Marine Electronics - Sales & Service


Seamaster ApS trades and support a number of the most recognised brands within maritime electronics such as Marport, Sonic Kaijo Denki, Wesmar and KNS.


We conducts service and repair work on a large number of different products within Marine Electronics.

Used Equipment

We restore and repair used Marine Electronics equipment and products. Bringing used equipment back to life is a big part of our business. 



Since 1999 Seamaster has helped our customers within Marine Electronics for ships. Our specialty is sales of new products, repair and restauration of used equipment such as Sonar, Radar and off shore internet.

Products & Brands

Seamaster offer products from the most recognised producers of Maritime Electronics such as Sonic Kaijo Denki, KNS and Wesmar. If you need a new systems or service regarding Sonar or Satellite, please contact us. We are constantly optimising our solutions and we guarantee high performance.

Marine Electronics

Sonar Technology

Sonar is an abbreviation of SOund NAvigation and Ranging and is a technique that uses an acoustic impulse to track and determine the distance and direction of objects in the ocean.  A modern advanced sonar is a natural part of marine electronics and navigation equipment on any ship.

The equipment is often used to find shoal of fish and in military applications. The sonar is essential when trawlers and other materials are traced. The sonar was intensely developed during World War II when the Allied forces became able to find the enemy’s submarines.


Today, commercial fishermen and shipowners have access to advanced marine technologies based on the sonar and its historical development. A sonar is a type of ship electronics that transmit signals and impulses of so-called ultrasound.

The sonar captures the sound impulses when they are reflected from objects in the ocean. In practice, sonar reflections are seen on a screen showing the section of the ocean in which sound waves propagate. When the sound is reflected, the object is displayed on the screen and the image is updated each time a new reflection is received.

How it is used

The signals (echo) that the sonar collects can be further processed by a computer on the ship, and if the object moves, its speed and motion can be determined when the Doppler effect is taken into account. The echo from the sonar is set slightly up or down in frequency depending on whether the object moves away or approaches the source of sound in the sonar.

The marine electronics used to determine the position and speed of a fishing shoal is today at an advanced stage. 
Therefore, precise measurements can be obtained, which may be crucial for fishing boats and other vessels. The predecessor of the sonar was the so-called hydrophone. The hydrophone can only capture signals from objects in the water, and therefore does not provide the same information as the sonar.

An echo sounder is actually a sonar system, but in practice it is a simpler solution that primarily measures sea depth and indicates fishing shoals under the ship.

With satellite antennas it is possible to obtain robust and reliable internet connection and television at sea. At Seamaster, we mainly deliver SATCOM products from KNS.


Screenshot of sonarinformation

Some of our other products

The trawl sonar can show the net profile, messure debt and temperature.
Internet, TV and phone when you are out at sea.

Marport door sensors that, among other things, measure parameters on the blades.
Come and visit us at the DanFish International 2019 fair. You will find us in hall H, booth 96.
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