Where this fits
- Day Skipperrelevant
- Coastal Skipperrelevant
- Yachtmasterrelevant
Free tide-cycle tool
How tides work, shown in motion
Explore how Moon phase, spring and neap range, a local harbour tide curve, and the rule of twelfths fit together without treating them as one clock. It is an independent revision aid, not official RYA training or assessment.
Direct answer
Tides are mainly driven by the Moon and modified by the Sun, local coastline, seabed shape, and weather. Most UK tide work for small craft uses published high and low water times and heights, then interpolates between them with a curve or the rule of twelfths.
- Best for
- Lunar day, springs, neaps, tide curves
- Includes
- Separate Moon, harbour curve, and twelfths views
- Practice mode
- Guided lesson, local curve slider, quiz
- Cost
- Free, no login required
Springs, neaps, tidal curve
Tides in motion
Use separate controls for Moon phase and today's harbour tide curve, then see where the rule of twelfths fits.
Simplified model
For learning relationships only. Use official tide tables and local data for navigation.
HW height
4.2 m
LW height
1.0 m
Range
3.2 m
Current height
2.5 m
Tide is rising.
Link to this tool
Use this canonical URL in club newsletters, lesson notes, or student revision plans.