Re: Forward looking Sonar - Amel 54 - Echopilot FLS 2D frequency vs B&G Sonic Speed Sensors or Depth Sounders

James Alton


   Thanks for the response.  To me a good Depthsounder has always been very important and I will usually leave  one on even while we are anchored as additional confirmation that all is well when doing the nightly anchor checks.  Sueno currently has two Depthsounders and I am really glad to have a backup of this instrument.  FLS will actually give me another backup.   We also carry a depthstick for checking channels and or some anchorages by dinghy when the situation dictates though maybe there is a better way using modern tools to handle these mini surveys.  With good conditions and water clarity such as in the Bahamas, I think that it is pretty hard to beat having a good lookout when navigating in shallowish water so under those conditions my eyes are not normally looking at an instrument very often.  The FLS concept really appeals to me for those times when there are issues with water clarity, sun angle etc.  and chart data is iffy or even non-existent.  

   I have been reading about OpenCPN and it’s functionality with Google overlays etc. but I have not used it so far.  I agree, dedicated chart plotters are expensive but they can have super bright daylight viewable screens, can be really waterproof etc.   I currently have a B&G Zeus3 plotter,  a smaller back up plotter,  1 tablet, (want to add a back up tablet).  Also a weatherproof, daylight viewable ToughBook laptop with built in GPS that I intend to use for OpenCPN.  Can you comment on how much data storage is sufficient given the storage of the Google map data and full time cruising?  

    The idea of using AIS information from other vessels to plot a path on a chart into a channel or anchorage is new to me and I appreciate you mentioning this option.  That does sound like a very useful tool!  So if I understand correctly, you can ask OpenCPN to plot the track of an AIS target on a chart just as it can plot your own GPS track?   I agree to the concept of having many tools to keep our boats in safe water and especially for those times that I am literally running blind, FLS sounds very appealing.  I will try the 5 meter setting of the alarm as you suggested and consider the value of a pretty constant alarm to remind me to dedicate attention to the FLS.  Constant alarms can certainly be annoying to me so we will see!  

 Thanks for the helpful input,

James Alton
SV Sueno
Maramu #220



On Oct 3, 2020, at 1:39 AM, Ken Powers SV Aquarius <ken@...> wrote:

Hello James,

As Danny wrote in his comment above, the FLS is not the only thing used to provide information about the dangers in front of you.  Good maps, eyes on the bow, are also helpful.  But, good maps are not good everywhere, and eyes on the bow get tired.   I have also noticed that many US sailors don't know about OpenCPN.  Download OpenCPN for your computer, connect to a GPS device, and you have a back up chart plotter ..... FOR FREE.  Get the maps from your sailing friends.... I also download all the Google overlays for areas and add to my map folders in OpenCPN before I take off.  This gives me one more input to keep Aquarius from touching anything.   Another thing about OpenCPN.....  You can connect to a Vesper 8000 AIS over WIFI, and now if you're going into a tight place and other boats are in front of you, you can plot their path.  I used this method in Fiji, and Malaysia entering marinas.  I didn't know the exact path in so I just plotted the path of a few larger boats going in and out and just followed their path.  This also helps in shipping lanes you can see which boat are moving and where they're going.  All for free.  If you have two computers loaded with OpenCPN, 2 Pads with charts, and 2 Smart Phones with Charts,  spending money on the standard chart plotter might be a waste of money?

For the question.  I set the alarm on the Echo Pilot for 5 meters.  And though it's annoying, it works.  If I am entering a marina, and it's 4 meters deep for a 100m the alarm will constantly beep.  Someone might say, "turn it off", but it's my reminder to keep my scan going.  The scan is just like flying a plane, you're constantly looking for an display/device/person that may not giving you correct information.  And, another good thing about having a FLS.  Most of us are carrying spares if something goes wrong.  How important is your depth sounder?  I would say VERY.  But, many of the SM's are getting older, and everything is not always working 100%.  If your depth sounder goes out, it's really nice to have a back up...  And the FLS is also my backup depth sounder... 

My 2cents, as someone else on this channel would say.  

Aquarius is currently in Thailand getting her mani-pedi.

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