Depth Finder Doesn't Work- Back Again

[frank1492]

I apologize for this long delay in responding, but I have been without
land-line phone service since Thursday night, hence no Internet. It
was just restored this afternoon.
Thanks for all the replies (which I have printed out and
studied.) I would certainly feel capable of removing the transducer
(which seems clearly to be the problem.) DMI Electronics (the
reincarnation of Data Marine) has the transducers for $150, and I have
actually seen them as low as $129.
Because the boat will have to be pulled ($150) in order to remove
the transducer (from the bottom), which would make total of $300, I am
looking at other options. Most obvious is to buy a new complete unit,
display and transducer. I'd like your opinion on a couple of points,
however, before I go that route.
(1) Some of these have "in-hull" transducers which are simply
epoxyed to the inside the hull. If these are accurate, they sound
appealing. Your thoughts?
(2) As I occasionally fish (but am by no means "avid") I am
wondering why I don't just buy a fishfinder. Some don't have
fractional readouts, and I would avoid those, but for those that
do read tenths of feet, is there any reason these would be less
accurate than a dedicated depth sounder? To get a good
depth sounder plus all the other features (including temp) is
very tempting UNLESS you tell me the depth sounders on these
are junk.
Again thanks for your past ( and possibly future) help.
Frank

 

[GBM]

Because the boat will have to be pulled ($150) in order to remove
the transducer (from the bottom), which would make total of $300, I am
looking at other options. Most obvious is to buy a new complete unit,
display and transducer. I'd like your opinion on a couple of points,
however, before I go that route.
(1) Some of these have "in-hull" transducers which are simply
epoxyed to the inside the hull. If these are accurate, they sound
appealing. Your thoughts?

Frank - These work fine, so long as you can find a good spot to mount them -
A "good spot", is one that is relatively flat, has no core material (i.e. is
solid fibreglass) and is clear of external items that could give a false
echo (keel, prop shaft etc). You can install any transducer this way, but
the more powerful ones work better. They can be epoxied in or can be
installed in a "water" box - usually a piece of ABS pipe epoxied to the hull
containing a small amount of a suitable fluid (Castor Oil works well - water
evaporates). One way to find a "good spot" is to put the transducer in a
Zipock bag full of water and then move it around until you get a good
reading. You could even buy the Datamarine transducer and install it this
way until you get a chance to haul out, but a complete new unit may be a
better bet.

Thes links provide more detail:

http://www.tomneale.com/tips13.html
http://www.tacktick.com/products/userguides/InHullDepthAdaptor.pdf

and to show you are not alone:

http://continuouswave.com/maintenance-logs/newDS/

Regarding a fish finder - By all means - some of them are quite reasonable
and they provide a lot more information that a basic sounder. Perhaps going
this way would not cost much more than the DMI transducer?
I have used them, but never owned one, but if you buy from a reputable
company you should be fine - check reviews on google.

If you want to go really cheap , you can buy small dash mounted sounders for
a reasonable price and I believe they work quite well:

http://makeashorterlink.com/?J10325C6D

What would be interesting, is if the 200Mz transducer that comes with these
units would work with your Datamarine head?

Have Fun!

GBM

 

[Garland Gray II]

Rather than epoxy -- hard to remove if necessary-- you can put a wad of
petroleum jelly on the face of the transducer, and after pressing it to the
hull, squirt something like silicon around the rim of the transducer to
secure it.
My boat was struck by lightning once, and one of the exit points was the
thru mounted depth sounder. Wasn't much left to keep the water out. I
remember wondering why this particular locker seemed to have more light in
it than I had previously noted. Understood why at next haulout. I now rather
favor inhull transducers.

 

[frank1492]

Thank you. A wealth of info. I did not realize the Datamarine would
even work as an in-hull as the DMI guy did not mention it. Tell you
the truth, if it did work, I would consider it as I do like the
current display. Perhaps I will call him again.
I have a panel-mount head and in-hull transducer combo home
from West Marine, but I think I will return it as I really don't like
the panel mount feature all that much ($129 though for the whole
unit!)
I would propose to place the new transducer near the site of the
old one, which is just forward of the engine in this stern drive
Grady White 22' Seafarer. I am told the Grady would probably be
a good boat for an in-hull as there would likely be no bubbles,
cavities or foam, at least at that point.
The "continuous wave" article surely describes my transducer
and mount to a "T." It certainly tells a cautionary tale and I now
doubt I really would want to get into all those issues!!!
I will look harder at fishfinders and you are right- for about
the same price as the DMI transducer I can get a very nice fishfinder.
(Humminbird or Garmin.) I just want to make sure I get fractional
depth readout.
Again many thanks for your continuning interest!
Frank

 

[frank1492]

Based on this and GBM's link I would certainly agree that the
in-hulls make sense, though the thru-hull has served me well for many
years.

 

[Dennis Pogson]

I apologize for this long delay in responding, but I have been without
land-line phone service since Thursday night, hence no Internet. It
was just restored this afternoon.
Thanks for all the replies (which I have printed out and
studied.) I would certainly feel capable of removing the transducer
(which seems clearly to be the problem.) DMI Electronics (the
reincarnation of Data Marine) has the transducers for $150, and I have
actually seen them as low as $129.
Because the boat will have to be pulled ($150) in order to remove
the transducer (from the bottom), which would make total of $300, I am
looking at other options. Most obvious is to buy a new complete unit,
display and transducer. I'd like your opinion on a couple of points,
however, before I go that route.
(1) Some of these have "in-hull" transducers which are simply
epoxyed to the inside the hull. If these are accurate, they sound
appealing. Your thoughts?
(2) As I occasionally fish (but am by no means "avid") I am
wondering why I don't just buy a fishfinder. Some don't have
fractional readouts, and I would avoid those, but for those that
do read tenths of feet, is there any reason these would be less
accurate than a dedicated depth sounder? To get a good
depth sounder plus all the other features (including temp) is
very tempting UNLESS you tell me the depth sounders on these
are junk.
Again thanks for your past ( and possibly future) help.
Frank

You are never going to believe this, but when searching for the most
suitable place to locate an in-hull transducer, a British company found that
of the 15 or more different materials they tried for maximum sensitivity on
the transducer head, MARMALADE was far and away the best!

Most boats have at least a jar of marmalade in their food lockers. Save you
paying for exotic materials to do the same job!

Spread it thickly!


Dennis.

 

[GBM]

My boat was struck by lightning once, and one of the exit points was the
thru mounted depth sounder. Wasn't much left to keep the water out. I
remember wondering why this particular locker seemed to have more light in
it than I had previously noted. Understood why at next haulout. I now rather
favor inhull transducers.

I have heard of several instances where the depthsounder transducer was
blown out of the bottom a boat on a lightening strike.

One of these, was a trimaran which was fortunate because the centre hull was
completely flooded. The mast was grounded and there were several seemingly
better paths for a strike to reach the water - But, the lightening somehow
caused the thin transducer wiring to fry and had sufficient power to blow
the entire thru-hull out and char the bottom in approx a 2' radius.

Just the other day, I saw a boat being sold for salvage that had had a
similar strike while at dock - the boat had sunk at it's mooring - cause -
depth transducer blow out.

And a bit earlier, I read about a similar instance in the Great lakes - I
forget the details.

Not sure if an in-hull installation would be better, but I suspect so.

Seems strange - Any theories?

GBM

 

[GBM]

You are never going to believe this, but when searching for the most
suitable place to locate an in-hull transducer, a British company found that
of the 15 or more different materials they tried for maximum sensitivity on
the transducer head, MARMALADE was far and away the best!

Most boats have at least a jar of marmalade in their food lockers. Save you
paying for exotic materials to do the same job!

Spread it thickly!

Dennis.

Reminds me of a chorus the rugby teams used to sing:

"Rule Britannia, Marmalade and Jam
5 Chinese crackers up your a??-hole
Bang, bang, bang, bang BANG."

 

[frank1492]

I suppose it should be that English marmalade with
the Seville oranges for best results, no?