Which echo sounder is good up to (almost) zero depth?
 

Gene Kearns wrote:
On Mon, 09 Jun 2008 09:28:39 +0200, Salomon Fringe penned the
following well considered thoughts to the readers of rec.boats:

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.

This one is pretty accurate and good to the depths you suggest. Very
low current draw.....
http://tinyurl.com/5wn4pr

The best info yet, was in your article:

"When sailing in shoal waters, soundings can be taken much quicker with
a pole or boat hook than with a lead.?

I give my wife or daughter the boat hook, when backing into a beach for
a Mediterranean mooring.

Which echo sounder is good up to (almost) zero depth?
 

Short Wave Sportfishing wrote:
On Wed, 11 Jun 2008 19:49:31 +0200, Salomon Fringe
wrote:


Thanks all for all the replies, couldn't reply until now because I am
cruising. Hadn't expected such a great response either ;-)
Of course, about zero depth, I am not referring to water just a few
centimers deep (...) but to water that is close to 0 below the
transducer. The thing is that my more than 20y old unit that I had
wanted to replace *is* able to measure as little as 15cm below the keel.
My trawler-style boat has about a 25cm difference between fore and aft
so if I were to mount it at the best (highest) position I would still
have a gray zone of 25cm with the transducers I am looking at (50cm min
depth), and I don't like that. There are quite a few harbours where I
have less than 50cm below the keel, and if so I want to know how much
exactly e.g. to predict if I am going to hit the bottom in a falling tide.

A Furuno rep actually told me I should look at a simple smart sensor
depth-only device (similar to advice given in this thread) so I guess
the big improvement I am looking for (depth graph) is not in the cards
for me. Can't believe that sounder technology has made no major
improvements in this sense for more than 20 years.

Something else is that I have two sea chests with transducers, one with
the old digital depth meter I am using and the other from a Lowrance
X16. That unit has been enjoying its retirement somewhere on the sea
bottom for years now but the transducer is still there and apparently
works at a funny frequency, 196khz. Is there any way to detune any brand
of 200khz sounder to work with this unit? If not I have no other option
than to have the transducer replaced.

Some people said I am asking for the impossible when I asked for a
near-zero-water-below-the-keel sounder, but when you do the math it sure
doesn't seem impossible, at 200khz one cycle takes 5 microseconds, the
speed of sound in water is approx. 1500m/s so in principle you should be
able to measure down to 0,75 cm. About 1/3 of an inch. Perhaps you can't
make the pulse that short or something, dunno.


Holy smokes - an X-16? Dude - you need to move up to the 21st
Century. :)

What kind of unit did the 196 KHz transducer connect to?

The X-16 used that 196khz transducer. It was long gone when I bought the
boat.The sounder still there, the one I am using (the 20yrs old unit)
uses 200khz. Move to the 21st century, right, problem is that my sounder
from the last century seems better for shallow water operation than the
new ones...

Which echo sounder is good up to (almost) zero depth?
 

On Jun 11, 6:03 pm, "Reginald P. Smithers III" "Reggie is Here
wrote:
Gene Kearns wrote:
On Mon, 09 Jun 2008 09:28:39 +0200, Salomon Fringe penned the
following well considered thoughts to the readers of rec.boats:

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.

This one is pretty accurate and good to the depths you suggest. Very
low current draw.....
http://tinyurl.com/5wn4pr

The best info yet, was in your article:

"When sailing in shoal waters, soundings can be taken much quicker with
a pole or boat hook than with a lead.?

I give my wife or daughter the boat hook, when backing into a beach for
a Mediterranean mooring.

We always back in to our favorite swim spots. I just watch the depth
sounder and my wife secures the bow anchor line when the stern is in
3~3.5 feet of water at the stern.

We went swimming today at our very favorite beach (Ruggles Beach on
Lake Erie) after we took a good friend (78 years old man, dock
neighbor for many years when we had our 32 footer) out for a river and
lake cruise. He sold his boat several years ago and I figured he
needed to get his sea legs back. His health is also going downhill
and I figured a day on the water would do him good. He enjoyed the
day and the company, as my wife and I did.

Great day on the water!

Which echo sounder is good up to (almost) zero depth?
 

On Jun 11, 8:32 pm, Gene Kearns
wrote:
On Wed, 11 Jun 2008 18:03:03 -0400, Reginald P. Smithers III penned
the following well considered thoughts to the readers of rec.boats:



Gene Kearns wrote:
On Mon, 09 Jun 2008 09:28:39 +0200, Salomon Fringe penned the
following well considered thoughts to the readers of rec.boats:

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.

This one is pretty accurate and good to the depths you suggest. Very
low current draw.....
http://tinyurl.com/5wn4pr

The best info yet, was in your article:

"When sailing in shoal waters, soundings can be taken much quicker with
a pole or boat hook than with a lead.?

I give my wife or daughter the boat hook, when backing into a beach for
a Mediterranean mooring.

I can't beat the Mediterranean thing, but after setting the main
anchor at an appropriate distance from the beach, we do back into the
shallows and take an anchor ashore to anchor stern-to.....

I can't quite wrap my head around the OP's situation, since my local
navigable areas that challenge vessel draft are not in any way a safe
haven.... quite to the contrary, they are *very* dangerous!

--

Grady-White Gulfstream, out of Oak Island, NC.

Homepagehttp://pamandgene.idleplay.net/

Rec.boats at Lee Yeaton's Bayguidehttp://www.thebayguide.com/rec.boats


We sometimes anchor just off the Cedar Point Amusement Park or
Kelley's Island beaches (usually very crowded) and have to contend
with idiots anchored without stern anchors.

Which echo sounder is good up to (almost) zero depth?
 

On Wed, 11 Jun 2008 20:32:39 -0400, Gene Kearns
wrote:

I can't quite wrap my head around the OP's situation, since my local
navigable areas that challenge vessel draft are not in any way a safe
haven.... quite to the contrary, they are *very* dangerous!

I gave up - I don't get it either.

Which echo sounder is good up to (almost) zero depth?
 

On Wed, 11 Jun 2008 03:16:09 +0000, Larry wrote:

Wayne.B wrote in
:

On Mon, 09 Jun 2008 19:24:42 +0000, Larry wrote:

What I always thought we needed was a sort of underwater "curb feeler"
like we used to put on the pimpmobiles. A couple of stiff wires that
would protrude down into the water 3 ft from the BOW that would make an
awful griding noise

Such devices exist.

They are frequently called propellers.


When they grow up on steroids, we call them "screws", which make contacting
the bottom with them MUCH more exciting!

At 30 inch diameter are they props or screws? At $4k each I don't
think I could handle much more excitement.

Which echo sounder is good up to (almost) zero depth?
 

Wayne.B wrote:
On Wed, 11 Jun 2008 03:16:09 +0000, Larry wrote:

Wayne.B wrote in
:

On Mon, 09 Jun 2008 19:24:42 +0000, Larry wrote:

What I always thought we needed was a sort of underwater "curb feeler"
like we used to put on the pimpmobiles. A couple of stiff wires that
would protrude down into the water 3 ft from the BOW that would make an
awful griding noise
Such devices exist.

They are frequently called propellers.

When they grow up on steroids, we call them "screws", which make contacting
the bottom with them MUCH more exciting!

At 30 inch diameter are they props or screws? At $4k each I don't
think I could handle much more excitement.

At $4k they are called screws, as in, If you break one, you are screwed.

Which echo sounder is good up to (almost) zero depth?
 

Wayne.B wrote in
:

At 30 inch diameter are they props or screws? At $4k each I don't
think I could handle much more excitement.


I'd call them screws.....

Which echo sounder is good up to (almost) zero depth?
 

On Jun 12, 11:47*am, Larry wrote:
Wayne.B wrote :

At 30 inch diameter are they props or screws? *At $4k each I don't
think I could handle much more excitement.

I'd call them screws.....

The crabbers and fisherman in Alaska call them wheels.

Which echo sounder is good up to (almost) zero depth?