An omni install is a hull job and an electronics job. This lesson turns Furuno's installation requirements into questions you can put to a yard or dealer, so you can tell a careful quote from a casual one.
At a glance
- Mount 1/3 to 1/2 of the boat's length back from the bow, on or near the keel
- Dome reaches at least 500 mm below the keel
- Tank flange at least 100 mm above the waterline
- 24 VDC supply and its own breaker for the hull unit
About 9 minutes. Part of Own it in the CSH-10 course.
Where it goes
Furuno's hull unit manual puts the unit between one third and one half of the boat's length from the bow, on the keel or within a meter of it. The dome should reach at least 500 mm below the keel to stay out of aerated water. Keep it at least 2.5 m from other transducers, with nothing ahead of it that would shadow or aerate the water, and nothing protruding below it. Ask: where exactly will the tube sit, and what is ahead of it?
The tube
The retraction tank has a 190 mm inner diameter, with shims covering 188.1 to 195 mm, and no weld beads inside. Tubes come in 1,000, 1,800 and 3,500 mm lengths and are cut to suit. The shortest allowed tank is 550 mm for the 400 mm travel unit and 750 mm for the 600 mm unit, and the tank flange must be at least 100 mm above the waterline. If you are replacing a CSH-8L MK2, Furuno says the CSH-10 uses the same tube. Ask: can we reuse the tube, and who inspects it?
Headroom and speed
At the shortest tank lengths the hull unit stands about 698 mm (27.5 in) above the tank flange for 400 mm travel and 898 mm (35.4 in) for 600 mm travel, and Furuno recommends 150 mm of service clearance above that. Boats that run 25 knots or more need a fin ahead of the tank hole, or the fairing Furuno sells for small fiberglass boats. Ask: how much room is there above the tank, and does the hull need a fin?
Power and cables
The CSH-10 runs on a stable 24 VDC. The hull unit gets its own breaker. If your boat is AC only, Furuno offers a supply for 100 to 230 VAC. The processor and transceiver connect by a serial cable and an Ethernet cable, each up to 100 m, and the monitor connects by HDMI. All units need grounding to the ship, not the engine. Ask: what is the supply, the breaker size and the cable route?
What it costs
Marlin magazine (Steve Katz, October 2026) put tube installation at about $20,000 and electronics installation and commissioning at about $10,000, as of 2026 and depending on the boat and yard. Before the CSH-10, a CSH-8L MK2-era installed system was reported at $110,000 to $120,000 (InTheBite, February 2024). Hull work and yard time move the total more than the electronics do. Ask for a written scope that separates the tube, the electronics and the sea trial.
Check yourself
Three questions
Sources
- CSH10 Hull Unit Installation Manual: Sections 1.3 and 1.4 and outline drawings
- CSH10 Installation Manual: Chapters 1 to 3
- Marlin, October 2026: Choosing the Right Omni Sonar for Your Boat: Installation cost, October 2026
- InTheBite, February 2024: installed cost in the CSH-8L era: Installed cost before the CSH-10, February 2024
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.