Transducer Mounting Question

[BoatNoobie]

Re: Transducer Mounting Question

Looks like the same transducer on my HB 798CI SI.

If you bought it brand new, it should have came with a rubber plug to fill that void between the transducer and mount. They also come in the transducer mounting kit.

If you bought yours 2nd hand, the person may have lost it. Check on Hummbird's website, they may sell it there.

I might have a spare 1 actually.
*edit* I do have a spare 1. If you cant locate one, PM me.

 

[l008com]

Re: Transducer Mounting Question

HAH! I DO have one of those plugs! I have a few boxes of stuff I've been buying for my boat, I think i thought that was just a stray part that fell into the depthfinder box! I just found it and I'll try to install it tomorrow. I'm not sure that's going to be enough though, I'll have to wait and see. The water wasn't just coming straight up, it was going to the sides a good amount too, bathing my engine in salt water. I'll install it, go for a ride, and see how it goes. I suppose I could always just install it way too high, and have a depth finder that only works when i'm not planed out, which is actually fine by me. But I'll install that stopper and see how it goes.

 

[SteveRoss]

Re: Transducer Mounting Question

There have been sooooooo many posts/threads on proper transducer mounting, and I have learned a lot from each of them.

However, I am firmly convinced that in order to get the transducer properly mounted so the system functions like the big bucks we spend for them, a few conditions have to be met:

1. Jupiter has to be aligned with Mars,
2. Washington has to balance the budget, and
3. It just has to be your lucky day.

After 4 or 5 tries at mounting (working on another attempt today), I'm still not sure I have it right. Guess I'm just another stupid Mechanical Engineer... LOL

 

[RickJ6956]

Re: Transducer Mounting Question

Everything I read and everyone I talked to said that you get better readings mounting it out back. I was originally going to put it in the bilge but I read enough "there may be issues going through the fiberglass" to mount it externally instead :-/

That's why the tests are done prior to permanently mounting to find a spot that will work. The signal will shoot through fiberglass provided there's no foam, air core plywood, or air bubbles in the fiberglass. That's also why the water is used inside to flood the transducer while placement tests are conducted -- so there's no air between the transducer and the hull. Signals won't pass through air.

It won't work on all boats, but it may work on yours.

 

[Capt'n Chris]

Re: Transducer Mounting Question

So I've read through the manual, gone through the equipment, and I think I'm ready to install this thing. Based on the "fins" on the bottom of my hull, there are two places where I can mount this transducer. Spot B is just about 15" from the motor (what they recommend for a minimum) and it's very close to the speedometer. Spot A is further away from everything, but I worry that it's too far out, and could catch on a rope, or maybe be in the way if I hook a trailer strap to the hook. Give me your thoughts on this...

Shoot-thru:
The transducer is mounted inside of the hull, usually in a bilge, sump or keel, permanently adhered to the hull with an epoxy or may be contained in a liquid reservoir. The sonar ping emitted from the transducer must penetrate a solid unblemished hull material to effectively record a sounding. The transducer has no contact with the water outside of the boat. These generally are installed to avoid the necessity of making screw-holes in a transom below the waterline, for protection, and in most instances, will reduce or can compromise the effectiveness of the transducer and equipment sounding. Compromises are made in regards to eliminating a speed wheel, if equipped, recording water temperature and a reduction in the quality of its sounding performance. Unlike the easily maintained and adjustable transom-mounted transducer, this method of mounting is generally fixed in place with a bonding material and cannot be adjusted, serviced or changed without the likelihood of destroying the transducer during removal. The user generally will install his transom-mount designed transducer in this manner and will settle for reduced performance as a compromise to sacrificing his boat hull as a "trade-off" for screw-holes and leaks.

Transom-mounted

The transducer is externally mounted on the transom whereby the face of the transducer makes contact with the water. Typically, these are the most effective, the easiest to service, to adjust for an optimum sounding, easily replaceable and, of course, the most popular. This type of transducer mounting allows for maximum performance of your electronic equipment as designed by its manufacturer. To mount a transom-mounted transducer, screw-holes are required by drilling holes below the waterline of your boat. Review and understanding your boat warranty disclaimers and the disclaimers made by the electronics manufacturer should be considered before mounting this type of transducer. Many boat owners are justifiably reluctant to mount transom-mounted transducers. Oftentimes they can be very cantankerous to adjust properly and generally will leak when you least expect it.

 

[l008com]

Re: Transducer Mounting Question

^^
That's why I went with transom mount. So I stuck the plug in today, and I still have yet to wire up the gauge. Once I get that done, I'll see if the plug stops the splashing, and see if I'm actually getting a good, accurate reading or not.

 

[Jeremy Williams]

Re: Transducer Mounting Question

I have a similar size boat, and same transducer shape/size. I tried the transom mount as it was replacing an older unit. The brackets (and holes) were already there - so it was the obvious choice.

I could not stand the splashing, and spraying so tried putting it in the bilge, near the center of the boat. I have read that 1/3 forward is preferred, but the center that was the most convenient place for routing the cable. It worked great (no real difference noticed between outside boat in water and inside bilge water). So I elected to epoxy it to hull. Just finished, but nervous if it will work as well with resin as it did with the bilge water.

I'll post my results, with a photo.

 

[l008com]

Re: Transducer Mounting Question

I actually put the little rubber plug into my transducer and the splash is all gone. And I even sketchily hooked up the gauge to the battery and verified it's working with decent readings. Now I just need to get a 3.3" to 2" adapter for my dashboard so I can install this thing!

 

[l008com]

Re: Transducer Mounting Question

I FINALLY got a gauge adapter fabricated, and I wired up the depth finder, got it programmed for 1ft keel offset and 4ft alarm. It seemed to be working quite well on it's maiden voyage. One thing happened though that was weird. I was in boston harbor where the depth is 30-50 feet. Every once in a while though, it would jump up to only 14 feet or so, then jump back to 40. Then at one point, it jumped to 3 feet and the alarm went off, then it jumped right back down. Am I picking up fish? I can't imagine it's debris, because lots of good sized ships come through here, and debris would get pulverized. Maybe a shark is stalking us :-D

 

[Pez Vela]

Re: Transducer Mounting Question

Simplified menu settings may help you get dialed in until you have more experience with the unit. If the alarm is disconcerting, turn it off for now. If your range setting is set to "auto," I'd change it to "manual" and pick a suitable depth so that you'll always see the bottom, say 60 feet. You may be getting interference from water turbulence around the transducer, and if your machine is "auto ranging" it's going to jump around and give false readings. Try slowing the boat down to idle speed and see if the problem goes away. This would provide your first clue that you have turbulence at higher speeds and a less than ideal mounting location as previously mentioned.

 

[Moose1am]

Re: Transducer Mounting Question

Remember that the Side Imaging Transducer have to be mounted outside the boat to work in the Side Imaging Modes.

If you mount the si tranducer inside the boat using epoxy or anything else for that matter it will only work in 2D mode or regular sonar mode.

Remember that SI tranducers have to send the sound waves out at a 90 Deg Angle to the boats line of travel. With the tranducer mounted inside the boat the hull will block the sideways signals and stop the Side Imaging sound waves from going out into the water.

If you want to have high speed readings and Side Imaging readings at the same time you need to link two different types of sonar tranducers together. One (the High Def SI tranducer) on the back of the boat's transom and the other 2D type transducer inside the boat using the thru the hull mounting method that he is describing.

Humminbird Greg can explain this to you much better than I. He may frequent this web side and if not then check out the other web forums that have to do with the Humminbird SI units.

Hope this helps.

You could try mounting the transducer inside the boat. Fill the bilge with enough water to "seal" the bottom of the transducer to the inside of the hull (the transducer doesn't work if there are air bubbles) and use something heavy to hold it in place. Try different placements. Once you've found an ideal spot (and if it gives you the same readings as it does now) dry the hull and use two-part slow cure epoxy to permanently mount it. The key is to have no air bubbles in the epoxy or the hull.

 

[Moose1am]

Re: Transducer Mounting Question

The Humminbird's manual shows how to mount the SI transducer on the boat. But each boat is different so you have to adjust the mounting to fit your particular boat.

Just remember that if you mount the transducer lower than the bottom of your boat it's more likely to hit an underwater obstruction or log floating in the water.

The transducers only have to be mounted low if you are using them to do high speed 2 D readings on the new Humminbird SI type units. The SI units when using the SI modes don't need to go at high speed. SI works best when going less than 4 mph. So you don't use the SI transducer for high speed sonar. To get the high speed readings Humminbird recomends adding another sonar transducer to the boat. A see though the hull transducer can be hooked up to the unit along with the SI high Def transducer which is mounted on the transom most of the time.


The second transdcuer can be a see though the hull type and epoxied into the hull of the boat for high speed 2D depth readings.

Humminbird makes cables to attach these two transducer to the unit at one time.

With the Humminbird SI units you switch screens using the menu or exit button and any view that's turned on in the views menu will show up as you cycle though the views.

The SI high Def transducer sends out sound waves straight down in the 84 KHz and 200 kHz frequencies. Then it sends out sound waves in the 455 KHz and 800 kHz frequencies to the side of the boat. The 2010 Humminbird Catalog clearly shows how the sound waves work in the very front of the catalog's pages. They have a diagram that shows what areas of the water the sound waves cover. I wish I had a link to that picture as I can't describe it in words. But once you see the picture you understand how SI and regular sonar soiund waves travel though the water and reflect back to the transducer.

Knowing how sound travels though the water and how it's produced and focused helps you understand how these sonars work.

http://www.humminbird.com/leading_innovation/humminbird-sonar/side-imaging.aspx


http://www.dougvahrenberg.com/images/HB008.jpg

In the link above note how there are two cirlces that look straight down right under the transducer. These are what I call 2D sonar sound waves. These are the 83 and 200 kHz frequencies.

The 455 and 800 frequencies go out to the sides in a very thin slice of sound and stretch from the surface to the bottom. This is shown in the link shown above in the top down veiw and the side view in the picture.

QUOTE=MM3Canuck;2829616]I have yet to install my Humminbird.

So the question is, is "008com" transducer in the right location?
I was under the impression that it should not go under the hull?[/QUOTE]

 

[l008com]

Re: Transducer Mounting Question

I have a basic hummingbird that just gives you a number in feet, and that's all I needed. But I still get lots of strangeness with mine. Most of the time it works, but it jumps to 3-4 feet a lot. Even when I'm going very slow. The way mine is mounted, its fully submerged when i'm not planed out. Is there a problem with it? Or does it ping off of fish and jelly fish? That's what it seams like. I can't adjust my speed when it happens, because it goes back to normal before I could even do that. It's very odd.

 

[Moose1am]

Re: Transducer Mounting Question

How level (fore and aft and starboard to port) is your boat?

First. Level the boat with the water's surface on a calm day.

Your transducer should be mounted so that the sound waves travel straight down to the bottom and bounce straight back up to the transducer.

If your boat is stopped and level the transducer's flat bottom surface should be parallel with the calm water's surface and shooting the sound waves straight down to the bottom and not at an angle to the bottom.

Think of a flash light beam pointed down from the boat to the lake bottom. The center of the beam of light should take the shortest path to reach the bottom of the lake. The light hitting the lake bottom should form a perfect circle of light. The light should reflect off the lake bottom and bounce straight back up to the transducer or the flashlight in this example.

If your boat is not level the transducer sound beam will be shifted. For example if you are taking off and the bow of the boat is raised up then the transducer will be pointing slightly forward instead of straight down.

When your boat is on plane and traveling a cruising speed you should adjust the transducer to point straight down to the bottom of the lake while you are moving.

If the boat leans to the starboard side or to the port the beam of sound will be deflected to the side. This is why sometimes when you are going fast and make a hard turn you lose the sonar screen's signal.

I use extra weight to level out my boat to get the best readings. If I didn't do that I'd have to drill new holes in my boat and reposition my transducer into a new position.

So the position of the boat in the water has a lot to do with how your sonar works.

If your boat moves to the left or right your transducer also will move slightly to the left or right as well.

Take a flash light and point it straight down at the floor while holding it. Change the angle of the light and watch how the beam of light on the floor changes shape. Imagine your sound waves as that beam of light. Note the angle that the light reflects back up off the floor. Sound waves in water act much like the light beams of a flash light's light waves.

You just can't see the sound waves like you can the light waves.

I have a basic hummingbird that just gives you a number in feet, and that's all I needed. But I still get lots of strangeness with mine. Most of the time it works, but it jumps to 3-4 feet a lot. Even when I'm going very slow. The way mine is mounted, its fully submerged when I'm not planed out. Is there a problem with it? Or does it ping off of fish and jelly fish? That's what it seams like. I can't adjust my speed when it happens, because it goes back to normal before I could even do that. It's very odd.

 

[l008com]

Re: Transducer Mounting Question

My boat leans way back in the water because it has a large engine. But if I tilted the transducer back, to make it level with the water, that's the opposite of what the instructions say, which is tilt it forward a bit, so that it always has good solid contact with the water?