4G Radar - Gimballed mount worth it?

[ErBrown]

Howdy Folks,

To minimize shading of our upcoming arch mounted solar array, we've decided we'll be mounting our radar on the mast around the spreaders. Our current plan is to go with the B&G 4G system.

The tech that we're working with for the install is trying to convince us to spend ~1k on a gimballed mounting bracket. After reading through a few older threads I believe our initial reaction that it's not worth the $$$ is correct. That being said, I figured I'd ask if anyone out there has EVER been in a situation where you actually needed the gimballed mount?

In theory I understand the reasoning behind the self leveling mount is to offset heeling, but find it hard to believe it would make a huge difference. By the time we get past 15-20 degrees of heel, we typically just reef.

Still, if I'm wrong, now's the time to address it.

Thanks again,
EB

[a64pilot]

I haven't had the need, I believe maybe a more tender boat might


Sent from my iPad Pro using Cruisers Sailing Forum

[Jim Cate]

See if you can find what the vertical beam width is for that unit. Thn compare that number with your typical heel angles. For the sort of pulse radars used on small yachts, +/- 15 degrees or so is normal. Some rotors have sharper cutoff angles than others... I've noted that our Furuno, which uses a flat "circuit board" rotor has pretty soft cutoffs, whilst an Aritsu that we had before, with a small parabolic rotor was quite sharp. I haven't heard anything about the FM radars in this respect.

If you find out about this, I'd be interested to have it posted.

Jim

[Cheechako]

I went thru this decision process a couple of times, in the end I decided it was not worth it and only adds higher failure possibilities.

[ErBrown]

Originally Posted by Jim Cate

See if you can find what the vertical beam width is for that unit. Thn compare that number with your typical heel angles. For the sort of pulse radars used on small yachts, +/- 15 degrees or so is normal. Some rotors have sharper cutoff angles than others... I've noted that our Furuno, which uses a flat "circuit board" rotor has pretty soft cutoffs, whilst an Aritsu that we had before, with a small parabolic rotor was quite sharp. I haven't heard anything about the FM radars in this respect.

If you find out about this, I'd be interested to have it posted.

Jim

Thanks Jim

According to B&G, vertical beam width is 25 degrees (+/- 20 degrees). So that makes me think we're right in going with a simple (non-gimballed) mount.

[onewadd]

My ScanStrut self leveling mast mount was only around $150 more than a fixed mount and here is one of about three videos that convinced me and I've never regretted spending that $150.

https://www.youtube.com/watch?v=n9dLy8Rt5R8

You can lead a horse to water....

[tml]

After several sail snags on mast mounted radar domes we installed a Questus back stay mount.
After 20 plus years and 3 different radar units we have had no problems. The gimbaled mount was really just a plus. The ability to get a clean stern mount without new stern pole was the key factor.
I suspect when healed we do see some enhanced radar performance but absolutely no empirical evidence that is true.

[DDabs]

I don't see any issues when heeled over using my 4G radar. The gimballed mount seems like more moving parts to fail over time, whereas the stationary mounts seem much more solid.

[Cheechako]

When I thought it thru, I figured the gimbal would only help on a sailing day when there was no waves in protected waters... like when you are heeled over and sailing fast and smooth. Otherwise, the boat is pitching (Gimbal doesn't solve that), Rolling, (a dampened gimbal may not level fast enough to help before the next roll) etc At sea is just not a stable environment even for a gimbal.

[Formosa46AK]

"According to B&G, vertical beam width is 25 degrees (+/- 20 degrees). So that makes me think we're right in going with a simple (non-gimballed) mount."

Correct me if I'm wrong but that 25 degrees is 12.5 degrees above the horizon and 12.5 degrees below the horizon, maybe as little as 10 degrees above and below. If you are heeled over as little as 15 degrees, you're looking at birds on one side and waves on the other side.

Sure it cost a thousand dollars. But heeled over at a minimum of 15 degrees, you are seeing only straight ahead and straight back. Kinda like using headlights out front and out back but nothing to the side.

I'm putting the B&G G4 on this summer but I'm going gimballed. Isn't that what BOAT stands for, Break Out Another Thousand.

[wrwakefield]

Hi EB,

We have the set-up you describe, and without a gimbaled mount.

Our 4G dome is mounted just below the spreaders on our mizen mast approximately 18ft above the waterline at zero degrees of heel. At that height, and given the typical angle of heel of our rather stiff monohull rarely exceeds 10-12° [which is roughly half of the specified vertical beam width of the 4G unit] the trigonometry didn't reveal any advantages to having a gimbal. [But we have not tested a gimbaled mount first-hand to see if there are any discernible differences on our set-up...]

We have yet to notice any blind spots on RADAR when heeled at those angles in benign sea states [e.g., 5-15ft troughs]

I could see where a gimbaled mount might be worth re-evaluating if the RADAR dome was mounted much closer to the waterline or on a more tender vessel with a higher degree of heel.

In case this is helpful.

Cheers!

Bill

[KWISPEL]

I remove my swinging ting and I see no diffrence. It is havy and expensive. Alsothe cabel on my 3g simrad looks to fragille to move hole days, but sill after 2 oceans, the cabel was still fine. But I removed it and it looks a waste of monney in my opinion.
I am now in Pucket and my Scanstrut is for sale.

[Cheechako]

12.5 degree width projected out 5 miles is what... about 5000 feet vertical width?

[wrwakefield]

Originally Posted by Cheechako

12.5 degree width projected out 5 miles is what... about 5000 feet vertical width?

When we first started using our 4G, I had the smoke trails feature activated one day. Occasionally we would get a fast moving dash-line smoke trail. I determined those trails were revealing low flying float planes and the occasional bald eagle and flock of birds...

Cheers!

Bill

[wrwakefield]

Originally Posted by ErBrown

According to B&G, vertical beam width is 25 degrees (+/- 20 degrees). So that makes me think we're right in going with a simple (non-gimballed) mount.

Thanks for posting these specs, EB.

I want to offer one minor correction for anyone doing the trig for their vessels: 25° ± 20% [percent, not degrees- which is what I suspect you meant to say and is the value you were using in your own calculations...]

In hopes of being helpful.

Cheers!

Bill