Radar question

Avidmagnum12 · Posted: Wed Oct 05, 2016 8:25 am Post subject: Radar question

I've never had radar on a boat but now that we are spending months boater homing we've decided to have one installed on our 25. We are going with the Garmin 18 xhd which will integrate with the 4208 MFD that came with the C-Otter. Marine Metals at Williston Florida will be fabricating the mount. The mount will need to pivot the radar in order to have clearance to fit through my shed door.

Now for my question. Will the present location of the all around light (For me the anchor light) cause a problem with seeing forward with the radar? I've seen some photos on this site where they stay there but many folks add a light on the rear of the radar riser mount. Thanks in advance...Tom

South of Heaven · Posted: Wed Oct 05, 2016 9:12 am Post subject:

Tom,
My new radar is a couple feet behind the anchor light. I was told that was the best spot for it. If you want yours closer to the light then maybe you could "shim" it somehow and get a higher angle, if you think that you need that.

Avidmagnum12 · Posted: Wed Oct 05, 2016 10:03 am Post subject:

Hi Jason
Great looking radar on your boat. I need to put mine forward so that I can still put my dinghy on top and so that it can be rotated forward for door clearance. I will be using a riser to raise the radar about 6". This will put my anchor light about a foot or less away. Of course durning the day it can be removed. However with the new radar we may run more at night than in the past. I'll add an all around light on the rear of the riser for my enclosed radar if I must. Just don't know for sure what the effect that close will be.

Sounds like you're going to be putting your 25 away for the season. You may want to consider trailering down to Florida next March for our Hontoon Island C-Dory gathering. We get "brats" from all over. The St. John's river is a great place to explore.

Thanks....Tom

South of Heaven · Posted: Wed Oct 05, 2016 10:13 am Post subject:

thataway · Posted: Wed Oct 05, 2016 10:34 am Post subject:

Tom,
The anchor light stanchion will present no problem, because of the width of the magnetron. (18" vs 7/8"), so it will see right thru it. I have had aluminum masts which were about 8" x 12" and no effect on the radar. One of the other keys is that the objects are round, and prevent little echo surface.

I would suggest if possible to go with the Garmin 24xHD, it is a generation newer than the plain 18HD.

My experience with small boat radar spans over 35 years, and a number of vessels.

Avidmagnum12 · Posted: Wed Oct 05, 2016 11:45 am Post subject:

Thanks Bob

I know with radar "bigger really is better" but I have already paid for the Garmin 18 XHD radar. At least it is the newest model. I'll skip the light mount on the riser and stick with my original light. My boat goes to Marine Metals next Monday for the folding mount if Hurricane Mathew does not mess things up too bad around central Florida. I'll be securing things on Thursday.

Troy said he would have the boat done by the end of the week. IF THAT HAPPENS we would be able to make the Apalachicola Gathering if you still have space. Had a great time last year....we were just hoping to get some Florida Keys SCUBA diving in this fall. Not going to happen with the weather.

Jason...we always get some north east brats to join us. It's a drive but I tow my boat to Lake Superior every year for some summer boating. No excuses! Smile

hardee · Posted: Wed Oct 05, 2016 12:18 pm Post subject:

thataway · Posted: Wed Oct 05, 2016 1:45 pm Post subject:

Tom,
As long as you are getting the xHD in the 18, it should be good. Just a little better discrimination with the 24".

Yes, any radar reflector will help. We found that with the newer radars, we can pick up some really small targets. I was using the 1996 JVC radar on my son's 25 this summer, and it was amazing how good it was for a unit that old. (Probably not used much!)

The simple "Davis Echomaster" ion the "Rain Catch" position under an radar arch is both economical and reasonably efficient. To beat it you probably will have to go to the $900 large "Tri-Lens" reflector--which is about as large as the radar dome!

We used something equivalent to the current large EchoMax (29" long: x 13" diameter) on our large ketch. This was up about 50 feet off the water, and we could be seen by large ships at a range of 13 miles. For most of us, a range of 3 miles is all we will worry about.

Tom, Hope you both can make it to Apalachicola! We also hope that there is no hurricane damage in your area!

journey on · Posted: Wed Oct 05, 2016 5:55 pm Post subject:

South of Heaven/Jason, that's the first C-Dory Ive seen with a 4' rotating antenna. Awesome, but overkill.

Boris

South of Heaven · Posted: Wed Oct 05, 2016 5:58 pm Post subject:

rogerbum · Posted: Wed Oct 05, 2016 6:12 pm Post subject:

Kushtaka · Posted: Wed Oct 05, 2016 8:22 pm Post subject:

Sorry if I'm repeating what you already read.

I have that radar on a boat at work and have similar lights, etc. a dinghy with aluminum oars attached, spotlights, and other antennae and it doesn't bother the radar a bit.

Radar can't really see round things very well. It likes flat surfaces and right angles.

hardee · Posted: Thu Oct 06, 2016 1:04 am Post subject:

I believe that the radar can see round things, but you are right, not so well. I think the real difference maker is how close they are. Anything within a certain distance, like 10 feet or something, is not imaged, as the return is too soon. I don't know exactly how it works, just that it does.

Harvey
SleepyC Moon

Avidmagnum12 · Posted: Thu Oct 06, 2016 2:48 pm Post subject:

Thanks for all the information. I knew that I could get the help I needed from fellow brats! I'll post photos of the radar setup when it's done.

Back to hurricane prep.....glad I don't live on the shoreline! But one never knows.......Tom

JamesTXSD · Posted: Thu Oct 06, 2016 5:39 pm Post subject:

It's not just what the radar "sees," it is also what can see you... as in: is your anchor light still visible all around, without being blocked by the radar? Our 25 had the tall radar arch, and needed the anchor light behind and above the radar dome in order to be seen by other boats at night. The stock light would not have been seen from behind the boat.