B&G forward scan

[lamadriver]

I put one in this year when i had the boat out of the water in Thailand.

I opted for a 500 dollar vulcan 7 ( a friend bought a v5 for the same purpose) as it has the fwd scan built in and there is no need to buy the sonar hub. the V% is a great option becasue you basically added a Multi function instrument with sonar capability.

After a month single handing in the Maldives, i woudnt want to be with out it and my GE2KAP files. the two of them combined are a game changer.

It took a bit of fiddeling around and playing with it to figure out the little oddities. But its awesome when your creeping in and out of coral passes.


LD

[Dave_S]

Originally Posted by JPA Cate

Dave, with a 20-25 ft. beam, maybe you want one for each hull?

To evaluate if you need one, ask yourself if you will be needing to "see" into murky water, one thing they really shine at. Or, are you expecting to travel coral-laden lagoons? The way bommies and reef structure shows is also excellent. Our old Probe is not too sure where soft mud starts, but gives a good return on hard mud, sand, and rock. Mostly Qld water is clear enough for it not to be a worry. You might be happier with a depth sounder (just a simple one) for each hull. Or, ask some of the catamaran folks, if it is a problem for them, and why, or why not?

Ann

Ha, I actually asked if I can fit one in each hull. B&G say it won't work as they will conflict with each other.

I have gone without. I did think I could set up a probe on a pole to swing and lock down from the prodder on the centreline if I find I need one later.

I haven't yet but probably will go into murky waters but likely to be well charted.

[Catapault]

Originally Posted by Frankly

I did a quick search of the WEB site and they are not very forthcoming with any specs. When I look at the size of the transducer and guess a frequency of 300 to 400 KHZ then that thing is going to have a pretty broad beamwidth (30 to maybe 50 degrees both horizontal and vertical). A few degrees off vertical is going to be NBD.

When we (Navy) got sophisticated enough to calculate the actual direction of the beam travel based on a vertical sound velocity profile, some small changes in salinity/ temperature makes for some large variation in the path the sonar signal. Then what we had observed in those tests years earlier all started to make sense.

Assuming you are not experiencing a hardware problem, then get out and play/practice a little bit. What you and others are trying to do is not an easy nut to crack. Even with expensive and sophisticated sonar equipment, results will be heavily influenced by the water column conditions.

One secret I have learned over the years in difficult/ unknown navigation situations, "slow speed is your very good friend".

As someone who used to maintain Navy Submarine Sonar for a living, I second everything Frankly is saying !. At times sonar performs as specified, at times its as unreliable as HF... (or worse) And it has a LOT to do with the water conditions.

Unfortunately, a forward looking sonar at near-surface is potentially hitting some of the worst possible sonar conditions. Surface effect (Air/water interface, and waves) , Large temperature differences in the first 5m -10m of water which vary radically throughout the day, Inversion in same layers, also changing during the day.

Short version, I agree it is a short range device, and going SLOW is definitely needed.

It is however something I'm also seriously thinking of fitting to our Cat. Just not sure which yet. Steerable beam sounds interesting.


One interesting point. Phylis and John on Morgans cloud (Attainable Adventure Cruising folks) have one. I recently read their e-book on trip to Greenland, and they commented that they were regularly glued to the forward sonar looking for ice. So does seem worthwhile for some uses.

Regards
Mark.

[Sputnik]

I had one of the guys at PRS Comm's to have a look when I was in the local area, he brought another transducer which I have connected temporarily, it seems to have much improved its performance........I will let you know how I get on.
Neil

[Sputnik]

Originally Posted by Sputnik

I had one of the guys at PRS Comm's to have a look when I was in the local area, he brought another transducer which I have connected temporarily, it seems to have much improved its performance........I will let you know how I get on.
Neil

The new transducer certainly seems to show more reliably....but have not had the chance to too much shallow work.

Neil

[Sputnik]

.....definitely better, but still unreliable in the last 1.5m below the transducer.