Have you ever wanted to a walk safely along a beach, across a tidal estuary or around a rocky headland? Well of course you could check the BOM website from home before you left, but what if you had forgotten and only had your iPhone with you?
Sometimes knowing when high tide is going to be can be critical to planning a safe bushwalk. There are many locations where part of the walk will be along a beach, around a headland or across a tidal estuary. Often the guide book will warn that if the tide is high you must take and alternative inland route or even camp and wait for the next low tide. Being caught on an exposed headland as the tide advances is not much fun.
In Australia, I have used this information to safely plan walks along the Great Ocean Walk in South West Victoria and along the South Coast Track in Tasmania.
The following list of iPhone apps includes one that is actually a weather app which includes tides as one of its features.
|AU Tides Pro Screenshot|
Contains downloaded database for 2010-2012, which means you don’t need to be connected to the internet
Contain downloaded database for 2012 only, which means you will need to buy a new version at the end of 2012. This app only allows access to tide predictions 6 days ahead. World Tides uses the Simply Harmonic Formula and harmonic constants provided by the UKHO to give 7 day tide predictions without the need for an internet connection. Features: Moon/Sun Rise/Set times, large slidable tide graph, recent locations, built in zoomable map, gps sensor, search, and details page.
|Pocket Weather screen shot|
I have used this as my weather app for over a year and don’t see the need for an additional tide app. It does need internet access which makes it useless in remote areas, unlike the other three which actually download the tide database. Weather is sourced directly from the Australian Bureau of Meteorology (BOM) – an Australian Source for Australian Weather! #1 Weather Application in Australia, Best Australian App winner, Staff Pick in iTunes Store many times –
Shralp Tide (FREE)
|Shralp Tide Screenshot|
No network connection is required, so you can check anytime, anywhere. ShralpTide displays the current tide along with the high and low tides for the current day and the next 4 days. Includes an INTERACTIVE FULLSCREEN TIDE GRAPH in landscape mode. Turn the device on its side then touch the screen to see the tide at any time in the 24 hour window. Shralp Tide does not include all of the tide stations in the world. It has good coverage of the US and Canadian coasts as well as Australia, New Zealand and Japan. Beyond that there is spotty coverage of international locations.
The benefit of an iPhone tide app is that the calculations are done automatically for you if you select one of the non-standard ports. Of course, your iPhone probably has a GPS, in which case the app will work out what is the appropriate location on which to predict your tides.
You can of course use the Bureau of Meteorology’s tide predictions available on their website, which are based on a series of “standard ports” around Australia. In Tasmania, Hobart is one of the five standard and one secondary ports with calculated tide predictions available. Time differences for a limited number of other secondary ports are provided so you can work approximate tide times yourself by adding or subtracting the time difference.( see map below)
I don’t know the technical side but my iPhone app Shralp Tide gives the following for Wednesday 28 December for the first high tide.
- Maatsuyker Island (south of the bottom of Tasmania) high tide at 1.31 am as 0.69m
- Hobart: high tide at 12.34 am of 1.05m
- Bramble Cove : HIgh 3.17 am 0.78m
Bathurst Harbour is not listed nor Port Davey; you must use Bramble Cove.
BOM Tasmania gives Hobart as the nearest standard port and lists tides at secondary “ports” as a time difference from Hobart
Hobart HIGH at 1:02 AM 1:07m
- Maatsuyker Island +0:25 H:M
- Bramble Cove, near Port Davey is -0:48 H:M
- Hobart 0:0
Using these differences the iPhone app gives a pretty close estimate except for Bramble Cove which seems to be way out!
PS Don’t forget to allow for daylight saving if not done automatically by the app.
This article by Bush Walker is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.