34 
Instructions and Examples 
Geographical list of subordinate stations and their tidal differences 
General remarks. Part I of the tide tables con 
tains complete, Independent dally predictions of 
high and low water for the reference stations. The 
tide data for other stations are computed by using 
tidal differences to the predictions for the reference 
stations. 
Part II contains a list of subordinate stations, for 
which tidal differences are given In geographical 
order. A region map is shown at the beginning of 
Part II. The alphabetical Index of stations at the 
end of this volume helps to locate a particular 
station. The numbers behind the station names 
listed In the index refer to the numbers of the 
stations in Part II. 
Even with carefully selected reference stations, 
the tidal differences computed for the subordinate 
stations are not constant values but are more or 
less variable and have similar periodic disparities 
as the tide itself. To determine the times of high 
and low water, it is usually sufficient to use an 
average time difference. However, the variabili 
ty of the height differences has to be taken Into 
account. 
Therefore, to calculate the approximate times and 
heights of the tide at subordinate stations, Part II 
of the tide tables provides the: 
(1) Mean high and low water time differences 
and for some places, additional corrections 
for semimonthly Inequality (Part III, Table 5). 
(2) Mean high and low water height differences 
for spring and neap times. Differences other 
than those at spring or neap time can be 
obtained by simple Interpolation between the 
given values. 
Application of tidal differences. Every subordi 
nate station In Part II can be associated with Its 
reference station by the corresponding header 
line. Adding the tidal differences of a subordinate 
station with the given sign to the appropriate 
reference station yield the predicted times and 
heights of the high and low waters at the subordi 
nate station. 
In this context It Is necessary to determine spring, 
mean or neap time by applying following methods: 
1) The simplest method is to use table 2 In Part III. 
2) By comparison of the predicted high or low 
water heights of the reference Station (see Part I) 
with Its tidal levels (see Part II, lines highlighted 
in grey). 
Any differences in the time zone and chart 
datum between reference station and those of 
the subordinate station are already included 
in the tidal differences. Thus, one obtains high 
and low water times for the subordinate station 
in the time zone of the reference station given 
In Part II as well as the heights based on the 
chart datum at the subordinate station. For times 
and heights the remarks In Part I hold true. 
For some subordinate stations only limited evalu 
able observations are available or the area falls 
dry during low tide. For those stations the tidal 
differences can only be partially given. Missing 
data Is marked by “*no data”. The according 
values can be estimated roughly by using tho 
se of the adjacent stations. Other methods are 
the assumption of a constant duration of rise 
(6 h 12 min) or duration of fall (6 h 13 min) or the 
durations at an adjacent station. However, in doing 
so, caution has to be exercised, especially In river 
areas.