Sonihull Installation Instructions

Please read over the instrucitons carefully before attempting to install a Sonihull Ultrasonic Antifouling System. If in doubt contact a professional. If you have any questions please Contact us.


This installation guide will help you go through the simple steps of installing either the Sonihull Mono or Sonihull Duo systems, or multiples thereof depending on the size of your yacht.

The Sonihull is suitable for fiberglass, aluminum, steel and cement hulls, where the transducer can be bonded to the inside ofthe outer skin of the hull. If your yacht is a sandwich construction we strongly recommend using the services of a professional marine engineer, as the outer skin will involve cutting through the inner skin and removing some ofthe inner core filling to expose the inside surface of the hull.

Please note that the Sonihull system is not suitable for wooden boats due to the poor transmission of the high frequencies through wood.

For concrete hulls to achieve the best results it is recommended that you double the number of transducers required compared to the illustrations in this guide to achieve the best results.


It is highly recommended that the electrical installation of this system is installed only by a competent marine electrician.

When mounting the control box please find a suitable dry position above the water line.

Connect all AC connections in acoordance with IEC wiring regulations, ensuring the correct plug and socket are used, or directly to a 5 amp breaker.

Color codes for main cable provided:
Brown = positive
Blue = negative

If connected to DC supply please ensure that an inline 5 amp fuse is used.

What's Included

  • Sonihull control unit - qty:1
  • Transducer - qty:1 (Sonihull Mono) / qty:2 (Sonihull Duo)
  • Mains cable with 3 pin US standard fused plug
  • Marine grade epoxy qty:1
  • Vaseline qty:1

What's Not Included

  • 4 screws for mounting control box (some people prefer to use strong Velcro to secure)

Installation Tips

Transducer Placement

  • For vessels up to 30 feet transducers should be installed in the rear 3rd of the yacht.
  • For vessels up to 50 feet transducers should be installed 1/3 and 2/3 along the length of the yacht hull.
  • For vessels larger than 50 feet, the Sonihull is a modular solution, please contact PYI to discuss your requirements.

The transducer needs to be mounted to an obstruction free area below the water line and on the inside of the external skin. To enable the transducer to create resonation it must be away from any bulk heads, bracing and ribs etc, ideall in the center of a panel and not closer than 12 inches from any obstruction. Compare this to the skin of a drum, to make the best noise you would hit in the middle, not at the edges, transducers need the same consideration. It is also common to place one transducer very close to, and sometimes on a Bow Thruster tunnel.

Installing The Transducer Mounting Ring

The transducer needs complete face to face transmission, and that means flat, not curved, bowed or rough, only flat will work. Also ensure that there are no drips of glue inside the ring. A little pimple of glue splash can hold the transducer off the surface by just 1mm. That air gap is enough to stop any signal transmission. If there are any concerns that the surface is not flat, follow the manual for using the aluminum disk as a problem solver.

Applying Vaseline

The transducer needs to have a smear of Vaseline on the face to ensure correct transmission, just a smear. Do not put too much that the signal is insulated, as the transducer face will not get close to the surface. A good practice when you first screw in the transducer, tighten it up firmly by hand, (not overly tight). Then remove the transducer and observe the swirl marks of the Vaseline on the face of the transducer, and look for the wetting on the hull inside the ring. This will give you a clear indication of the quality of the surface contact.


Mains cable can be totally removed or simply coiled for potential future use. Connect to DC through a 5 amp inline fuse. Please ensure correct polarity.

  1. Once you have located a suitable location for mounting the transducer, close to the center line of the hull, paying special attention to be sure that there is suitable access for running the cables back to the Sonihull controll unit.
  2. Prepare the hull by sanding down the area to ensure a smooth flat surface, (it is important that both the hull and the transducer surfaces are flat to ensure the best possible surface to surface transmission of the transducer pulse).
  3. Clean the hull and transducer faces to ensure that there is no dust or grease.
  4. Apply a thin layer of Vaseline (any petroleum jelly will work) to the threads of the transducer mounting ring. Ensuring to keep the outer face of the ring free from any grease. (This is to stop any epoxy from accidently getting stuck in the threads).
  5. Prepare the marine epoxy as per the manufactures instructions. You will note on the mounting ring that a gutter has been provided to try and capture any stray epoxy before it gets to the tread. Apply the epoxy to the face of the mounting ring, on the outside of the gutter and attach to the hull. It is important toepoxy the full "circle" of the transducer to make a complete seal with the hull once set.
  6. Allow the epoxy to fully set prior to attaching the transducer.
  7. Prior to screwing in the transducer to the mounting ring, apply a thin layer (1mm) of petroleum jelly to the face of the transducer. This will enable better contact between the surface of the transducer and the hull.
  8. Screw in the transducer fully into the mounting ring, ensuring a firm contact has been made with the hull. Do not over tighten as this could cause the epoxy to break.
  9. Run cables to the Sonihull controller and then connect.
  10. If you have already run the transducer cables please wind the transducer back (counter clockwise) about 8 rotations so not to leave the cable twisted once you have screwed in the transducer to the mounting ring.