Radar/Plotter Overlay with 6-9m RIB

houser · 20 March 2004, 09:50

Dear all,

Anyone using a radar/plotter overlay with a 6-9m RIB?
Is it working out for you?
I have only seen one of the two systems I am aware of, Raymarine and Furuno on larger vessels.
Anyone heard if Garmin are coming out with something new along these lines?
Ah well,
These units are still rather pricey but interesting nevertheless...but what I would like to know is if it is likely that these units are fast enough to cope with all the micromovements of the hull and coarse deviations on a 6-9m RIB.
Are the readings likely to make sense if the installation is optimized with a fluxgate and all, or will it just stutter about, trying to figure out where it's going?
Some people I have spoken to indicate that the Radar/Plotter Overlay is unlikely to work on smaller vessels. Apparently this feature requires a fairly steady coarse to make sense. I have only seen these systems over the shoulder of someone else at the helm an asked only basic questions...but it looks the biz...if price drops a bit more I am all over it ;-)...
I am sure Scandinavian darkness and fog is on par with that of the British Isles so others on this excellent board should be interested too as price drops....,-)
Any knowledge to be obtained?

curious as ever
Janne A.

P.S. broken Furuno link fixed, sorry 'bout that..

Brian · 20 March 2004, 12:18

Janne
I have the Raymarine setup and I know three other boats with it ranging from 6.5 to 9.5m.

The systems work fine with no worries about "micro-movements".
Only slight problem is that small boats (ie other RIBs) are dificult to see easily on the RADAR, especially in rough seas.

But apart from that, the RADAR is invaluable in fog, rain and at night. Try to make sure that if you do get such a system, it is equiped with MARPA or ARPA (vessel taget tracking software). In busy sea lanes, in poor weather or at night, this takes a lot of the stress out of collision avoidance.

houser · 20 March 2004, 12:45

Hello Brian,

Thanx for reply.
What system exactly if you have a sec?
Do you often use the overlay of radar on chartplotter? If so, when, typically?

best
Janne A.

Brian · 20 March 2004, 15:48

I (and most of my pals) have the RL80C.

The RADAR is not used very often, only in sea-fog or other bad weather or to pick up a RACON or look for each other if separated.

I find it's actually not how often it is used, but the value in when it is used. For the relatively small addiditive cost of the radome, I think it is well worth it. Some people I know have even retro-fitted the RADAR after using just the plotter.

Raytheon is possibly more expensive than other brands, but you get what you pay for. As the man says "Nobody is ever disappointed wiith quality".

houser · 20 March 2004, 16:02

Ok,

So the radar/chart overlay feature does not get used much, if at all?
I thought it would be a killer feature...

best
Janne A.

Brian · 20 March 2004, 16:10

I wonder if I am mis-reading your question?....probably.

When you say "overlay" do you mean superimposition? The Raytheon system does not do that. I am told it makes the screen far too "busy" to make sense of.
The Raytheon allows:
-either chart or RADAR
-chart plus RADAR split screen
-when in RADAR mode or split screen mode, your course or heading and bearing to target are superimposed on your screen. Thus you continue to navigate succesfully whilst keeping RADAR and/or MARPA watch.
You can download the Adobe PDF of the RL80C manual from Raytheons website if you want more info. on what exactly it does.

My apologies if I mis-read your question-it is very foggy here today!

houser · 20 March 2004, 16:18

Foggy question warrants foggy answer I guess...and how very appropriate for the topic of this thread.. ,-)

Yes, it is specifically the use of overlaying radardata on a chartplotter that I am curious about..
and that is what I am told requires more from the unit and installation to make sense on a smaller vessel, as the micro side-movements of a small hull will make it hard for the system to display it.
If this is your unit, then it should do it anyway...

regards
Janne A.

Pitkis · 20 March 2004, 16:35

I have used 10,4" Furuno NavNet plotter in 6m boat and it worked fine. I have also tested same system on 6,5" screen and it didn't work out as well, the screen was just a bit too small. Invest to Furuno 10,4" screen if you have resources, that's the best system you can buy to small boat. New Raymarine 120C is too light structurally, I don't like it, the mechanical quality is not enough for heavy-duty RIB use although the software is good. For Furuno RIB is not a problem, they are 100% reliable and built like tank.

Brian, for a small vessel ARPA is not recommended dual major unreliabilities. Also, in ranges 3 miles and below the use of MARPA and ARPA is generally not recommended even in commercial shipping. Pleasureboat ARPAs are nice toys, but one should never trust on them during night or low visibility. They contain so many possibilities to failure that especially for small RIB automated collision avoidance should be phohibited. Instead, navigation should be based on reading the screen in an ordinary way.

houser · 20 March 2004, 16:54

Hi Pitkis,

Furuno is what the old naval guys at the yard is advising me to get also...
I have only seen the new Raymarine C-stuff on the net and it looks really nice...but I hear you...

Very interesting to hear that you liked the Furuno in a small boat.
May I ask if you have any comments specific to the radar/chart overlay feature of the FurunoNavnet system?
Did you try that, and if you did, did it simply work for you with no glitches?
What is in your view a typical scenario when this is a useful feature?

I don't know about other parts of the world but here in Sweden Maritime law pretty much requires that you have your radar switched on if you have one.
If you are in a collision and it is established that your radar was not used you are in trouble.
Not so in your neck of the woods?

FWIW

best
Janne A.

Brian · 20 March 2004, 16:56

Houser
That is the RL80 C Plus model. I dont have the plus and my system does not do superimposition. I guess we need a Raytheon person to tell us exactly what elements of the Raytheon family are required to give you the result you need ie do you need a fluxgate compass, what other hsb2 device do you need, the literature is not at all clear is it.

Pitkis
I bow to your superior knowledge and expertise. ARPA/MARPA may be a toy but it is better than not having a toy and ABSOLUTELY agree it must not be relied on ass some sort of automatic, failsafe system. I use it to complement and add-to to good watchkeeping etc.

Both
Any comments about the "business" of an overlay screen. I have not seen it but would imagine that the amount of detail would be either confusing or unclear.

houser · 20 March 2004, 20:18

Brian,

Well, like I said, I have only seen it over the shoulder of someone else at the helm and never used it myself.
But it looked extremely useful...not to be used all the time but as an option perhaps.
A search for overlay in this forum gave this

Crazyhorse (how is his cabin rib coming along btw?) seems to have opted for this feature
a bit more than a year ago..

The theoretical advantages are I guess obvious..
it should give you a very fast overview of what is going on with other boats around you, without having to refer positions between the chartplotter
and radar displays and the closest you can get to having the other boats moving about as numerical dots in your chartplotter, until those digital ID transponders for ships become
a reality for recreational vessels next month...;-)

..but seriously..it should be a great feature if properly implemented as a nice read-out.
I mean GPS chartplotting is already such an incredible luxury for anyone who has spent more than a few years at sea from time to time and remembers the old days annoGPS.
Now add basic radar functionality scaled and mapped into the same display
I mean...who would have thought that would be possible in a recreational vessel..
These are the good times.
Safer, further and more fun too..

best
Janne A.

Pitkis · 20 March 2004, 23:58

Well, I have no special comment regarding the NavNet overlay, it worked like all dealers and brochures say. Very clear on 10,4" screen, you have also a lot of different color options for screen, so I am sure you get clear vision for targets easily. Note that you need an electronic compass also, I'd suggest Furuno PG-500 that is a great one even for a small commercial boat or workboat.

I drove nearly 1100 NM during 8 days with 10,4" Furuno, on sunny days we used chart only, but in dark (300-400 NM) we used also radar on divided screen or overlay mode. It's a choice of yours, which mode you want to use, of course overlay will validate your chart nicely, for example in some ranges C-Map chart did not show ceratin markings and your radar could see them. On the other hand, in clear sea you might use divided screen and just follow on chart that you are on the right track and check shortly on radar that no-one is nearing you....difficult to say, which one is clearly the best scenario. Anyway, just buy the compass to your system, it's worth investment, a cheap price for overlay function.

Mechanical quality in old Raymarine systems like RC80 etc. were better, but current C-series was a disappointment for me. Cheap prices, mechanical quality low. Furuno unit went through nearly hell on our boat, I really don't think many Furunos sold has gotten that rough handling, but there were no problem with gear through the trip.

Petrov · 21 March 2004, 11:16

I am going for the Simrad CA44, combined with radar, plotter and sonar.
They use a LCD screen wich is very nice because it`s not very deep.
If you look at the similiar Furuno the screen is very deep and takes a lot of space, what is pretty cool on Furuno is that you can install a camera for not very much money, for example have the camera set up in the back and than you will se on the screen if it`s coming up any boats from behind.

codprawn · 21 March 2004, 12:15

I would be rather worried about radar on a RIB - that magnetron would be too close to my head for comfort - also what sort of range do you get so close to the water?

Petrov · 21 March 2004, 12:22

Quote:

I would be rather worried about radar on a RIB - that magnetron would be too close to my head for comfort - also what sort of range do you get so close to the water?

Depends on how high you put the radar.
actually a radar is not much stronger than a cell phone, people thinks that but it`s not.
Why i need a radar is because we are navigating in 30,000 islands and very often during the night in speed around 30-50knots, sometimes it`s not more than 40m between islands.
You have 15m wrong on GPS than the radar is perfect complement.
Somtimes you have a lot of red and green and you have to pass them with 10m, GPS 15m wrong, radar is the true pic not the GPS.
Than you use radar for passing.
It`s one of the best compelement, it`s very often i apss boats with only GPS, they are looking into GS and never looking forward, it`s like htey think that the GPS is the radar so they forget to look after boats in reallity.

codprawn · 21 March 2004, 12:33

"Not much more power than a mobile/cell phone"? Are you sure??? Even a small radar puts out something like 1.5kw at microwave frequencies - a mobile phone is measured in milliwatts. Radar uses a magnetron just like a microwave oven! In fact you can cook with some radar!

houser · 21 March 2004, 12:39

I researched this for the same obvious reasons.
The WHO says this
if you want to know.
The antenna right behind your head, like you see on many pleasurecraft with a JRC, does not appear to be a good idea regardless.. ,-)

best
Janne A.

codprawn · 21 March 2004, 12:58

there are a couple of mistakes in that report but basically it's right - one typing mistake is that it says boat radars are 1 - 25w in power - that should have read KW - quite a difference.

Radar power does drop off exponentially - I wouldn't be worried on a normal boat but on a smaller RIB the Radar woul;d be beaming right through your head - NOT good!

Also the lack of range so close to the water makes me wonder how useful they are on a craft so fast - the higher the transmitter the better.

I would say a radar detector would be more useful

Pitkis · 21 March 2004, 15:23

We asked from Furuno recently, how long distance have to be to the nearest crewmember when installing a 2 kW radome to our RIBs. The answer was 1 metre. The antenna is now located in A-frame, but will be lifted to upper position on later models in order to prevent radiation.

So, after all, if you are more than 1 metre from radome the radiation is not a problem. For open antennas with higher power the range is the whole different thing.

Petrov · 21 March 2004, 16:06

Quote:

We asked from Furuno recently, how long distance have to be to the nearest crewmember when installing a 2 kW radome to our RIBs. The answer was 1 metre. The antenna is now located in A-frame, but will be lifted to upper position on later models in order to prevent radiation.

That`s what Simrad said to me to and that`s what i mean when i say that it`s not stronger than a mobile.
Maybe i was`nt really clear.