Info on Depth/Fish finders?

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Charles

Hello Everyone! I've read here somewhere that some of you are using Fish Finders as depth sounders. What brands do you recommend, and which ones come with the "glue inside hull" transducer. All I've found have transom mount transducers. On a different tack, I may just need to replace the transducer on my existing depth sounder. It's a '83 Standard Communications DS-1, does anyone know if the new "glue inside hull" transducer for the Standard Horizon DS45 will work for my old unit or will I need to make major modifications for it? Thanks, Charles
 
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Bill Trahan

depth/fish finder

I bought a Humminbird 200DX Dual Beam and siliconed it inside my hull and it works great. Paid less than $100 for it.
 
Apr 19, 1999
1,670
Pearson Wanderer Titusville, Florida
Piranha fishfinder

I paid $70 at WalMart for one with a transom-mount transducer, which I potted in epoxy on the inside of the hull. Silicone works fine too. The material doesn't matter too much as long as it holds the transducer securely in place and provides a good acoustic connection to the hull. To make sure the hull isn't cored at the location you select, set the transducer on a Ziploc bag half full of water and move it around until you get a good solid signal. The only drawback with a fishfinder is that most of the display is taken up by the picture of the bottom and the depth is presented in small numbers off to the side somewhere. However, it still beats $250 for a "real" depth sounder. Good luck. Peter H23 "Raven"
 
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Dale I

Eliminate one hole in your boat...

Seems that in the archives I ran across a diagram for internally mounting a depth x-ducer inside the hull... SOOOoo, I experimented with doing it. I beveled a 4" long piece of 3" pvc to the internal slope of the hull so that it'd point down and punched a hole in a slip-on pvc cap to mount the ring nut of the x-ducer in.... 5200 held the pvc to the hull and, (probably overkill), I painted epoxy inside the pvc and hull inside the tube. I experiemented with the use of petroleum jelly as a medium to shoot thru with no luck...so as recommended , put enough mineral oil in the tube to cover the bottom of the x-ducer--but not so much as to spill when heeled over... Dropped the cap and x-ducer into the tube and it works great.... Never again need a haul out to work on that thing and no concerns for leakage... (Don't forget to glass over the old hole ;) ) Seems that the bottom paint on the hull has not effected its functioning. Wish that I could do the same on the speed paddle wheel... Next time, I might try that jelly stuff that they use for OB-GYN ultra-sounding of fetus's....would never spill and may be better than other stuff. A word of caution...My C&C is cored to the keel, but I found a spot forward that was evidently made for holes and had no coring.... In direct response to your question....I'd get a fish finder next time as they give a better profile of the bottom than a numerical read out....MORE information is always a good thing.
 
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tom

glue in place

I put depth sounders in two different boats. I made a puddle of polyester on the hull and placed the transducer directly into the puddle making sure not to make any bubbles. They both worked fine. I found a flat(er) spot in the hull near the stern on both boats. The first was a fish finder from wal-mart the second a depth sounder from west marine. I missed the fish finder as it provided more information compared to the depth finder's simple numbers. They would both read to over 100' though I supposedly lost some depth by mounting it inside the hull. The problem with silicone is that it is flexible and may absorb some of the sound energy. I never tried to remove the transducers but imagine it would be difficult. I just couldn't bring myself to cut a hole in the bottom of the boats!!!!
 
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Bruce Trotter

fish finder

I am using a Bottomline 1100 with the transducer mounted on the inside of the hull by the keel. It is pretty accurate because I grounded it on a sand bar one time and it was reading 5 foot which is with in 6 inches . It was not the fish finders fault/operator error. The only thing is the transducer has to be wet to work but generally that is not a problem. Thats why I mounted it as low and near the keel as possible because it stays wet there quit a bit. You can also check the charge on your battery and turn off the fish locater part and it will just show the bottom and numerical depth. I am pretty sure it will also tell you what kind of bottm (hard ,sand etc) but I have not taken the trouble to figure it out. It might help when anchoring. I fastened it dowm with silcone the first time but it came loose in the mosture so the last time I use Marine tex and so far it has not come loose. It has to be dry to stick it down though. Slao the curved side has to be down just like it would be if mounted on the exterior. They cost about $70 to $80 bucks at academy sports.
 
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tom

directly to hull

If the transducer is glued directly to the hull it doesn't have to be wet. The transducer vibrates very rapidly and this sound energy will go right through a solid hull. The problem is air gaps or anything not rigid that won't transmit the sound efficently. I followed the manufacturer's mounting instructions and they specifically advised against using any flexible glue such as silicon. They also stressed not trapping any air bubbles in the glue. The instructions did recommend putting the transducer into a plastic bag full of water and moving it around the boat to find the best spot. I mounted mine near the stern as there were flatter areas and when I anchor in lakes it is usually with a bow anchor with the stern tied to a tree on shore. In the mountain lakes there was sometimes 20-50' of water under the bow and 5-6 ' under the stern. With the unit from west marine the maximum depth of 199' was detectable. When sailing the deeper parts of the lake it would bounce around at near the maximum depth though I have no idea how accurate it was. Remember that lakes have thermoclines and cold water transmits sound faster than warm water. Different transducers have different cones of sound. Or angle of transmission. A wider angle is important in a sailboat as the boat heels and the depth reported would be the first sound reflected. A narrow cone might give a false depth when the boat is heeled over.
 
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Ramblin' Rod

Some additonal fishfinder notes

Because of the larger market and economies of scale, fishfinders give you a lot more bang for the buck. (As long as you don't want to tie your depthsounder into universal displays or repeaters with other instruments.) For shooting through the hull, pretty well any adhesive will work, but harder adhesives (like polyester resin or epoxy) will attenuate the signal less, resulting in deeper measurement range. Our Eagle Strata 128 Plus (Lowrance) fishfinder shoots through the hull and reads reliably down to 340 feet. Most fishfinders give you all kinds of display options, where you can shut off the "fish" display and only show large digits. I prefer to have the bottom "grayline" displayed normally. Beware the ones with the additonal speed impeller. Some people have gotten them to work sorta, but I never could (mounted on a suction cup and moved all over the transom to no avail). The guys at Lowrance said it isn't designed for sailboat transom's (big help).
 
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Pops

Mounting display

I have a Piranna finder ready to install but haven't come up with a good place to mount the display. I was going to mount it on the bulkhead below the compass, but am afraid the main sheet will grab it when I tack (my traveler is mounted just in front of the companionway). Has any one come up with a way to mount theirs to avoid this problem? Thanks.
 
Apr 19, 1999
1,670
Pearson Wanderer Titusville, Florida
Mounting fishfinder, for Pops

I had mine on the bulkhead below the compass and got tired of it being fouled by the mainsheet. I found a cool idea in SAIL magazine's book "Things That Work". Here it is. Use a couple of spring-loaded cabinet hinges to mount a wooden panel on the inside edge of the wooden companionway framing. The edge of the panel should be flush with the framing with a little tension on the hinges. Mount the fishfinder display on the panel. When the unit isn't needed, the panel swings out of the way into the cabin. Make the panel as narrow as possible to minimize the obstruction in the companionway. Peter H23 "Raven"
 
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