User's Manual

FutureWaves™ User Manual
FutureWaves™ v1.7.0.1
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Appendix B – Frequently Asked Questions
Why is the FutureWaves™ heading different from the ships Gyro?
FutureWaves™ derives ship heading from the ship motion as measured by the FutureWaves™
Ship Motion Sensor. This sensor can drift off course, especially when the ship is at anchor, pier-
side, or stationary for an extended period.
If the heading is off by more than 2 degrees, reset the SMS sensor once the ship is underway and
on a steady heading. It can be reset at any time, but the ship should remain on a steady course
for 15 minutes after an SMS reset.
Why is the FutureWaves™ system unable to display any position?
FutureWaves™ will not display any position or ship motion data until it achieves a ‘heading
lock’. Even when good satellite data is available, if FutureWaves™ can’t determine a heading,
then no data is sent. This is to guard against providing incorrect forecasts.
Why is the depth displayed in FutureWaves™ different from the Fathometer?
A couple of reasons. The main takeaway is to never use this value for navigation or as a
reference for water under the keel. This value is only used to improve the accuracy of a wave
forecast in shallow water.
The depth displayed in FutureWaves™ is a value read from a file. The ship position is used to
look up a value from the file. The file only contains data at approximately 1/10 degree
resolution, so many small features picked up by the fathometer may be missed by
FutureWaves™.
A change in FutureWaves™ depth will reset the wave forecast, so there is a check to prevent this
from changing too often. Even in a rapidly changing environment, the depth will never update
more often than every 60 seconds. Additionally, since it is used solely to improve the accuracy
of the forecast in shallow water, the system may stop updating the depth value entirely if the
water depth is greater than 2000 m.
Finally, the depth displayed is the total water depth, from the surface to the bottom. It is not
depth under the keel.