New Advances in Forward Looking Sonar

[Roy M]

Panbo has an update on forward looking sonar:
Panbo: The Marine Electronics Hub: Simrad ForwardScan, a challenge to EchoPilot FLS?

[MarkJ]

You notice in the screen shots they are only showing you 8 meters in front of you?
The max one was 25 meters.

There was one photo showing the boat going at 6 knots with an obstruction 30 meters in front. Sorry! But thats too late!

Its ok when you are coming into a marina... But thats all.

[gamayun]

This will be cool -- eventually. If the sonars could be tweaked to focus only on the first 20 feet of the water column and if they could sound a collision alarm like they do in planes if objects are greater than a certain specified size (I'm thinking a "large" log, for example), then this has promise. But having to keep your eyes glued on a screen, interpreting signals from all sorts of floating objects such as birds, and getting lots of bottom info you don't need, seems tedious and not very useful.

[skipmac]

Originally Posted by MarkJ

You notice in the screen shots they are only showing you 8 meters in front of you?
The max one was 25 meters.

There was one photo showing the boat going at 6 knots with an obstruction 30 meters in front. Sorry! But thats too late!

Its ok when you are coming into a marina... But thats all.

30 meters at 6 kts. That would give you about 9 seconds to dodge, plenty of time unless you are getting old and slow.

[zboss]

9 Seconds is plenty of time to steer back into the ICW groove.

[Jim Cate]

From the data provided I can't see any improvement over the old Interphase Probe that has been around since 1996 at least (when I bought my firs one). I know that Interphase was bought up by (I think) Ray marine, and that they are no longer on the market, but they were always better than the similarly priced Echo Pilot models that I saw in use.

Wonder what is going on in this market place?

Cheers,

Jim

[IslandHopper]

You could always go with one of these units, Forward Looking Navigation Sonars for Obstacle Avoidance | FarSounder unfortunately the price is in the range that only a Super yacht or commercial ship owner could absorb, plus the transducer has about the same dimensions as a medium sized microwave oven...

[skipmac]

Originally Posted by zboss

9 Seconds is plenty of time to steer back into the ICW groove.

Certainly if you are standing at the helm in the ICW and drift to one side of the channel that 9 seconds would be enough time to alter course to get back to center channel.

But consider a boat at sea, under sail, self steering and sonar detects an obstruction dead ahead. Unless you were sitting at the helm with your hand on the wheel ready to dodge immediately, 9 seconds would be nothing. Even if you were sitting at the helm; to see an obstruction on the sonar, confirm what it is, decide to dodge left or right and actually alter course far enough to clear would be unlikely.

Never had the chance to use or even look at one of these but the general conclusion from those that have is they are useful at slow speed in calm water to spot obstructions or shallow areas, but at higher speeds and especially in any kind of seas the benefit is minimal if any at all.

[Roy M]

Ease off folks. FLS range is dependant on depth. I have an Interphase SE200C that provides only about 100 feet of range inside the 20 foot deep harbor, and as much as a 1000 in blue water. It was Garmin that bought out Interphase, but Simrad has beat them to market with a new unit. This is only the beginning of a new series of FLS units with superior resolution and features than what we have seen to date. Or, you can pass it off as a temporary fad, kind of like multihulls, flying machines, and Dick Tracy wrist communicators. Personally, I'm happy with my current, low tech unit, and will be even happier when the new ones come out. I merely brought this to your attention to inform some of you of the coming technology, not to sway the unconverted minds.

[skipmac]

Originally Posted by Roy M

Ease off folks. FLS range is dependant on depth. I have an Interphase SE200C that provides only about 100 feet of range inside the 20 foot deep harbor, and as much as a 1000 in blue water. It was Garmin that bought out Interphase, but Simrad has beat them to market with a new unit. This is only the beginning of a new series of FLS units with superior resolution and features than what we have seen to date. Or, you can pass it off as a temporary fad, kind of like multihulls, flying machines, and Dick Tracy wrist communicators. Personally, I'm happy with my current, low tech unit, and will be even happier when the new ones come out. I merely brought this to your attention to inform some of you of the coming technology, not to sway the unconverted minds.

Sorry, I haven't seen any previous posts on this thread that are not easy.

I am pretty sure that there is no misunderstanding about the depth dependence of forward looking sonars. After all, it's just basic geometry.

Sailing in deep water and approaching a shoal you would get plenty of range and warning. However in shallow water the range will be quite limited and you will get very little warning if the depth drops from say 8' to 4' or say from 4' to 2' which would put even most catamarans aground. Extrapolating from your example of 100' range in 20' depth then in 8' of water you might get a 40' range or 20' range in 4' depth. That's not much.

The other issue is a lot of cruisers are looking for something that would give warning for a floating hazard like deadheads or shipping containers. In that situation forward looking sonar, from all reports, offers little to no assistance.

[robert sailor]

So could they pick up a partial sunken container??

[Randy]

Originally Posted by MarkJ

You notice in the screen shots they are only showing you 8 meters in front of you?
The max one was 25 meters.

There was one photo showing the boat going at 6 knots with an obstruction 30 meters in front. Sorry! But thats too late!

Its ok when you are coming into a marina... But thats all.

Exactly! The thought of using this as early warning for obstructions in front of a boat is nice but fantasy.

Sent from my SAMSUNG-SGH-I337 using Cruisers Sailing Forum mobile app

[skipmac]

Originally Posted by robert sailor

So could they pick up a partial sunken container??

Sure. You will pick up the container about a nanosecond before you hear the loud crash.

Seriously, you might get a few seconds warning or none at all, depending on the sea state at the time. A partially submerged container might sit 8-10' down in the water. If the seas are running 4-5' the pitching of the boat, and the container rising and falling in the waves plus all the surface turbulence the chance of getting any significant warning of a floating container are pretty much nil.

[skipmac]

Originally Posted by Randy

Exactly! The thought of using this as early warning for obstructions in front of a boat is nice but fantasy.

Sent from my SAMSUNG-SGH-I337 using Cruisers Sailing Forum mobile app

[Jim Cate]

FWIW,

I have now used an Interphase Probe for nearly twenty years. During this time we have been cruising in many areas of the SW Pacific, and many of these areas are poorly charted.

I have found the Probe to be very useful in entering strange anchorages, especially under poor visibility conditions or at night. They are not useful for avoiding floating containers or other such hazards... no question about that! But for slow speed exploration of unfamiliar waters they are VERY useful, at least in our cruising experience, and it has kept us off uncharted and invisible shoals more than once. IMO, even once paid for the instrument well and truly.

I was disappointed to find that in the situation where one is following a shallow channel, and worried about it going from just enough to float to not quite enough to float... well, jsut as the naysayers think, not very much use, for the resolution isn't good enough.

If I was to comision a new cruising yacht, I would definitely fit some sort of FLS. It would be great if further improvements in the technology came through to us yotties who can't afford the 10k$+ versions.

Cheers,

Jim