max Power’s minimum), $1,772 to $3,992 for all four; Max Power’s cable table gives 4/0 to 2 x 3/0 AWG, priced on 4/0 to 2 x 4/0 AWG, the nearest size cut to length: $180 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 of Max Power’s own videos, from its YouTube channel. They play only when you tap. A maker’s video is its pitch, so take any claim back to the figures on this page.
Know before you buy
What sets this model apart, what it costs to keep, and what to weigh.
Price per pound of thrust
$9.08 a lb The unit’s price over its published thrust. The bars are Max Power’s next sizes and the nearest other makers.Controls
Delivered without accessories: the fuse, holder and control panel are bought.
- Max Power 318200, no US price found.
- The control cable your manual names, no US price found.
Anodes
We found its anodes in Max Power’s parts list, with no US price. The parts below name them.
They sit below the waterline, so a change means a haul-out or a diver.
Service and 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.
See Max Power’s warranty Max Power's warranty conditions.Special mentions
Battery: at 24 V it wants four batteries of 1,200 CCA or more, Max Power's figure. The cheapest that meets it is the Dyno Group 8D heavy duty marine starting (flooded), $443.02. A sealed one is the Odyssey Extreme PC1800-FT start / deep cycle, $998.12. Check your own bank.
Charger: a NOCO GEN5X2 two-bank shore charger, $146.41. It is the one our estimate prices.
Max Power 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.
Short pushes only: Max Power rates the motor for 2 to 3 min at a stretch.
Parts for the Max Power CT325 (24 V)
See the Max Power CT325 (24 V) 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 on the maker's site. It has the hull, wiring and fuse figures for this model.
From Max Power’s CT325 installation manual, July 2024, read 25 October 2026.
- In the box
- The manual: "The thruster is delivered without accessories (fuse, fuse holder, control panel)." The motor comes with its relay and the electronic controller, and the leg with its screws, gasket and propellers.
- 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 and the tunnel.
- 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.
In Max Power’s words, from its CT100 and CT125 installation manual, 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 covers these parts as a range, $1,189 to $2,130 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 “Sleipner fiberglass tunnel tube, 300 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. No dealer we read lists a 315 mm tube. This is the 300 mm one, the largest bore listed. No Max Power tube is listed at this bore. This one is another maker's.
Control panel
Ask for Max Power 318200.
Not sold at Fisheries Supply. Ask a Max Power dealer.
Control cable, panel to thruster
Ask for The control cable your manual names.
Not sold at Fisheries Supply. Ask the panel dealer.
Main fuse
Ask for 400 A.
Max Power sizes the fuse on the cable section installed, not on the amperage drawn, in its own words. Buy the type the manual names.
Fuse holder
Ask for The holder for the fuse type your manual names.
Match it to 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”.
The maker asks for an 8 A fuse on the control supply.
Batteries
Fisheries Supply lists it as “Dyno Group 8D heavy duty marine starting (flooded)”.
You need 4, each at 1,200 CCA or more, 2 in series for 24 V, 2 such strings in parallel. 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”.
This is the short run. A longer run takes heavier cable: the wiring calculator sizes yours. You need 5 ft of each color. For about 10 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”.
This is the short run. A longer run takes heavier cable: the wiring calculator sizes yours. 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
The metal that wears away in the water so the drive does not. Max Power calls it “Anode”.
Max Power prints two numbers for this anode: 315300 on its product pages and the CT300 24 V manual, 630506 in the CT325 manual and the 48 V manuals. Confirm with your serial number.
Anode
The metal that wears away in the water so the drive does not. Max Power calls it “Anode”.
Max Power prints two numbers for this anode: 315300 on its product pages and the CT300 24 V manual, 630506 in the CT325 manual and the 48 V manuals. Confirm with your serial number.
Propeller
The propeller on the drive. Max Power calls it “Propeller 315”.
Listed for the bronze leg CT325. Max Power does not say whether the aluminum leg version takes the same propeller.
Propeller shaft seal
It keeps water out of the joint it sits in. Max Power calls it “Propeller Seal”.
Propeller pin (drives the propeller)
The pin that locks the propeller to its shaft. Max Power calls it “Propeller Pin”.
Not listed for the bronze leg CT225; the bronze 250 mm leg on the ECO 150 takes a different pin.
Drive leg (complete)
The leg under the motor that turns the propeller. Max Power calls it “Metal Leg Ct325”.
Drive leg gasket (seals the leg to the tunnel)
The leg under the motor that turns the propeller. Max Power calls it “Leg Gasket”.
Listed for the bronze leg CT325. Max Power does not say whether the aluminum leg version takes the same gasket.
Drive leg seal
The leg under the motor that turns the propeller. Max Power calls it “Seal”.
Inside the boat replacement parts on board
Rubber coupling (flexible link between motor and drive leg)
The leg under the motor that turns the propeller. Max Power calls it “Rubber Coupling PG66”.
Motor brush
Carbon brushes inside the motor. They wear down with use. Max Power calls it “Motor Brushes”.
Max Power lists the brush singly; the motor takes 8. The 48 V CT300 and CT325 manuals list no brushes.
Relay (the motor switch)
A small switch in the motor’s control circuit. Max Power calls it “Relay 24V”.
The 48 V CT125, CT300 and CT325 manuals also print this 24 V relay.
Relay and control box assembly
A small switch in the motor’s control circuit. Max Power calls it “Relay and Control box Assembly”.
Controller (control box)
The electronics that run the motor when you press the panel. Max Power calls it “Electronic Controller”.
Main fuse (400 A)
The main fuse at the battery, in the rating the maker gives. Max Power calls it “Fuse 400A”.
For the 24 V units. The holder is 35018 (T2). The 48 V units take a 325 A ANL fuse, 636345.
Main fuse holder
The main fuse at the battery, in the rating the maker gives. Max Power calls it “Fuse Holder T2”.
Control panel, on/off dual joystick (bow and stern)
The control at the helm. Max Power calls it “Dual joystick, black (318205 gray)”.
The gray one is 318205.
Control panel, on/off single joystick
The control at the helm. Max Power calls it “Single joystick, black (318203 gray)”.
The gray one is 318203.
Control panel, on/off touch panel
The control at the helm. Max Power calls it “Touch panel, two buttons, black (318201 gray)”.
The gray one is 318201.
Motor heat sensor
The electric motor that turns the propeller. Max Power calls it “Heat sensor”.
Replacement motor
The electric motor that turns the propeller. Max Power calls it “Electric Motor CT325”.
Max Power's CT300 page and manual give this same number for the CT300 motor.
No part matches. Try the number without spaces, or the part’s name.
The install parts are matched to Max Power’s own figures and priced at Fisheries Supply, with the battery cable at Defender, cut to length.
Spare part numbers come from Max Power’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 Max Power CT300 (24 V) 661 lb
- Size up Max Power CT550 (three-phase) 992 lb
- Aluminum leg Max Power CT325 (aluminum leg) 717 lb
- Other maker Sleipner SE300/300TC 750 lb · $12,850
- Other maker VETUS Bow Pro Boosted 300 661 lb · $10,161
- Other maker Lewmar 300TT GEN 2 two sizes, 550 to 616 lb · $7,339 to $10,499
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 | 717 lb (325 kgf) As printed: 325 kg / 715 lbs |
| Motor | 19.69 kW |
| Voltage | 24 V |
| Run limit | 2 to 3 min at a stretch, depending on the air temperature. The motor's S2 rating is 3 min |
| Installation | |
| Type | Tunnel, fixed mount |
| End of the boat | Bow or stern |
| Tunnel diameter | 315 mm |
| What it does to the hull | Tunnel bore below the waterline |
| Haul-out to install it | Yes |
| Maker’s boat length | 51 to 100 ft |
| Price and ordering | |
| Price | $6,510 equipment only, a dealer's price, marinedeal.com, 26 October 2026 |
| Part number | 42542Duo propeller, bronze drive leg, 24 V |
| Documents | |
| Manual | Installation manual (PDF)on the maker's site |
| The site’s review | Max Power thruster review |
Every published figure the site holds for the Max Power CT325 (24 V), 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 | 980 Ameasured draw | 4/0 AWG for up to 16 ft of cable counted out and back. Longer runs take heavier cableCT325 installation manual | 400 ACT325 manual | 2,400 CCA minimum, as the manual gives 2400 CCA maximum total output, 165 Ah for 10 minutes a dayMax Power installation manual CT325 | 2 to 3 min at a stretch, depending on the air temperature. The motor's S2 rating is 3 minCT325 manual |
The Max Power CT325 (24 V)’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
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).
Our notes from the manual and listings
In the box: Delivered without accessories: the fuse, holder and control panel are bought.
Our note
The biggest electric tunnel unit with a dealer price, 325 kg in a 315 mm tunnel with a bronze leg. It ships by truck freight. Its rating assumes a tunnel one diameter below the waterline and no longer than twice its diameter. That condition is the product page's own. The product page prints no run time. 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.
Where each point above comes from
- Max Power 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
Not sure this is the one? The thruster finder asks about your boat and prices every unit that fits.