About Kahlenberg UK

Kahlenberg UK Ltd is the European distributor for Kahlenberg Industries, Inc. providing full European support and local stock for Kahlenberg marine and industrial air horns, sound signals, controllers, air compressors and the company's other products.

Please contact us for further assistance at or on +44 (0)1635 35353

Sound signal legal requirements

IMO COLREGs bookWhile countries across Europe will have local laws that apply to ship and boat navigation, there is a common requirement worldwide for all leisure, commercial and military vessels to conform to the IMO International Regulations for Preventing Collisions at Sea. As Steve Austin, Senior Policy Lead at the UK Maritime & Coastguard Agency (MCA) explains: "The COLREGs apply to all vessels, there is no differentiation between coded and non-coded vessels. Should the whistles prove not to conform then they will need to be modified or changed."

"Whistles should conform to the performance in COLREGs, Appendix III and the appropriate parts of IEC 60945 to EN60945 which deal with the marine operating environment."

All Kahlenberg products meet or exceed these requirements. Many other new and currently installed sound signals are non-compliant and might be breaching maritime law and invalidating insurance cover.

M-485A Sound Signal Timer

Kahlenberg M-485A Sound Signal Timer front viewThe Kahlenberg M-485A Sound Signal Timer offers a simple but elegant solution to relieving a skipper or watch from repeatedly sounding the vessel's air horn or other sound signal apparatus. Full concentration can instead be focused on the helm, keeping a good watch and dealing with any emergency.

The M-485A Sound Signal Timer is packaged as a neat, waterproof two rocker switch module with clear labelling to explain operation. It can easily be used in conjunction with the matching M-126 push button switch.

Power consumption is zero when the switch is off and just 6mA in standby and 75mA in operation. The M485-A Sound Signal Timer comes in 12V and 24V versions and can handle up to 20A load.

The M485-A Sound Signal Timer automatically sounds the appropriate signal for the following restricted visibility requirements under Rule 35 of the International Regulations for Preventing Collisions at Sea, 1972 (COLREGs):

  • Vessel underway (Rule 35a)
  • Vessel underway but stopped (Rule 35b)
  • Vessel restricted in ability to manouevre (Rule 35c)

The rear face of the controller is sealed with protruding 6.3mm terminals for easy connection and it comes with straightforward instructions for installation.

M485-A Sound Signal Timer downloads

Kahlenberg M-485A Sound Signal Timer technical information (PDF 121Kb)

Further information

Call Kahlenberg UK now on +44 (0)1635 35353 or email