Max Power CT100 & CT125 Tunnel Thrusters — Installation Manual

Specifications (Data Sheets)

Thrusters are designed to run at 10.75V (12V units) and 22V (24V units); higher voltage gives more thrust, more consumption and a shorter duty cycle. Performance at one tunnel diameter immersion, tunnel no longer than twice its diameter, +/- 6%. General dimensions drawing 42534 & 42535: 364 mm high, 284 × 196 mm, propeller Ø199 in Ø185 int. tunnel, 24 kg. The thruster is delivered without fuse, fuse holder or control panel.

Position, Tunnel and Drive Leg

• Minimum acceptable tunnel position: 139 mm below the waterline. Ideal: 185 mm between the waterline and the top of the installed tunnel. As far forward as possible. Above the ideal depth, performance drops progressively.
• Support the electric motor whether vertical, inclined or horizontal. The motor heats up in use: the compartment must be dry and ventilated.
• Thruster batteries charged by both the engine alternator and a battery charger; a dedicated bank must be as close as possible to the thruster.
• The drive leg must be centred in the tunnel; the propellers must never protrude from it.

Tunnel

1. Mark the tunnel centre on both sides of the hull and drill 8–10 mm holes.
2. Make a compass from a metal rod with a 100mm radius, pass it through the holes and trace the ellipses; cut them out.
3. Grind the hull inside and out for laminating (approx. 10 to 15cm around the holes). Dry-fit the tunnel, mark components and laminating areas; drilling the tunnel before laminating is advisable.
4. Secure the tunnel with reinforced fibreglass filler, filling the gap completely, then laminate a minimum of 8 layers of ISOPHTALIC RESIN alternated with mat and roving (filler only in hard-to-reach areas such as under the tunnel).
5. Finish outside with waterproof undercoat, sanding and waterproof finish coat; fair the tunnel ends with reinforced filler (the manual mentions leaving 1 to 4 cm) for clean hydrodynamic lines, then apply sealant.
6. DO NOT laminate the area of the tunnel where the motor support will be fixed.

Motor Support, Drive Leg, Motor, Propellers

1. Mark the fixing-screw and leg-hub holes using the motor support and the leg gasket as templates (easier before laminating); check axes with the gasket and adjust with a round file; holes must be clean.
2. Dry-assemble leg, gasket (between leg and tunnel) and motor support, tighten the two screws alternately and fit the propeller(s) to check alignment; then dismantle.
3. Coat both sides of the gasket with silicone grease or sealing compound (resistant to hydrocarbons and water), keeping holes and screws free of compound. Reassemble and tighten the two 8mm screws alternately with a 5.5mm Allen key (maximum torque: 25 Nm). No graphite grease. Check the propellers turn freely.
4. Use only the original screws (part 11) supplied with the leg: longer screws can damage the leg and let water in.
5. Motor: the upper (motor-side) coupling is factory set. Push the lower shouldered coupling fully onto the lightly greased leg shaft, fit the flexible coupler (part 8), set the motor on the support and tighten the four 10mm motor support screws alternately (maximum torque: 40Nm). Check 2mm of play (+/- 1mm) between the two couplings; readjust the motor-side coupling if needed. Leave free airflow for cooling.
6. Propellers: fit the drive pin and propellers, tighten each M12 DIN985 lock nut with a 19mm wrench (maximum torque: 25Nm); protect your hands from the blade edges. Coat shaft and stainless cover with silicone grease against calcium deposits.
7. Protection grids may be fitted but can affect performance.

Electrical Installation

• Excessive voltage drop wears relays and brushes prematurely; the installer must protect the thruster electrics from direct water contact. Tighten all connections; no flammable products nearby.
• A manual battery isolator is essential (visible, clearly marked, easily accessible), plus if possible an electric battery isolator: Max Power advises ref. OPTI3160/3 (12V) or OPTI3170/3 (24V). Without it, seal off the two grey wires from the control box.
• Reference: batteries 100% charged at 13.8V or 25.4V; approx. 680A and 11V for the CT100, or 430A and 22V for the CT125, at the motor connections.
• Power cables: shortest route, in a well-ventilated area, PVC insulation rated 105 degrees Celsius or more.
• Control box: fused breaker / switch marked BOW THRUSTER on the main DC panel, ideally from a different bank than the thruster; 8A fuse on the control box positive; voltage drop under 5% of nominal.
• Batteries: maintenance-free starting type with high CCA, e.g. Exide Maxxima 900, 12V, 55Ah / 800CCA with 2000 CCA maximum total output (120 Ah needed for 10 min/day). With lithium batteries, the thruster current must be regulated not to exceed their maximum. When charged by the alternator, take the charge after the diode-splitting block.

Maintenance & Troubleshooting

• Protect control panels from the elements when not in use.
• Check battery condition and charge regularly (voltage drop is the most frequent cause of rapid relay wear) and all electrical connections and cables.
• Remove the motor and blow dust out of the brushes with compressed air; keep the motor dry and ventilated.
• Composite drive leg: oil-filled and sealed for life, no oil change, no anode, never disassemble it (voids the warranty); worn oil seals = standard exchange leg.
• Out of the water: clear fishing line and debris from the propellers, antifoul leg and propellers over primer, keep propellers and tunnel clean; annually grease drive shafts and stainless seal covers with silicone grease. No aggressive solvents.

Spare Parts (Serial No. 83338 On)

The separate spare parts sheet (July 2013, Lalizas Group service manager) lists some different new codes: pin 630490, propeller 35031, electronic controller 315308. Order by the current list above; ask us if your thruster is older.