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Electric linear actuator in the marine industry — applications and selection
An electric linear actuator converts the rotary motion of a motor into the reciprocating motion of a piston rod. In marine applications, force and stroke are not the only things that matter: resistance to water and corrosion, supply voltage, duty cycle and control method are just as important. Concens CON and ICON actuators, as well as the underwater UW100, can be selected for such applications.
On a yacht or ship, an actuator can open hatches, reposition equipment, adjust flaps or drive deck mechanisms. Compared with hydraulics, an electric solution needs no pump, pressure lines or oil circuit, which simplifies the installation and removes hydraulic fluid as a potential source of leaks.
How does an electric linear actuator work?
In Concens actuators, a DC motor works together with a gearbox and a screw mechanism. The gearbox reduces the motor speed, and the screw converts the rotary motion into linear travel of the piston rod.
The simplified layout looks like this:
DC motor → gearbox → screw → nut → piston rod
The gear ratio determines the trade-off between force and speed. The CON50 is a good example: the 1:4 version can reach about 70 mm/s at 500 N, while with a 1:84 ratio the speed drops to about 3–4 mm/s and the available force rises to 4,500 N.
This means an actuator should not be selected only on the basis of the maximum force stated for the whole series. You need to check the specific combination of size, gear ratio, stroke and speed.
Why is the marine environment so demanding?
On deck, a drive can be exposed at the same time to moisture, splashing, salt spray, rain, sunlight, vibration and temperature changes. In some places it also has to withstand high-pressure washing or periodic flooding.
That is why two parameters must be assessed separately: sealing, defined by the IP rating, and corrosion resistance of the materials.
A high IP rating does not automatically mean resistance to seawater. The IP rating describes the ingress of water and solids under defined test conditions, while resistance to chlorides and salt spray depends on, among other things, the material of the housing, piston rod, fasteners and seals.
Versions intended for more aggressive environments can use AISI 316 or 316L stainless steel and HE versions with improved sealing. This is not, however, standard for every CON or ICON configuration.
How to choose the IP rating for a marine application?
IP ratings should be related to the actual installation location, not to “use on a yacht” in general.
| Rating | What it means in practice | Where it may matter |
|---|---|---|
| IP66 | Protection against powerful water jets | Locations exposed to rain and splashing, without immersion |
| IP68 | Protection against immersion under conditions specified by the manufacturer | Mechanisms that are periodically flooded or submerged |
| IP69 | Protection against high-pressure, high-temperature water jets | Areas that are washed intensively |
For selected CON models, HE versions tested to IP68/IP69 are available; the product data sheet specifies, among other things, an immersion test at 1 m for 1 hour. This does not mean that every CON version has the same degree of protection. Standard models are available, for example, as IP66.
If the drive is to operate permanently underwater, you need a design made specifically for immersion, not just an actuator with a higher IP rating.
Where are linear actuators used on yachts and ships?
In the marine industry, linear drives work well in mechanisms that perform relatively short, occasional movements. This includes adjusting backrests and tables, opening hatches, windows and skylights, controlling flaps and positioning deck equipment.
AMG presents a wider range of such applications on its automation for the marine industry page, which also covers sensors, encoders and components designed for harsh environments.
For larger mechanisms – such as ramps or heavy structural elements – a more detailed analysis of force, geometry and duty cycle is required. Compact Concens actuators are designed primarily for intermittent operation, not for continuously driving heavy industrial axes.
Application example: an adjustable yacht seat backrest
One practical application was a drive for the adjustable backrest of a seat designed for the outer deck of a yacht. Small dimensions, environmental resistance and the possibility of hiding the drive inside the furniture were all important.
This application used an ICON35 with an integrated controller. The AISI 316 stainless steel version was suitable for marine conditions, and the control electronics located directly in the actuator reduced the space needed for additional components. The operating temperature range for this configuration is −20 to +70°C.
The full example can be found in the case study electric actuator in yacht production.
Which linear actuators does AMG offer for marine applications?
The range of electric linear actuators includes several Concens designs that can be matched to the control method and operating conditions.
| Parameter | CON | ICON | UW100 |
|---|---|---|---|
| Control | External controller | Integrated controller | Depending on version |
| Force | 120–10,000 N | 120–10,000 N | up to 4,500 N |
| Stroke | 50–750 mm | 50–750 mm | up to 400 mm |
| Speed | 3–70 mm/s | 3–70 mm/s | depending on version |
| Supply voltage | 12/24 V DC | 12/24 V DC | 12/24 V DC |
| Environment | IP66 as standard, HE versions available | versions for demanding conditions available | underwater design |
| Controller in housing | No | Yes | depending on configuration |
The CON and ICON ranges depend on size and gear ratio. Both can reach up to 10,000 N and are available with strokes of up to 750 mm. ICON differs mainly in its integrated controller and Modbus RTU communication over RS-485.
CON – a simpler setup with an external controller
The CON actuator is a good choice where the control electronics can be located outside the actuator. Sizes CON25, CON35, CON50 and CON60 are available, together with various gear ratios that let you choose the right balance between force and speed.
Selected versions can be ordered in stainless steel and with increased environmental resistance.
ICON – controller integrated with the actuator
The ICON actuator uses a similar mechanical design but has built-in control electronics.
It supports Modbus RTU communication over RS-485, configuration of motion parameters and synchronised control of several actuators – up to eight units.
This design is particularly interesting where there is little room for an additional controller, for example inside yacht furniture or a compact deck mechanism.
UW100 – for real underwater operation
If the actuator has to work submerged, the solution is the UW100.
The series was developed for underwater operation at depths of up to 100 m. The design uses AISI 316 stainless steel and special seals, and the factory-fitted cable is also covered by the sealing.
It is important to make a distinction: the declared resistance applies to the actuator and cable in the manufacturer’s configuration. Cable termination, connectors and the cable entry into the equipment housing must be designed separately.
How to choose an electric linear actuator for a yacht?
Selection should start with the mechanics. First determine the required force over the entire range of motion, not just the weight of the element being lifted.
The most important factors are:
- Mounting geometry – the distance of the attachment point from the hinge and the angle between the actuator and the element change the required force during motion.
- Stroke – it must provide the required opening angle and fit into the available space.
- Force and speed – these result, among other things, from the actuator’s gear ratio.
- Duty cycle – CON and ICON are drives for intermittent operation; for selected versions the manufacturer specifies a duty cycle of up to 10%.
- Supply voltage – 12 or 24 V DC should match the vessel’s electrical system as well as cable length and cross-section.
- Control – CON requires external control, while ICON has built-in electronics.
- Environment – requirements for water, corrosion, temperature and possible immersion should be defined separately.
- Mounting – the actuator should work axially and must not be treated as a guide carrying significant side loads.
How to make a preliminary calculation of actuator force for a hatch?
Let’s assume the hatch weighs 20 kg, its centre of gravity is 0.4 m from the hinge, and the actuator attachment point is 0.2 m from the pivot axis.
The weight force is:
F = 20 × 9.81 ≈ 196 N
The moment caused by the weight with the hatch in the horizontal position:
M = 196 × 0.4 ≈ 78.4 Nm
If the actuator acts at this point perpendicular to the 0.2 m lever arm, the minimum force resulting from the static weight alone will be:
F = 78.4 / 0.2 ≈ 392 N
This is not yet a value on which to order an actuator.
The actual force changes with the opening angle and the position of the mounting points. You also need to take into account friction, seals, acceleration, external loads and the worst-case geometry over the whole range of motion. In marine use, the vessel’s heel and dynamic loads may also be significant.
That is why, instead of applying a universal “1.5–2× margin”, the design factor should be chosen for the specific application and its safety requirements.
What to watch out for during installation?
In a linear actuator, the force should act as closely as possible along the axis of the piston rod. Side loads can increase wear of the guide and the screw mechanism.
Particular attention should also be paid to:
- electrical overload protection,
- free rotation of the mounting brackets on the pins,
- cable routing and sealing,
- protecting connectors from water,
- correct mechanical limitation of travel,
- preventing the actuator from twisting, if the version requires it.
In the UW100, the sealing does not automatically cover the free cable ends or external connectors.
FAQ
Is an electric linear actuator suitable for use on a yacht?
Yes, provided that the right version is chosen for the installation location. Not only the IP rating matters, but also the material, corrosion resistance, duty cycle and cable protection.
What IP rating is needed on a yacht?
There is no single rating suitable for the whole vessel. IP66 may be appropriate for a location exposed to water jets, IP68 refers to immersion under conditions specified by the manufacturer, and IP69 matters for high-pressure washing. In every case, the materials’ resistance to a salt environment must be assessed separately.
Is 12 V or 24 V better?
Both voltages are available in the CON and ICON series. The choice should primarily match the vessel’s electrical system. Over longer distances, voltage drop along the cables must also be taken into account.
Can an electric actuator work underwater?
Yes, if it is designed for it. The UW100 series is designed for underwater operation at depths of up to 100 m.
Can CON and ICON operate continuously?
They are not actuators designed for typical continuous operation. For the CON series, the manufacturer specifies a duty cycle of up to 10%, e.g. 2 minutes of motion and 18 minutes of rest for the indicated configurations.
What is the difference between CON and ICON?
CON uses an external controller, while ICON has a controller integrated in the housing. ICON supports Modbus RTU over RS-485 and can work in synchronised systems.
Which actuator to choose for a marine application?
On deck, inside the vessel and underwater, the operating conditions are completely different. That is why “an actuator for a yacht” is too broad a description to select a device on that basis alone.
First, define the mechanism geometry, required force, stroke and speed, and then match the duty cycle, control, material and environmental resistance.
AMG’s range of Concens electric linear actuators includes both compact CON and ICON units for intermittently operating mechanisms and the UW100 designed for real immersion. This makes it possible to match the solution to a specific location and function on the vessel, instead of treating all marine applications as the same.