The hull unit is a motor-driven shaft that carries an expensive transducer through the bottom of the boat. These are the rules in Furuno's manuals that keep people, the boat and the transducer safe.
At a glance
- Breaker off before anything manual
- Never transmit out of the water
- Check the depth before lowering
- Retract before powering off
About 6 minutes. Part of Own it in the CSH-10 course.
Around the moving shaft
Keep hands, tools and loose line clear of the shaft while the transducer is moving. Before you do anything by hand on the hull unit, turn its breaker off. Furuno warns that wrong wiring of the motor or the brake can let the shaft drop, so leave wiring to a technician.
In the water and out
Never transmit with the transducer out of the water. The sonar stops transmitting on its own when the transducer retracts, and if transmission was left on it starts again when you lower. Check the depth before you lower it, because a shallow bottom can strike the dome. Slow below 18 knots to lower or raise it, and retract it before you power the sonar off; if power is lost while the transducer is out, the unit retracts it automatically.
Retracting by hand
If the transducer will not come up, the Operator's Manual describes a manual retract. Turn the hull unit's breaker off, open the handle cover, fit a 19 mm ratchet, release the motor brake and turn counter-clockwise. Do not force it. If anything binds, stop and call a technician. A tangled net is one cause Furuno lists for the problem, so check the shaft area first.
Handling the parts
Do not paint plastic or coated parts of the units. The soundome is filled with oil; wear gloves and eye protection when handling it, and do not clean the dome with alcohol. Never connect or disconnect a powered cable, and respect the compass safe distances in the manual so the sonar does not disturb your compass.
A habit worth having
Make a quick routine of it: depth, speed, transducer position indicator, then transmit. The indicator at the top left of the screen is green when retracted, red while moving and yellowish brown when protruded, so one glance tells you the state.
Watch it done
Furuno USA publishes these CSH-10 videos. They play from YouTube when you press play.
Operator Orientation Part 1: initial settings, P settings and manually moving the hoist unit
Check yourself
Three questions
Sources
- CSH10 Operator's Manual: Safety notes and chapter 10
- CSH10 Hull Unit Installation Manual: Chapter 1 cautions
- CSH10 Recommended Annual Service: Hoist unit
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.