Radar "Arch" on a sailboat

Zanshin · #1 (**permalink**) 11-22-2006

I am getting a wind generator installed next month, mounted on a pole with supports off the aft of the boat. I just realized that since I have plans on adding a radar sometime early next year it might behoove me to look into getting a radar arch installed and then mount both of these devices (and who know what else might accrue over time) on that. I've bounced around the net with some google searches, but it seems that the manufacturers I've found concentrate on powerboats.
The boat is in the Caribbean (a Jeanneau 43DS) and I welcome any pointers, comments or suggestions (perhaps with the exception of people telling me I don't need a wind generator or radar

) - are there companies in the US or elsewhere that already have preconfigured arches or will any installation be, effectively, a one-off? I've cross-posted this on the Jeanneau owner's forum but this one certainly is busier and might help me further.
Are there any serious drawbacks to a radar arch? I'd love a fiberglas one for the looks, but feel that it would probably be prohibitively expensive.

trantor12020 · #2 (**permalink**) 11-22-2006

For me, I would put the radar on the mast so that its high and away from people height (like people standing on coach roof or forward deck. I think, with radar on arch (over at cockpit I suppose) the microwave signal would radiate people at forward deck and maybe the head of people in cockpit. I don't have a radar onboard but that's what I think.

camaraderie · #3 (**permalink**) 11-22-2006

Zanshin...these guys are the ones you are looking for;
http://www.wellsmarine.com/

Every one is somewhat custom...but I'll bet they already have the pattern for your 43DS. They go to all the boat shows and have a good rep. If you do this, make sure you get enough of a vertical pole mount for the wind generator to insure that you don't cut your head off when messing with other stuff on the arch! Other things to mount there: dual wind generators!, GPS mushroom, satellite dish, wifi antenna, VHF/SSB whip, dinghy davits, solar panels and a partridge in a pear tree! Be sure to get another 100' of anchor chain for the bow locker to keep the boat balanced!

As to the radar danger...there is limited vertical radiation which you need to account for (it is in the specs of the radar unit), and insure that the vertical deflection clears your head comfortably or we'll be building an arch for you hospital bed!

Zanshin · #4 (**permalink**) 11-22-2006

thank for the quick response. That company, Wells Marine, was the only one I found yesterday and I fired off an email query to them (haven't read my email from work, so I don't know if they've answered yet). They were the only company that I found which specifically mentioned and displayed sail arches.
I must admit that I found the lopsided single pole for a wind generator (with it's supporting struts) to be a bit of a blemish on the aesthetics of the boat - the arch is the lesser devil.

My worry with the radar mounted aft instead of on the side of the mast wasn't the stray radiation but that the mast, boom and stainless steel standing rigging might block too much of the forward sweep [don't know how susceptible radar is to that type of potential blockage].

I won't want too many electrical toys - but I'm singlehanding so the radar is going to be necessary and you've seen the thread about my addiction to caffeine and therefore the wind generator needs to supply the power for the massive electrical drains that an inverter for my coffeemaker will have [and perhaps an amp or three for the autohelm].

I have heard that hoisting a dinghy and/or engine off a radar arch is OK, but that permanently hanging a dinghy off such an aftermarket mount can cause a lot of damage over time since sailboats are not meant to handle the heavy loads where the arches are mounted; particularly in violent seas.

I was surprised that Google pictures didn't show more than a handful of reference for "radar arch" and combinations of sailboat, yacht. It would seem to not be a popular or oft photographed accessory.

TrueBlue · #5 (**permalink**) 11-22-2006

Quote:

Originally Posted by Zanshin

I was surprised that Google pictures didn't show more than a handful of reference for "radar arch" and combinations of sailboat, yacht. It would seem to not be a popular or oft photographed accessory.

Google Hunter sailboats for pictures and you'll think they hold the patent rights to radar arches.

hellosailor · #6 (**permalink**) 11-22-2006

There are folks who say targa bars and radar arches don't belong on sailboats and they are unaesthetic, but if you've got the toys and need a place to hang them...Do it. Just make sure to "measure twice cut once" and be sure the mounting scheme and mounting points are adequately enforced for whatever purpose you have, i.e. putting a radar up there is a small load. Putting a wind generator up there, a much bigger one. Adding an engine or dingy hoist, or bracing against green water, all add more load.

This is a bad spot for *any* excess weight, since it is outboard of the transom and will add to the pitching motion of the boat and that's something also to consider. The weight of the radar--and the relative stability of it (the more relative motion) compared to mounting a radome part way up the mast. If your boat is already tender about pitching, I'd think twice on it. If she's stable...less to worry about.

Faster · #7 (**permalink**) 11-22-2006

Zanshin

We installed a radar (small lightweight JRC1000) on a stern post this spring, and made some good use of it in fog this summer and fall. We have not noticed any significant interference from the rig/sails being in front of the antenna. The biggest loss from this installation, I think, is limited range by being relatively low on the boat. For simplicity we chose not to gimball it, but that would improve performance when heeled.

The other advantage of an aft mount is, with limited cable length, I was able to mount the unit at the helm, rather than below where it is less handy, especially when shorthanded. The display unit quickly disconnects for security and stowage if need be.

Vasco · #8 (**permalink**) 11-22-2006

Zanshin,

I installed a radar arch when I got my boat and it's the best thing I ever did. Much better than davits. I have radar and a Kiss wind generator on mine and a 10'06" AB RIB with a 15 hp Yamaha on it. There are many manufacturers and I'm sure you'll be able to find one. I got mine from Beneteau (much cheaper than Wells ) so maybe you should check with Jenneau. The radar works fine on the arch no dead spots.

Zanshin · #9 (**permalink**) 11-22-2006

Vasco,

I can sort of see the arch in your avatar. Did Beneteau add any backing plates or other reinforcements when they installed it - I'd love an easy way to get the dinghy out of the water but am worried about the weight, especially in heavy seas.

Vasco · #10 (**permalink**) 11-22-2006

a

photo of when i was commissioning the boat. Didn't have the motor on the dink then but I usually sail with the motor on. Just to the bahamas.