radar
Hello all - am considering radar installation, one of three ways - aft post, backstay with swivel, or mast mount, the the question is - screen in nav station, do I have a repeater screen at helm, if so, how to do without overcomplicating the whole deal?

I just want to be able to see big ships in fog if I get stuck in shipping lanes, and not rely on my reflector and hope the big ships maintain a good watch - which they don't frequently.

Any tips or advice are appreciated,

Thanks,

Geoff on Corazon, 411 #41

Hi Geoff,
while I am absolutely positive that a radar is necessary for additional safety in sailing, I am not equally confident in advising the kind of setup. My setup is fine but I am not sure it is the best. It consists of:
1) 2kW (24Nm) radome mounted on the mast, 1m above the lower spreaders on the strbrd side (do not ask me why, at that time I thought it was better to avoid interference with the sails).
2) Integrated nav display inside.
For what concerns the antenna, the height is good enough to reach the expected range and the mast does not interfere. If the boat is heeled, the side view is almost completely cluttered or void but not the front view. If the sea is rough the radar sees clutter all around and it is useless.
Regarding the location of the display, my choice is based on the fact that up to now I never sailed alone.

Daniel, 411-004

Dear Daniel,

  I got rid of the radar fitted to my 41 , and replaced it with AIS class B (the Simrad set with its own small screen). This gives a really clear and easy to understand picture of all the ships round you, with the collision risk of each indicated just like a big ships radar with ARPA. No small boat radar can give anything like the same ease of use and clarity. We do not need radar any more for coastal navigation as position fixing(GPS) is so reliable and accurate.

     The radar was an ugly lump half way up the mast, the boat looks so much better without it.

regards Cosmo Little

Dear Daniel,

Cosmo -

That is very interesting - was not aware, thanks. Question - am I correct in assuming that the system works based on the 'other guy' being on the system also? So if there is an intermediate sized fishing boat for example, or large yacht, they might not be on, and therefore might not show up on my screen?

Assuming the big commercial ships are required to be on system, is this true? IF so, you might have helped me address my problem very nicely -

Thanks,

Geoff
Corazon

Cosmo - That is very interesting - was not aware, thanks. Question - am I correct in assuming that the system works based on the 'other guy' being on the system also? So if there is an intermediate sized fishing boat for example, or large yacht, they might not be on, and therefore might not show up on my screen? Assuming the big commercial ships are required to be on system, is this true? IF so, you might have helped me address my problem very nicely - Thanks, Geoff Corazon

Looks like all vessels over 300 tons and all passenger vessels on the Great Lakes (where I am presently) must have AIS Class A, not all Class B users are fully visible to older Class A units.

One other question on the Simrad - is there a separate antenna? All the data I can find on their website just shows the screen and calls it a 'unique all in one transceiver' - ?

Thanks,

Geoff
Corazon

Looks like all vessels over 300 tons and all passenger vessels on the Great Lakes (where I am presently) must have AIS Class A, not all Class B users are fully visible to older Class A units. One other question on the Simrad - is there a separate antenna? All the data I can find on their website just shows the screen and calls it a 'unique all in one transceiver' - ? Thanks, Geoff Corazon

Looks like i need a separate GPS and VHF antenna for this device, yes?

G

Hi Geoff,
not necessarily.
If you have already a GPS you may o may not need a NMEA multiplexer depending on how is your system made.
If you have a VHF with its antenna you may use the same antenna either acquiring an AIS with enclosed a switch or with an external switch as an additional device.
I used to be very suspicious on those switches but apparently they work pretty well.

Daniel, 411-004

I want to add something: my belief is that AIS is another helpful addition to a safe sailing but does not totally substitute the function of a radar. Analogous as a GPS being a very good way of knowing one´s geographical coordinates but not being a substitution of other safe sailing practices.
My personal plans are to get an AIS-B, which I presently do not have, and keep the radar.
AIS and GPS, contrarily to other means, are easy to use and interpret but I think that relying only on them would be an error.

Daniel, 411-004

Daniel, i agree with you 100% about radar and AIS. Security is having multiple means of doing everything on board. From the Azores to well after the Straights of Gibraltar we had sometimes over 20 ships on the AIS and many others on the radar, the PC and the AIS were not stable. In mid Atlantic with poor visibility it is very reassuring to verify cargos using both AIS and Radar. I am also against having both on the same screen, they should be separate systems. Concerning Radar placement, I have had both mast and back pole installations on different boats. Though i worry about sail deterioration with a mast mount I prefer it so as to reduce the amount of stuff that tends to accumulate at the stern. One added advantage with radar which I have been very happy to have was following storm clouds. One point i'm not sure about is the need for an AIS transponder, I have a transponder but it usually takes a certain amount of yelling on the VHF to awaken interest with ships at sea. All this is not of much use for coastal sailing but... a presto Pippo 411/22

Pippo,
nice to hear you!
Your post made me remember the useless VHF yelling I once tried crossing the crowded lane of cargo ships between Sardinia and Africa.
:-)
Targeting rain cells by radar is a good point I forgot to mention but had the chance to appreciate.
Just to add another point: all the sensitive zones where coast guard or warships control the traffic are observed by both AIS and radar: there are very good reasons for this.

Daniel, 411-004