# Tide Calculation for Secondary Port Dungeness

## Tide Calculation for Secondary Port Dungeness

The height of a Lt. Ho. at Dungeness (ATT Vol.1, 87) is charted as 40m. What height would you use when taking a vertical sextant angle at 1800 GMT on June 8th?

## Tide Calculation for Secondary Port Dungeness

Since the range is not same as spring or neap, interpolation required.
Spring range – Neap range = 6.0 – 3.2 = 2.8 m
Spring range – Current range = 6.0 – 5.5 = 0.5 m
The fraction required = .5 / 2.8 = .1
So, Height at 1800 hours = 5.3 – 0.1 = 5.2

Spring Height for Dover = 6.8m
Ht. Diff for Dungeness = + 1.0m
MHWS at Dungeness = 7.8m
Height of tide at 1800Z = 5.2m ( At Dungeness )
Tidal Ht. Less = 2.6m
Charted Height of L/H = 40.m ( against Spring Height )
Tidal Height Less at 1800Z = 2.6m
Height of L/H at 1800Z = ( 40.0 + 2.6m) = 42.6m
(Ans)

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