Radar Mounting

[jmoneilthe2]

I have purchased a Radar Mount and Radar for my Seafarer 22. I have a Bimini top not a hard top so I'm looking for advise on how high I need to set the Radar at to clear the Bimini Top. I have read about 8 inches? Does anyone else have this setup and can give me some advise?
Thanks,
John

 

[seasick]

What are going to mount the radar to? Do you have a radar arch or some other hard structure. Mounting the dome or array to the bimini top doesn't sound like a good idea.

The radar array should be mounted level to the water line while cruising. In addition, the beam of the radar should clear any obstacles like hard top, spot lights, antennas etc.
Since the beam is usually 15 degrees above and below the dome or array, the array needs to have a clear line of sight so if the beam hits the top, the unit needs to be raised and or moved forward or a combination of the two.
The closer to the boat that you want to see objects, the higher or more forward the array would have to be mounted.
The angle of the beam depends on the particular radar model. Call the manufacturer's support line . I am sure they will have the documentation and guidance.

 

[Sardinia306Canyon]

The radar array should be mounted level to the water line while cruising.

Yes and no as this is a decision what depends on where one is boating and on boa and it's bow rise below planing speed.
A radar level and reading perfectly at plaing speed and perhaps with trim tabs read not very well at non planing speed due unavoidable bow rise except 0-3 knots where bow rise is low.
For one who is boating in for example channels or other busy areas with speed limits he may choose a different radar tilt than boaters who speed at 30 knots 100 miles out and back and don't have speed limit areas where bow rise could be a problem.
In some conditions it's a good idea to make some shims and experiment when and under what condition radar reads at best and that could be just between 3-6 knots and planing speed to work for both acceptable well.

I have a Bimini top not a hard top so I'm looking for advise on how high I need to set the Radar at to clear the Bimini Top.

Can you explain better what you have and what you bought?
Do you have a thin tube foldable fabric Bimini top or a strong T-Top made of sturdy pipes with fabric cover?
The radar mount you bought is a long enough pole to stay above the top or a ScanStrut type 1 ft high one?

Yes, 8 inches is about right and also above your head as you don't want the radar beam to hit your head.

Chris

 

[seasick]

Yes and no as this is a decision what depends on where one is boating and on boa and it's bow rise below planing speed.
A radar level and reading perfectly at plaing speed and perhaps with trim tabs read not very well at non planing speed due unavoidable bow rise except 0-3 knots where bow rise is low.
For one who is boating in for example channels or other busy areas with speed limits he may choose a different radar tilt than boaters who speed at 30 knots 100 miles out and back and don't have speed limit areas where bow rise could be a problem.
In some conditions it's a good idea to make some shims and experiment when and under what condition radar reads at best and that could be just between 3-6 knots and planing speed to work for both acceptable well.


Can you explain better what you have and what you bought?
Do you have a thin tube foldable fabric Bimini top or a strong T-Top made of sturdy pipes with fabric cover?
The radar mount you bought is a long enough pole to stay above the top or a ScanStrut type 1 ft high one?

Yes, 8 inches is about right and also above your head as you don't want the radar beam to hit your head.

Chris

Agreed. I didn't explain the level issue well at all.
The point I was trying to make was that the angle of the dome determines what parts of the forward view is covered by radar beam. If you want to 'see' things close to the bow, the radar may need to be angled down a bit. If looking at clouds and birds is important, maybe the dome needs to be angled up. What you want to avoid is having some or all of the radar beam blocked by equipment like a hardtop. You can almost think of radar as similar to a spot light where the beam is about 30 degrees tall, half of that above level and half below. Tilt the light beam down and the top may block the light beam. Tilt the light up and you may not see objects in front of the boat.

 

[Halfhitch]

Yes, 8 inches is about right and also above your head as you don't want the radar beam to hit your head.

This is something I have always tried to be careful about. During the years I had radar and on our work boats the radar was always shut off if there were guys working the bow but that was during the analog radar days. Now that we have digital radar, does anyone know if that is still a consideration or is it a non-issue now?

 

[luckydude]

I have the Garmin dome, I think it was about $2K, whatever one that is. Maybe 18 inch?

I don't particularly care for it, it doesn't see kayakers, it doesn't see Montauks but it sees birds? WTF?

When I did my pilot house, Charlie Hicks put it up on a pedestal and leaned it down in the front 4-5 degrees. That helped, it sees more stuff, still doesn't see everything. I've fiddled with the settings, still no joy. It mostly works but doesn't work enough of the time I really don't see the point of radar. You can't depend on it, you still have to look, so what's the point?

Personally, I'd put in autopilot WAY before I would put in radar if I was doing things over. I use the autopilot every single trip, I rarely use radar.

If you are going to put it in, I'd get it as high as possible and then tilt down 4-5 degrees relative to the line of the gunnels. The reasoning is you care more about what is ahead of you than behind you.

Good luck. Have you considered autopilot instead?

 

[seasick]

That's the point that I was trying to get across. Some folks want to see nearby kayaks and some want to see clouds and birds. None of the radar domes or pleasure boat open arrays will 'see' both, the radar beam is too narrow ( top to bottom). Also the resolution is physically tied to the width of the array The best 18 inch dome won't have as detailed images as a 20 inch would. Each application is different and the angle of the hull while operating the radar will change your coverage area. Adding height to the mount is one way to raise the beam above nearby obstacles. Adding a wedge will tilt the beam up or down. In general the higher the dome off of the hard top, the greater the need for a wedge to aim the beat at the seas in front of the vessel and avoid the blocking of the beam as the dome is angled down.

With respect to the question about radiation exposure, I need to bush up on my knowledge to align with current radar technology. If you are old enough, you may remember all the warnings about standing too close to a microwave oven, especially for those who have a pacemaker ( I do). The radiation concern is somewhat similar but a microwave is designed to shield the user from the radiation whereas the marine radar is designed for the best and strongest beam signal. I think that modern marine recreational radars generate less powerful signals than older technologies. The bottom line concern is the signal strength that you will get exposed to. Modern recreational radars use lower strength beams ( I think) and have much better receivers and digital processing for better imaging). So am I worried? Not really when at the helm but I wouldn't recommend standing in front of the array while working on something.

 

[Sardinia306Canyon]

Out of the Garmin 18 HD3 and xHD3 Radar Instruction Manual from HERE

The radar transmits electromagnetic energy. To avoid possible personal injury, damage to the vessel or device,or poor product performance, ensure that the radar is installed according to the recommendations in theseinstructions and that all personnel are clear of the path of the radar beam before transmitting

You must mount the radar out of range of people, with the vertical beam width above head height. To avoidexposure to harmful radio frequency (RF) levels, you must not mount the radar closer to people than theminimum safe distance value listed in the product specifications.

There are also many informations about where and how to install a radar.

Chris

 

[Sardinia306Canyon]

I don't particularly care for it, it doesn't see kayakers, it doesn't see Montauks but it sees birds? WTF?

As i wrote, your boats level is too high for the 4-5° point down you gave it.
Just do a simple test and go towards a obstacle at planing speed, a bit less than planing speed and 2 knots and check if you see i difference in showing the target due to different boat level.
Otherwise do it right and add spacer/s behind and give it another few degrees down and you will see kayaks and buoys, but you will reduce the sensitivity to see birds loitering above fish.
Some radars have a bit wider beams than others, what is good and bad depending on what the reason for a radar is.

I got the radar already installed to the Canyon but would have bought one to use only when returning to harbor in the dark to avoid small boats and bigger fishing net buoys.
Last year i returned at day and despite the 1-2ft wave there was a kayaker so i fired up the radar and to my surprise i could see him.

Chris