Forward Scanning Sonar ?

[pilot]

Interesting! They call it "obstacle avoidance"! Thanks for the hint!

[Roy M]

I have installed an Interphase SE 200C (photos of tranducer installation in Photo Gallery, Multihull forum). Have not actually hooked up the unit yet, but hope to within the next month (too many simultaneous projects). I purchased it as the most advanced unit of its class (under $10,000) and its compatibility to my Raymarine network. I'm as anxious as anyone here to see how it performs, but I'm still trying to locate my tools and stuff after a three week haulout.

[AnchorageGuy]

The Farsounder looks interesting but see no dealers or pricing on them. That usually means most of us can't afford it.

[Agility]

I had the Interphase forward sonar and found it fairly useless. First off, if I really needed to see coral in close quarters I could see it much better with a look-out on deck. I used it a few times to center a channel, but on my next boat (a multi-hull) I think dual depth sounders would give the same quality of information.

I never noticed the ability to see the anchor, but seeing it drag seems like a funny way to determine if your holding.

Just my $.02.

[44'cruisingcat]

Originally Posted by BlueRhapCity

I had the Interphase forward sonar and found it fairly useless. First off, if I really needed to see coral in close quarters I could see it much better with a look-out on deck. I used it a few times to center a channel, but on my next boat (a multi-hull) I think dual depth sounders would give the same quality of information.

I never noticed the ability to see the anchor, but seeing it drag seems like a funny way to determine if your holding.

Just my $.02.

Who said anything about seeing the anchor drag? What I said was I can see it lifting clear of the bottom when we are raising it. So if we are in a tight anchorage we know when we are free of the bottom and can maneouver.

[Agility]

My mistake. Sorry for the confusion.

[pilot]

3D Forward Looking Sonar for Obstacle Avoidance

Here the official answer for price and availibility for "normal sailboats":

currently our systems are appropriate only for very large sailing
yachts. (30 m +). This is due to their size and perhaps to some
extent, their cost.
Systems run from $74,000 US to $86,000 US and the diameter of the
transducer module is ~250 mm.
Please keep watch on our website for future product expansion, though
it may be a while before we have a product appropriate for smaller
sailing yachts.
Thank you for your interest.
Regards,
Cheryl

Out of my budget region!

[44'cruisingcat]

Our Echopilot cost us AU $1200. You can buy a pretty decent boat for US $74,000- $86,000.

[pilot]

Is your ECHOPILOT capable of detecting floating objects? Any experience report?

Thanks

[44'cruisingcat]

It would depend on how much of the object was below the water. We haven't encountered a shipping container, so I don't know, but I don't think it would see it from very far away, and even if it did, I doubt if I would interpret it from the display. It would show one from up close though, but whether it would give enough warning to avoid one, I don't know.

[Jentine]

Prior to last year, I was extremely interested in purchasing a forward scanning sonar. I, wrongly, assumed that the screen would display data similar to radar. That is not the case. I had the opportunity to use the sonar for seven days and was very displeased with the results. The scanner can find the bottom, but everything else is questionable.
At one point we entered an uncharted harbor in broad daylight. The visual appearance of the entrance was that there were no objects in the way and that the way was clear. The sonar had a different story to tell. The water, being less than 15' deep, seemed to be a challenge and the screen displayed things that weren't there. We shut it off and reserved its use as a depth sounder only.

[pilot]

What type/manufacturer was it?

[atraitees]

Ok, I have a very strange question. If a fish finder uses sonar to find things, and display them on a screen, what would happen if you turned the transponder from down to forward and developed your own "system" on the display. Example:
Through your anchor in the water and record what the screen does.

That kind of thing. I know it would work. It is a basic technology. What I don't know is; how would it fair as a make shift FLS??

Just thinking out loud here. I picked up a hummingbird system that goes up to a dept of 900 feet. I only paid 50$ for it, so I am going to give it a shot anyway. I would just like to hear you points on the subject. :-p

[Nauticatarcher]

We have a Interphase twinscope, saved me from hitting a coral head in New Cal, and great in Fiordland, NZ where you anchor and then tie back to land to make sure there was no rocks etc, like anything you have to learn how to read it and know its limitations but as we like poking our noses into places less charted, I use it alot

[Jim Cate]

We have had a Probe (scans from straight down to straight ahead) since 1996, and despite the above reports as to their uselesness we find it to be indespensable.

Yes,it does require some interpretation, rather like a radar does, and yes, it does not help much in very shallow water. But it really helps when entering a strange anchorage in poorly charted areas or when navigating in murky water, or trying to find a safe spot to drop the hook when one has arrived after dark. All of these situations seem to occur in real life cruising, and the Probe has saved our bacon a number of times.

It has some practical problems: at longer ranges the scan rate is slow (it takes a finite time for the sound pulse to travel several hundred feet and then return), the alarm systems are confounded by noise and are about useless as mentioned in other posts, the extremely bright backlight in the display has no dimmer, and remarkably it does not have a keel offset adjustment. None the less, when we sold Insatiable and bought Insatiable II 5 years ago I bought a new Probe to install during the survey haulout -- I didn't want to prang my new boat!!

How good is it in the real world? We have "seen" coral reefs at ranges of 500 feet in lagoon situations (200 feet deep and steep, hard coral walls rising nearly vertically), and beach shallows 150 feet off. It also sometimes "sees" thermoclines and discontinuities in salinity near river mouths (I think), but I'm willing to suffer some false positives if it faithfully spots the real hard bits.

The newer "twin-scope" versions are likely even better,but I have never used one of them.

All in all, it ain't perfect, but it is a lot better than guesswork and thumps!

Cheers,

Jim and Ann s/v Insatiable II lying Gladstone Qld Oz