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Fish Finder works only without moving???

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spazio

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Apr 18, 2005
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I've heard that the basic fish finders work only when the boat is stopped
can it be true?
I'm going to buy a garmin fishfinder 90 or 120 or 140 but I see no use to buy it if it works only with the boat stopped
what do you know about that?
tks
emidio
 
samdive

samdive

Mermaid, Musician and Marketer
Nov 12, 2002
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yes - all of the cheaper ones are pretty useless if you are moving. I've tried two and both were only any good on a moored platform. They work by bouncing sonar waves up and down so if you are moving, the sonar doesn't hit you on its way back up
 
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dave

Dicentrarchus labrax
Jan 13, 2003
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The cheaper units are ok if you are moving slowly, but no good at speed. They are fine when you are looking around slowly for a wreck etc, but will not tell you if you go over an unknown lump at high speed when travelling somewhere else. This is true also of a lot of more expensive units. At high speed transducer location becomes very important. I have known people complain that their sounder does not work at high speed, then noticed that is is not actually in the water when the boat is on the plane:head

cheers

dave
Spearguns by Spearo uk ltd finest supplier of speargun, monofins, speargun and freediving equipment
 
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Bill

Bill

Baron of Breathold
Oct 17, 2001
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In my boat the transducers were mounted inside, in a wet bowl. It worked fine at 20 knots. In theory, you lose about half your depth capability but it wasn't that bad in practice and I was shooting through 4-5 mm of fiberglass.
Aloha
Bill
 
Bill McIntyre

Bill McIntyre

San Clemente, CA
Staff member
Forum Mentor
Jan 27, 2005
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I have a thru-hull transducer, and my Furuno works fine at over 20 knots. There is just a bit of noise on the screen, but I can clearly see the bottom.
 
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MKDVR

MKDVR

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May 1, 2005
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Occasionally my old Hummingbird would act up at speed but most of the time it worked fine. At speed I was more focused on the depth reading than anything else.
 
Marwan

Marwan

Gear Buying addict
Supporter
Sep 3, 2005
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had a garmin that would tell me that theres fish all over the place...threw it away after a while
 
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deckhand mike

New Member
Feb 26, 2007
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If you have a cheap fishfinder don't use it to look for fish. I know this sounds weird but just turn down the sensitivity and use it to look for structure. Cheap fishfinders ae only good for structure but depending on what kind of fish you are looking for this often all you need to know. If you find good structure you should find the fish. Plan on spending alot if you want to look at speed.
 
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Old Man Dave

Old Man Dave

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Feb 19, 2005
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Agree with most of what's been said. However I think the type of boat hull and the shape, type and position of the transducer has more influence on performance at speed than price. Even cheap models will work at speed if they get a clean signal, but I suppose more expensive ones might be more tolerant.

Humminbird, all American sounders and some others all would have you believe the sea beneath your boat was full of fish. My very expensive Humminbird would show tuna in a bath tub if you let it. I use sounders for checking the depth and contours of the sea bed and hence I find fish.

Thinking of ordering the new Garmin colour (140c ?) myself.

Dave
 
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spazio

New Member
Apr 18, 2005
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there's an important difference between colour and black&white?
 
Old Man Dave

Old Man Dave

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Black and white sounders use what they call greyscale to show additional information, such as hard/soft bottom which could indicate the difference between sand/weed/rock. There are only so many shades of grey that can be viewed, typically 3 or 4. Colour sounders use many more colours to display this extra information. In theory they can also show temperature thermoclines and large/small fish etc. Also because colour is more expensive most colour sounders are high powered models. Colour costs 5 to 10 times as much as monochrome, except the new garmin which is only about 2 to 3 times the price.

Dave
 
K

KWM

Well-Known Member
Jan 7, 2006
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I am looking at buying the new Garmin 450s colour model whish is a combined GPS/fishfinder. Does anyone have any idea how much power these new colour models will actually use and hence how big a battery I will need.

Regards Kev.
 
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MKDVR

MKDVR

New Member
May 1, 2005
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Mostly I watched the depth and second to that the contour. I did find the Hummingbird fish icon useful to identify wrecks over other types of structure. When I came across the wreck the fish icon would explode. Overall it was very reliable in my case.

A scuba buddy of mine had a high end color sounder on his boat. It gave you a better idea of the bottom composition which helped a lot. It would also pick up the teams bubble stream. Pretty cool but pretty expensive.
 
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A

aksurfer

New Member
Mar 13, 2007
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Fish finder technology has come so far in the last 5 years that the cheaper models are actually very good compared to what we used 10 years ago. If you can't read at speed, then it's most likely the install of the transducer. The angle is wrong or the it's not mounted at the correct depth on the transom. I've had properly installed $500 fishfinders read at 25kts and improperly installed $1500 not read at 10kts.

Color makes a world of difference on your eyes and your ability to read bottom hardness and bait density. I make my living by my ability to read a fish finder and they do take some practice to get good at.
 
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miles

miles

BORN WILD!!!
Supporter
Jun 13, 2003
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Hiya

Coming from a commercial fishing background, having and being able to use a decent echo/fish-finder is extremely important. I've used many makes, ranging from entry level units to top of the range units from manufacturers such as Garmin, Lowrance, Eagle, Hummingbird, JRC, Koden, Furuno, Nav-man, etc

As mentioned before, placement of the transducer is critical for the best performance on a unit. For spearfishing purposes, where a spearo is mainly looking for reef and structure, not really schools of fish, any entry level unit will work well. How-ever, once you start needing to find pelagics and schools of fish, a colour unit is definitely a better choice.

I've used the Garmin 120 (pre-decessor of the 140) and wasn't very impressed with it. Similar to their entry level unit, so not really worth the extra money.

I can HIGHLY recommend ANYTHING from the FURUNO make. Their LS4100 is a fairly in-expensive entry level unit, but works BRILLIANTLY. It shows squid on the bottom and fish, flat on the bottom, EXTREMELY well for a monochrome unit!!

Hope that helps!!

Regards
miles
 
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Mr. X

Mr. X

Forum Mentor
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Jul 14, 2005
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Some years ago I had some dealings with some high end sonar/ultrasound transducers. The quality varied greatly from one to another -- anything from fantastic to complete rubbish. Turned out the problem was how they were assembled ("potted")-- apparently little care was taken with orienting the crystal in the transducer housing, consequently some fired towards the side of their housing, others straight-ahead, etc. As the transducer concerned both fired and received the signal, the orientation was particularly important (the received signal is relatively tiny at the best of times).

Anybody tried the el cheapo Lidl's fish finders? Somebody offered to buy me one for the kayak but I declined the kind offer - it seemed like an inappropriate level of technology for my activities. I usually stay fairly close to shore, the kayak can handle very shallow water, I can often see the bottom and I usually troll a handline, which does the fish finding for me!;)
 
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spazio

New Member
Apr 18, 2005
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very interesting info

I'm curious about this furuno...
 
TheDude

TheDude

New Member
Oct 12, 2006
99
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A bit of topic, but has anybody tried to use a fish finder to monitor a freediver during his dive? Might be quite useful for safety reasons - to see at what depth the diver is currently, and to indentify possible problems by the buddy from the surface.
 
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