Can this speed control kit be used on boats, ships and in marine environments?

The kit can be connected on marine engines with a mechanical throttle lever, but the IP67 declaration covers only the button and sockets, not the servo body.

If the throttle control on the boat works by a mechanical cable or lever, the kit can technically be connected; what it does is only to drive the position of the lever, just as on land. The IP67 declaration, however, does not belong to the whole kit: on the GS740 it is given only for the metal button and on the GS740-3P only for the connectors, and no protection rating has been declared for the servo body. For that reason it would not be right to count the kit as a marine product.

1) Mechanical compatibility

The decisive question is this: is the throttle control on the engine still mechanical? On a marine engine working with a mechanical cable or lever the kit pulls the cable, drives the lever and does not take the place of the governor. On engines with an electronic (drive-by-wire) throttle, on the other hand, there is no physical lever to drive; the kit is not applied there.

The operating side is simple: the potentiometer stays in the wheelhouse, the working speed is held in memory and idle is returned to with a single button. So the lever is not hunted for by hand at every manoeuvre; the same speed is returned to again and again.

2) What the protection rating declaration covers

According to IEC 60529, IP67 means complete dust-tightness and resistance to temporary immersion at a depth of 1 metre for 30 minutes. It does not mean continuous immersion or a high-pressure water jet.

Knowing which test the definition of IP67 satisfies is useful here: the immersion test and the water jet test are separate tests and neither covers the other.

In a salt environment the real problem is corrosion

In a marine environment most failures arise not from water getting in but from what salt does at the connection points. The practical precautions to take:

• Put the servo somewhere that gets no spray, in an enclosed compartment if possible; fit a shield against dripping from above.
• Leave the wire ends facing downwards and form a drip loop.
• Protect the chassis connection against corrosion; in a salt environment a loose or oxidised ground is the most frequent source of failure.
• Look over the points where different metals meet as well; galvanic corrosion speeds up in a salt environment.
• If you are going to put it in a sealed enclosure, allow for the fact that condensation can collect inside the enclosure.

Finding a point that will stay dry is usually possible, but the dry place is often the one closest to the engine. A second limit comes into play here: temperature and vibration. The drawbacks of mounting the servo close to the exhaust or the turbo are the same at sea as on land. The right order is this: first identify the points protected from spray, then choose from among those the one furthest from hot surfaces. If the two do not coincide, fitting a shield is a better solution than moving the kit into the hot area.

How emergency stopping is built on a boat

In marine applications emergency stopping again has to be built over fuel shut-off; pulling the throttle actuator to idle does not stop the engine. The stopping duty belongs to the fuel shut-off solenoid, and the emergency stop chain is built accordingly. This is not a preference; it follows directly from what the kit does and does not do.

What to do

Before installation, check by eye once where the servo will sit as far as spray and dripping are concerned; every point that stays dry saves the kit. Put the chassis connection, the connector ends and the cable route on the periodic maintenance list; in a salt environment those three points want regular checking. If you are going to make the steering side electronic on the boat as well, the electronic steering assist application is a separate subject and has to be assessed separately.

The full topic: Electronic speed and throttle control on diesel engines

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