Drift Effects On Expanding Square Search Patterns; Creeping Line / Parallel Line Search Pattern - Raymarine LIGHTHOUSE 4 Operation Instructions Manual

Drift effects on expanding square search patterns

As the search patterns account for drift the resulting [Route] may not
resemble the pattern shown above.
Example
148
Example
Drift
Direction: 0°
Speed: 0 Kts
Direction: 45°
Speed: 0 Kts

10.4 Creeping line / Parallel line search pattern

The [Creeping line search pattern] and [Parallel line search pattern] both
cover a rectangular area. A creeping line search pattern provides greater
coverage of the area but takes time to cover the whole area. A parallel line
search pattern can cover the same area more quickly whilst still providing
reasonable coverage.
Drift
Direction: 0°
Speed: 0.5 Kts
Direction: 0°
Speed: 1 Kts