We probably don't spend enough time questioning the accuracy of our charts. "How accurate are nautical charts? How much faith can be placed in them? Unfortunately, the answer is quite complex - far more complex than simply saying one chart is accurate whilst another is not. However, having the necessary skills should be essential for any mariner venturing into unfamiliar waters."
That's the beginning of a very useful paper by Mike Prince, the Director of charting at the Australian Hydrographic Service. Download it from the Hydrographic Office site.
]]>
Sofar in this series about AIS, we’ve mainly talked about options for receiving AIS, assuming it is more important to “see” other vessels than “be seen” by them. While there is no obligation for vessels under 300 ton to transmit their position, there is nothing lost by installing a full class B transponder on a boat. And it’s not hard to think of occasions where this may save an embarrassing or life threatening situation. ]]>
Most of the Class B Transponders (the ones normally used on leisure vessels) are similar in capabilities. The Comar CSB200 (pictured) is typical of the units available. Because the transponder transmits identifying information such as the name and size of the vessel and its Marine Mobile Service Identity (MMSI), it needs to be programmed before usage. In Australia, a MMSI code needs to be applied for from AMSA. Take care not to make a mistake entering that code as the unit would need to be returned to the supplier for re-programming to change it. For units sold in the USA, the authorities there don’t allow programming of AIS units by end-users. The supplier will set up the transponder before delivery to a customer.
When purchasing a unit, don’t forget to order a compatible GPS antenna and if planning to share the VHF antenna with the radio, you will need a compatible antenna splitter. For example, in the case of Comar, use the AST200 splitter rather than the ASR100(which is for receive only units).
Next time, we’ll discuss the difference between class A and B AIS units and discover that Class A is not restricted to large commercial vessels.
Manufacturer’s website:
]]>
I've been preoccupied with some other projects, so part 4 of the AIS series (about full AIS transponders) is on hold - hopefully we'll get back into it next week. 
This week we'll continue our discussion of Class B AIS systems, by looking at the clear trend to incorporate AIS receivers into other items of Marine Electronics. As we saw last week, one way of simplifying the installation of an AIS receiver is to use an antenna splitter (aka multiplexer) to share the boat's VHF radio antenna. Taking that concept further, VHF radio manufacturers are now starting to incorporate AIS receiver into the radio itself. An early example was the iCom IC-M505.
]]> Recently the Standard Horizon GX2100 (pictured) VHF radio raised the bar with a comprehensive set of features including AIS and even the option of having an AIS display on the microphone.
Inevitably, radios have only a limited display, although they do offer a standard NMEA output to interface with a chart plotter. So, rather than building AIS into a radio receiver to save on the antenna, why not build AIS into a chart plotter?
And yes, it’s been done. Pictured is the Digital Yacht chart plotter which includes a dual channel Class B AIS receiver – just connect a VHF antenna and off you go!
No doubt over the coming period, we’ll see even more options to put a Class B receiver on our boat. Meanwhile here are links to items mentioned this week:
Standard Horizon
iCom
Digital Yacht
Next week, we’ll look at the case for buying a Class B Transponder and be seen as well!
]]>
You’re probably aware by now that the original (Class A) Automatic Identification System was designed for commercial shipping. Class B AIS was designed to be simpler (cheaper) to implement and to be suitable for recreational vessels. It is compatible with Class A systems and available either as “Receive Only” or as a “Transceiver”. In this post we’ll described a range of options for “Receive Only” systems, typically the initial choice of most yachties.
]]> AIS uses two VHF channels to provide redundancy (in case of a failure, one channel might be locked) and responsiveness (you can transmit twice the information). It is a very cleverly designed system which allows thousands of boats to (almost) simultaneously transmit their position without interfering with another (explanation).
While single channel AIS receivers are available, dual channel units are clearly superior and the price difference is relatively small. A popular unit is the Comar unit (pictured above). Of course to be able to use it you’ll need two additional items, a VHF antenna and a way of displaying the vessels picked up by the receiver. The usual way is to connect the receiver to the boat’s chart plotter via the unit’s NMEA connection.
To save on installation cost, you might consider a unit with a built-in antenna splitter, which allows an AIS unit to share an existing VHF radio antenna. Both Comar and Raymarine have such units in their range.
One interesting newcomer to the scene is the Digital Yacht ANT200, pictured in part one of this series. It is designed to mount on the rail just like a GPS receiver and includes a stubby VHF aerial. It will also combine the signal from the boat’s GPS receiver with the AIS NMEA connection so that only a single connection to a chart plotter is required.
Dual channel Class B receivers start around A$500.
Manufacturer’s web sites:
In our next episode, we’ll discuss the trend to build AIS receivers into radios and chart plotters.
]]>
Installing an Automatic Identification Systems (AIS) is becoming a mainstream option for yachts. Prices are dropping and AIS equipment is evolving, resulting in a greater variety of instruments on the market. That variety will no doubt increase further, but we can see distinct categories of AIS equipment emerge. For those looking to invest in a system, we're going examine those categories in a series of six posts. We will look at the full gamut of equipment, ranging from economical class B receive-only units through AIS integrated with Radio Receivers and Chart Plotters, right up to standalone class A systems.
There is already so much choice that we won't be able to cover every available unit, but we will highlight representative equipment and discuss which features to look for.
]]> This week, we'll start off by asking some questions and providing some background reading. Next week, we'll get stuck right into practical options, their pros and cons..When considering the installation of an AIS system, you'll need to ask yourself some pertinent questions:
Question : Do I want to install yet another antenna on my boat?
Question : Do I want to just be able to "see other boats" with AIS (Receiver), or for them to "see me" as well (Transponder)?
Question : Do I want a system with an independent display of vessels, or one that integrates with my existing chart plotter?
Question : Should I just consider class B units?
In the next five posts here, I hope we can supply enough information to help you make the right choice when selecting an AIS unit for your boat.
While you're waiting for our next installment, here are some interesting links with information about the history and operation of AIS.
Wikipedia's comprehensive entry on AIS - Link
The US Coast Guard's Navigation Center - Link
SOLAS regulation for the carriage of AIS - Link
]]>
I started a listing of magazines including their online companion sites which might be of interest to Australian Cruising Sailors. Please have a look and comment on what you think and if you'd like to add any other magazine to the list.
]]>
At last there are now some tangible signs that Coastal Patrol and Coast Guard organisations along the NSW coast are integrating their operations. 
Nick Jaffe just cleared customs in Coffs Harbour after a 2 year solo sail from Europe. Apart from being an accomplished sailor, Nick also worked out how to make the Internet work for him along the way. And not just by getting regular weather reports via a Satellite…
Check out his Website, Blog, his Flickr photostream, his Video and his Tweets. And of course, there is a tracking page.Well done, Nick!
I guess it had to be a 27 year old to show us how it’s done…
]]>The iPhone reported positions via the boat's wireless broadband connection. Because of restrictions by Apple on the way applications may be developed, the phone needs to be devoted to reporting GPS positions, rather than report "in the background". If a phone call is received, the iPhone stops tracking, but will resume after the call is finished.
]]>
A few friends have asked about the Wireless Broadband Internet and phone setup aboard Te Moana. Last year, we fitted an Ericsson W25 on our boat. Previously, we had USB modems (Maxon CDMA and later the Maxon Turbo modem) with Telstra mobile data plans. Today I still use the (orange) Maxon Modem while we're ashore (handy in the train or at a customer). But while on the boat I take the SIM card out of the modem and plug it into the Ericsson W25 which Andersen Marine installed on Te Moana last year. ]]>
Installation 
As part of the installation, Marty Andersen installed a high gain antenna atop of Te Moana's mast with low loss (fat) cable down to the W25. We found a spot for the W25 at the base of the mast, minimizing the cable run and the power losses.
We bought a standard telephone at Dick Smith, which was installed at the Navigation table and wired to the W25 telephone connector.
Configuration 
Our original modem was from Telstra Mobile (as opposed to from Telstra BigPond). This means that it has a telephone number. Using its SIM card with the W25 means it can operate as a standard (mobile) telephone.
Along the way I programmed that SIM to divert calls to my personal mobile when not answered. To program the SIM, put it into a normal mobile phone handset and set forwarding up.
Of course the really useful aspect of the W25 is its wireless router. My computer and mobile phone use the boat's wireless internet access automatically when on board.
Performance
We've experienced excellent coverage from this set-up over the past year with flawless reception all the way along the NSW coast. The only glitch was on a hot day last summer when the temperature on the boat was well into the forties. The W25's internet access dropped out and only came back when the temperature dropped. Overall, we've been very happy with it.
I'm aware that some yachties have installed Antenna booster on their phones/modems. Personally, I have not seen the need for one with the set up which we have in place. Beside the fact that it's illegal to own one.
By the way, I'm no particular fan of Telstra, but their Next G Mobile Phone network gives superb coverage along most of the coast of Australia. Don't use any other carrier.
Alternatives
Ericsson now have a newer, smaller unit on the market, a W35 with similar features and it is a few dollars cheaper.
Maxon just launched a similar unit, the Maxiport, which uses VOIP (Voice Over Internet Protocol) to deliver telephony services.
Netcomm is now distributing a Sierra Wireless unit, the PinPoint X , which doesn't have wireless support, but does have a built-GPS unit (which I would have some use for).
Last weekend's Sydney to Gold Coast race provided an opportunity to see the difference between class A (commercial shipping) and class B (leisure vessels, work boats) versions of AIS as a couple of the boats in the race carried AIS transponders. Here is what I found....
]]>Around mid morning, Joy and I took Te Moana to near the race's rhumb line, around 8 Miles off Barrenjoey. We enjoyed a quiet lunch on the glassy seas and the winter sun. Meanwhile, as participating yachts struggled to get out of Sydney Harbour in the light conditions, I was delighted to see two of the competitors, Scarlet Runner and Imagination using class B AIS responders. I monitored their progress on marinetraffic.com and was pleased that it did a good job putting them "on the map". Certainly, it provided a much more timely and accurate position for them, than the CYCA race tracker (which was no surprise).
I was less impressed with the effective range of their AIS transponders (mind you, I don't know the make or installation details of the units used by either boat). Here is the plot created by Imagination, showing it was out of range (the uninterrupted straight line) between Palm Beach and Port Stephens. Significantly, the repeater at Newcastle did not pick up either Scarlet Runner or Imagination, while ships with class A transponders were clearly present and visible in the same area. 15NM appears to be the limit for Class B AIS. Vessels carrying class A will have a larger range because of a better positioned, dedicated antenna and the higher power output of Class A devices.
Coverage of class B boats on sites like Marine traffic can be improved by having more shore based repeaters, but it is unlikely that boat signals will be reliably picked up when more than 15 mile offshore, no matter how many repeater stations are dotted along the coast.
The moral of the story then, is that AIS is a terrific on-board navigation resource, but it cannot provide the kind of yacht tracking which many of us would welcome, automatically keeping track of cruising boats along the East Coast of Australia for family and friends. And that's even before we look at spoofing and spamming, about which I'll write another time.
]]>
We went out on Te Moana yesterday to check out the Sydney to Gold Coast fleet as they passed Broken Bay. It was a gorgeous day apart from the fact that there was no wind. So we parked ourselves near the race rhumb line, killed the Volvos and just waited for the fleet to crawl towards us. I kept myself entertained playing with various yacht tracking technologies. I'm eagerly awaiting the day when we can use 'off the shelf' economical systems to track yachts, rather than clunky, expensive satellite transponders or cheap but error prone manual systems.
Every since the 2nd generation iPhone was launched last year, users can determine their location through the built-in GPS (the blue dot marks our position off the coast on the Google Maps iPhone display),
Recently, Google has been promoting its "Latitude" service, where you can share your location with your friends. This works by allowing your phone to transmit its location to the Google service, but...
]]>
There are two ways to determine where a mobile phone (and its user) is located, either by determining which cell tower the mobile phone is using (and triangulating between them) or by using the phone's built-in GPS, if it has one.
Google announced the iPhone version of Latitude last week, so I was keen to try it out on the boat. Could we track boats by simply having an iPhone on board? The answer is no on two counts.
Firstly, positions are only taken while the Latitude page on the phone is open (it is not kept up to date when doing something else with the iPhone or it's asleep).
Even more challenging is that it doesn't seem to be using the built in GPS, but insists that we're on land near a cell tower..... Ahoy Google, Ahoy Apple, not good enough.
]]>
We've been tracking yachts on this site for almost 4 years. Over the coming year, we're expecting to introduce more ways to conveniently track your boat. Most of those features assume internet access while at sea. But we're not forgetting internet deprived boats. From today, we're starting a trial allowing users to submit position reports by mobile phone. You'll still have to register your boat as per usual (here's how), but to submit a position report, you can send us a SMS text message in the following format:date time latitude longitude comment]]> for example:
D20090731 T1230 S33 39.387 E151 18.169 <Did our best to secure the boat with the onset of the seasonal Westerly winds>