Radar Reflectors

[carolmarie]

Sorry, but I'm missing your point. Is your bost equipped with a detector?

[Tree]

Yeah i have HD radar but other people can't see me on radar.

[Pitou]

Sorry, but I'm missing your point. Is your bost equipped with a detector?

Yeah i have HD radar but other people can't see me on radar.

Lee / Tree basically started this thread asking what others have for radar reflectors in order to have their boats be seen / showing up as a strong target on other boats radar screens, as fiberglass boats are not known for generally showing a strong target or showing up at all until you get very close.

Some have added AIS systems to pick-up signals from boats that are sending an AIS signal as an additional tool. Others have systems that not only receive, but transmit their signal as well.

Adding a suite of tools, electronics an automatic fog horn and a reflector can make you safer, but not everyone has everything or anything so there will always be a risk of collision and close calls when boating in weather, darkness and fog. Equp yourself with what you can to minimize risk and traveling slowly is probably the best course for all.

[Tree]

We have some of the busiest waters in the world here, and during fog harbours are closed due to the vast size of some of the shipping.

We are equipped with pretty much everything and foolishly I assumed that the Albin would show up on radar no problem. It's really quite amazing how bad of a signal it gives on radar. Usually we have the radar on and that will always produce a brilliant signal to other ships with radar on transmit. However, much of our fishing is at anchor near shipping lanes and in fog I would rather that the next 150,000 ton supertanker can see me. We sometime have the radar operating while at anchor on a timed transmit. Couple that with the AIS overlay on the chart plotter and I have all the information I need. It is however, not enough to stop a large ship, or any ship for that matter travelling at speed!

[denchen]

Hi `Tree` but unless I have got it wrong, I dont think the fact you have your radar on will make you show up on another vessels radar more than having it switched off.

[Tree]

Transmitting radar will give quite an echo. The only problem is having the transmitting and receiving stations in synchronisation.

Racal also sends out a massive echo, usually in the shape of a trapezoid.

[denchen]

Either you or I have got it wrong `Tree` but I believe a transmitting radar gives off a strong radio signal that can be detected on a wide band DR receiver. It is usual for the SAR boys and Grey Funnel Steamers to have this gear not the normal merchant boys. On the DF gear it will only give a bearing. AIS transponders give a location and all the big boys HAVE to have this fitted. All the ijits will be charging around using eyeball navigation or `waiting for the bang` system. I agree with you that Albins and fibre glass boats do not return a very goo radar echo without a reflector of some sort.

[ScubaPete]

I am by no means an expert on radar, but my old Raytheon radar unit can pick up channel markers (just a piling with a red or green number on it) quite well. It seems like if I can clearly see those, then any boat should show up also. Maybe at long range, you would be invisible, but I can easily see a pair of channel markers over 1/2 nmile away.

[Pitou]

I am by no means an expert on radar, but my old Raytheon radar unit can pick up channel markers (just a piling with a red or green number on it) quite well. It seems like if I can clearly see those, then any boat should show up also. Maybe at long range, you would be invisible, but I can easily see a pair of channel markers over 1/2 nmile away.

If you are talking about Coast Guard Nav Aids, they are made of steel and are designed to produce a good target on radar especially the harbor / river entry bell buoys. Nuns and Cans give strong targets as well.

Fiberglass does not give a great target. A boat with an aluminum tower makes it better, but not great. A fiberglass sailboat with a single mast .. forget it. A buddy was doing a delivery from Virginia to Maine aboard a 48 ft. sailboat with a stubborn owner who would not put up his radar reflector because "my boat is big and throws a good target". Off of NJ my buddy saw a container ship about 3 miles out and identified himself and course and found out it was a boat he did some early sea time on right after graduating from maratime academy. He got the captain on the mic and it turned out to be an old buddy. He asked if he could see him and the response was that on his radar they looked like sea clutter. The owner quickly assembled his reflector and hoisted it up. Guess what they were now noticed as a boat and not sea clutter.

I'd suggest practicing with radar on a sunny bluebird day to see what and when you see things on radar compared to your visual. You will be surprised as to what shows up and when.

Just for thought: Picture a boat doing 12 kts and another boat coming on at 12 kts at 1 mile. point of meeting is 5 minutes away. A 28 ft glass boat may not show up until 1/2 mile and at that speed your 2.5 minutes form meeting. Throw a little more speed on one of those hulls and there's not much time from first target visual to meeting.

My two cents: A radar reflector is something that a boater will use more often than a life jacket, is cheap. and can help to avoid needing those life jackets!

[doughat]

Most, if not all, of the channel markers on wooden pilings have a small radar reflector mounted on top. At least for those markers maintained by the USCG.

Doug H.

[coolchange]

http://store.hamiltonmarine.com/prodimg/PTO-25586.JPG

If this shows up as a picture...it is what I use...I put on a nice oak dowel and attached a 3/4 threaded pipe (male) and then attached a radio antenna holder the kind that can fold down.

now I can raise or lower, or remove..the sail boat guys say these are excellent and hang them on the shrouds...I can find a pic if you want

[Tree]

I had similar in previous boats and they worked reasonably well but with the Albin we go much further offshore and want to be seen on radar for more than 30 seconds in a 1 minute period. Those type are fine for inshore use when ships radar sweeps are more frequent but not so good offshore when the sweeps are less.

[denchen]

To make a home made radar reflector, try getting some aluminium foil, cooking foil will do if you double it or fold it three thick, and fold it concertina style about every 3 inches. The more the better, then join your folds end to end making a cylinder. Place your cylinder in a protective tube, plastic will do and you have a very good reflector. The folds of alloy give the reflector a capacity function so giving the receiving vessel a deeper contact than a flat surface. Next is to get it as high as you can. The maximum theory range being 1.23 times (square route of (reflector height in feet plus the transmitting radar aerial height in feet))

[coolchange]

I had similar in previous boats and they worked reasonably well but with the Albin we go much further offshore and want to be seen on radar for more than 30 seconds in a 1 minute period. Those type are fine for inshore use when ships radar sweeps are more frequent but not so good offshore when the sweeps are less.

If you don't mind...I am having an understanding problem..probably due to lack of knowledge..but I thought the issue would be reflectivity of the radar device and the timing of the "sweeps" would be important only in showing the speed and direction the reflector is travelling...if you have a giant reflector, larger boat or tall metal boat the radar unit would see a brighter spot..every sweep cycle (desirable?)

[Tree]

It's something to do with the bands that large ships work on. I read something about it a while back that in long range smaller objects don't show on radar as well as they do at short range. I'll find the article when I'm on a PC next.