Why do we not see open array radar antennas on sailboats?

[rslifkin]

Open arrays are also significantly heavier than domes. Using the Simrad HALO radars as an example, the 24" dome weighs about 15 lbs. The 4 foot open array weighs 66 lbs (3 foot array is 64 lbs, 6 foot is 70 lbs). For Furuno, the 24" NXT dome weighs 16 lbs. The 4 foot open array is 46 lbs.

[hjohnson]

Originally Posted by Lodesman

Have you ever seen what happens when a loose halyard wraps around the antenna?

$$$$$

I was working on a 27,000 ton deep sea ship last year while they were crossing the Atlantic in February. One of the flag halyards got loose in a storm and wrapped itself around the S-Band radar. It was not pretty, and the radar was inop for the rest of the voyage.

[Dockhead]

Originally Posted by hjohnson

I was working on a 27,000 ton deep sea ship last year while they were crossing the Atlantic in February. One of the flag halyards got loose in a storm and wrapped itself around the S-Band radar. It was not pretty, and the radar was inop for the rest of the voyage.

There are some advantages to domes on sailboats or any vessel with halyards of any kind.

[Nightcrawler]

Ok, not a sailor - but on our 42' trawler with a Garmin 18" round xHD mounted 22' above the water, I cannot imagine needing more. It picks out crab pots, I tracked 3 pelicans parallelling us 3 miles off and watched them cross our bow. I saw fishing boats on the other side of a masive thunderstorm on Lake Erie. It had a range longer than the bridge horizon and would track ships we couldn't see over the horizon.

[betwys1]

The 'wings' on a radar antenna improve adjacent target discrimination. For a slow-moving sailboat helm, it is not vital to know if it is one or two targets which intercept ones track. It is important to reduce weight at height.

[Dockhead]

Originally Posted by betwys1

The 'wings' on a radar antenna improve adjacent target discrimination. For a slow-moving sailboat helm, it is not vital to know if it is one or two targets which intercept ones track. It is important to reduce weight at height.

I don't think the weight of any radar will make any detectable difference to a boat's motion and certainly not to its heeling angles, and even much more so if it's at a reasonable distance below the masthead (mine, for example, is 10 meters above the waterline, less than half way up my 23 meter mast).



And height greatly influences the radar horizon and therefore the ability to detect low objects like fishing boats, which are so important to see with radar since they often don't use AIS. More height greatly improves the ability to discern lower objects in sea clutter, also important.

[pcmm]

Originally Posted by The Wolf

Good case for halyards internal to the mast?

That only covers half the halyard!