Radar returns, active, passive and no reflector comparison

[Babylon]

I sometimes wonder, when a yachtperson says they often have edgy incidents with ships, if it was the yacht who helped cause it , eg by not standing on unpredictably?

I assume you mean 'predictably'?

 

[Ohlin Karcher]

I assume you mean 'predictably'?

Yes I did

 

[Stemar]

I'm sure that applies to 99% of ships, but I haven't forgotten a MAIB report of a smallish coaster - the type with a Russian captain, a Polish mate and a handful of Filipino crew. One night, the mate was on watch, with only a bottle of whisky to keep him company. He got bored, so he turned off the bridge alarm and went down to his cabin to cuddle the bottle. No one was any the wiser until the boat drove full ahead up Dungeness Point.

Since then, I've always worked on the basis that any ship that's heading in my direction is paying the same amount of attention until I'm proved wrong. I'm pleased to say I've been proved wrong many times, but I have no intention of being proved right, or having my inconspicuousness demonstrated, Ouzo style.

 

[zoidberg]

.....I haven't forgotten a MAIB report of a smallish coaster.... Since then, I've always worked on the basis that any ship that's heading in my direction is paying the same amount of attention until I'm proved wrong.

There's real benefit to be had from reading the periodic MAIB Accident Digest, from learning just how inattentive the merchantmen pros often are, to the frequent incidence of crab-potter fisherfolk falling off or getting sunk/fired up/capsized. Helps confirm the determination to keep well clear, and treat every boat this side of the horizon as a 'potential collision hazard' until it has gone away.

 

[Topcat47]

Both the Tri-Ball and the Cyclops reflectors (incidentally the two best, most consistent reflectors ever produced) are currently out of production because of poor take up. For some reason, yachtsmen would rather spend a couple of bob on a tubular reflector (that tests prove does not work) to lash onto a shroud, than shell out a hundred quid or more for something developed, tried and tested in Anachoaic chambers. Radar reflectors (and transponders) unfortunately rely on others keeping a good radar watch which doesn't help. The Advantage of Passive reflectors is that they work all the time. Transponders only work if the target yacht has sufficient "wiggly amps" to drive them. Yacht Radars are fine if the crew know how to tune them and interpret the returns. AIS is OK if you have the spare electrical capacity but it does rather rely on other vessels actually transmitting.

I don't know where you got the advice that an octahedral works better "upright" than "catch-water" but I have tried then in an anechoic chamber and can assure you that this is completely untrue. If an octahedral is fixed to a mast, it's effectiveness will be reduced by the heel of a yacht, but for an "upright" octahedral to work as well as a "catch water" one, the vessel would need to be heeled at an angle of at least 22.5 degrees. Even so this would only be the case in the Port/Stbd aspect, it would still be worse fore and aft.

 

[Ohlin Karcher]

AIS transmitters use more leccy than RTE's.

 

[[163233]]

I'm sure that applies to 99% of ships, but I haven't forgotten a MAIB report of a smallish coaster - the type with a Russian captain, a Polish mate and a handful of Filipino crew. One night, the mate was on watch, with only a bottle of whisky to keep him company. He got bored, so he turned off the bridge alarm and went down to his cabin to cuddle the bottle. No one was any the wiser until the boat drove full ahead up Dungeness Point.

Wasn't there a similar thing where they hit Cornwall?

 

[Stemar]

I think there've been a few, but this one struck me as it was the first one I heard about.