Can a modern radar pick up a fishing buoy ?

[Maka]

Here in the PNW we are more concerned with Logs, mostly submerged.
In my experience neither Radar nor Forward Looking sonar can detect them.
So I dread running at night.
Anyone have a solution?

[Ip485]

I reckon the best bet is a really good rope cutter. Few times in the middle of the night there has been a slight bang on the IP as a lobster pot rope finds its way into the prop and is quickly despatched.

The new FLIR cameras look interesting and might provide another answer as they seem remarkably good at detecting very small objects but I havent yet added one.

[Gung Ho]

Surely radar is not the answer.It is too expensive and complicated for most coastal cruising. I would suggest a short range AIS signal,say 500metres, transmitted from the the fishing buoy with a dedicated symbol on the AIS screen. Most yachts here in the UK carry passive AIS because it is easy and cheap to fit in a couple of hours.

The big question is how many yachts actually get tangled in fishing buoys and how much equipment and catch do the fishermen lose when their buoys are cut away by entangled yachts. Is the cost to them ,the fishermen, of buying a dedicated AIS transmitter going to exceed the value of their catch and equipment?

The fishing industry is the last hunter gatherer profession left and they are notorious for over fishing. They should put something back and this may be one way of doing it.

I am not a techie so AIS may not work but nobody has ever told me it would not work in this scenario, so over to you techies to provide a cheap solution for both fishermen and yachties.

[sailjumanji]

I've used FLIR to spot crab trap buoys. Works really well.

[roland stockham]

Unfortunately it depends on the bouy. Mooring bouys show up on radar if they have a steel rod or chain attached above water. A plastic can with rope attached is as good as radar transparent so nothing will catch it. Things have to be reflective to show up on radar regardless of the system. As an illustration I was once navigating down an estuary do a 'blind' radar trial so I was below with the curtains drawn. We where easily following the chanel looking at the banks and thrings on top of the mooring bouys. The crew on the helm after asking a couple of times if I saw anything slowed the revs and called me on deck. When I came up we where 5om behind a large racing cat, super light, carbon masts, synthetic rigging and no radar reflector made it the ultimate stealth vessel and totally invisible to radar and a good lesson learned...

[waterman46]

Originally Posted by Maka

Here in the PNW we are more concerned with Logs, mostly submerged.
In my experience neither Radar nor Forward Looking sonar can detect them.
So I dread running at night.
Anyone have a solution?

Steel hull

[Brann-]

Originally Posted by Maka

Here in the PNW we are more concerned with Logs, mostly submerged.
In my experience neither Radar nor Forward Looking sonar can detect them.
So I dread running at night.
Anyone have a solution?

What's the issue with logs ? They won't foul your prop and your bow will just toss them aside as you go, won't it ?

[coastalexplorer]

Brann-... To anyone who navigates the west coast of north America, & especially Canada. That would seem like a stupid question.

So I will explain...The traditional way of harvesting soft wood lumber is to fell the trees and transport them by various means to navigable tide water where they are rafted up into what is called log booms. Generally only the outside logs are chained. Then these boom's are towed by tug boat to a log sort or a sawmill. During transit If rough water conditions are experienced some logs may break free.

These radical logs are frequently gathered up by Log salvagers who tow them in to get a small reward. However any logs they miss continue to absorb water and sink.
Because most trees are tapered one end typically sinks lower than the other. As they float in on the tide into shallower water; The low end anchors into the mud.

Thus running into the barely floating end has a destructive battering ram effect on the vessel that is unfortunate enough to hit it. Some people carry small flags to mark them when they find them. low free board of a dinghy is need to do that.

[Brann-]

Originally Posted by roland stockham

Unfortunately it depends on the bouy. Mooring bouys show up on radar if they have a steel rod or chain attached above water. A plastic can with rope attached is as good as radar transparent so nothing will catch it. Things have to be reflective to show up on radar regardless of the system. As an illustration I was once navigating down an estuary do a 'blind' radar trial so I was below with the curtains drawn. We where easily following the chanel looking at the banks and thrings on top of the mooring bouys. The crew on the helm after asking a couple of times if I saw anything slowed the revs and called me on deck. When I came up we where 5om behind a large racing cat, super light, carbon masts, synthetic rigging and no radar reflector made it the ultimate stealth vessel and totally invisible to radar and a good lesson learned...

Well, I don't think that being made of metal is a preriquisite for being radar reflective. For example, radars routinely show up birds or weather cells ...

I'm also surprised you didn't see the carbon boat at all, since it probably contained a lot of highly reflective parts, albeit small. Are you sure the boat wasn't in your blind zone (eg below your rardar beam) ?

[deblen]

Originally Posted by Brann-

Well, I don't think that being made of metal is a preriquisite for being radar reflective. For example, radars routinely show up birds or weather cells ...

I'm also surprised you didn't see the carbon boat at all, since it probably contained a lot of highly reflective parts, albeit small. Are you sure the boat wasn't in your blind zone (eg below your rardar beam) ?

You may find this post helpful./ Len

http://www.cruisersforum.com/forums/...on-191861.html

[boatman61]

I was stopped by the Spanish Guardia Civil patrol at 0230 or thereabouts 20nm from Barcelona on a 45ft racer I was delivering from Palma de Mallorca because the radar return was 'suspiciously small'.. and the course was slow and erratic..
I was tacking into light and variable winds and the little O/B and fuel that the owner had provided was only any good for in and outa the marina.. just.
Big does not always = PING...
Sometimes its just ping

[RidgeRunner]

Originally Posted by coastalexplorer

Brann-... To anyone who navigates the west coast of north America, & especially Canada. That would seem like a stupid question.

So I will explain...The traditional way of harvesting soft wood lumber is to fell the trees and transport them by various means to navigable tide water where they are rafted up into what is called log booms. Generally only the outside logs are chained. Then these boom's are towed by tug boat to a log sort or a sawmill. During transit If rough water conditions are experienced some logs may break free.

These radical logs are frequently gathered up by Log salvagers who tow them in to get a small reward. However any logs they miss continue to absorb water and sink.
Because most trees are tapered one end typically sinks lower than the other. As they float in on the tide into shallower water; The low end anchors into the mud.

Thus running into the barely floating end has a destructive battering ram effect on the vessel that is unfortunate enough to hit it. Some people carry small flags to mark them when they find them. low free board of a dinghy is need to do that.

A little flashback for my Canadian friends:

https://www.youtube.com/watch?v=EXfuLuEln-k

[deblen]

Originally Posted by roland stockham

Unfortunately it depends on the bouy. Mooring bouys show up on radar if they have a steel rod or chain attached above water. A plastic can with rope attached is as good as radar transparent so nothing will catch it. Things have to be reflective to show up on radar regardless of the system. As an illustration I was once navigating down an estuary do a 'blind' radar trial so I was below with the curtains drawn. We where easily following the chanel looking at the banks and thrings on top of the mooring bouys. The crew on the helm after asking a couple of times if I saw anything slowed the revs and called me on deck. When I came up we where 5om behind a large racing cat, super light, carbon masts, synthetic rigging and no radar reflector made it the ultimate stealth vessel and totally invisible to radar and a good lesson learned...

What a great eye opener lesson!
A blind test with the radar operator unable to see anything but the radar screen. Let him navigate a busy/narrow channel using radar only-with a responsible person at the helm following his orders. Should be reqd training for first time radar users.

Would you believe my perfectly working & adjusted radar would not pick up this 60ft steel ketch when I rounded a point & met her head on @ 1/4nm on a clear sunny day? No radar reflector.
https://www.dropbox.com/s/7vc0975ahx...Elsie.JPG?dl=0

Another poor target close in bow on
https://www.dropbox.com/s/wv1ytkmeo2...20bow.jpg?dl=0


Local fog https://www.dropbox.com/s/mfpneqq3p4ink43/Fog.jpg?dl=0

https://www.dropbox.com/s/e6du03tx9l...Small.jpg?dl=0

[GTom]

I am more worried about 90% sunk steel containers and 99% sunk logs, afraid the latter are hopeless with radar...

[sailjumanji]

Originally Posted by roland stockham

Unfortunately it depends on the bouy. Mooring bouys show up on radar if they have a steel rod or chain attached above water. A plastic can with rope attached is as good as radar transparent so nothing will catch it. Things have to be reflective to show up on radar regardless of the system. As an illustration I was once navigating down an estuary do a 'blind' radar trial so I was below with the curtains drawn. We where easily following the chanel looking at the banks and thrings on top of the mooring bouys. The crew on the helm after asking a couple of times if I saw anything slowed the revs and called me on deck. When I came up we where 5om behind a large racing cat, super light, carbon masts, synthetic rigging and no radar reflector made it the ultimate stealth vessel and totally invisible to radar and a good lesson learned...

Roland, are you saying that something has to have metal to be reflective? I've seen a lot of wooden pilings reflected very well on 4G radar.