Humminbird Side Imaging Forums

Side Imaging Forums => 798c SI => Topic started by: rlazop2004 on June 04, 2012, 02:29:40 AM

Title: Horizontal black lines (no data) 798ci HD SI
Post by: rlazop2004 on June 04, 2012, 02:29:40 AM

I recently bought a "798ci HD SI" unit for a kayak. It was installed in the stern and no other electrical device is on board.
I tested on a lake and at sea, but all side images comes with horizontal  (No  data)  black lines.

I would appreciate any help with this issue.

Title: Re: Horizontal black lines (no data) 798ci HD SI
Post by: SonarTRX on June 04, 2012, 03:08:41 AM

Hi Rlzop2004,

Could it be that the transducer is not always submerged or surrounded by very turbulent water?

If the transducer is mounted to the stern and in a shallow location, are you 100% sure that it is not coming out of the water? (...due to pitching-motion of the kayak) Any kind of turbulence along the hull or turbulence in the wake behind your paddle strokes might also partially obstruct the sound-beam.

I am also using a Humminbird on my kayak, but I have the transducer and the GPS mounted on a rotating "pole", to the port side, just forward of my feet. When launching the kayak, the pole is rotated so the transducer is out of the water. I rotate it down when I am ready to record. When the pole is vertical, the transducer is deep and has a clear view to both sides of the hull.

If a stern-mount is the only option for you, I would try to mount it deeper.

Tore

Title: Re: Horizontal black lines (no data) 798ci HD SI
Post by: Roddy on June 04, 2012, 05:25:14 AM

ralzop2004, Tore hit it on the head! In the screen shot turbulence can be seen on alternating sides paddle strokes in the watter column and the a slight drift when paddling stoped for the Mark button to be pushed.

Roddy

Title: Re: Horizontal black lines (no data) 798ci HD SI
Post by: sonar2000 on June 04, 2012, 09:04:23 AM

RLAZ...Thios most likely is a bounding of the transducer by a bouoncing kayak. As others have indicated a deeper transducer will most likely fix the problem. Kayaks sit almos on top of the water and if your transducer is right at the top it is bouncing.
Most option to place the transducer a bit deeper in the water by use of a verticle pole which can be adjusted for depth.
You might also check around this forum for center mounted or side mid mounted pictures.

Chuck

Title: Re: Horizontal black lines (no data) 798ci HD SI
Post by: rlazop2004 on June 07, 2012, 02:20:38 PM

Thank you all for your comments and recommendations. I will work on the suggested changes.

Best regards

Rodrigo