Self-Levelling Radar Mount

[scarab]

Any thoughts on using one of these ?
It's a device that should keep your radar always at level
with the horizon.
As you know when sailing as the boat heels or rolls the ( fixed ) radar
will do the same.





There are different mounting possibilities : Backstay, Mast or Pole.

Manufactures : Scanstrut, Waltz, Questus Marine, etc..

Greetz,

Koen

[Extemporaneous]

I'm also looking into this.
Going to install on my wishbone back stay.
I'm going to try to make my own, hopefully this winter.
Have any do it your selfers out there done this?
Any ideas would be appreciated.

Thanks,
Extemp.

[David M]

Have you gone out, put your boat at a severe heeling angle and checked to see if there is a difference in your radar image?

The vertical arc on many radars is larger than the picture indicates. The manufacturer of course wants to sell more of of these devices. The acid test to confrm this is to go under a relatively tall bridge (one that a ship can pass under), put your radar on the shortest scale and watch the image of the bridge ahead and above you on the screen. Notice what angle between the horizon and the bridge that the image of the bridge disappears off the scope as you pass under that bridge. That is your vertical arc measured from the horizon on up. Figure the arc from the horizon down is about the same. Is the angle greater or less than your boats maximum angle of inclination?

I have an older Furuno 1040 radar. Bridges for this radar disappear off the scope at about an 80 degree angle.

The maufacturer also publishes the vertical arc of your radar. I would though go by your results rather than the manufacturers specs.

Hopefully you will find that you dont need a radar antenna leveler at all.

[AnchorageGuy]

David, I guess you guys sail under the Golden Gate but most of us don't sail under bridges too often but sometimes. To address the self leveler, we used one on our mizzen for several years and was very pleased with it. We used the Waltz and it is still on the boat doing its job after some pretty extensive cruising.

[David M]

Chuck. Thats great that it works. I was just trying to save Scarab some money if he did not actually need one.

[roverhi]

Talked with the owners of a boat in SF that abandoned their backstay self levelor. It failed on the trip down from Seattle. IIRC, it tore loose from it's fixing and swung on the backstay rendering the radar useless and causing great anxiety as it whipped around. Sorry, I don't remember the brand of self levelor.

FWIW, the idea of a backstay mounted radar has always seemed like a dangerous idea. The backstay just wasn't designed to have that sort of forces applied to it.

I think I'd stick with the manual levelor like on the Garhauer radar tower. It won't give you an always level antenna but will allow you to dial out enough angle so it should make any radar work, no matter the heal angle.

Correct me if I'm wrong but doesn't the width of the beam decrease as the power of the antenna increases? One reason not to invest in super long range antennas for a sailboat.

Aloha
Peter O.

[Maine Sail]

I live and sail in foggy Maine. I have owned a Questus, a regular pole mount system and multiple mast mount domes.

I currently own a boat with a conventional pole mount.

I NOTICED NO DISCERNIBLE DIFFERENCE BETWEEN THE QUESTUS PERFORMANCE AND THE CONVENTIONAL POLE MOUNT!!!

I do however notice significant differences between a pole level dome, either self leveling or fixed, and a mast mounted dome! I will, at some point, convert back to a mast mounted dome and ditch the pole mount..

Just so folks don't think I'm shooting from the hip, here are photos of three different boats we've owned and the three of the different radar set ups.
Current Boat:

Questus Boat We Owned:

One of our boats with mast mount:


When you sail in as much fog as we do there is no question a spar mounted dome is the best option.

I've Been using radar since the 1980's and have literally thousands of combined hours of actual "in the fog" experience as I was a commercial lobsterman spending 60+ hours per week on the water. I've also used just about ever brand of radar and they all work, some better than others, but they all work..

If your heart is set on a pole level dome I can honestly say don't waste your money on a self leveling unit. Been there done that.

[svHyLyte]

I second Acoustic's comment. Moreover, most Radar has a vertical beam angle of 20* or better--10* above and below the horizontal. Normally few people sail at a heeling angle beyond about 15* for an extended period lets assume 20* however for the sake of argument. With a horizontal been angle of 10* below the horizontal, and a 20* heeling angle, the beam would cover everything on the leeward side of the yacht and up to 45* on either side of directly ahead or directly astern to windward [(90* x 10*)/20* = 45*]

FWIW...

s/v HyLyte

[AnchorageGuy]

Our Waltz was/is mounted on the mizzen but could have been mounted on the main mast, just our choice. It has been through some horrendous seas, more gales than I would like to count and several, yes several named storms. The big plus for us was the built in dampener that really worked and kept it from getting out of control.

[Sandero]

HyLyte nails it and I believe I mentioned this earlier. The rotating mount has absolutely NO impact on targets from 90° 45 to port and 45 to starboard both fore and aft. For heeling at small angles the returns on the beam will hardly be any different or noticeably different.... and perhaps if you are heeled way over targets on the beam will be affected. But who would sailing like that in poor visibility? Isn't it prudent to reef down, flatten the boat, even slow down a bit and get the benefit of the radar?

And don't forget the fatigue of the wire/cable moving back and forth thousands of times when you are NOT even using the radar.

This is one dumb idea and it is amazing how many people have fallen for it.

[Rick]

My last two cruising boats had radar about 8ft of of the deck on an arch and I could "see" low flying aircraft on them. Sailing at sea posed no problem in "seeing" those craft that you need to be aware of.

The problem of damaging the special cable is very real and one should do everything possible to keep it safe and not bend it with relative motion of the boat.

There is no point in an autoleveling radome device. Manually set it if you must but don't let it swing.

[Jesse]

In my experience the leveling device is a solution to a nonexistent problem and agree with defjef and Rick.

Jesse

[Pelagic]

Ditto!

[James S]

Originally Posted by Extemporaneous

I'm also looking into this.
Going to install on my wishbone back stay.
I'm going to try to make my own, hopefully this winter.
Have any do it your selfers out there done this?
Any ideas would be appreciated.

Thanks,
Extemp.

Have you had any luck on the radar mount?
I built my own, but have still not left the dock, so can't comment on how it works, and the cables are just hanging and not sorted.
In the bottom picture you can see an opening between the backstays nylon insert and the pole....this is the path for the SSB antenna connection.

[meyermm]

I purchased the boat with a self levelling mast mounted Radar dome. Radar was at the end of its life so invested in a brand new Furuno unit which failed within six weeks due to cable fatigue at mast exit caused by constant movement. Although the mast exit hole could have been improved my next boat will not have a self leveller.