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Thruster specs
Max Power CT325 (24 V): specs, price and the boats it fits
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.
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.
Fitting 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)
Key facts
- DIY level 2 of 5 Wiring prep only
- Thrust 717 lb 325 kgf, Max Power's rating
- Boat length Not published See our sizing below
- Price $6,510 equipment only, marinedeal.com, 15 September 2026
- Fitted by a yard $16,247 to $29,387 Our estimate at 70 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 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 houseboat gets full thrust to 67 ft, and a sailboat to 80 ft.
The table below 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. Max Power publishes no boat length, so thrust alone decides.
| 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 67 ft | 68 to 80 ftfull thrust to about 13 knots at 80 ft |
| 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. | |
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 four 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 $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. 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 |
|---|---|---|---|---|---|---|
| 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 | $15,997 to $28,657 |
| 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 | $16,247 to $29,387 |
| 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 | $16,407 to $29,867 |
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 1,200 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.
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, $1,189 to $2,130 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. | Max Power names none | $852–$1,315300 mm fiberglass tunnel tubes up to 60 in (1.5 m) long (Sleipner Side-Power), at Fisheries Supply, read 16 October 2026. No dealer we read lists a 315 mm tube. This is the 300 mm price, the largest bore listed. |
| 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.
| Thrust and motor | |
|---|---|
| Thrust | 717 lb (325 kgf) As printed: 325 kg / 715 lbs |
| Motor | 19.69 kW |
| Voltage | 24 V |
| Fitting | |
| Type | Tunnel, fixed mount |
| End of the boat | Not stated |
| Tunnel diameter | 315 mm |
| What it does to the hull | Tunnel bore below the waterline |
| Haul-out to fit it | Yes |
| Maker’s boat length | Not published |
| 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 | $6,510 equipment only, a dealer's price, marinedeal.com, 15 September 2026 |
| Part number | 42542Duo propeller, bronze 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 review | Max 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.
| 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 |
- At 24 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
- Max Power 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 Max Power CT325 (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
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.
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.
Other sizes and close alternatives
Max Power also sells this thrust built another way. Each has its own page:
- Aluminum leg: Max Power CT325 (aluminum leg).
These are Max Power’s next sizes in the same line, by thrust.
- One size down: Max Power CT300 (24 V), 661 lb.
- One size up: Max Power CT550 (three-phase), 992 lb.
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.
- Sleipner SE300/300TC, 750 lb, $12,850.
- VETUS Bow Pro Boosted 300, 661 lb, $11,291.
- Lewmar 300TT GEN 2 Tunnel Thruster, two sizes, 550 to 616 lb, $7,339 to $10,499.
Every model with a page here is listed, maker by maker, on the thruster index.