Transducer placement issues

[TyGuy02]

The first several times I went out with the new HB 998 and transducer I was loosing readings (both depth/SI/DI) at speeds of +10 mph. So I had moved it up each time. Now after I have moved it up I cannot get the correct reading of depth even when drifting (SI and DI work just fine). The DI can get the depth right, but not the digital depth reading. It would fluctuate between the correct depth (6') and a much higher depth (30-40'). Where do I go next? Do I keep moving it up, or try to find a spot somewhere in-between?

On a side note, the base of the transducer has wiggle. Everything is tight, yet the kick-back portion of the base wiggles inside of the bracket.

[EBass]

I just have a cheap lowrance, but my ducer sits lower than yours. I think it would need to be lowered so the bottom of ducers is lower than you hull.

[chak]

I never had any luck on aluminum transoms with the ducer not at 1/2 a width under the hull bottom. This is where I go for any Hummingbird questions, they have factory reps answering posts. Some of it may a software issue I know they just had a update Hummingbird Forum

[lawman]

I have the same issue with my 958.....DI reads well but the sonar loses signal at about 5mph. Tried lowering my ducer but no luck.

[TyGuy02]

I have a hunch that I need to move it up even more. That is the main reason why I wanted to ask because I'm tempted to try lower again, but it didn't help before having it lower and how would a fraction of an inch really help if it didn't at -1" and at -0.5" (if that makes any sense). I almost want to try +1" from where it is now.

I think the reading issue last time out 6-30' was more of a sonar sensitivity issue than a placement issue, after reading the HB forum.

[hitthebricks]

From what I see the ducer is too high. The equator of the transducer, being the middle line of the transducer should be inline with the lowest plane of the hull.

My 997 HB has the same style ducer and I run it much lower, lots of spray but good results.

Check out [email protected] fo the best Q and A's with Humminbird's

Keep it fun

HTB

[CaptainMusky]

No experience with the Birds, but by the looks of that ducer the tail end of it is pointed down. That goes against any rigging I have ever done. Is it supposed to be that way or is it an illusion that makes it look like that?

[TruthWalleyes]

http://www.hotspotoutdoors.com/forum/ubb...rve#Post3083384

I drew a picture near the end of this thread to show how i have mine installed. I also recently adjusted a buddies transducer, also on an aluminum hull, and his is working perfectly on plane as well.

[TyGuy02]

truthwalleyes, your post a few weeks ago is the reason I want to try higher.

captainmusky, I think it's because I have the trailer unlevel/pitched. It was just sitting in front of the house not on the pickup so that the rain last night wouldn't settle on the cover.

Hitting the water this afternoon to get some slabs with Uran, we'll get it figured out...eventually. I'll raise it up and have him peek his nose back there at WOT to make sure that it isn't too high. A little difficult to do with the wavewhackers, but it'll make good use of a fishin buddy

[TruthWalleyes]

AN 1/8" can make all the difference.

If it isn't working at idle, then you likely have an angle problem. When it quits working at 10mph (Which is most likely half plane) i wouldn't worry about it too much, when it quits working on plane, then it is usually a height or distance from transom.

Based on the picture above, i'd try to get some more space between the boat and transducer and also between the mounting block and the transducer.

I'll probably go fishing tonight, i'll take a picture of mine if i can remember.

[TyGuy02]

Well it was better today, not great, but better. I was able to get really good readings at 7 mph and less. I reset the factor settings and corrected the readings at idle. I had raised it another 1/2" before I went out today, and like truthwalleyes mentioned, I bet I need to be a little further from the transom, because it's sitting flush against the mounting plate right now.

[TruthWalleyes]

Carp, i forgot to take a pic of mine, i have fished the last 6 days in a row, but have softball tonight, so it'll have to wait until next monday.

Mine is in the same bracket as yours, but instead of the black transducer bracket sitting in the stainless bracket like you have yours pictured above, i have the black piece extending out from the boat, and the stainless bracket part is actually squeezing the black transducer bracket holding it in place at an angle. This keeps the transducer about 1" from the transom, and also about 1/2" above the transom.

Here's a picture.

This is not the way the bracket was designed to be used FYI, this will negate the "Break away" feature of the mount.

Here's where i got the idea http://www.sternmate.com/Where.html

You could also use the all plastic mount which gets you away from the transom a little bit - bottom pic.

I have the bottom bracket for my quadrabeam transducer, but still use the above bracket for my side imaging transducer. The plastic bracket will get your ducer a little bit further from the boat. I just adjusted the stainless bracket setup to work similar to the all plastic version.

[reddog]

The depth function (2D) comes out of the right side crystals. With the transducer mounted on the left side of the transom, the right side crystals lose contact with clean water first. If you want higher speed readings, the right side must be in the cleanest water off the hull.