Sleipner SEP PRO and eVision proportional thrusters

An on/off thruster is a light switch. A proportional thruster is a dimmer. That sounds like a small upgrade until you are easing a 45-footer into a slip with a breeze on the beam and you only want a little bow thrust, for a while, quietly. That is the job Sleipner's PRO and eVision models are built for.

This page covers both, because right now you cannot really talk about one without the other.

Two families, one job

SEP PRO

The SEP PRO is the classic Side-Power SE thruster with variable speed control added. Same tunnels, same gearlegs, same thrust ratings. An SEP80 PRO on 12V is rated 80 kg at 10.5V and 96 kg at 12V, draws about 530 A, and fits the same 185 mm tunnel as an SE80. That makes it an easy upgrade path on boats that already have a Side-Power tunnel.

The big difference besides speed control is what happens when the motor gets hot. Sleipner's on/off thrusters shut off. PRO thrusters reduce power to keep temperature in a safe range and keep running. The rated duty cycle is still 2-3 minutes at 20°C, but you lose thrust gradually instead of losing it all at once.

eVision E-series

eVision is the newer design. Sleipner uses a brushless 6-phase PMSM synchronous motor with the inverter for speed control built into the unit, and claims these thrusters are up to 50% lighter than the models they replace. The headline number is run time: Sleipner rates eVision for continuous operation at 100% thrust at 22°C ambient, "typically limited by battery capacity."

The eVision tunnel range runs from the E100 (100 kg, 185 mm tunnel) to the E420 (420 kg, 386 mm tunnel). Voltage is 24V or 48V. The E240, E300 and up are 48V only. There are no 12V eVision models listed.

What is current, and what is being replaced

This is the part dealers will not always volunteer. On Sleipner's own site, the product pages for the SEP130, SEP150, SEP170, SEP250 and SEP300 (and several ignition-protected PRO versions) now show a link to an eVision replacement: E130, E150, E170, E250 and E300 respectively. The SEP25 through SEP100, along with the SEP120 and SEP210, are still listed without that notice.

In plain terms: on smaller boats, SEP PRO is still the main proportional option. On bigger boats, eVision is where Sleipner is heading. If you are quoting a large proportional thruster, ask which one you are actually getting and how long parts support is planned for the outgoing model.

Features that change how you dock

Variable speed. You use only the thrust you need. It is quieter, the boat moves more smoothly, and you are less likely to overshoot.

Hold function. With PRO or eVision thrusters at both ends of the boat, one press keeps the boat pushed against the dock while you step off with the lines. Sleipner pitches this as making docking a one-person job. It does require two thrusters.

Joystick integration. Sleipner says speed-controlled thrusters are the right choice for joystick systems, and both families talk over S-Link, Sleipner's CAN-based control bus with keyed, color-coded plugs.

Safe start-up. The PRO control panels use dual on-buttons to prevent accidental activation, a small detail that matters on boats with kids aboard.

Installation notes

Retrofitting an SEP PRO in place of an SE of the same size is usually straightforward: same tunnel, swap the unit and the controls, and run S-Link. It is one of the cheaper ways to get proportional control on an existing boat.

eVision changes the electrical plan. Because there is no 12V version, a 12V boat needs a dedicated 24V or 48V bank near the thruster, plus a way to charge it. On the plus side, higher voltage means much lower current. An E130 on 24V draws about 270 A with an ANL 250 fuse, compared with roughly 530 A for a 12V SEP80 that makes less thrust. Lighter cable, less voltage drop.

The eVision run-time claim also changes how you size the battery. If the motor can keep going, the battery becomes the limit. Lithium banks handle this kind of sustained draw better than lead-acid; see our lithium thruster battery page and plan the bank with the installer, not after.

Sleipner's spec sheet for the E130 lists IPx7 and ignition protection to ISO 8846, which makes it suitable for gas-boat engine rooms and wet stern compartments.

The weak spots

• Transition period. Parts of the SEP range are being replaced. That is not a reason to avoid them, but it is a reason to ask questions.
• No 12V eVision. Owners of 12V boats who want the continuous-run benefit have to add a higher-voltage bank.
• More to diagnose. CAN bus, inverters and controllers mean troubleshooting needs a technician who knows Sleipner's system. Our thruster repair service handles this.
• Cost. Expect to pay more than for the matching SE.

Against the alternatives

The obvious comparison is the Vetus BOW PRO and BOW PRO Boosted, which use brushless induction motors and offer 12V models at the small end. Max Power VIP is the other proportional line people ask about. For a direct look at the two European brands, read Sleipner vs Vetus.

Verdict

For boats under about 45 feet, the SEP PRO is a solid, easy upgrade from an SE, especially if the tunnel is already there. For larger boats, eVision is the better buy, and on Sleipner's site it is now the replacement for most big SEP models. Its continuous-run rating and lower current draw are real advantages, as long as you budget for a 24V or 48V bank. If you are weighing the two for your boat, send us the boat details and we will spec both.

Questions people ask