where is the forward looking sonar at?

[Siberian Sea]

In Alaska I own a commercial fishing vessel with a a sonar made by Furuno. What most everyone here calls a “sonar” for their pleasure boat is not really a sonar rather it’s a depth sounder with a forward looking transducer. Real sonars start at around $10,000 and need the installation of a sonar tube into the hull to house the special transducer. These transducers are not small nor cheap. Don’t believe the advertising by marine electronics companies like Ray Marine or B&G telling you these things they sell in the stores are sonars, they are not. If your have ever been around a real one you will understand why it’s just not something found on most pleasure craft and why it’s not talked about in the cruisers fleet.

[rslifkin]

Originally Posted by CarlF

I had the Garmin Panoptix forward looking sonar on my boat for a couple of years but took it out and sold it on Ebay.

The problem is that the range depends on the water depth. Garmin says right in the manual (but not in the ads)

"The transducer has an effective forward range of between five and eight times the depth of the water. For example, in 3 m (10 ft.) of water, the effective forward range is between 15 and 24 m (between 50 and 80 ft.). Water conditions and bottom conditions affect the actual range"

So in 7 feet of water - where I'm worried about running aground - the range is 35-56ft forward from the transducer. Since the transducer is about 8ft back from the bow, I have less than a boat length to turn or stop.

If I needed a forward looking fish finder, it would be a much better idea

That's exactly my concern. A boatlength isn't much time to stop or turn, and in a high windage boat that does 4 kts at dead idle with both engines in gear (mine, for example), it would only be useful on a dead calm day where you can maneuver well enough by just coasting along with short bursts in gear to maintain forward progress.

[mickand]

I have been using Simrad Forwardscan as my primary depth sounder for 3yrs+.
I cruise at 6kts and normally have the forward range set to 160ft. It seems fairly accurate at these levels but it comes into it's own when seeking out a strange anchorage. Apart from idling around to find the best spot, I will stop and do a 360. This works well and gives confidence. How often have you seen a gull standing in what looks like perfectly deep water but you can still see his legs.
I would be loathe to go back to a regular depthsounder.

[dougcn]

For those with a ForwardScan, where is yours mounted in relation to other transducers and the keel?

I have a 38’ fin keel sailboat (Pearson 386) with two transducer locations on centerline forward of the keel.

The forwardmost location is about 2ft below the waterline and 4 ft aft of the bow at the waterline. A depth transducer was previously in this location and worked well at all speeds.

The aft location is 3ft further aft and deeper. It is about 30 inches forward of the keel. Originally this was a speed sensor. I currently have a DST-800 installed in this location and it works very well at all speeds.

I’m looking to add the ForwardScan for use primary in navigating shallow channels and harbors at low speed. I’m hoping you can offer advice on location of the two transducers. I’m inclined to mount both on centerline to use existing holes, avoid dead rise, and avoid the drag of large fairing block protruding off center on the hull.
- Given the three feet of separation, I’m thinking of putting the Forward Scan forward of the DST800 assuming the paddle wheel will generate more bubbles and turbulence. Does this make sense? Or would it be better to put the DST800 ahead of the Forwardscan?
- Due to the shape of the prodtruding ForwardScan transducer, I’m thinking of make a small teardrop fairing aft of the ForwardScan transducer to smooth the flow coming off it and also to prevent lines from snagging on the back side of the protruding transducer at anchor. The fairing would not extend forward of the transducer. Is there a issues with this?

[GordMay]

Since 1 knot is roughly equal to 1.68781 feet per second, or 0.514444 metres/second.
4 knots = 6.75124 feet per second
Giving us about 7.4 seconds warning (@ 4 kts), of an obstruction 50 feet (15.24m) away.

[mvweebles]

On TrawlerForum.com, I asked a similar question about Simrad forwardscan. Small handful of responses from actual users. All said they found it useful at low speed for skinny water/braille conditions: entering a shallow anchorage, which is very common in Florida's gulf coast and ICW, my long term cruising area. At $700 plus install, I decided to go with it.

I liked Ann's comment about investing more heavily in safety gear vs insurance in an earlier phase of their cruising. Harkens back to the classic self sufficient days of cruising.

[mickand]

Google ForwardScan Installation Manual - full of info..

[conchaway]

Here's what I do-- Have a chart of the area. If it looks like it might be shallow, take a rod and reel. Put a sinker on the end. Put a bobber at the 7 foot mark (or whatever). Cast it ahead of the boat going dead slow. If the bobber goes under, you have enough water. Hello!

[boatnerd]

We have a Garmin forward scan that I can select between 3 different frequencies. It's been surprisingly useful in finding a sandy patch in coral or rocky anchorages especially in deeper waters. We've use it along with digital images and it's saved us on several occasions from potential grief. When using cruising guides and anchor waypoints It's been our experience that you can't always rely on what's been written. .

[Moo]

Originally Posted by Siberian Sea

In Alaska I own a commercial fishing vessel with a a sonar made by Furuno. What most everyone here calls a “sonar” for their pleasure boat is not really a sonar rather it’s a depth sounder with a forward looking transducer. Real sonars start at around $10,000 and need the installation of a sonar tube into the hull to house the special transducer. These transducers are not small nor cheap. Don’t believe the advertising by marine electronics companies like Ray Marine or B&G telling you these things they sell in the stores are sonars, they are not. If your have ever been around a real one you will understand why it’s just not something found on most pleasure craft and why it’s not talked about in the cruisers fleet.

They are SONARs... Not what commercial fishermen call sonars but that is what they are... Remember that SONAR like RADAR is an acronym...

[Wayne hoath]

Originally Posted by conchaway

Here's what I do-- Have a chart of the area. If it looks like it might be shallow, take a rod and reel. Put a sinker on the end. Put a bobber at the 7 foot mark (or whatever). Cast it ahead of the boat going dead slow. If the bobber goes under, you have enough water. Hello!

+1. Nice. Reminds me of the the USA inventing the ballpoint pen to write in space and the Russians taking a pencil. Sometimes the simplest answers are the best.

[Kiwi.]

Originally Posted by Siberian Sea

In Alaska I own a commercial fishing vessel with a a sonar made by Furuno. What most everyone here calls a “sonar” for their pleasure boat is not really a sonar rather it’s a depth sounder with a forward looking transducer. Real sonars start at around $10,000 and need the installation of a sonar tube into the hull to house the special transducer. These transducers are not small nor cheap. Don’t believe the advertising by marine electronics companies like Ray Marine or B&G telling you these things they sell in the stores are sonars, they are not. If your have ever been around a real one you will understand why it’s just not something found on most pleasure craft and why it’s not talked about in the cruisers fleet.

You're quite correct. I have the Simrad system that was on my five year old boat when I bought it 2 years ago. I hoped it would be useful when passage making: spotting containers and other floating obstructions at a long enough range to do something; no such luck. I absolutely love it for feeling our way through coral strewn passages and bommie rich anchorages. But it is not a sonar.

[merrimac]

I've also got the B&G/Simrad ForwardScan. Same experience as already mentioned: very useful for rocky / coral anchorages where there are patches of flat, meaning sand or clay. I used to use a real fishfinder for this, but this only tells you *after* you've been there.


Note that the FS will see water less than 2m deep but not when it is itself already in such skinny waters. Since our boat only draws 1m I would like it to work when there is only 50cm under the transducer, no such luck. It needs about 1m50. In other words, it is not useful for tidal areas that are all sand/clay where the water goes from 1m70 to 1m, so in my home waters (Waddenzee in NL) I fall back to the old system. Next year (Covid willing) I may tell you how it works in the Bahama's.


Our scanner is mounted +- 1m50 from the front, in an aluminium sailing yacht. We have an access pipe that goes above the water line as it is in an area where we don't want water directly in the bilge. We also have guard flaps to the side of the transducer so that debris will have a harder time knocking the sensor off. These seem to have minimal impact.


Like others, I was disappointed at first with the results but now that I know the limitations I still like it and use it in every anchorage we approach here this year in the Caribbean.


One tip: switch on the display of the actual sensor returns; this shows up as "noise" but it gives away how it gets more returns closer by. I found this made me worry less about how the software is interpreting the raw results. Sometimes it has 1-2 second "flukes" when the boat pitches or there is wave action.

[SeanPatrick]

Originally Posted by Wayne hoath

+1. Nice. Reminds me of the the USA inventing the ballpoint pen to write in space and the Russians taking a pencil. Sometimes the simplest answers are the best.

If only that were true.


https://www.scientificamerican.com/a...ion-nasa-spen/

Originally, NASA astronauts, like the Soviet cosmonauts, used pencils, according to NASA historians. In fact, NASA ordered 34 mechanical pencils from Houston's Tycam Engineering Manufacturing, Inc., in 1965. They paid $4,382.50 or $128.89 per pencil. When these prices became public, there was an outcry and NASA scrambled to find something cheaper for the astronauts to use.


Paul C. Fisher and his company, the Fisher Pen Company, reportedly invested $1 million to create what is now commonly known as the space pen. None of this investment money came from NASA's coffers--the agency only became involved after the pen was dreamed into existence. In 1965 Fisher patented a pen that could write upside-down, in frigid or roasting conditions (down to minus 50 degrees Fahrenheit or up to 400 degrees F), and even underwater or in other liquids. If too hot, though, the ink turned green instead of its normal blue.


According to an Associated Press report from February 1968, NASA ordered 400 of Fisher's antigravity ballpoint pens for the Apollo program. A year later, the Soviet Union ordered 100 pens and 1,000 ink cartridges to use on their Soyuz space missions, said the United Press International. The AP later noted that both NASA and the Soviet space agency received the same 40 percent discount for buying their pens in bulk. They both paid $2.39 per pen instead of $3.98.

[Wayne hoath]

Originally Posted by SeanPatrick

If only that were true.


https://www.scientificamerican.com/a...ion-nasa-spen/

Another myth shattered! Thanks for the link.