View Full Version : Off Shore Sonar vs. Inland Water Sonar
It was mentioned on a previous post that there was some sort of distinction between off shore sonars and inland water sonars. I'm curious what the difference is?
Is it power? My sonar has 1000 watts of power like many other brands and that seems like a lot of power. Do off shore sonars have more power?
Is it Frequency? I've seen some people post that a 50KHz or transducer frequency is for off shore or deep water only. My sonar is dual frequency, 50KHz and 120KHz. I use the 50 KHz frequency in shallow water to provide a wider view of whats below. Even in shallow water. Although I do switch over to 120KHz for better detail once I'm in the area I want to fish. Do off shore brands only operate at 50KHz or similar low frequencies?
Do off shore brands operate better or worse than inland water brands and if so, whats worse about them? Limited bashing please if possible.
Maybe someone could clarify what brand(s) is considered an "off shore only" brand so people in the market for sonars know what they're buying if they don't work well for inland water.
Please take notice. I figured out what I was doing wrong with logging in :) What a moron! I meant that toward me.
bobco
02-27-2002, 03:29 PM
good question, I've been wondering the same thing. Thom, the other week talked about a Furuno 600L ,it is a color LCD priced reasonable, but it seems that only saltwater people are using it? What makes them different or is it just a marketing thing?
bobco
02-28-2002, 09:56 AM
top
This is a great question and I'm probably not the one to give a great answer. There is a fellow named Alan Tarvid who you may have run across on the message forums or in various magazines (he's the Electronics Editor of several publications including Salt Water Sportsman) who is very good at talking about electronic equipment, a lot better than me.
Anyway, its not a matter of power. Many 'freshwater' machines have gobs of power and a lot of 'saltwater' boxes are of modest power. For instance my Furuno (600L) only puts out 350 watts (RMS). The real differences are in how the machines are made in terms of construction and in their sensitivity/selectivity. I think it should be pretty clear to anyone that fish finder's built for salt water use are expected to stand up to much more and much more severe pounding. Its just a simple fact of life that very few freshwater fishermen consider a day with 3' seas to be a very nice day to go fishing. We get pounded to death out there and our equiment has to be able to withstand that pounding. Also, deep water fishing is usually associated with salt water fishing. The one great difference between most equipment designed for freshwater fishing as opposed to the saltwater stuff is its protection against corrosion, and to a lessor extent its actual waterrproofing. Its not at all unheard of for us to be soaked from head to toe on a moderately choppy day, and of course this is saltwater we are drenched in and it drenches our equipment too. So there's two differences you may not have though of and they are two that, when you think about it, really recommend some saltwater type equipment to the serious freshwater fisherperson. After all, it it can live on my boat it will thrive on a freshwater boat.
As to the frequency question, that's an interesting one. If life was perfect I'd be using the 200 kHz side of my bottom box all the time. Unfortunately it won't hit bottom in depths greater than about 300 feet and so I usually switch over to the 50 kHz somewhere around 250 feet or so. Now you have to think about that for just a moment. If I'm shooting into water deeper than 300 feet, and for me its usually water between 600 and 1,000 feet, what is it that I'm looking for? Certainly its not for fish on the bottom, or even in the middle of the water column. Well, maybe in the middle, but not the bottom feeders. What I'm looking for is bottom structure (or wrecks and such) and I understand that is not the main concern for you all.
Then there is that old sensitivity and selectivity queston. To put it bluntly the machines that serve you all well would be useless to me. The typical Lowrance or Pinpoint simply does not have the selectivity to pick out bait fish at depth and its the bait I look for, not the fish itself. The typical high power freshwater machine uses its high power to overcome its lack of sensitivity. Think aobut that one for a few moments, why do you need 1,000 watts to shoot into 100 feet or less of water when I can get away quite comfortably with 350 watts in 1,000 feet? Its because my machine can hear better than yours can - to put it in ver simple terms.
Anyway while you could use the ones I use without any problem it wouldn't work the other way around. When you consider that the price is about the same it would appear that I get more for my money than you do. Oh, and there's something else, and I know this one brings howls of protest, but I'll just say it as my opnion, and my opnion only. You all pay a lot of money for advertising that we pay for engineering. So in the end unless you fish with advertising brochures rather than hard equipment I would have to say that we get more for our money. I can pick up any fising magazine I choose and find page after page of advertising for Lowrance products, but try to find something from Furuno? So which company is sinking its funds into product and which company is sinking its money into trying to sell product?
From time to time I say this, and once again its is only my opnion, and I'll say it again here. If a freshwater guy on a limited budget wants the very best bang for his buck that he can get in a fish finder he should go out an buy a Furuno LS6000 in the 200 kHz version (its a single frequency finder that comes in either 200 or 50 - and I'd just bet they don't sell meany of the 50's). One can be had for around $350 and I honestly think it is the best shallow water (down to about 300 feet) depthfinder made in the world for the money, even though its an older model that probably won't be around much longer.
Thom
There isn't a difference bobco. Once again I was responding to an invalid statement pulled out of an individuals a** in the heat of battle. I don't know for sure if it was directed at me but my brand of sonar is from a manufacturer who's business is directed mostly toward commercial and recreational off shore marine. But it happens to work very well inland too.
A sonar is a sonar. It's up to the person buying the sonar to decide what's most important to them for the money their investing. What is important to me is 15 years, and counting, of reliable operation. The few times I did need customer service, the manufacturer went above and beyond to make sure I was a satisfied customer.
When it came time to buy a more current sonar, that manufacturer gave me a 40% discount, off a rather high retail price, simply for being a previous product owner. The manufacturer contacted me when there was a free software upgrade for my sonar, replaced my scratched display lens for free, gave me a new protective cover, and paid express shipping back to me. I was without it for 4 days. And I'm just Joe customer. No sponsor deal or anything like that. I don't even fish tourneys...yet.
I know there are sonars with better resolution in the same price range but that's not the only thing important to me. It's a very good sonar and I know how to work with it to be successful. It's the manufactures loyalty to me that will make them my first choice when it's time to upgrade again. Will I give them a plug when it's appropriate? You bet. But I won't try to shove it down anyones throat.
Excellent response from a guy with off shore experience Thom. Especially the sensitivity and selectivity factor that I believe is just as important as resolution. I've never tried my sonar in anything deeper than 100' but I know it's capable of 20 times that.
What do you mean not fishing when there's 3 footers? Sometimes that's the best time. And I have the advantage of being able to generate my own chum in those conditions.
RANGER
02-28-2002, 11:49 AM
Thom,
Thanks for the info. Last year I bought a new to me boat. With the boat came a Furuno LS 6000. I thought it was a great sonar but I found out that the screen would go totally black in the hot sun. I was very disappointed and decided to look for another type for this year! Now you have me thinking! I'm wondering if I did something wrong or had the adjustments set incorrectly. Can you give me some guidence here? I have to admit I didn't reset anything from previous uses where it was working fine. The times it went black it was a VERY HOT, sunny day (over 90)! I have owned Bottomline and Lowrance in the past and never had this happen. Can you help?
Thanks in advance.
RANGER
02-28-2002, 06:18 PM
bump
RANGER
03-01-2002, 04:57 AM
bump
ranger,
Unfortunately what you saw was purly the result of heat. If you haven't seen it on your Lowrance unit I would guess its a matter of the Lowrance having used a more recent screen technology than the Furuno does. That is the one killer on the LS6000, its screen. The unit was put on the market about 7 years ago and its simply old technology. That's why I said that I didn't think they would be on the market much longer. The good side on them is that if you can mount it such that it is even reasonably cool, and I don't mean completely out of the sun or anything like that, just were they can get some air flow or whatever it takes, they are the most sensitive and selective inexpensive (how can anyone call several hundred bucks inexpensive for anything - I must be getting more prosperious than I though) depth finder available.
Actually it is a shame that Furuno hasn't improved the screens in those things. It appears that the company is moving toward integrated units, with the new Navnet being their flagship line now days. I've see a couple of them and they are simply astounding, no other way to describe it, but they are simply so very expensive. I was talking to the owner of a Marine Electronics place in the Carolinals last fall while we were looking at the one on his boat. It has the full package (they sell the things and then all the inputs are sold as modules). He had his radar, sonar (full 360 user selectable degree scanning), depth finder (2 kW power RMS - 6,000 foot depth capability) and GPS all in that one magic 10" color box. He told me that it was less expensive than buying the unit separately and that I might want to give some thought to scrapping my individual components and moving to something like his. What he couldn't get in his head was that it took me years to save up the money and individually buy the equipment on my boat, there was no chance of me setting down and writing the check for five or six grand for one machine at one time. So it goes.
Anyway the point is that you hit the nail on the head with your assumption of what casued the black screen. It was heatand old screen technology by Furuno. Its a shame your mounting location couldn't accomodate the unit, but that's Furuno's problem, because if it had you'd have never gone back to brand-L.
Thom
RANGER
03-01-2002, 07:26 AM
Thank you! It is appreciated. I really liked the unit and thought it did a great job up until this happened. Unfortunately, there are a number of days that I'm on the water when it is hot and sunny and a black screen was unacceptable.
Thank you, again, for taking the time to answer my question.
Ranger,
If your not planning to use your Furno anyway, why don't you try installing a small, 1 1/2" x 1 1/2", 12 volt, cooling fan. You can buy them at just about any electronics parts store and tap into the power feed to the sonar. A flow through system is ideal. Cut two separate sets of slots in the case in an area least exposed to water. Like maybe the bottom. Cover the slots with a thin, breathable foam that will provide additional protection from water and dust. Tape or screw the fan over one of the foam covered slots. You may not even need the fan. It may not look great but I'll bet it drops the internal temperature 10 or more degrees. And it beats leaving it on a shelf or worse yet, in the garbage.
I have an older CRT display sonar that in sunlight, the screen appears blank. The manufacturer provided a plastic, 6" long, 45 degree angled, rectangular tube veiwer that blocks sunlight. The thing looks like the viewer Spock looks into on Star Trek. Goofy, but it works.
RANGER
03-01-2002, 10:03 AM
KP,
Thats a good idea! It isn't like I haven't "Gerry wired" other things! I do want to find a way around this shortcoming simply because the unit does work nicely at all the other times. Good idea! I'll let you know what I end up doing. I will say that this is the first unit I have had an "A" scale on and I really, really like that feature!