The beam, tilt and what each angle shows

Tilt decides what depth and distance you are looking at. With a beam about 13 degrees tall, the angle you pick changes what you see far more than most owners expect.

The beam

The vertical beam is about 13 degrees at the -6 dB points. That is tall: at 100, 200 and 300 m it is roughly 23, 46 and 68 m deep, so a single ping covers a thick slice of water. Furuno USA's tilt diagram for 5 degrees shows coverage heights of 101, 202 and 303 ft at 500, 1,000 and 1,500 ft.

Setting tilt

Tilt is manual from 0 to 55 degrees in 1 degree steps, set with the TILT lever. Less tilt looks farther out and shallower; more tilt looks closer in and deeper. Automatic tilt scans from 4 to 52 degrees within a window you choose, for example 2 to 10 degrees, and the window narrows at long ranges.

Which angle for which job

• 30 to 40 degrees: uses the full beam on the bottom and shows the whole bottom echo. Fish can hide in it.
• 10 to 20 degrees: shows fish above the bottom echo, which suits midwater schools.
• 0 to 5 degrees: shows fish close to the bottom or close to the surface.
• About 5 to 6 degrees for surface fish: the upper edge of the beam sits parallel to the surface. Add a little tilt in rough water.

At 0 degrees the picture shows sea-surface reflections out to 300 or 400 m, which is one reason to add a few degrees of tilt for surface fish.

What makes a good target

Furuno notes that vertically distributed schools return better than flat ones, and that bottom fish are hard to see unless they stand up off the bottom.

Check yourself

Sources

• CSH5LMK2 CSH8LMK2 Operator's Manual: Sections 1.4 and 6.3
• CSH8LMK2 Base Settings Guide: Tilt diagram
• CSH8LMK2 Sportfishing Brochure: Specifications

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.