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  AL SHAHEEN - COMMUNICATIONS

There are many informal marine radio “nets” which allow cruisers to keep in contact with one another to exchange information and to seek assistance. Being a radio system (as opposed to satellite), reception quality depends on time of day, distance apart of the two stations and atmospheric conditions, particularly sun-spot activity. We have a computer programme which gives the optimum frequencies to use depending on these factors.

 

Email by SSB

 

By using a radio modem between our laptop computer and the SSB set we can send/receive emails, in theory, at any time and anywhere. This is a very powerful tool, as it allows communications with shore when offshore or ocean sailing and beyond the reach of cell-phone signals. We use a provider called Sailmail (www.sailmail.com) and pay a fixed annual charge of $250 regardless of usage. This is email only and not Internet. Transmission speeds are relatively slow and attachments are not allowed, but nevertheless it is an extremely useful service even when we are at anchor, as it avoids the need to plodge ashore in the rain to an Internet Café!

 

To avoid collecting unsolicited material (spam), which would swamp us, we are particularly careful about revealing our Sailmail address only to friends and family. If you would like to communicate with us by Sailmail, please send an email using the link at the bottom of the page.

 

Inmarsat C

 

This is a satellite-based, data only (not voice) system primarily intended for commercial shipping. It has almost worldwide coverage and provides free weather forecasts, navigational warnings, email and delivery of fax messages ashore. However, its most important function is sending of an automated distress signal by satellite to a Maritime Rescue Co-ordination Centre, in our case, Falmouth Coast Guard. This distress signal contains the boat’s name and current position. It allows messages and email to be sent between vessels similarly equipped. Email, however, is expensive and not very user-friendly so we normally use Sailmail.

 

Our IMN number for Inmarsat C contact is: 423590216. We only have this system switched on during ocean passages due mainly to its power consumption.

 

Cell phones

 

Obviously, cell phones are only usable when a signal can be received and this is normally only within 10 miles of shore, although in remote areas there is often no coverage at all, even on land.

 

Our UK cell phone numbers is: + 44 77 66 66 33 94

In the USA we normally buy a pre-paid SIMM card but these tend to lapse if not used for more than 90 days, so our US numbers change annually!

 

Satellite Phone

 

Thanks to the fabulous generosity of my two sons we have just been given a satellite telephone which we shall be using aboard in 2010 and also in the Land Rover in remote places.  A SatPhone allows calls to be made from practically anywhere to anywhere and also presents another option for email.

 

Internet, email and Skype

 

In the USA, the standard “Internet Café” has all but disappeared and has been replaced by WiFi services (normally free) in coffee-shops, public libraries and marinas. Normally, this means taking the laptop ashore, although it is sometimes possible to receive a signal at a mooring and enjoy free, fast, Internet on the boat. We use WiFi extensively and have now installed a WiFi antenna which greatly enhances reception and means we can often pick up a usable signal out at an anchorage. A secondary feature of this is the use of the VOIP service, Skype, which gives us voice calls free of charge between computers and at nominal rates to land lines. We use Skype extensively to call family and friends in the UK and South Africa.

 

AIS (Automatic Identification System)

 

We have recently fitted a Class B AIS transmitter/receiver aboard Al Shaheen.  Strictly this is a communication system, in that we receive certain data on vessels in our vicinity and transmit our data to be received by other vessels.  AIS is a transponder system rather like that which has been used by aircraft for many years.

 

AIS signals are transmitted and received digitally on a dedicated VHF frequency and, as a minimum, give a vessel’s name, MMSI number, vessel type, position, course and speed over the ground, closest position of approach (CPA) and time of CPA.  As the signals are carried on the VHF frequency this restricts range to line-of-sight and normally less than 20 miles.  By International regulation, vessels over 300 g.r.t are now required to fit Class A AIS transponders whilst other vessels may voluntarily fit Class A or Class B equipment.  Class B sets are primarily intended for small craft and leisure craft, are built to lesser standards than Class A and transmit more restricted data than Class A.

 

Data received may be displayed on a dedicated screen or overlaid on a chart plotter or radar screen. In our case we display it on our Raymarine C80 chart plotter, where AIS targets appear as a magenta arrow in their true position on the chart.  Clicking the cursor on a target brings up a data screen showing all the data on that target.

 

AIS is a very valuable information system and an aid to collision avoidance. It is not infallible and should be used in conjunction with radar and visual observations. One great benefit is that it identifies a target by name so that one can now call up the target by voice VHF and address it by name with a much better chance of response than by calling an anonymous target.

 

Distress communications

 

Voice distress messages would be transmitted over VHF and/or SSB and satellite data messages sent by Inmarsat C or EPIRB (see below).

 

EPIRB

 

The EPIRB (Emergency Position-Indicating Radio Beacon) is a device which, when activated, transmits a signal by satellite on a dedicated frequency, continuously for a period of about 30 hours or until its battery is exhausted. This signal contains a unique code, which is registered to the vessel, and the position of the beacon is determined by the satellite. The beacon may be activated manually or by immersion in sea water.

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You can email us at jj@alshaheen.co.uk

Aboard “Al Shaheen” we have the following means of communication:

 

VHF Radio

 

This is our primary means of voice communication for short distances (up to 30 miles) and is used for talking to other vessels within range, marinas, harbourmasters, Coastguard etc. VHF is line-of-sight, and range depends on the height of the transmitting and receiving aerials (antennas) above sea level. Many coastguard stations have very high antennas, often giving a 50 mile range. Yacht-to-yacht communication distances are rarely better than 10-15 miles. VHF is a “broadcast” system, which means that any station tuned to the same channel can hear our transmissions. Thus, it is not secure for private conversations, but this feature makes it ideal for distress working.

 

An advanced feature of VHF communication is Digital Selective Calling (DSC), which allows a set equipped with DSC to alert either all vessels within range (for distress), or a single station using their individual MMSI number. Many yachts are not yet equipped with DSC, especially in the USA, although Al Shaheen is.

 

Our radio call sign is: ZQYF3 and our MMSI number is 235000882.

 

SSB Radio

 

This is the “work horse” of long-distance cruisers. It is a system of radio transmission using medium and high frequencies (short wavelengths) and allows long-distance communications, subject to the vagaries of propogation. It allows radio contact over distances of several thousand miles. We use it mainly to talk to other yachts beyond VHF range and to obtain weather forecasts, although it may be used for distress and for placing telephone calls whilst at sea to lines ashore.