iPhone at sea

Strictly, this is not a Morgan Giles 30 subject, but the very limited space aboard Santana for electronic instrumentation, not to mention  cost, has kept me away from advanced modern electronics such as chart plotters and radar, etc.  I have just VHF marine radio, digital echo sounder, NavTex and Garmin GPS with a repeater dislay in the cockpit.

For many years I have also carried a hand-held GPS which I loaded with a duplicate copy of the waypoints and routes in the Garmin, and ran as a hot standby in case the Garmin or power failed.  This proved its value one very dark and stormy night when we were approaching St Hellier through the NW passage when the Garmin GPS stopped working.  I was too wet and tired to take sights, and working on the chart table under those conditions would probably have added ‘sick’ to the list of my woes.  So I was very grateful to switch over to the hand-held device, until I eventually got the Garmin back. [A restart seemed to
clear the problem.]  So at the start of this season, when I found my hand-held could no longer get a fix, it was important to replace it.

And here I made a radical decision: instead of paying out money for a modern hand-held GPS, I took the plung and paid out money for an iPhone.  I have to say it has revolutionised life on-board and our recent cruise to and from the Scilly Isles.  I thought I would share this experience with you.  Now the iPhone is not rugged nor waterproof for in-cockpit use, but I discovered it works very useably inside a Aquapac waterproof camera bag.  It takes a bit of care to use the touch screen through the thick layer of plastic, but it is useable. Given the limited battery life when sealed in the bag without the charging cable connected, I also purchased an InCase PowerSlider, which both protects the iPhone and doubles the battery life.  This worked well in these two ways, but unfortunately in my experience cripples the GPS reception and weakens mobile signal reception, so when I really needed the iPhone for navigation I had to remove the case.  And now to how I used it:

First, one touch on my home screen each day displayed that morning’s Met Office four-day pressure model.  Weather predictions were vastly improved, as was advanced planning, such as where to be when heavy weather arrived, and when a fair weather window might appear.

Second, another touch and the latest shipping forecast or inshore waters forecast was on my screen.  Only twice, when out of mobile
phone range, did I have to resort to listening to the coastguard transmission and try and write it down accurately.  With the forecast
in written form on demand I could study it and relate it to the pressure chart to understand the basis of the forecast and reach my
own judgement on what to expect – not always the same.

Third, I had purchased iNavX from the Applications Store, a marine application, which provided all I got from my old hand-held GPS and much more.  With iNavX I was able to load in my waypoints and routes and there was the functionality of a hand-held marine GPS.  But additionally, compared with my old hand-held, iNavX provided my position, waypoints, routes and track plotted on marine charts from Navionics, which are available through X-Traverse for just $39 for the whole UK and Ireland waters.  Although raster based, these charts proved excellent and with great detail where needed.

Fourth, tidal hight calculations were handled by the application AyeTides, which, knowing my position, offered a choice of the closest ports or places where it had data and then displayed the tidal curve with the present time indicated upon it, together with present height above chart datum and the height of the coming low waters.  The coming
tidal drop was, therefore a trivial deduction, enabling me to know exactly how much depth I needed to anchor.  Given there were no
extreme barometric pressures or storm surges on this trip, I learnt to judge it finely, and, when over an even bottom, I  sometimes left just one foot spare for low water, which proved very accurate.  Finding our way into an anchorage, the chart display in my hand at the tiller proved invaluable.  I found it possible to use this to edge close in turning to port or starboard for the deepest water as shown.  After our return crossing from the Scillies we used this to particular good effect at night to tuck ourselves snuggly into an anchorage in the unlit Helford River.

Fifth, the BlogPress application allowed me to run a cruise blog to keep family and friends apraised of our whereabouts and well-being, including selected photos taken on the iPhone.

Sixth, when gazing in wonder at the stars and curious about what we were looking at, launching Starmap and pointing the iPhone at the sky provided the answers and more.

Seventh, and last here, we were able to keep in email contact and even make phone calls!

Some cautions: Wisely, I did not over-rely on this new technology and carried a full set of up-to-date charts.  I cross-checked with other information, and necessarily too.  The iPhone position was not as accurate as the Garmin, with its external antenna, and sometimes it lost its GPS position altogether.  It then fell back on cell-tower positioning, but since there was at best only one tower available, would suddenly teleport us to some nearby town or airfield where the tower was located.  Particularly in chart view, this was immediately obvious. Sometimes it seemed necessary to restart the application or even the iPhone to re-establish a GPS position.  And uses one, two, five and seven above required a mobile phone signal, only available in coastal waters and then not everywhere.

Nevertheless, my experience has been extremely positive, and I look forward to further developments.  iNavX is also capable of displaying other on-board NMEA data, including AIS data from other ships, relayed from its companion program MacENC running on a laptop.  There is no room to run my laptop when under sail, but maybe a future ‘iTablet’ would help here?

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