Brian,

I agree that I want to see him early and your radar detector idea might
work. Still, if a 600 ft ship is approaching at 22 knots, I don't want
to be the only guy trying to get out of the way.

On the "legal" issue. I'm probably overly suspicious of the FCC's
interest in anything that transmits (although my radar transmits on the
same frequency). I just can't figure out why you don't see these things
around. I've never had any faith that a radar reflector that's small
enough to put up in the rigging can do much good.

Carl

On 23 Oct 2005 17:48:19 -0700, "Carl" wrote:
I agree that I want to see him early and your radar detector idea might
work. Still, if a 600 ft ship is approaching at 22 knots, I don't want
to be the only guy trying to get out of the way.

Ok, forgive my being a bit persistent but: not having this enhanced
reflector (btw: I was always clearly visible using a cheap passive
one, mounted correctly) doesn't mean you'll be the only guy trying to
get out of the way.

After sighting by eyes or radar (or,thanks to your post,my new 50usd
radardetector) I'll turn on my marine-pc and my 250usd ais-receiver.

I'll be able to see the 600ft ship's course and speed and when needed
I'll hail this ship by it's right name on vhf70 or call it by dsc
using it's unique mmsi-number. After identyfying myself and my
position we'll discuss and verify the probably one and only right way
to avoid any risk of a collision-course.

Here in the Netherlands the government is contemplating making ais
mandatory (also for 300t vessels and indeed also for yachts) cause
freigthers increasingly tend to use ais as sole informationsource over
radar. This is imo a good development. Ais will work 100% when
everybody, everywhere uses it. One might expect these rules will find
their way into supernational legislation.

Just my 2 cts.
Len
S/v Present

Len wrote:
On 23 Oct 2005 17:48:19 -0700, "Carl" wrote:
After sighting by eyes or radar (or,thanks to your post,my new 50usd
radardetector) I'll turn on my marine-pc and my 250usd ais-receiver.

I'll be able to see the 600ft ship's course and speed and when needed
I'll hail this ship by it's right name on vhf70 or call it by dsc
using it's unique mmsi-number. After identyfying myself and my
position we'll discuss and verify the probably one and only right way
to avoid any risk of a collision-course.

Here in the Netherlands the government is contemplating making ais
mandatory (also for 300t vessels and indeed also for yachts) cause
freigthers increasingly tend to use ais as sole informationsource over
radar. This is imo a good development. Ais will work 100% when
everybody, everywhere uses it. One might expect these rules will find
their way into supernational legislation.

Len, following your post about AIS Live I went to check into what was
active in my cruising area, the Adriatic. Zilch - zero - nada - not a
single AIS equipped ship was reporting in the entire Adriatic Sea,
although clearly the system was active as there were a few clusters
around Malta, Athens and Marseilles when I included the whole Mediterranean.

Now I know there are masses of freighters and large ferries converging
on Trieste, Venice, Rijecka, Ancona, Bari, Split, etc, etc. every day of
the year, indeed, I had a hair-raising close call with a monster, 50
knot, catamaran ferry 10 nm off the Croatian coast last year - but it
would seem that AIS would not have helped me.

It is likely that all the small companies that can avoid installation
until the mandatory 2008, under whatever regulations they fall under, or
are illegally avoiding installing, or the crews are not bothering to
activate if they are installed, are doing so.

Best,
BrianH.

On Mon, 24 Oct 2005 11:47:04 +0200, BrianH wrote:
Len, following your post about AIS Live I went to check into what was
active in my cruising area, the Adriatic. Zilch - zero - nada - not a
single AIS equipped ship was reporting in the entire Adriatic Sea,
although clearly the system was active as there were a few clusters
around Malta, Athens and Marseilles when I included the whole Mediterranean.
Is it possible that the web based system you used missed some data
where the ships themselves were actually transmitting?

Now I know there are masses of freighters and large ferries converging
on Trieste, Venice, Rijecka, Ancona, Bari, Split, etc, etc. every day of
the year, indeed, I had a hair-raising close call with a monster, 50
knot, catamaran ferry 10 nm off the Croatian coast last year - but it
would seem that AIS would not have helped me.
You will never know afterwards.
In my knowledge commercial vessels never switch ais off. What
sometimes occurs is that they don't update their status in time. You
can sometimes see a freighter do 20 kts with the status "moored" or
"anchored". This doesn't affect safety though.

It is likely that all the small companies that can avoid installation
until the mandatory 2008, under whatever regulations they fall under, or
are illegally avoiding installing, or the crews are not bothering to
activate if they are installed, are doing so.
I agree 100% and in a previous post in this thread I already pointed
out one can't rely on one single system and when trusted naievely, ais
(as well as any other system) can lead to unsafe situations. In
intervals intense lookout is simply necessary. The discussion with
Carl is (in my interpretation) focussed on what subsidiairy system to
choose, the enhanced radar-reflector or ais, given the situation one
isn't filthy rich. Of course there always will be ships (fishermen fi)
without ais but there also will always be ships (fishermen fi) that
don't turn on their radar or -when it's operating-, don't constantly
watch their screen or even set the alarm.
Carl suggested not having a boosted reflector would lead to the
situation he would be the only guy getting out of the way. My answer
just referred to the reasons why I disagree on that.

Len wrote:
On Mon, 24 Oct 2005 11:47:04 +0200, BrianH wrote:

Len, following your post about AIS Live I went to check into what was
active in my cruising area, the Adriatic. Zilch - zero - nada - not a
single AIS equipped ship was reporting in the entire Adriatic Sea,
although clearly the system was active as there were a few clusters
around Malta, Athens and Marseilles when I included the whole Mediterranean.

Is it possible that the web based system you used missed some data
where the ships themselves were actually transmitting?

I really don't know, I just registered and clicked on Med. - Adriatic.

This was AIS Live, from, I think, your own posting. I was surprised
there was nothing shown - and the paucity of ships in the entire Med.
I've just repeated it and the display is similar. Perhaps the Public
site has limited ship data, but the explanation doesn't indicate that:
"As you can see the public site shows a snapshot of vessels with a
random time delay of at least one hour and with only limited information
available." Unless "limited information" refers to numbers of vessels
and not their data as I had inferred.


Now I know there are masses of freighters and large ferries converging
on Trieste, Venice, Rijecka, Ancona, Bari, Split, etc, etc. every day of
the year, indeed, I had a hair-raising close call with a monster, 50
knot, catamaran ferry 10 nm off the Croatian coast last year - but it
would seem that AIS would not have helped me.

You will never know afterwards.
I meant because if the site is a true reflection of the data, it would
not have shown. Had it shown on the screen I could have ascertained its
course; as it was, its approach speed and twin hulls made it difficult
to judge its exact heading.

In my knowledge commercial vessels never switch ais off. What
sometimes occurs is that they don't update their status in time. You
can sometimes see a freighter do 20 kts with the status "moored" or
"anchored". This doesn't affect safety though.


It is likely that all the small companies that can avoid installation
until the mandatory 2008, under whatever regulations they fall under, or
are illegally avoiding installing, or the crews are not bothering to
activate if they are installed, are doing so.

I agree 100% and in a previous post in this thread I already pointed
out one can't rely on one single system and when trusted naievely, ais
(as well as any other system) can lead to unsafe situations. In
intervals intense lookout is simply necessary. The discussion with
Carl is (in my interpretation) focussed on what subsidiairy system to
choose, the enhanced radar-reflector or ais, given the situation one
isn't filthy rich. Of course there always will be ships (fishermen fi)
without ais but there also will always be ships (fishermen fi) that
don't turn on their radar or -when it's operating-, don't constantly
watch their screen or even set the alarm.
Carl suggested not having a boosted reflector would lead to the
situation he would be the only guy getting out of the way. My answer
just referred to the reasons why I disagree on that.

I wasn't arguing with that - I totally agree with you.

Best,
BrianH.

Hi Len,

I would agree (this has also been a fun thread):

a) Universal (or close to universal) use of AIS would be the best
solution.

b) Radio contact is a close second if it can be established in time and
everyone involved can figure out who is who.

c) Good radar watches should not be assumed on either offshore yachts
or commercial ships (Naval vessels are another matter) -- how much
money you want to throw at the problem -- for radar reflectors, alarms,
or extra watch-keeping crew -- is a captain's decision that probably
has something to do with a memory of a close call on a foggy night.

Carl

My limited experience with seeing passive returns was a big surprise. A
50' wooden boat broadside in calm waters 300 yards off didn't give
any return until the gain was turned up to the point it would give too
much cutter in rougher water. I also don't see too much of the folks
with the Davis type reflector, three sheets of metal put together at
right angles. The type I have is the Ferdel Bilpper, I was seen by
everyone I asked. I was able to see everyone who had a the any of the
more expensive reflectors that were covered in plastic. Apparently they
have more facets that are in more directions and give a better
reflections. I buddy boated 200 miles up the coast once with some
friends in a 46' Kelly Peterson and a 38foot sloop. The Peterson had
a Davis type reflector and the other sloop had a more modern reflector.
The sloop and I rarely saw the Kelly Peterson and were able to see each
other consistently. I was always amazed at how many boats I didn't
see on the radar. It's a Raymarine SL72
Unfortunately the active radar reflector is not cheap, about 50
percent the coast of the low end Raymarine and about $100 less then a
JRC Radar 1000 MKII. If I had a limited budget and had to choose, I
would take the radar.

John
S/V Pangea

wrote in message
oups.com...

My limited experience with seeing passive returns was a big surprise. A
50' wooden boat broadside in calm waters 300 yards off didn't give
any return until the gain was turned up to the point it would give too
much cutter in rougher water.

snip

John
S/V Pangea

There's a "possible" tuning flaw here.....
Set your picture up for maximum clarity and target acquisition first, then
use "sea clutter" controls (and often, "rain clutter") to reduce clutter in
rougher water, rather than gain/intensity.
Admittedly, you may have to reduce gain at lower ranges, but always try
clutter controls first.
When doing the initial set-up, use a higher range to begin with (3,6,12mi.
depending on your set) and get your best picture there.

otn

"otnmbrd" wrote in message
nk.net...

wrote in message
oups.com...

My limited experience with seeing passive returns was a big surprise. A
50' wooden boat broadside in calm waters 300 yards off didn't give
any return until the gain was turned up to the point it would give too
much cutter in rougher water.

snip

John
S/V Pangea

There's a "possible" tuning flaw here.....
Set your picture up for maximum clarity and target acquisition first, then
use "sea clutter" controls (and often, "rain clutter") to reduce clutter
in rougher water, rather than gain/intensity.
Admittedly, you may have to reduce gain at lower ranges, but always try
clutter controls first.
When doing the initial set-up, use a higher range to begin with (3,6,12mi.
depending on your set) and get your best picture there.

otn

That procedure works well with my JRC Radar 2000. Keep the gain turned up
all the way and increase the sea clutter setting as you go to shorter
ranges. I just started using it this summer and I'm impressed with its
ability to pick up targets. There was, however, an initial tuning
adjustment that I had to go through to get this level of performance. This
procedure peaked the tuning to obtain the maximum number of targets. After
that I just leave it on Auto Tune and adjust sea clutter.

Those active radar reflectors seem overpriced considering all they are doing
is transmitting/receiving just like a radar unit but not providing a display
or any of the other bells/whistles associated with modern radar.

I have a small Furuno on my boat and it picks up everything. On a calm
day I track seagulls and logs. Its only when the sea surface is really
disturbed (25+knots and lots of fetch that the radar starts missing
small boats.

Having driven large ships, I would say that if they are watching their
radar, they will see you even in a small fiberglass boat unless the sea
state or weather is such that clutter is a problem