Max Power CT electric tunnel thrusters

Max Power's CT range is a big family of plain DC tunnel thrusters, and the thing that sets it apart is how much thrust it tries to fit into a small tunnel. The CT45 puts twin props in a 125 mm tube. The CT80 and CT100 do the same in 185 mm. For a boat where you can't fit a bigger hole, that matters more than any brochure line.

The range at a glance

All figures below are from Max Power's product pages. The boat lengths are Max Power's guidance, and they are wide on purpose: a heavy trawler and a light sport cruiser of the same length need very different thrust.

Max Power also lists a CT550, a 30 kW three-phase AC unit in a 400 mm tunnel. That's superyacht territory and a different install entirely, so it's not covered here.

Read the fine print on thrust

This is the most useful thing to know about Max Power numbers. The company says its thrusters are designed to run at 10.75V on 12V units and 22V on 24V units, and that higher voltage means more thrust, more power draw and a shorter duty cycle. The CT100 sheet shows both: 96 kgf at 10.75V, 105 kgf at 12V.

The figures also assume the thruster sits one tunnel diameter below the waterline in a tunnel no longer than two diameters, with a plus or minus 6 percent tolerance. Longer tunnels mean less thrust and more current. None of that is unusual; Max Power is just more explicit than most about it. When you compare a CT80 with another brand's 185 mm unit, compare like with like. Our Lewmar vs Max Power page walks through it.

Build and electronics

Max Power's patented composite drive legs are standard on most CT models, with case-hardened spiro-conical gears and line shields around the props. The company describes the range as zero maintenance, and the CT25 page specifically says no anodes are needed. The CT300 and CT325 move to bronze drive legs, and the CT225 is offered in composite or bronze.

The control box does more than switch a contactor. Per the CT100 spec sheet, the system includes:

• Childproof activation
• Automatic shutdown after 30 minutes of inactivity
• A visible and audible motor overheat warning, then shutdown
• Standard automatic battery isolator control
• A time delay between port and starboard thrust
• Software protection against short circuits

The port/starboard delay is the one owners notice. It protects the gear train and motor from a hard reversal when someone slams the joystick from one side to the other.

Install realities

The CT range rewards careful electrical work more than most, because so many of the popular models are high-power 12V units. The CT100 is a 7.1 kW motor on 12V. That is a lot of current through a long cable run, and every bit of voltage drop shows up as lost thrust, especially given the rating basis above. We plan these installs around the battery first:

• A dedicated bow battery close to the thruster almost always beats running cable from the engine room.
• If the boat already has 24V, take the 24V version where one exists. A CT80 on 24V is rated at 89 kgf against 80 kgf on 12V.
• On the bigger CT125, CT300 and CT325, Max Power says the 48V versions cut current draw by 48 percent and lift the operation cycle by 50 percent versus 24V. Smaller cable, less heat.

Battery chemistry matters too. See AGM thruster batteries and lithium thruster batteries for what holds voltage under a several-hundred-amp load.

Mechanically, the CT units are compact. The CT80 leg is listed at 15 kg, the CT35 under 10 kg. That helps in a narrow forepeak where you're working upside down with one arm. Tunnel placement follows the usual rules, covered on our bow thruster installation page.

Weak spots

On/off only. If you want variable thrust, Max Power's ECO proportional range is a separate product line, reviewed in Max Power VIP and ECO proportional.

The CT300 and CT325 have an oddity worth flagging: Max Power lists the 48V versions at slightly lower thrust than the 24V versions (275 vs 300 kgf, and 300 vs 325 kgf). The trade is lower current and longer run cycles, not more push.

Support is the other question. Max Power has authorized dealers and service centers in the US, but the network is smaller than the big northern European brands. Before you buy, know who will service it in your area and where parts will come from.

How it stacks up

The CT line's closest rivals are Lewmar's Gen 2 TT, Quick's BTQ, and Sleipner's SE. Max Power's twin-prop small-tunnel models are the main reason to pick it: if your hull only allows 185 mm and you want over 100 kgf, the CT100 and CT125 are on a short list. If you want the widest dealer network or a proportional ecosystem from the same brand, look at the others first.

Verdict

A solid, broad DC range with real engineering behind the composite legs and control electronics. Pick a CT if tunnel size is your constraint and you're prepared to wire it properly. Plan the battery and cable before the thruster, then get a quote with the boat's length, displacement and where the batteries live.

Questions people ask