side imaging sonar

adrianevo · 18 November 2007, 10:58

Hi i am looking at buying a humminbird 797c2 si combo,this is gps/fishfinder with side imaging sonar built in.Cost in uk circa £1000,cost from us circa £420.My question is will the us model be compatable with uk charts?
which are available in navionics gold mmc or sd cards.
cheers adrianevo.

jyasaki · 18 November 2007, 23:40

A dive buddy of mine just got one of these (not sure it's the same model as what you're looking at.)

She was less than impressed with it's performance. She's only been out with a couple of times, though.

jky

adrianevo · 21 November 2007, 08:36

Quote:

Originally Posted by jyasaki

A dive buddy of mine just got one of these (not sure it's the same model as what you're looking at.)

She was less than impressed with it's performance. She's only been out with a couple of times, though.

jky

Thanks for info,maybe i'll go for the 997c si they must work
cheers adrian.

Divingthedream · 22 November 2007, 03:52

I have the 797c2 si model and have been relatively impressed with it since installing it about 6 months ago. The bottom profile display does give a nice, detailed view. Rocks, trees, even a scuba tank someone dropped overboard are easily made out. Of course, speed really affects the imaging and anything over 10 knots renders it useless. I went with the 797 over the larger 997 model due to space constraints on the top of my console. If you have the room then the bigger model would be an even better choice.

Simon B · 22 November 2007, 10:50

Divingthedream,

What is the maximum depth you've used it at? Our normal range is down to about 50 metres 150 feet (ish)

Divingthedream · 22 November 2007, 14:49

Simon,

Max depth so far was 105 feet (32m) to a sandy bottom with small pieces of wreckage visible on the screen. We made a dive on one of our local rigs that sits in over 700' (200m+) and the structure that did show up on the display was cool. Based upon my limited experience though, I would say their max depth rating is probably fairly accurate while the range to the sides is somewhat less than stated. Hope this helps.

Alex

Quote:

Originally Posted by Simon B

Divingthedream,

What is the maximum depth you've used it at? Our normal range is down to about 50 metres 150 feet (ish)

Diver · 06 December 2007, 12:35

Hi,

I have the 997 unit. I have sailed 2200 NM this season and found quite a lot of new wrecks, primarily in the Baltic Sea. Here the bottom is flat as a pancake and of mud and sand, therefore anything that shows up on the scanner is a good chance of being a wreck. I can get a fair picture down to 43-45m and down to 40-42 its perfect. In 25-30m the picures almost look like a really pro side scan piture. The harder the bottom is (sand), the better the picture is. The deeper you go, the narrower the angle has to be and with max. output.

Regards
Henrik

captnjack · 06 December 2007, 17:14

I have the 797si model. Over mud the sidescan is not very effective IMO. Its much better over hard bottoms. I am very pleased with the downlooking sonar and the GPS portions of the unit. As well as the "snapshot" functions. The screen is very viewable in daylight.

I have broken 2 of the plastic mounts though and I'm having to have a new one made on Ali. My console is too giggly for cheezy plastic mounting brackets. So bunch of pluses and a couple minuses on these units.

Richard

Simon B · 07 December 2007, 10:28

Diver,

They look impressive images, that's about our average depth too, might look into these units more. Would only need the sonar if it will take a position from something else and record.

Diver · 07 December 2007, 11:32

Thanks Simon,

This is the the deepest scan I have made, a german 1ww light cruiser. The bottom is pure mud and the wreck is on its side, 105m long. The other is a 20 m long fishing boat, also on muddy bottom. This is the limit I think..

We have found a new wreck in 40 meters of water which was 200m from the position we used, an old Decca. We would never have found it with normal sonar and gps. This one wreck is worth it all:-)

Henrik

Simon B · 07 December 2007, 17:08

is that big bend in the middle due to a change of course made when scanning it?

The initial reports about this unit werent too impressive but your scans are exactly what a small diving outfit need.

Diver · 08 December 2007, 08:40

Hi,

Yes, it is difficult to maintain a 100% straight line, in this case, is the wreck more than 100m. All the best results are made in really calm weather. Just a little waves makes it hard to get good pictures, but still ok for the initial searching for wrecks. To go with the waves also helps the problem, in case of not to great weather.

I bought mine as a supplement (not an alternative to real side scan sonar) and back up gps, and it´s worth every dollar!

Regards

Henrik

Pete7 · 08 December 2007, 13:31

Quote:

Originally Posted by Simon B

The initial reports about this unit werent too impressive but your scans are exactly what a small diving outfit need.

Thats what I thought too, might have to have a chat with Santa

Pete

captnjack · 10 December 2007, 20:18

Quote:

Originally Posted by Simon B

Diver,

They look impressive images, that's about our average depth too, might look into these units more. Would only need the sonar if it will take a position from something else and record.

It does have a NEMA hookup athough why would you want to input GPS coordinates to it?? All of the sidescan units have intergrated GPS with a remote antenna. If you want to program in coordinates you already have that's easily accomplished. The images can be recorded on SD memory cards.

Simon B · 11 December 2007, 11:48

Quote:

Originally Posted by captnjack

All of the sidescan units have intergrated GPS with a remote antenna.

Have they stopped making the SI Sonar stand alone unit? i.e. no GPS?

captnjack · 11 December 2007, 22:49

Humminbird does not make a stand alone SI unit. There's another company that does make something compable - although I can't remember the name right now...

Andy Gee · 12 December 2007, 07:51

Quote:

Originally Posted by captnjack

Humminbird does not make a stand alone SI unit. There's another company that does make something compable - although I can't remember the name right now...

Interphase (sp)

Andy

captnjack · 12 December 2007, 16:45

Yup that's it, although its not really a sidescan unit more of a "forward looking". I haven't heard good things about its utility.

Andy Gee · 13 December 2007, 11:21

Quote:

Originally Posted by captnjack

Yup that's it, although its not really a sidescan unit more of a "forward looking". I haven't heard good things about its utility.

Was on a boat in Norway a couple of years ago and he had one fitted, worked great and once it was explained what we wre looking at it is pretty good but complicated to operate.
A Multi-beam sonar is the ticket, just a bit on the oh dear side

Andy

paul holder · 29 January 2008, 10:18

Hi Henrik,
We too are divers and we are about to purchase a 997 unit. We are very impressed with your pictures of the 6th December but could you please explain the following:-
a. What do the numbers in the top right hand corner represent?
b. Can you scan only to right or left or can you scan both at once?
c. Are you able to remove the information down the left hand side of the screen?
We have just changed our engine to a 200 Optimax so I hope we can go slow enough. Have you any other tips or info you could share with us to maximise the use of this unit?
We go out of Plymouth and any information or tips from UK Divers using this equipment would be greatly appreciated.
Many thanks,
Paul.