innomar SBP smart - 13 FAQ (Frequently Asked Questions); 13.1 System Performance

User’s Manual INNOMAR Parametric Sub-Bottom Profilers / SESWIN 153
Innomar Technologie GmbH (2023-01) 153
13 FAQ (Frequently Asked Questions)
13.1 System Performance
13.1.1 I do not get the seabed echo.
Q: When I start pinging there is no seabed visible on the echo plot screen.
This may have different reasons:
 The seabed is out of range. Check “Range Start” and “Range Length” settings and set
to appropriate values. If in doubt, start with a low (shallow) “Range Start” and a large
“Range Length”.
 The amplifier gain is too low. Check if acoustic noise is visible on your echo plot
screen. If not, increase the “Gain” value of the affected channel until noise is shown.
 The thresholds for colour mapping are inappropriate. Check if acoustic noise is
visible on your echo plot screen. If not and the gain values look reasonable, check the
threshold settings in the “View” menu tab. Defaults are 5 / 5.
 There are gas bubbles washed down below the transducer. Reduce the vessel
speed and/or change the course regarding the waves to reduce bubble wash-down. Re-
consider the transducer mounting location.
13.1.2 I do not get a seabed echo in the HF channel.
Q: When I start pinging there is no seabed visible on the HF channel, but it is shown in the
LF channel.
Again, there are different reasons possible:
 The water depth is to deep. The HF channel energy dissipates much faster than the
LF energy while travelling through water. Thus, the HF range capability is more limited
and you might lose the HF seafloor bottom track in deep water.
 The amplifier gain is too low. Check if acoustic noise is visible on your HF data. If not,
increase the “HF Gain” value until noise is shown.
 There are gas bubbles washed down below the transducer. HF and LF channels
might be affected differently by gas bubble wash-down. Reduce the vessel speed and/or
change the course regarding the waves to reduce bubble wash-down. Re-consider the
transducer mounting location.
13.1.3 There is no data file recorded.
Q: I did a survey line and got good data on the screen, but there is no data file on the hard
disk.
There are several possible explanations:
 Make sure the data destination is set properly in “System Setup – General – Files” and
that you have write permissions on the selected folder.
 Data recording is not switched on/off automatically with the transmitters going on/off.
You have to start/stop recording separately using the “Record” button.
 Check if the “Record” button is highlighted during recording and if there is a file name
shown in the SESWIN status bar. The file size is also shown and should increase over
time.
13.1.4 Transmitters are not switched on during data recording.
Q: I start data record, but the transmitters are still off.
Transmitters are not automatically switched on/off with data recording start/end. This has to be
done separately. This behaviour is on purpose to be able to record (noise) data without pinging.