Hi all, I want to upgrade my echo sounder but I find that all of the
units I am looking at give up at around half a meter - unlike my 20
years old unit that I wanted to replace (I need zero depth performance
for inland waterways). Does anybody know of a unit/brand/type that would
work for me? I'm not interested in fish, just displaying depth.

TIA,

S

"Salomon Fringe" wrote in message
. ..
Hi all, I want to upgrade my echo sounder but I find that all of the units
I am looking at give up at around half a meter - unlike my 20 years old
unit that I wanted to replace (I need zero depth performance for inland
waterways). Does anybody know of a unit/brand/type that would work for me?
I'm not interested in fish, just displaying depth.

TIA,

S

To heck with a depth sounder, you need one of these.
http://www.mudbuddy.com/News%20&%20P...nformation.htm

"Jim" wrote in news:g2j7hd$rer$1
@registered.motzarella.org:

http://www.mudbuddy.com/News%20&%20P...nformation.htm

.....like a trip back to Vietnam or Cambodia....(c;

"Salomon Fringe" wrote in message
. ..
Hi all, I want to upgrade my echo sounder but I find that all of the units
I am looking at give up at around half a meter - unlike my 20 years old
unit that I wanted to replace (I need zero depth performance for inland
waterways). Does anybody know of a unit/brand/type that would work for me?
I'm not interested in fish, just displaying depth.

TIA,

S

I'm guessing they are all that way. Mine doesn't like it much less than 3
feet. They have to program it to wait a little bit for the return so it
ignores the initial ping. Even at the speed of sound in the water that
distance is covered pretty fast.

On Mon, 09 Jun 2008 09:28:39 +0200, Salomon Fringe
wrote:

Hi all, I want to upgrade my echo sounder but I find that all of the
units I am looking at give up at around half a meter - unlike my 20
years old unit that I wanted to replace (I need zero depth performance
for inland waterways). Does anybody know of a unit/brand/type that would
work for me? I'm not interested in fish, just displaying depth.

With the newer digital units, you can degrade the sensitivity down
that the return ping is discriminated against the noise. Even the
cheaper units are 800 watt so you are dealing with power problem
decreasing the sensitivity would help a lot.

You will be hard pressed to find a single frequency transducers for
200 KHz which is what you are looking for - 50 Hz units are for deeper
water - more than 30'.

So, simply put, you need to find a digital unit where you can select
200 KHz and be able to decrease the sensitivity enough to get zero
depth performance. I have a Raymarine DS-500 that is selectable to
200 KHz or you can use the dual function and decrease the sensitivity
to find dead bottom.

The only other thing I would recommend is a single frequency depth
flasher which is different from a full sonar. Those work in a
different fashion and most of the new ones are 200 KHz which will give
you depth discrimination without having the mess around with menus.
Some are programmable, some aren't.

I wouldn't recommend anything specific because this is a special
circumstance and you have to fit your needs to what is available on
the market. Hope that helps a little.

Now, with respect to zero depth performance - pardon my ignorance but
I'm curious why you would be running around in zero depth waters. Do
you have a deep draft sailboat or cruiser of some sort?

On Mon, 09 Jun 2008 14:55:54 GMT, Short Wave Sportfishing
wrote:

Now, with respect to zero depth performance - pardon my ignorance but
I'm curious why you would be running around in zero depth waters. Do
you have a deep draft sailboat or cruiser of some sort?

Measuring zero depth is relatively easy in a deep draft boat becuase
the transducer typically has more ping delay to work with, assuming it
is not mounted on the bottom of the keel. I find it much more
difficult in something like a dinghy that only draws maybe 10 inches.
I have trouble getting reliable measurements under 3 ft or so.

On Mon, 09 Jun 2008 11:04:13 -0400, wrote:


In a sailboat, the transducer would be mounted in the hull, above the
level of the top of the keel, so you would have 4-10 feet (depending
on how deep a keel you have) of water even with the keel scraping
bottom. Sounders usually have a "keel offset" setting to compensate
and tell you how much depth remains after the keel height is
subtracted.

I understand that - I'm not clear on the whole zero depth concept.

On Mon, 09 Jun 2008 23:31:21 +0000, Short Wave Sportfishing wrote:

On Mon, 09 Jun 2008 11:04:13 -0400, wrote:


In a sailboat, the transducer would be mounted in the hull, above the
level of the top of the keel, so you would have 4-10 feet (depending
on how deep a keel you have) of water even with the keel scraping
bottom. Sounders usually have a "keel offset" setting to compensate
and tell you how much depth remains after the keel height is
subtracted.

I understand that - I'm not clear on the whole zero depth concept.

If the water's muddy and you can see the bottom that's the zero depth
concept or just use the acronym ZDC.

The sounder is the noise the hull makes scrapping in the mud.

On Mon, 09 Jun 2008 19:50:06 -0400, RLM wrote:

On Mon, 09 Jun 2008 23:31:21 +0000, Short Wave Sportfishing wrote:

On Mon, 09 Jun 2008 11:04:13 -0400, wrote:


In a sailboat, the transducer would be mounted in the hull, above the
level of the top of the keel, so you would have 4-10 feet (depending
on how deep a keel you have) of water even with the keel scraping
bottom. Sounders usually have a "keel offset" setting to compensate
and tell you how much depth remains after the keel height is
subtracted.

I understand that - I'm not clear on the whole zero depth concept.

If the water's muddy and you can see the bottom that's the zero depth
concept or just use the acronym ZDC.

The sounder is the noise the hull makes scrapping in the mud.

That's kind of my point. Zero depth implies no water. If there is no
water, why do you need a depth finder?

On Jun 9, 8:29*pm, Short Wave Sportfishing
wrote:
On Mon, 09 Jun 2008 19:50:06 -0400, RLM wrote:
On Mon, 09 Jun 2008 23:31:21 +0000, Short Wave Sportfishing wrote:

On Mon, 09 Jun 2008 11:04:13 -0400, wrote:

In a sailboat, the transducer would be mounted in the hull, above the
level of the top of the keel, so you would have 4-10 feet (depending
on how deep a keel you have) of water even with the keel scraping
bottom. Sounders usually have a "keel offset" setting to compensate
and tell you how much depth remains after the keel height is
subtracted.

I understand that - I'm not clear on the whole zero depth concept.

If the water's muddy and you can see the bottom that's the zero depth
concept or just use the acronym ZDC.

The sounder is the noise the hull makes scrapping in the mud.

That's kind of my point. *Zero depth implies no water. *If there is no
water, why do you need a depth finder?- Hide quoted text -

- Show quoted text -

And if there's an engine involved, there may well be an overheating
problem.