ELECTRONICS
Garmin’s new forward-looking transducer lets you “see” underwater obstructions
A new forward-looking depth sounder is put to the test
When I started sailing 40 years ago, all I had was a leadline: no depthsounder, no electricity, in fact, but I managed (with a little luck) to cruise from Europe to the Caribbean, through the Panama Canal and on to the Pacific islands. I cannot tell you how much easier that would have been had we been able to see under the surface 100 yards ahead—as is now possible with Garmin’s new PS51TH transducer, which turns a Garmin plotter into a forward-looking echosounder.
In the box with the transducer is a rugged stainless steel through-hull fitting, the same size as other Garmin transducers. For a oneday test, it was simple to swap out the standard transducer for the forward-looking one, but for permanent installation, you’ll need to lift the boat and change to the new skin fitting. Stainless steel is used to give greater strength in case you hit something hard and break the protruding transducer.
Our test boat was well equipped with Garmin electronics, so after installing the transducer it was a simple matter to connect it to a 12V supply and the Garmin network. Immediately we could see the underwater view ahead—even the mooring chain hanging down at the bow of the boat—so it was pretty impressive from the outset.
On Garmin systems it’s a simple matter to program the offsets for transducer depth and keel depth, plus the distance to the bow, so the view ahead showed the depth from the surface at the bow of the boat. Of course, if you prefer to see depth below the keel, that’s your choice.
At this point, I was introduced to Garmin’s smartphone app, Garmin Hub. It was impressive, to say the least, to be able not only to view the plotter’s screen on my iPad and iPhone, but to control the chartplotter from either device.
To test the practical application of the forward-looking sounder we planned to go out to, and over, a well-known submerged obstacle outside Portsmouth Harbor, on England’s south coast. The submarine barrier was built in WW2 and lurks just below the surface. It links the shore with a stone fort and was deemed too expensive to remove when the war ended. We also planned to approach mud banks and slipways, to see how accurately the forward-looking feature worked.
Forward-looking sounders come in two basic types, 2D and 3D. The 3D systems draw an image of the whole channel ahead, whereas 2D keeps it simple and just shows what’s in front of the boat. The Garmin system is 2D, so it’s not as sophisticated as some, but what do you really
need to know in a sailboat? A pretty picture of the whole channel might be cute, but is it relevant? I don’t think so. Having said that, for a 2D system, the Garmin is expensive, so they’ll probably have to do a little work on that.
For the first time in my life, I sailed a boat over the top of the submarine barrier off Portsmouth. On the first, cautious approach we could clearly see the obstruction ahead, but having taken care to get the offsets right, we passed straight over something I have always gone around, no matter the state of the tide.
It’s clear that as you approach the edge of a bank or a solid wall that comes right out, the Garmin tells it as it is. As with many plotters, you can customize the display to show combinations of chart view, radar and sonar, and I spent a long time trying to decide—unsuccessfully—which was best.
Conclusion: My verdict on this product is clear. I think a forwardlooking sounder that really shows precisely what is ahead is the most useful piece of electronics you can put on a coastal-cruising boat. I’d put it in front of radar and every other gizmo. The ability to repeat the information around the boat on iPads isn’t lost on me either.
It’s a bit pricey at $1,499.99, but perhaps it will come down. My grandma always said, “You pays your money and takes your choice.” She’d have been a Garmin fan. s