Big projects like adding SONAR make us nervous. In spite of all the research, and actually testing the gear on another boat, our experience over the years is that fancy electronics are often long on pizzazz and short on function. So, we were somewhat nervous when we maneuvered Wind Horse out of Ventura Harbor using SONAR to con her the first time.

However, we’re pleased (and relieved) to report that the the Furuno CH270 SONAR does work as expected.

Here is a screen shot leaving our dock and heading down the channel. You can clearly see the edges of the channel and moored boats (bright red) on the port side, with the channel edge plus the dog leg at the north end coming into view at the top of the screen. Range is set at 500 feet (150 meters). The thin trail alongside to starboard is the wake of an outboard-powered inflatable dinghy.

The controls for the SONAR are at the top of this photo (radar is at the bottom). The control box is on a long cable, so we can move it to a position more in front of the monitor, if that seems to make sense later.

Having read the manual twice, and spoken with Steve Bradburn of Furuno a couple of times during set up, we found the controls are actually quite simple to use. It will be a while before we’re really up to speed, but for nosing our way into a new anchorage, where we do not trust the charts, we’d be comfortable with just a few days of practice.

This photo was taken coming up on the Ventura Harbor breakwater from the southeast (see the photo below) in 3- to 5-foot (0.9 to 1.5m) swells. Range is still at 500 feet (150 meters). The detached breakwater and the section projecting out from shore (starboard forward quarter) are clearly visible.

One of the things we’ve learned is to reduce the angle through which the SONAR scans. The narrower the angle, the faster the data updates. In this case, we know we’ve got deep water off to port on the ocean side. It is ahead, and to starboard on the beach side that we want the undersea image. So, the SONAR is scanning through 168 degrees in total width, and the center of this beam is offset about 40 degrees to starboard. This way, we’ve got the image ahead and along the beach side. We could have it centered, of course, and increase the scanning width, but this would take more time between updates.

The photo above was taken at the same time as the SONAR screen shot.

Here we’ve entered the area between the two breakwaters. Range is set at 700 feet (215 meters). The channel is clearly shown. Of course, we could see this with the radar as well, along with charts. But if we were making an entry into a new harbor, and visibility was not the best, it is nice to know that as long as the image shows white ahead of the boat on the SONAR, there are no unmarked obstructions.

This image is looking ahead into the area where we dock Wind Horse. The channel on both sides is clearly shown as is the open channel to the east toward Ventura Harbor Boat Yard. The SONAR is now taking a 360-degree look around, with the boat at rest. We expect to use the SONAR in this mode from now on to each time we drop the hook to check the bottom for obstructions.

This photo is looking the same direction as the SONAR.

What we know now is that with our type of installation, where the transducer is in a relatively shallow location, the system works great in calm conditions. With the range dialed down to 500 to 1000 feet (150 to 300 meters), we are getting good images, and these will no doubt improve once we get hands-on training from the experts. We’re not sure if we can make the system work for us offshore in waves, due to our very shallow installation. But Steve Bradburn at Furuno has some ideas for us to test on this.

Stay tuned!