Station · mixed

Cargreave Sound

A mixed tide. One of the two daily highs is worth having and the other is not.

48 hours · height in metres above chart datum · all eight constituents

Mean spring range: 1.66 m
Mean neap range: 0.82 m
MHWS: 2.88 m
MLWS: 1.22 m
Form factor: 0.90
Classification: mixed, mainly semidiurnal

Mixed station. The diurnals are comparable with the semidiurnals and the two daily highs stop matching.

Deep sound behind an island chain. The semidiurnals are largely cancelled here.

The constituent table

Amplitude and phase lag at Cargreave Sound. The periods are astronomy and are the same everywhere; the two right-hand columns are the whole of what a tidal analysis produces.
Id	Constituent	Period, h	Amplitude, m	Phase g
M2	Principal lunar semidiurnal	12.4206012	0.62	96°
S2	Principal solar semidiurnal	12.0000000	0.21	130°
N2	Larger lunar elliptic semidiurnal	12.6583475	0.13	78°
K2	Lunisolar semidiurnal	11.9672348	0.06	128°
K1	Lunisolar diurnal	23.9344697	0.44	44°
O1	Principal lunar diurnal	25.8193417	0.31	18°
P1	Principal solar diurnal	24.0658902	0.14	40°
M4	Shallow water overtide of M2	6.2103006	0.03	250°

High and low water, 48 hours

Turning points of the curve above, read off the same series that draws it.
Time	Event	Height, m
day 1 03:23	High water	3.89
day 1 10:28	Low water	0.73
day 1 16:15	High water	2.25
day 1 21:00	Low water	1.21
day 2 04:02	High water	3.93
day 2 11:04	Low water	0.69
day 2 16:57	High water	2.27
day 2 21:41	Low water	1.22

Survey sheet CS/1

150 soundings on run lines 64 units apart, 3 of them drying heights, deepest 71.5 m. One stroke on the sheet — the coastline — and no depth contours. Why.

Get Wrackline

Wrackline is an aid to planning and is not a substitute for an official tide table. Do not navigate on it.