'06 320EC radar dome height and mounting angle

Itzken

Please advise a radar dome mounting tower height and mounting angle which work well with the '06 Rinker 320EC.  Available towers seem to be 6 or 12 inches, and many come with a 4 degree top plate mounting angle.  This is a Great Lakes boat, 5.0 Volvo DP.  

Michael T

Raymarine has suggestions regarding "shimming" of their units and West Marine and Defender Marine sell set shims that will give you a proper angle. The idea is to have the radar shoot level with the horizon when you are on plane  with the bow up slightly. Your manufacturer could give you a rough guideline and you might have to adjust that based on your boar's  "usual" attitude when on plane. 

Itzken

My boat is out of the water, and I have no idea what the "usual" angle is at the top of my arch when the boat is on plane, or what experience anyone has had with mounting the radome on the arch, with a 6 inch tower, or with a 12 inch tower.  

Serenity

I own a 2005 320 have a 12 inch tower and no shims. I am running a Garmin 18HD Dome with a Garmin 741xs unit. I am out a lot at night during the season and never had any issues. Works great.

TonyWalker

I had the shim taken out from under my radar antenna.  I figured that if it was important to run the radar, the boat would be at trawler speed anyway running pretty flat.  Did it make sense for me to do this?

Tony
Salt Shaker 342

Dream_Inn

No shims on mine either and I can tell you I've tweeked my radar that I can not only see the "V" shaped wake trail behind me but I can also see any buoys in the water. (of course, radar is in my line of work)

Itzken

Serenity said:

I own a 2005 320 have a 12 inch tower and no shims. I am running a Garmin 18HD Dome with a Garmin 741xs unit. I am out a lot at night during the season and never had any issues. Works great.

Thanks Serenity.   You've got the same Garmin 18 HD system I'm looking to install in my '06 320.  The towers I've seen have a built-in 4 degree angle before adding a shim.  What tower are you using, part number, manufacturer?  I'd love any pictures.  Did you install or have it done?  Any tips?

Serenity

It was installed with a Raymarine Dome when I bought the boat 10 years ago. The boat is covered now but come to think about it--there is a slight angle to the tower. I upgraded last Spring with the Garmin and absolutely love it. I also moved the unit up on the dash from the location left of the wheel and lower to the right of the wheel covering the cup holder. I am six foot and stand when I drive the boat. It was a pain to always bend over to the side to see the screen. Best move I did. At the same time I threw out the Faria gauges which I sent back to them three times for there lifetime guarantee which cost $100 each time. They never worked so I installed all Smartcraft. Amazing the difference. Here is a picture of what I did.

Itzken

Nice layout.  I'm also over 6ft so might mount the Garmin over a cupholder but maybe on the left so my co-pilot can diddle with it.   Most towers I've see have a built-in 4 degree angle so I think I'll start there.  What bow thruster do you use and would you buy the same thing again?  I'm looking at SidePower and thinking of mounting the joy stick where the stereo control is, then relocating the stereo control.  I just bought my 320 in October and had it trucked to Michigan from Ontario, so no real time on the water yet.  

Serenity

I have the Vetus 55 electric. It is great. Where my slip is--I back in against the bulkhead. Every afternoon the wind kicks up over the Bay from the ocean and the way my marina is laid out--the wind shoots down like a funnel. No matter what I did--I could never compensate quick enough with the ios. I had inboards in the past and never had an issue since the props were much larger and more spaced apart. In a perfect no financial worry world--Axius would be the ideal fix but who can afford a new cruiser with the Axius. This works for me.

Itzken

Plus inboard props are well ahead of the transom so your pivot is closer to the center of the boat.   Crosswinds are a PITA backing in.  

Itzken

OK, Garmin radome is on the boat with a flat 5 inch SeaView mount.  Its going to need at least the 4 degree shim.  

frodo13056

@Itzken - I have a 2008 320 with the Seaview 5" mount and use the Lowrance radar and have never used a shim. In the Lowrance radar setup software, it allows you to "tilt" the beam to compensate for a non-level mounting position.  I've never had any issues with not being able to "see" things including channel markers, small boats near me, etc. Not sure what Garmin uses but there should be a software setting to allow you to compensate for your angle. As you can see from my picture, my radome is probably at least 5 degrees off.

LaRea

TonyWalker said:

I had the shim taken out from under my radar antenna.  I figured that if it was important to run the radar, the boat would be at trawler speed anyway running pretty flat.  

When I cruise at night, I'm usually on plane, so mine is optimized for that condition.  But a boat with properly trimmed sterndrives stays pretty close to flat compared to inboard-powered boats, so the shim angle is not that big a deal either way.

Michael T

On my EC 360 it was shimmed forward.

I thought that was a mistake and argued my point with the dealer. They said they'd take the shim out if I really wanted them to but asked me to please do some checking first.

Not sure how many degrees it was shimmed but I suspect 4.

I spoke with Rinker who factory installed the Raymarine, Raymarine HQ and a Power Squadron Radar Course instructor.

They all said most cruisers and certainly my (former) EC 360 runs on plane run at 4 to 5 degrees attitude..... and that I should shim your dome at about 4 degrees.

I put a plastigauge - as seen on all of the boat test captain reports - on my EC 360. It ran at 4 to 5 degrees of attitude when loaded with fuel and water, the goods for the Admiral and I at 3400 rpm - properly trimmed according to the highly accurate Vessel View 7 System. 75% of the time I used the Radar the boat was on plane at 3500 RPM. I used the Radar whenever I was out the boat. The other 25% of the time I was at displacement RPM of about 1200.

If I had pulled the shim I would have been shooting the location of sea gulls 75% of the time - when going faster.....and IMO going faster is when the radar really shines as at 35 MPH with a boat I NEED a forward look..... at 5 MPH it's just nice to have a forward look.

At displacement speed it was not nearly as important to have accurate radar for MY uses.

Only once have I been caught in "soup" where I had to go slow - because I listen to the weather forecasts, go to the VHF for the area I intend to boat and use the Radar to see what's ahead.

Yes, one can get caught by surprise despite one's best plans, but I don't adjust anything for the 1% of the time that is exceptional. In a case like that I take other known marine measures to stay safe.

IMO shim it for on plane speed if that's what you do the most of and want the safety of forward vision at speed. 

Itzken

Thanks for the thought that went into all these comments.   I've been on Huron, St. Clair and Erie for 19 years without radar so I'm a novice to the technology.  It just looks to me like I should go ahead and give my Garmin the 4 degree tilt and learn from there.