England Ireland Find Havens
England Ireland Find Routes


Dealing with the three different GPS conventions for describing a waypoint
GPS has forever transformed the art of navigation, but there are sublties of expressing a position that need to be understood. There are three different GPS conventions for describing a waypoint, it is imperative for accuracy of position that you understand which convention you are using aboard and format of information you are being provided from external sources.

'Rule of Twelfths': a simple method for estimating intermediate tidal heights
Applying a graphical procedure, found by reference to an appropriate almanac and the times and heights of high and low water, a navigator may precisely work out intermediate tidal heights and times. This then enables depth restricted vessels to pass into shallow waters supported by tidal water and accurately plot a position where a vessel may anchor and stay afloat.However plotting tide to this level of detail is a skilled, onerous and time consuming task. It is for many cruisers more for the world of merchant sailors. Moreover, tidal curves are often only available for major ports where most leisure vessels would have ample water, not in out of the way anchorages. In the real world, even if the detail is available, few sailors would go to this level of detail.

Reducing the power draw of the vessels anchor light
Yachts lying to anchor must light up an anchor light. Mast based anchor lights are geared towards delivering a clear bright light that can be seen for some distance in busy waterways. Maintaining these lights throughout the night draws a lot of power.

Keeping track of tides when sailing in tidal affected areas
Sailing in tidal waters requires constant vigilance and quick maths to make best use of currents. As the tide times are constantly changing and there are many distractions on a sailing vessel, it is easy to forget the tidal times or make an error of maths.

Reef navigation
Sailing in reef strewn waters is very dangerous. The only safe way to operate in tight reef waters is to use eyeball navigation. To do this you need to get at least six feet above deck level to view the patterns on the water.

Preserving night vision
Operating a boat at night is a challenge. Typically the watchman has to keep track of the vessels sailing environment and maintain a chart plot or at least monitor the charted position. The problem is the chart plot has to be implemented with the aid of illumination causing the watchman to lose the night vision acquired above decks.

Harbour information at your fingertips
Harbour information can be spread across a range of pilot books, tidal books and ports etc. Bringing the information together when required, requires time to dig and search through reams of pages and indices.

A tide indication when cruising in unfamiliar waters
When crossing oceans or seas to new destinations as often as not you are landing into a sailing area without any tidal data to work from. Typically boats acquire local tide data after landing.

Getting to grips with sound signals
In busy waterways large vessels use sound signals to notify nearby boats of their intentions.

Marine radio handling easier
Certain ship names are difficult to hear correctly on the radio, our boat name was a particular case. Crews members who are unfamiliar with the boat name phonetics can get lost when they have to step through both the spelling and phonetics at the same time.

Pages: 1