Forward scan sonar revolution is coming

[Jammer]

Originally Posted by Bill O

If someone does make a good FS, would like to see another feature added and that would be a good side scan. It would be nice to detect openings in the reef as one runs parallel, instead of turning the boat to get a better look.

There are a number of fantastic side-vision sonars out there, mainly catering to sport fishing markets.


They work great, and provide a 3d image. Transducers for through-hull mounting are around $2500 a pair.

[S/V Alchemy]

Originally Posted by Aswayze

I have the above mentioned Forward Scan on my B&G system.

It may be useful somewhere but it is beyond useless sailing up on the Great Lakes. In particular, sailing up around Isle Royale where the water tends to shelf up fairly suddenly. It does not pick up the bottom until you are fairly shallow and then only after a little while so generally I am on or nearly past the shallow part before it begins to display anything and even when it is up and tracking, it's pretty flickery and crazy. It CAN give you useful data but only if you are staring exclusively at it which of course only an idiot would do.

Oddly enough when I have an EXTRA crew person, I'll generally try to employ the forward scan picking my way into tight spots but never when I am short. I need eyes up looking around the real world.

TO be fair to the system, it might work better if I twiddled with the settings a bit but thus far, it has not seemed to be worth the effort to do so.

I have the same system and it is worth learning (as is radar) to twiddle until you find its true, rather than its perceived, limitations. As I needed to replace a standard sounder and needed a small, if versatile, plotter, I got the transducer and the B&G Vulcan 7 display for my pilothouse. I set the offset for about 0.5 metre as I do not need to scour the zebra mussels off the box keel (it's a steel motorsailer). I found the FLS very useful in 2017 right after I installed it as the very high water that spring overtopped the seawalls and the FLS revealed "the gap" perfectly.

In addition, it's a perfectly good "standard" sounder, again, if you are willing to modify the settings and experiment. I've seen the outline of wrecked ships 20 metres down pretty easily. Just as gain must be tweaked on a radar to see squall lines/rain advancing aft, so the gain on a FLS can be tweaked (or the display changed) to reveal the hints of what's forward.



An additional feature I've started to use is the B&G "link" software on a tablet that allows me to operate the plotter and the display away from the pilothouse. I can see from the aft deck shallow rock formations ahead both on the FLR and through the changes in the waves as they go over what passes for a reef around here by eye.

I'm sure there's a few YT instructional videos out there. To me, it's one of the better instruments I've ever bought, but I don't expect it to do the dishes!

That said, as I have two crew, I will probably get a drone with a polarizing lens as a "crows' nest in the sky" or "mast steps, but better" to look forward of the boat as conditions permit to see wrecks or coral heads I want to avoid in some of the more desirable anchorages of the Pacific.

[rosatte]

We have had BG forward scan for 2 seasons now works great in clear water but throw in weed beds and it detects that as bottom so no good for Great Lakes region

[FabioC]

I agree that forward scanning, at least in principle, looks like an amazing thing to have on a boat. Unfortunately, current technology is fairly primitive and marginally useful. I was seriously considering installing the B&G forward scanner a couple of seasons back, but decided against after doing the research. First of all, the underwater profile of the "thing" is excessively bulky, then the accuracy and range are questionable at best, then by design it does not "see" ahead just below the surface, where arguably would be the most useful.

I would expect major advances in the technology in the not so distant future, since the use case is pretty obvious and the sensor technology, including SONAR based, is advancing at a very rapid pace.

[Aswayze]

I have found the Link system to be excellent as well.

I have never seen bottom past 35 feet. Most of the time, I don't pick anything up till I get into the mid 20s. Again, at least up in the Great Lakes, it just never gets me any actionable information in a timely fashion.

I'll try twiddling with it some next time I am up there. The home lake here is pretty shallow so it tends to keep track of the bottom pretty well down here.

[bcboomer]

I'm sure this is a stupid question but I'll ask it anyway.

What would one see if one pointed a conventional narrow beam transducer forward at maybe a 30 degree down angle?
Set for say 100 feet warning could it see a container or whale?

[Dennis.G]

We have an Interphase unit, and while it has come in handy at times, I find it very hard to use. The main problem is that one has to really watch it intensely to see the bottom come up in time to do something about it. Usually I am spending time looking at the water and other things around me, but the Interphase display isn't going to give you much of a prior warning, and if aren't watching it you can miss it. Also, if water is muddy or turbulent you can have a hard time determining where the bottom is anyway from the display. Useful, but comes short of what I want it to do for me.

[Paul L]

Originally Posted by Pete7

How slow have you got to go before the Echopilot gives a realistic or say reliable picture of what is ahead?

Pete

The speed you are going doesn't effect the FLS. It is the response time for the helm to do something about it. The deeper the water the further ahead you see. As the water gets shallower you are only seeing maybe a boat length ahead. So you have to be going slow enough to make a turn or stop within that boat length.

[Scrimshaw4]

Like everything else that Garmin gets it's hands on they kill the product line in favor of their own inferior technology. I've had an Interphase unit for 20 years, totally unsupported from the day they they bought it. Now they have Delorme In Reach and are gouging the market price.They are following the Navico and Xantrex business models of buying up technology and then leaving the customer base out in the cold. I'll NEVER purchase from any of them again. Rat Marine may seem pedestrian but at least they continue to provide their clients with support and a migration path!

[Scrimshaw4]

... hate not having spell check ... Ray Marine .....

[Jim Cate]

Originally Posted by Scrimshaw4

... hate not having spell check ... Ray Marine .....

They may be better now, but at times in the past your misspelling was correct!

Jim

[CapnBazza]

Originally Posted by Jammer

Forward-scan sonar has been around for a couple of years. I'll admit that I was dismissive of the technology at first.


YouTube videos of cruisers actually using it to navigate shallow water are finally starting to show up, e.g.:

It seems to me that this has the potential to open up previously unusable areas in much the same way GPS did. It makes it possible to pick your way through waters where you can't see (either because the water isn't clear enough or because it's night or the sun is at the wrong angle), and to get much closer to the bottom than most people would any other way.


And provides a backup in case the mark-1 eyeball misses something.



Also allows shorthanded boats to go into areas where it would otherwise be necessary to have a bow lookout or a scout ahead in a dinghy.


There are limitations. Posters here have said you have to go slow, about 1 knot, because the range is short. But still. Watch the videos if you're not convinced..

Geez cobber, you’re at least 25 years behind the times. People also used to say that the telephone would never be really useful and there would never be more than just a few computers.

[MickMeck]

Originally Posted by CatNewBee

I have fitted a B&G forward scan, same transducer and UI like the picture above, it works, but does not replace eye ball navigation.

Do not expect too much, it is just another source of information and may warn you before a collision, but not sufficient to maneuver around. The range is appoximately 4 to 1, means on 10ft depth you see 40ft ahead.

Agree, I also have the same equipment on a B&G and find it not worth the money or the effort to install. The cable is difficult to run and has a restriction of not adding more than 1 additional 20' cable. This was very tight to install as I have a 43' sailboat and mounted the transducer just forward of the keel. My depth is 5.3 so in 6 foot of water it can see only 24 feet in front - which is where my bow is. So, I must be going very slowly for it to work. Also, it gives way too many false positives (looks like zero depth even when the depth is 10'). I have it now but I would not recommend to anyone until they improve on it.

[Shrew]

Originally Posted by Pete7

How slow have you got to go before the Echopilot gives a realistic or say reliable picture of what is ahead?

Pete

I have an Interphase. It's not that the image is or isn't reliable or realistic. Rather, it is a matter of physics.

In the image provided in the first post, it looks like the image is going out about 38 feet.

1 Nm = 6076.12 feet.

At 6Kts, you're traveling at 10.12 feet per second. This gives you a reaction time of about 3.75 seconds. So you had better have your eyes glued to the FLS, with one hand on the wheel and the other on the throttle.

Slow speeds only serves to increase reaction time.

[patja]

I have the Garmin Panoptix and have yet to feel like it is really helpful. The biggest drawback I've found is that on my 7607xsv chartplotter, there is no option to split-screen the view to show the chart with charted depths at the same time as the forward scanning sonar. Use the sonar, sacrifice the chart, or vice versa. I've considered bringing an iPad to bear and having the chart on it with the sonar on the chartplotter, but it seems a bit much to manage in the moment of scouting an anchorage.