Shipping Containers on Radar

[zboss]

Do floating shipping containers show up on radar?

What about other floaty things that can cause damage?

[skipmac]

Very unlikely. From what I know, most shipping containers are not floating high in the water but just barely awash. To get a reliable radar return you have to have something sticking up out of the water to bounce the signal.

Same for any other objects in the water.

[martinjrichter]

The problem with floating containers is they are low in the water and therefore don't have much of a return to the radar. If the radar where above the container( ie an aircract or satelite) there would be a much better chance of a return, although the is some problems from "ground effect" to overcome.

[rockDAWG]

Using an underwater sonar system or a depth sounder mounted horizontally 2 ft below the water line.

[cruisehope]

I also heard that infra-red is being used and can pick up shipping containers. The container fraction that is on top of the water will pick up ambient and solar heat. However the detection distance is probably limited to a couple of 100 ft. May be enough to warn you of a problem and better than nothing. Not sure how this would be compared to sonar.

[Jim Cate]

Look, the problem with all these detection systems is signal to noise ratio. And all three (radar, sonar and IR) have real bad situations detecting a low floating object. Under the right circumstances they will all show the container, but those circumstances are not common, so what you see is a lot of noise with occasional blips of signal rising above the noise level. If an attentive watchstander is peering at the display 24/7 a useful warning might result, but if one depends on in-built alarms in the instruments the chance of detection is low.

Thus, for the typical short handed cruising boat, reliable detection of a floating container is dependant upon daylight and an alert lookout. In other situations the low statistical chance of hitting one is all that protects you. Fortunately, this seems to be pretty effective!

Cheers,

JIm

[foggysail]

Do many of the loose containers make it to shore? How big a problem do they present to cruisers?

[cruisehope]

Jim-You are absolutely correct. A good lookout is about the only effective means of spotting a container. However, after the new movie All is Lost, my wife may want more.

[barnakiel]

But if you place a small octa reflector on it, you may as well spot it on your radar.

b.

[DumnMad]

A lot more whales out there than containers.
I know people who've hit whales but nobody who has hit containers. (Maybe containers are more fatal.)

[Navicula]

Ok for real................has anyone seen one of these floating containers......I dont mean you know somebody or you read it somewhere............has anyone on this forum seen a loose container floating around....

[goboatingnow]

Me , no , whales yes


Dave

[benfairn]

what type are you using?

[benfairn]

Originally Posted by rockDAWG

Using an underwater sonar system or a depth sounder mounted horizontally 2 ft below the water line.

What type are you using?

[DumnMad]

Originally Posted by DumnMad

A lot more whales out there than containers.
I know people who've hit whales but nobody who has hit containers. (Maybe containers are more fatal.)

Actually, first took our boat out of the water just after this post and discovered severe damage (but no significant hole) to our very strong bow just below the waterline. She was delivered to us from Tauranga past the wreck of the container ship Rena.
We had discovered traces of salt water in the forward bilge but couldn't find the source