NauticTools2Tides
Tides BSH – height of tide and minimum height by the German BSH tide tables
What is the height of tide at a given time, and when is a required minimum height reached? NauticTools2 works this out by the method of the German BSH tide tables, with the mean spring and neap curves of the reference ports and, if you wish, for a secondary port.
- BSH 2027
- 38 reference ports
- Secondary ports
- Springs, mean, neaps
- Minimum height as a time window
- Tidal curve
What is the method of the BSH tide tables?
The tide tables of the German Federal Maritime and Hydrographic Agency (BSH) give the time and height of every high and low water at the reference ports. In between, the tide does not run evenly, so each reference port has mean tidal curves for springs and neaps. The actual duration of rise or fall on a given day differs from the mean: the target time is therefore related to the duration on that day and transferred to the mean curve. The height read there is converted in proportion to the heights of the day.
When do you need it?
- Draught and shoals: is there enough water over a shallow patch at the planned time?
- Planning a window: from when to when are there at least 2.50 m at the harbour or in the channel?
- Drying out: when does the boat take the ground, and when does she float again?
- Passage planning in tidal waters: the German Bight, the Netherlands, Great Britain and Ireland, France, Spain, Portugal, Gibraltar and Norway are available as reference ports.
The working
Springs, mean or neaps
The state follows from the date by Table 4 of the BSH tide tables. It can be overwritten by hand. At mean tides the average of the spring and neap results applies.
Apply the secondary port
Time and height differences are applied to all high and low waters of the reference port. The shape of the curve stays that of the reference port.
Place the target time
The target time is related to the actual duration of rise or fall and transferred to the mean duration of the curve.
Read the height
The height on the curve is converted in proportion to the heights of the day. For a minimum height the same calculation runs in reverse and gives the times at which the curve crosses that height.
Worked example
Scharhörn, Bake C as a secondary port of Cuxhaven on 7 July 2027, springs. The table gives for Cuxhaven (times in UTC+1) HW 15:27 at 3.9 m and LW 22:36 at 0.2 m. The differences for Scharhörn are HW −50 min, LW −60 min, and at springs HW +0.2 m, LW 0.0 m. What is the height of tide at 16:00 UTC+2?
HW Scharhörn: 15:27 − 50 min = 14:37 · 3.9 + 0.2 = 4.1 m
LW Scharhörn: 22:36 − 60 min = 21:36 · 0.2 + 0.0 = 0.2 m
Target time: 16:00 UTC+2 = 15:00 UTC+1, so 23 min after HW
Duration of fall: 6:59 h, mean at springs 6:49 h
On the mean curve: 23 min · 6:49 / 6:59 ≈ 22 min after HW
Share from the curve: about 0.99 of the range of 3.9 m
Height of tide ≈ 4.06 m
This task is saved in NauticTools2 and can be opened with Load.
What to watch out for
- Day starts with: enter the points in the order of the table. If the setting does not fit the heights, a red note appears.
- Only within the day: target time and minimum height must lie between the first and the last point entered. The app deliberately does not extrapolate beyond them.
- Double low water: at places like Hoek van Holland the table gives only one of two low waters. If the duration differs greatly from the mean, the app warns that the result is unreliable.
- Secondary ports that dry out: if the table gives no low water, as at Neuwerk, the low water values of the reference port apply. The app points this out as well.
- Traced curves: the tidal curves are traced after the BSH tide tables and are not original BSH data. Small differences from the original are possible.
How it works in NauticTools2
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Check the places in “BSH Ports”
The BSH Ports tile manages reference and secondary ports. The BSH 2027 data set comes with the app: all 38 reference ports of the 2027 tide tables with mean heights, time zone and tidal curve, plus a few secondary ports as examples. You add others from Part II of the tables yourself.
One-off data supply: the BSH 2027 data set is supplied once only, so that the traced tidal curves can be included. There is no yearly data update. You maintain new editions yourself: the ⋯ menu copies the data set into a new year, and you then compare it with the new tide tables.
BSH Ports: reference and secondary ports, separated by data set. Secondary ports with their differences, grouped by reference port. -
Choose the place
In Tides BSH, enter a name or number in the port search. A secondary port selects its reference port as well.
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Enter the table values
Choose the date and enter the time and height of the high and low waters from the table, in the time zone of the reference port. The values of the secondary port appear while you type.
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Target time or minimum height
A target time gives the height of tide, for example “4.06 m at 16:00 UTC+2”. A minimum height gives the time window, for example “at least 5.00 m from 07:43 to 12:47 and from 19:56 UTC”. The slider moves along the curve.
The time window for a minimum height, with the crossing points on the curve. -
Save and print
Tasks belong to the chosen data set. The printout contains the inputs, the result and the diagram.
New editions
The ⋯ menu next to the data set copies BSH 2027 into a new year. All entries of the copy count as unchecked until they have been compared with the new tide tables. Results calculated with it carry a red warning. The tidal curves stay valid through the port number.
Report to print
Every calculation can be printed as a report or saved as a PDF, with the inputs, the tidal curve and the result.
View the example report as a PDF ›
Frequently asked questions
Which places are included?
All 38 reference ports of the 2027 BSH tide tables, from the German Bight through the Netherlands, Great Britain and Ireland, France, Spain, Portugal and Gibraltar to Norway. Secondary ports can be added from Part II of the tables.
What is the difference between a reference port and a secondary port?
For reference ports the table gives every high and low water. A secondary port has no predictions of its own, its values follow from time and height differences to a reference port.
Do I still need the tide tables?
Yes. You enter the times and heights of the day from the tide tables. NauticTools2 uses them to work out the height of tide or the time window between those points.
Not for navigation: all tidal values are approximations for training, exam preparation and passage planning. Traced tidal curves and calculation methods differ from the actual tide, and wind and air pressure change it further. For navigation, the official tide tables are authoritative.
Related tools
- Tides ATT – tidal predictions with the Admiralty Tide Tables
- Age of Tide – springs, mean or neaps for any date
- Depth of Water – depth of water from charted depth and height of tide
NauticTools2 is available for Windows 10 and 11 (free) and for Android (€9.99 one-off).
Windows: get it from the Microsoft Store Android: get it on Google Play