Den Haan Rotterdam B.V.

Den Haan Rotterdam B.V. is a company that makes navigation lights, searchlights, floodlights and ship's horns for the shipping industry. It has a history in Rotterdam, the Netherlands. It was established August 7, 1922, by Marinus den Haan as a tinsmith workshop. The company also manufactures decorative nautical oil and electric lamps.
The company imports intermediates and exports products, adopting the logo "DHR" internationally.
Research and development.
The part of the Royal Netherlands Meteorological Institute that approved and certified the nautical lights, compasses and instruments in Rotterdam closed in 1988. This meant that all the lanterns had to be tested in house and certificates provided. For this purpose a room furnished with the necessary equipment, as directed by the government, was purchased.
After 1.5 years of research, the "Burtone" horn was brought to market. A TNO test report confirmed that the horns even meet German standards. The entire range ZEEKRO-search lights was tested and the entire structure was renovated to meet CE regulations.
In 2009, the noise test area was restructured due to increased air horns complaints from the immediate vicinity. In 2010, new products included a signal lamp with LED, and a new motor housing for searchlights. In 2012 development began for an inland navigation lantern with LED technology.