The CSH-8L MK2 is Furuno's electronic scanning omni sonar. This lesson covers what the system is made of, what its beam and display can do, and where it sits in Furuno's line.
At a glance
- Scans the full 360 degrees every 0.54 s at a 1,000 ft range
- 85 kHz in the US; a 107 kHz version exists in the manual
- 16 colors on a separate XGA monitor
- Hoist stroke of 400 or 600 mm
About 8 minutes. Part of Meet your CSH-8L MK2 in the CSH-8L MK2 course.
What it is
The CSH-8L MK2 is a full-circle scanning sonar. It transmits a pulse in every direction at once and listens with beams that scan continuously around the circle, so the whole picture is redrawn every ping rather than assembled one slice at a time. Furuno's brochure gives 0.54 seconds for the full 360 degrees at a 1,000 ft range, against about 32 seconds for a searchlight sonar such as the CH-250 stepping 6 degrees at a time at 400 m, and bills it as about 60 times more information.
The units
- Processor unit (CSH5210A): the black box that builds the picture.
- Control unit (CSH5211A): trackball, RANGE and GAIN knobs, a TILT lever, function keys F1 to F4 and the keys for marks, target lock and the hoist.
- Transceiver unit: a bulkhead-mounted unit of about 37 kg that creates the transmit pulse and handles the received echoes.
- Hull unit (hoist): the CSH8040A (600 mm stroke) or CSH8041A (400 mm stroke), which carries the transducer through the hull tank. It takes 20 seconds to move the 600 mm unit and 14 seconds for the 400 mm unit.
- Transducer: the 85 kHz element array in its dome, with about 6.5 m of cable.
- MS-100 motion sensor (optional) for the stabilizer, and a CSH7040 handheld remote (optional) for tilt, range and gain.
Furuno does not supply the display. Use an XGA monitor; Furuno lists models and allows up to two.
Frequency and beam
The US model runs at 85 kHz. Furuno's manual also covers a 107 kHz version, but the US page and packing list cover 85 kHz only. There is no dual-frequency option. The vertical beam is about 13 degrees at the -6 dB points, and both the horizontal and vertical beam widths can be set to WIDE or NARROW from the menu.
The display
Three display modes: NORM (sonar only), COMBI-1 (sonar with an audio picture) and COMBI-2 (sonar beside an echo sounder, which needs a fish finder connected through a VI-1100A). The picture uses 16 colors for echoes and one for marks, over two analog RGB video outputs at 1024 by 768.
Where it sits in Furuno's line
The CSH-8L MK2 follows the original CSH-8L of 2002, and Furuno's own documents for it date from 2015. The CSH-10 is the newer model. As of November 2026 the CSH-8L MK2 page is still live on furunousa.com and is not labeled discontinued. The CSH-10 course on this site covers the newer sonar; this course stays with yours.
Check yourself
Three questions
Sources
- CSH8LMK2 Sportfishing Brochure: Specifications and scan rate
- CSH5LMK2 CSH8LMK2 Operator's Manual: Specifications and chapter 1
- CSH8LMK2 Installation Manual: Equipment lists
This lesson summarizes Furuno's public documents in our own words. Limits and settings differ by model and software version, so your own manual and your installer have the last word. OmniCSH is an independent project, not a Furuno program.