Q&A: Forward Scan Sonar

Question: We are looking at sonar options for use in areas with poor charts and low visibility. Our interest is primarily for checking anchorages and narrow passages, looking for obstructions. We have a small plotter/sounder in the dinghy, but nobody wants to go out in the dink when it is cold and rainy (and warm and dry on the big boat!).

I have heard a rumour that you guys have an EchoPilot unit:

  1. How do you like it and how does it work?
  2. What do you do in a tight anchorage for checking what is around you?
  3. Is there a problem crossing your own wake at dead slow speeds?
  4. Where have you mounted the transducer and is it vulnerable to ice and debris? In our case, it would be on center, 16′ aft of the bow (in our forward watertight compartment) or centered fore and aft, offset to one side about 5′ and alongside one of the stabilizer fins (which reside in sealed coffer dams).
  5. Have you used it in the tropics with coral? I assume it would work well with the abrupt shape of the coral heads.
  6. Can you tell anything about bottom composition, i.e. mud vs. rock or kelp?
  7. Is it any good in ice?
  8. What do you do for a depth sounder? Use this, or something more specialized?

Silva Marine, NEXUS Network Wind Instruments, Problems

The Problem

In 2005, KVH abruptly stopped supporting the Quadra system, which had served us well for many years, albeit after its own set of teething problems. After considering most of the options and nearly settling on B&G, but finally being put off by a sudden and substantial increase to their already, in our opinion, ridiculously high prices, we settled on a NEXUS system from Silva Marine, a Swedish company.

ICS Navtex, Problems

The Problem

In 1999 our trusty old Furuno combination weather fax/navtex machine died after many years of faithful service. We decided to use our PC for weather fax and buy a dedicated navtex. We selected a unit from ICS.

The Joys And Tears Of TurboCAD

For the last few years we have been using TurboCAD for visualizing and designing projects on Morgan’s Cloud. TurboCAD is a great value, with much of the functionality of systems costing many times more, at just US$150, and you can often get it discounted to as little as US$80.00 by shopping around on the Internet.

EchoPilot Forward Scan Sonar FLSII

We have found that having a forward scan sonar has made exploring in the high latitudes safer and more feasible. Instead of feeling our way along at 2 knots when off the charts, we can now travel confidently at 6 knots, since the forward scan reaches out up to 200 meters ahead. Also, the sounder makes it possible to feel our way into tight anchorages, even when the water is not clear enough to see the bottom.