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  1. #11
    Join Date
    Nov 2009
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    Home UK Midlands / Boat Croatia
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    Default Re: Radar reflector in 'landscape' orientation

    Quote Originally Posted by Ohlin Karcher View Post
    I am confused why Echomaxes are not considered a standard, essential must-have item, while AIS is the must-have gimmick.
    Can anyone explain?
    Echomaxes are very good but are essentially a one trick pony for target boats which have radar. An AIS transceiver can do lots of things very accurately and a lot more boats have AIS.

    Richard

  2. #12
    Join Date
    May 2007
    Location
    Cambridge, UK
    Posts
    6,043

    Default Re: Radar reflector in 'landscape' orientation

    Quote Originally Posted by Gwylan View Post
    I think they are like horseshoes - they work if you believe in them.
    Never really know, unless you call up some large boat and ask if they can see you.

    Oh, and yes, we have one, but my opinion remains the same.
    And even if the big boat CAN see you, you don't know if it's because of the radar reflector or because it happens to be a day with little surface clutter and the "hole in the water" stands out on the display, or it happens that your mast and rigging are at a fortunate angle to the Big Ship's radar or that the radar reflector just happens to be in it's most effective orientation WRT the Big Ship's radar.

    Objective tests, conducted by Qinetic who are pretty expert in radar matters, show that only extremely expensive, high quality and heavy passive reflectors come even close to meeting the performance requirements for a radar reflector, and that even fewer meet the requirements when heeled.

    If you want to be SURE of being seen, a Transponder is the only safe bet.

  3. #13
    Join Date
    Jun 2019
    Location
    Tynemouth
    Posts
    278

    Default Re: Radar reflector in 'landscape' orientation

    Quote Originally Posted by RichardS View Post
    Echomaxes are very good but are essentially a one trick pony for target boats which have radar. An AIS transceiver can do lots of things very accurately and a lot more boats have AIS.

    Richard
    All ships have radar and they generally use it all the time, so painting my boat on their radars is the only trick the pony needs to perform..
    Ships don't use AIS for collision avoidance, even though most are obliged to install it.
    Last edited by Ohlin Karcher; 16-07-19 at 13:18.

  4. #14
    Join Date
    Nov 2009
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    Default Re: Radar reflector in 'landscape' orientation

    Quote Originally Posted by Ohlin Karcher View Post
    All ships have radar and they generally use it all the time, so painting my boat on their radars is the only trick the pony needs to perform..
    Ships don't use AIS for collision avoidance, even though most are obliged to install it.
    All ships have radar .... but all ships have AIS and so do many other boats, many of which would terminate your existence in a collision.

    Ships do use AIS for collision avoidance provided that you have a transmitter and once you have a transmitter you can use it for things other than collision avoidance, unlike an Echomax which is a one-trick pony.

    A number of port authorities have now introduced legislation which makes AIS compulsory for all boats. That trend will continue until such time as AIS is the dominant collision avoidance mechanism. Watch this space.

    Richard

  5. #15
    Join Date
    Jun 2019
    Location
    Tynemouth
    Posts
    278

    Default Re: Radar reflector in 'landscape' orientation

    Quote Originally Posted by RichardS View Post
    All ships have radar .... but all ships have AIS and so do many other boats, many of which would terminate your existence in a collision.

    Ships do use AIS for collision avoidance provided that you have a transmitter and once you have a transmitter you can use it for things other than collision avoidance, unlike an Echomax which is a one-trick pony.

    A number of port authorities have now introduced legislation which makes AIS compulsory for all boats. That trend will continue until such time as AIS is the dominant collision avoidance mechanism. Watch this space.

    Richard
    Have a look at the dire warnings about AIS in the MCA's MGN 324 which covers this exact topic, in the first few paras.

    Also covers using VHF for collision avoidance ( very negatively..)

  6. #16
    Join Date
    May 2007
    Posts
    37,302

    Default Re: Radar reflector in 'landscape' orientation

    Small boat AIS falls apart as soon as you get one of those mysterious GPS outages that the Russians inflict on people who keep their antennas indoors.
    Ships' radar may be on all the time, it doesn't mean they are looking at it or can use it to decipher the meanderings of a WAFI.

  7. #17
    Join Date
    Nov 2009
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    Default Re: Radar reflector in 'landscape' orientation

    Quote Originally Posted by Ohlin Karcher View Post
    Have a look at the dire warnings about AIS in the MCA's MGN 324 which covers this exact topic, in the first few paras.

    Also covers using VHF for collision avoidance ( very negatively..)
    I've no idea what the MCA have to say about AIS but I can absolutely guarantee you that, just like King Canute, it is absolutely futile to resist the onward march of progress. In relatively short order AIS will be the collision avoidance standard and, in many locations, you will be breaking the rules if you don't have it and use it.

    If you have ever used AIS it is immediately self-evident why it will become the de facto standard. Radar will still have a place but, like the sextant before it, it's now on borrowed time.

    Richard

  8. #18
    Join Date
    Mar 2002
    Location
    Scotland
    Posts
    1,987

    Default Re: Radar reflector in 'landscape' orientation

    Quote Originally Posted by RichardS View Post
    I can absolutely guarantee you that, just like King Canute, it is absolutely futile to resist the onward march of progress.
    As I recall, the Canute story was about the futility of resisting the forces of nature rather than anything man-made. "The onward march of progress" is one of these stirring phrases beloved of politicians and other orators which when closely examined turns out to mean very little, except that the speaker approves of the change they are referring to.

  9. #19
    Join Date
    Jun 2005
    Location
    Solent, UK
    Posts
    4,611

    Default Re: Radar reflector in 'landscape' orientation

    AIS and Seeme both need good, reliable supply of electricity all the way to the top of the mast from the battery. Not a problem on a modern TSDY, I’d suggest but not necessarily so on a small cruising yacht. I have had my masthead tricolour die mid channel due to water ingress by the deck plug, but at least I knew when it occurred. I cannot quite bring myself to wholly rely on an electronic gizmo which may or may not be working ( how would you ever know ?). IMO a
    good Passive reflector is always “on”. Anything else is belt & braces.
    Grow old disgracefully, it's more fun

  10. #20
    Join Date
    Oct 2004
    Location
    Firth of Forth
    Posts
    2,621

    Default Re: Radar reflector in 'landscape' orientation

    Quote Originally Posted by sarabande View Post
    Are there any technical (signal return) reasons why an encapsulated radar reflector cannot be mounted horizontally on top of a gantry about 11ft ASL ?
    Yes. It will only work as intended if the incoming beam is at 90 deg to its long axis so if mounted vertically it works in a horizontal circle around the boat.; if mounted horizontally, it will work in a vertical circle which is only relevant directly fore and aft of the boat (assuming it's mounted horizontally across he beam of the boat.)

    As others have noted, "working correctly" doesn't necessarily mean that it's particularly effective.

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