Need Info on FishFinder
I would like to get some info about fishfinder:1. Is this OK to mount a "shoot through hull" transducer right at the
center line of the boat hull? The center line of the bottom of the hull
is smooth; therefore, I am not expecting any turbulent at the center
line. The reason why I ask is that we are not supposed to mount a
transom-mount transducer at the center line where the outboard motor is
to avoid the turbulent from the propeller. I am hoping that this
restriction only applies to transom-mount transducer, and doesn't apply
to "shoot through hull" transducer. 2. Is "shoot through hull" transducer good enough for scanning the sea
bottom for fishes? In other words, I would like to know if I can use
the fishfinder as a fish-finder instead of using it as a depth-sounder
if I use a "shoot through hull" transducer. I only intend to use the
fishfinder in shallow water, like 10-ft to 150-ft; hopefully, losing
some range will not be a problem. 3. Does 3-D fishfinder present a relatively static picture instead of
scrolling endlessly like a regular fishfinder? I have a hard time to
interpret the scrolling image displayed in a regular fishfinder to
relate it to the sea bottom. I am hoping that a 3-D fishfinder can
solve this problem. Yes, I have already read a book about fishfinder;
but I still cannot interpret the scrolling image. 4. Is 3-D fishfinder any good? 3-D fishfinder seemed to be "hot" a
couple years or more ago. Recently when I checked Cabela's web site, I
could only find _one_ 3-D fishfinder. Is this 3-D technology too
immature that no other manufacturer wants to try? Thanks in advance for any info. Jay Chan |
jaykchan
Jan 9
2006
|
| My boat is a fiberglass boat, and I believe (not 100% sure) that the
bottom of the boat near the transom is made from solid fiberglass.
Unfortunately, I don't see the "round black spot" that indicates the
best spot for gluing down the transducer that other people mentioned.
Well... I guess I will find out... I understand that the possibility of losing some signal strength if I
use "shoot through hull" transducer. But this is acceptable. I am
planning to add a second transducer to the with the trolling motor at
the bow (for a second fishfinder) anyway. Therefore, I don't need to
get perfect signal strength from the "shoot through hull" transducer;
something acceptable is good enough. Seem like everyone says that I should not glue the shooot-through-hull
transducer right at the center line. OK, I will have to move it off
from the center line and need to experiment in different spots in the
bilge area to find the best spot. Thanks for the warning. Jay Chan |
jaykchan
Jan 10
|
| I will keep the transducer away from the center line. I thought the
"avoid the center line" restriction only applied to "transom mounted"
transducer. I didn't know that it also applies to "shoot through hull"
transducer. Thanks for the warning. Jay Chan |
jaykchan
Jan 10
|
| I've had shoot-thru transducers mounted on the center line with NO
appreciable loss of signal. Yes, the prohibition is normally for transom
mounted t'ducers.... But, you have a number of suggestions for trying any position out...why not
build the dam of plumbers putty on the center line and try it out also? |
RichG
Jan 10
|
| On a sailboat with a rounded hull like my Sandpiper 565, the common
wisdom is to mount the transducer close to the centerline and forward of
the keel.
You want the unit to shoot straight down to the bottom, not off at an
angle and the keel would create some turbulence. |
Don
Jan 10
|
| >use "shoot through hull" transducer. But this is acceptable. not if you are planning on doing any serious fishing it isn't. |
Shortwave
Jan 11
|
| Don't Carolina skiffs have flat bottoms though? |
NOYB
Jan 11
|
| Most do, some have a very very slight vee. But...the skiffs also have a
couple of inches of flotation between the deck and the hull buttom's
outer skin. |
Harry
Jan 10
|
| Yes. Which means that the foam must first be scooped out before mounting
the transducer on the centerline of the hull. |
NOYB
Jan 11
|
| Some of the boats have a pad for transducer mounting that has no foam. Is
solid. I would expect CS to have this. |
Calif
Jan 11
|
| Mounting the transducer at the center line is not recommended.This is
because the thickness of the hull .This would definitely cut down on the
return signal and make the readings erratic.
<jaykchan@hotmail.com> wrote in message |
Russ
Jan 10
|
| "Shoot-thru-hull transducers are epoxied directly to the inside of
fiberglass boat hulls. The sound is transmitted and received through the
hull of the boat - but at the cost of some loss of sonar performance. (You
won't be able to "see" as deep with a shoot-thru-hull transducer as one
that's mounted on the transom.) The hull has to be made of solid fiberglass.
Don't attempt to shoot through aluminum, wood, or steel hulls. Sound can't
pass through air, so if there's any wood, metal, or foam reinforcement, it
must be removed from the inside of the hull before installing the
transducer. Another disadvantage of the shoot-thru-hull transducer is it
can't be adjusted for the best fish arches. Although there are disadvantages
to a shoot-thru-hull transducer, the advantages are considerable. One, it
can't be knocked off by a stump or rock since it's protected inside the
hull. Two, since there is nothing protruding into the water flow, it
generally works quite well at high speed if it is mounted where a clean
laminar flow of water passes over the hull. Three, it can't be fouled by
marine growth. "
IMO, the center line of the boat hull (aka--the keel) is probably not the
best spot for the shoot-through transducer because this is usually the
thickest portion of the hull. |
NOYB
Jan 9
|
| Fiberglass boat is OK to shoot through the hull. Most fishing style boats
have a pad in the back area for transducers. They are made solid, no air
pockets in it. Before mounting the transducer with epoxy, make a little dam
of plumbers putty and fill the dam with water and set the transducer in the
water to see if you get good results. |
Bill
Jan 9
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