Nisr (pilot boat Kuwait) equipped with Shipsonic ultrasonic anti-fouling system

Big fouling problems

The SL Nisr (Smit Lamnalco) operates in the Persian Gulf, known for its relative severe marine fouling. The LS Nisr is not equipped with a box cooler, but has 2 small inlet chambers, protected with a grate, that lead to 2 strainers which strain the seawater before reaching the plate coolers.


Transducer location

Fouled inlet grate

Fouled suction pipe

The protective grates, inlets, strainers and piping used to get completely clogged with fouling.

The challenge, as so often, is where to locate the transducers. The grate has most fouling, bit it is impossible to install a transducer directly on it. Moreover, the contact that the grate has with the hull is only through its hinges and locking bolts, which might not be enough to conduct sufficient sound to protect it.



Cleaned strainers

Cleaned inlet










The ultrasonic solution

‘Mini’ sea chest with suction piping

Transducer 1

Transducer 2









HDS20-2 Transducers


After ample discussion with the client we decided to install anHDS20-2 Transducers HDS20-100, with 2 100 Watt transducers on the 2 inlets of the suction pipes. If, in the long run, that turns out to be insufficient, we can still place transducers on the piping and/or the strainer housing, using our adaptors for installing on curved surfaces.

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