Electric First: The Engineering Behind Syncrolift

This article was first published on Linkedin. 

Where the name Syncrolift comes from.

There is a clue in our name. When the first Syncrolift systems were built in the 1950s, the central challenge was the same one we face today: raising a ship evenly across many lifting points at once.

The answer back then was synchronous motors, whose speed is locked to the frequency of the electrical grid. Wired to the same supply and started together through simple contactors, every motor turned at the same rate, and the platform rose relatively level. That lock-step motion is where the name comes from. Because those motors could only run together at one synchronised speed, with no way to trim any of them individually, the platform itself had to flex to share the load, what we today call an articulated platform.

Today that founding principle is delivered in a very different way. Variable-frequency drives (often just referred to as "drives") with servo control became mainstream in the late 1990s. We adopted that technology, replacing the synchronous motors with asynchronous motors fitted with encoders and driven by VFDs in servo mode: the same technology found in robotics, electric cars, elevators, escalators, in fact in almost any modern high-power electric machine.

The drives now coordinate the lifting digitally, with a precision and flexibility the original grid-locked motors could never reach: each hoist individually controlled, monitored and trimmed up to a thousand times a second, while still moving in concert with all the others. It is this electric drive technology that made possible our 4th Generation Shiplift: the first in the industry to come with a contractual guarantee of fail-safe behaviour on a single failure and fault-tolerant operation.

Why we chose electric first

That instinct to solve the problem electrically runs through everything we build. Wherever it is possible, we use fully electric machinery, and we turn to hydraulics only where they remain the practical choice. It is worth explaining why.

Start with efficiency. An electric motor turns almost all the energy it receives straight into motion; modern motors run at over 90 percent efficiency. A hydraulic system has more steps to work through. Electricity drives a pump, the pump pressurises fluid, and the fluid then drives a cylinder or a motor. Each of those steps gives up a little energy as heat, so by the time the work is done a meaningful share has been lost along the way. Think of a relay race: every handoff costs a fraction of a second, and the more handoffs there are, the more time slips away. With hydraulics, between 30 and 70 percent of the energy is lost in that relay race as heat.

That founding concern with even lifting is also why precision matters more for a shiplift than almost anything else. The load has to rise at every point in near-perfect unison; if the points drift apart, the structure twists and the pressure on the vessel's hull shifts in ways no one wants. Picture a team carrying a long, flexible and heavy table: if everyone lifts at a slightly different rate, it tips and bends. Adjusting each hand continuously to keep that table flat, to within millimetres, is exactly what the servo-driven motors are there to do.

Maintenance and the environment

There is also the matter of where these machines work. A shiplift operates directly above the sea or the harbour. On equipment like that, a hydraulic leak puts the water below at risk. Reducing the amount of pressurised oil suspended above the waterline is a genuine environmental and safety benefit, and it is one of the clearest reasons we reach for electric solutions first.

Electric systems are also simpler to look after. There is less fluid to change, fewer hoses to perish and seals to fail, and fewer places for leaks to start. Electric drives pair naturally with sensors and data logging, which makes it far easier to spot a problem developing before it becomes a failure. As a bonus, the working environment is cleaner, quieter and safer for the workers nearby.

Where hydraulics still earn their place

None of this makes hydraulics the wrong choice everywhere. Hydraulics have one quality that is very hard to beat: they deliver enormous force from a remarkably compact package. For some jobs, that quality is decisive.

Our Fluid-Bed transfer system is the clearest example. Each lifting cylinder handles up to 600 tonnes. At the upper end, that is roughly the weight of a fully loaded jumbo jet, raised by a single cylinder. No electric drive can produce that kind of force in that kind of space, so for lifting in the confined space beneath a vessel, hydraulics are simply the right tool, and we use them with conviction.

The decision does not end at the cylinder, though. A traditional setup runs one large hydraulic power unit continuously and pipes pressure out across the system, which means long high-pressure lines and a pump that keeps working even when little is being asked of it.

We can do something smarter.

Each Fluid-Bed trolley can carry its own power unit: an electric motor that spins the hydraulic pump only when it is needed. Much of the energy a conventional system would waste is reclaimed, every trolley can be controlled precisely and kept in step with the others, and there are no long fluid runs snaking across the site. The muscle stays hydraulic; the intelligence driving it is digital and electric — it is what we call a Digital Fluid-Bed.

Customers can choose the configuration that suits them. Where simplicity and upfront cost lead the decision, a central hydraulic power unit makes good sense. Where efficiency, robotics-grade control and modularity are more important, local units on each trolley are the better fit. In both cases we are doing the same thing: bringing electric as far into the system as the physics will allow.

The same standard, across the board

This is how we think about engineering at Syncrolift. Choosing electric first reflects a clear conviction about how machines should be built: more efficient to run, more precise in operation, cleaner for the environment they work in, and easier to maintain across a long service life. Where the space limitations and forces involved call for hydraulics, we hold that part of the system to the same standards, designing it to work as efficiently and as cleanly as it possibly can.

Seven decades on, the name Syncrolift still describes the job: lifting in perfect synchrony. The next time you watch a vessel rise smoothly out of the water, it is worth remembering that the smoothness is engineered, and made possible by carefully selecting and configuring modern commercial-off-the-shelf industrial components.

How does your team weigh efficiency, control and environmental impact when choosing between technologies? We would be glad to hear how others approach it.