Radome Mounting on T Top

[thedink9]

The snow is almost gone and I'm getting ready to mount a 18" radome on top of my T Top, on my 23'. Question is should I be considering one of the struts made for raising the dome off the roof ( I'm thinking of a 5 1/2" model) and if so what forward tilt angle should I go with (5 degrees or more??? Dink

[ocuyler]

Dink,

First, I would consider what the overall height will be AFTER it's installed to be sure it fits where it needs to. I've seen them both ways. I, personally, like to keep the overall height of the boat as low as possible.

I think you have to split the difference of the angle of when you are underway and drifting/off plane. You may be able to not use a strut and shim the back bolts with plastic spacers.

[ScottM]

Rich,
If you go with a strut, just make sure none of your antennas or outriggers are in the beam path of the radome. I have a couple friends that have radomes mounted directly to the t-top just using a shim/spacer and they don't have any issues with the dome providing poor readings. I think if you mount it towards the forward edge of the top you'll get the best results. Check with your radar manufacturer to see what they recommend for an angle.

[SEAFARI]

Rich,
Check out Scott Patton's radar arch, I had that custom
made when I owned that top and made provisions for
the anchor lite and the Furuno mushroom (Edson Arm)
I got the angle where I wanted it(fog speed) with
a level before I had it welded.
BTW, I recommend the Furuno CRT displays!

R

[Scott]

Reading Rodneys mind [img]/images/graemlins/smirk.gif[/img] [img]/images/graemlins/smirk.gif[/img] [img]/images/graemlins/smirk.gif[/img]

Dink … My opinion
Since Radar is line of sight you want it as high as possible …not that a strut will get it up that much further.



You can have the GPS mushroom mounted off the anchor light masthead (there is an Edson mounting arm



that clamps right where that TNC/BNC connector is coming out of the mast).

I think this one has around a 4° pitch built right into it. No wedges or spacers ... I'm biased ...but this is one of the nicest setups I've seen.

[cSickNick]

Hey Dink,

- use a wedge angle to keep the radar beam parallel while running at slower speeds

- If you want to mount the radar close to the top, mount forward as possible. But you will have to mount GPS, and anchor light higher.

- If you mount on a (say 5", with wedge built in) strut, you can mount more in the middle or back more on the top, and can mount GPS antenna lower on the top, but you still need to get the anchor higher than the radar dome.

... like others stated .... - Nick

[ocuyler]

Scott has an ideal set-up. What is the min. bridge clearance on the the trailer?

[thedink9]

Nick /Scott

I understand the interference issues with mounting the other equipment on top, and my only other question relates to how much tilt angle I need to figure in. I was thinking about a 5inch high strut with a 5 degree forward tilt to account for the running angle of the boat at say 10 -15 kt's, which would be a reasonable speed to run at in fog.
Any thoughts? Dink

[cSickNick]

Dink,

5 degrees sounds standard, and my 10" mount from http://www.eastshoremarine.com/dimensions.php is 5 degrees.

I was concerned more about the height and angle to see over my front top mounted remote spotlight.

I ran all sorts of calculations to determine the min height of a radar mount to "see" over my top mounted spot light at 8" away with radar beam running down at 12 degrees …. Just to prove that I graduated from Ulowell Engineering …. Figured something like I would need 9.5" mount ….. 10" it is!

The reality is that 5 degrees with a little boat roll up and down will run and detect fine for most tops. If your top has a severe rake, you might want more.

The fog density will obviously determine a safe speed.

Good luck Nick

[thedink9]

Nick

Thanks for the input. My radar mounting plate is located on the forward third of the top so I'm thinking about the 5 inch strut with a five degree forward tilt. I'm just guessing that the boat running at 10 kts. or so will not be running very bow high, so the 5 degree rake should be adequate. Does this sound realistic? Dink