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Thread: AIS Systems

  1. #1
    AIS, the Automatic Identification System, similar to aviation transponder technology, provides the boater with the ability to broad cast his position obtained from his gps automatically over his VHF and similarly receive position information and have his plotted over on the GPS units of similarly equipped vessels. Helmar calls this the poor man's RADAR. Very cool in my view.



    What is AIS?

    AIS will place a triangular icon on the chart plotterís screen that represents any vessel sending out AIS signals. This includes most commercial vessels, which are required by law to have it, as well as numerous recreational craft with owners who are discovering the safety benefits of AIS. Just place the chart plotterís cursor on an AIS icon, and a list of valuable information unfolds. The shipís name and radio call sign are shown. This means you can pick up a VHF and hail a specific vessel that may be posing a threat. Additional information includes the vesselís length, beam and draft, its exact position, speed and heading, its rate of turn and even the calculated closest point of approach (CPA) and the time it will happen (TCPA). Commercial ships often also transmit vessel type, port of origin, destination and even the type of cargo, including hazardous materials.

    Since AIS operates on VHF frequencies, it can receive this vital information even though you may not see the vessel, such as when nearing the entrance to a marina or crowded commercial harbor or when there is boat traffic behind a low hill, building or other structure. In this sense, AIS can see targets that radar cannot.

    AIS Types
    There are two types of AIS: Class A and B transponders and receive-only sets. Class A is commercial grade, Class B the cheaper recreational version. Both not only receive AIS data but also broadcast information about your boat. A Class B-equipped boat should appear on the plotting screens of all other AIS-equipped vessels within about five to 10 miles. However, as with radar, you should never assume that another vessel has seen you and will take action to avoid a collision. But even a receive-only AIS receiver can help by making it easier to call the other vessel by name.

    AIS can be added to your boat in several ways. You may already have most of the equipment you need to enjoy AIS right now. Most recent multifunction GPS/chart plotter models, including those from Furuno (furuno.com), Garmin (garmin.com), Lowrance (lowrance.com), Raymarine (raymarine.com), Simrad (simrad-yachting.com), Si-Tex (si-tex.com) and Standard Horizon (standardhorizon.com), accept an AIS add-on module, though an additional VHF antenna or antenna splitter is needed. Most multifunction display manufacturers offer AIS add-on modules with receivers starting at about $500 and transponders at $900. Aftermarket black box receivers start at about $200 and transponders at $500, and all AIS gear tends to work well with other electronics because they all use standard National Marine Electronics Association (NMEA) data protocols. AIS units are also built into VHF radios and also stand-alone Class B transponders that have their own plotting. In any format, AIS is a great way to see and be seen.

    * * * * *
    Dave

    14 Skagit Sportster Blue (formerly red)
    16 Skagit Skimaster (blue)
    17 Skagit

    18 Skagit Runabout (1961?)

  2. #2
    Good stuff Dave,
    I used to sell the older used radios at 2 nd wave and the RDFs or Radio Direction Finders would come thru every now and again.They had 5 antennas that looked like 4 dimensional Rabbit ears for a TV.
    The Fishermen would "evesdrop" on location by pointing the gizmos knob until the VU meter would spike,thus telling who was talking where....and probably on the crab or fish.
    Some guys swore by these things.....now they are modernized with multiple devices intertwined.
    TimM
    unk.year 10` Mahogeny "DragonFly"racer
    15` SAFE boat w/120 hp Johnson
    SeaRay 175BR
    Hi-Laker lapline
    14` Trailorboat

  3. #3
    Administrator Helmar's Avatar
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    I don't remember if those new style radios took a different antenna.??

    I kind of remember that most commercial boats were supposed to have these radios now.
    Helmar Joe Johanesen
    1959 Skagit 20ft Offshore, 1959 Skagit 16ft Skimaster,
    1961 17ft Dorsett Catalina.1958 Uniflite 17 ft
    Outboards: 2.5 Bearcats, 3 50hp White shadow Mercs
    2 40hp Johnsons, several smaller Old kickers for a total of 12

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  4. #4
    Supporting Member Supporting Member McSkagit Tim Jones's Avatar
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    Automatic Identification System AIS

    The schooner Destiny I sailed on from San Diego to Cabo had an AIS transponder as did probably half of the 148 boats participating in the Baja Ha Ha. Was possible to keep track of the fleet, monitor their speed and heading as well as commercial fishing boats in the area, as well as ships and tankers.

    A very valuable navigation tool for offshore (coastal) cruising. The Garmin 7215 integrated navigation system was really fabulous. Also had a separate 5212 system at the navigation chart table.

    Amazing technology!
    Captain Tim (McSkagit) Jones 1959 Skagit 31 Saratogan

    http://www.closeencountersecotours.com

    Pay it forward.......take a kid for a boat ride

  5. #5
    I've studied the Garmin System in some detail.

    The 7215 is about the hotest rock out there. The high speed processor make response almost instantaneous.

    What else do they have on the system?

    Multi frequency DF and heavy transponder? Radar integration?

    With the proper engine you can also tie it in so engine data is real time on the screen as well, including A/P integration I believe.

    Very cool. Plan to put minature version on my 17 Skagit.

    Working on several products at work. If any pan out thinking about 31 moppie (based on your input) with twin Cummings. Prob about 25%. If it goes we can compare your vessel and the 31 SF as you suggest in a previous post. (No contest in my view in sea over 6". )

    :TakePicture1:
    Dave

    14 Skagit Sportster Blue (formerly red)
    16 Skagit Skimaster (blue)
    17 Skagit

    18 Skagit Runabout (1961?)

  6. #6
    Supporting Member Supporting Member McSkagit Tim Jones's Avatar
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    Garmin 7215 aboard SV Destiny

    Yes, the Garmin 7215 aboard Destiny had all the whistles and bells. Radar, sonar, photographic overlay of harbors and ports, 3D perspective, 3D sonar, odometer,
    anchor alarm, anchor chain payout measurement, barometer, alir temperature, true wind direction, apparent wind direction, current direction and speed, water temperature, interface to autopilot, ability to steer to true wind direction (similar to a vane steering system) and many other features too numerous to mention. Amazing!
    Captain Tim (McSkagit) Jones 1959 Skagit 31 Saratogan

    http://www.closeencountersecotours.com

    Pay it forward.......take a kid for a boat ride

  7. #7
    Supporting Member Supporting Member Skagit Hideaway's Avatar
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    The Admiral on this boat demanded the Garmin 7212, which is almost as nice as the 7215. It appears that for accurate RADAR overlay and MARPA functionality, you need the separate, 3 axis rate gyro/compass heading sensor - $899 list. There's no end in sight

  8. #8
    Administrator Helmar's Avatar
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    Dave, are you still checking in ?

    If I was to put a radio in my boat and wanted the AIS, I found most of them were RX only. Like it required a different AIS unit for TX.
    Is there a good combo that you know of ? Maybe a good Icom radio and a AIS RX /TX unit?

    I am sure you have already been looking at that stuff anyway.

    Hope all is well and you can get your boats wet this coming season.
    Helmar Joe Johanesen
    1959 Skagit 20ft Offshore, 1959 Skagit 16ft Skimaster,
    1961 17ft Dorsett Catalina.1958 Uniflite 17 ft
    Outboards: 2.5 Bearcats, 3 50hp White shadow Mercs
    2 40hp Johnsons, several smaller Old kickers for a total of 12

    Our Sister club
    http://www.goldenstateglassics.com

    Oh, and Where is Robin Hood when you need him??


  9. #9
    Helmar, it seems you have asked what we engineers call a nontrivial technical question. AIS radios functionality is an augmentation to some VHF radios in that they offer it as either transmit/receive or receive only. The AIS signal is a coded signal now required to be transmitted by most commercial vessels (e.g. tankers, container ships, trawlers) which will be picked up and decoded by AIS equipped VHF radios. The problem you have is that now you have to have a way of displaying the position information. The way I am doing it and is often done is by position plotters which display charts that are referenced to GPS signals. Without a way to display relative position data interpretation of the position signal data is extremely technical and requires special charts, etc. I strongly suggest working with your electronics vendor and have him guarantee or at least demonstrate compatibility.

    if it would ever stop raining long enough for me to get my boats loaded, it is my intention to join at some point. First will be the 16 Skagit, and then the 18 Skagit.
    Dave

    14 Skagit Sportster Blue (formerly red)
    16 Skagit Skimaster (blue)
    17 Skagit

    18 Skagit Runabout (1961?)

  10. #10
    Administrator Helmar's Avatar
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    Wow, Thanks Dave
    Man, you were right there watching. Glad your still here by the way !!

    Most of us that have radios in our boats have the standard VHF I was wondering what might be a lessor expensive option to get into this.
    Like what type of GPS/fish finder system has the capibilites of displaying the AIS information and what might be the lessor expensive AIS unit to put in line.

    I am just thinking about this as I am sure this will come up. Allot of us can't spend as much time on the water as we want and when we do, it would be nice to know some of the least amount we can get by with to make that happen.
    Helmar Joe Johanesen
    1959 Skagit 20ft Offshore, 1959 Skagit 16ft Skimaster,
    1961 17ft Dorsett Catalina.1958 Uniflite 17 ft
    Outboards: 2.5 Bearcats, 3 50hp White shadow Mercs
    2 40hp Johnsons, several smaller Old kickers for a total of 12

    Our Sister club
    http://www.goldenstateglassics.com

    Oh, and Where is Robin Hood when you need him??


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