suggestions for mounting an 18" radar dome on A27

[rockycoastcruises]

I need to mount an 18" Garmin Fantome18 radar dome on top of my A27 Sport pilothouse. I'm not interested in storing or carrying anything on the roof so I am planning on placing the radar directly onto the front edge of the pilot house roof. In this way I can run the cables under the lip of the roof and directly into the dome without drilling large holes in the roof inside the pilothouse (other than the holes for the mounting bolts). It will also fit nicely right in front of the anchor light so that doesn't have to be repositioned. It appears that the roof is sitting at an angle so the rear edge will most likely have to be raised to keep it level. I'm not worried about an angle created by the boat underway as it doesn't appear that while cruising at 7+/- knots will raise the bow any.
I am looking for any opinions on my plan for mounting this radar and if you have already gone through this exercise I would appreciate knowing what you did and any suggestions that you might have.
Thanks,
Joe

[dkirsop]

You probably will have to adjust and shim the final mounting angle for maximum performance. My radar had excellent rear view vision when I bought the boat but had myopic foresight. It was tilted too high when under way. A slight adjustment of the angle with some shims balanced it out nicely. It is a trial and error process as every boat sits slightly differently in the water when under way.

[WillieC]

Joe, I am going through pretty much the same process on my 25. My aftermarket BC Hardtop is my base and it sits fairly parallel to the waterline, but ever so slightly with an aft tilt. I have the top off and in my shop so I have free rein to wreak all kinds of havoc.

Anticipating needing to shim the Scanstrut riser base I am installing under the 18" radome, as well as providing a flat base for the riser, I poured an epoxy base big enough to accept the bolt pattern of the Scanstrut base. Built into it is about a 1/4" differential, thus tilting the radome slightly forward.

Like so:

IMG_4641.JPG

IMG_4642.JPG

I am only guessing on the angle of the dangle here, but one can hope. I think there are three, maybe four pumps of epoxy here and I could have done better with getting it at the level I wanted. My tape damming was weak also. I eased the edges of the form pieces in contact with the slightly rounded hardtop with a 1/4" rounding router bit. You might see the result in the second pic.

This was a fair bit of fiddling around but hey! It's not May yet! Need to deblush, finish sanding and touch up, prime, paint, etc, etc...

There are also factory shims you can buy for some 70-80 bucks. Each. I may still need to play with it once it is in the water. Mr. K is correct, again.

Note: this little project required getting the hardtop tilted so that the finished level of the epoxy was level. It seeks level quite nicely when pouring but you don't get to play with it much once it is poured.

[tego]

Joe, That's exactly how mine is mounted. It sits about 14" back from the front lip edge. I have a tilt-down mount for the unit. It's an older Raytheon unit but it works great. I made a teak overhead console for the radar, VHF, chartplotter, and DS/fishfinder. It's tilted forward a few degrees so the radar picks up small close-in objects but still gives me a good view aft. Ben "87 27FC

[Kkelly27]

Here are some pictures of my setup that may help. It's mounted on the roof overhang on an adjustable support that goes over the front running light so that it's not blocked (not the anchor light which is on top of the mast). If oyu zoom in on the night photo, you can see where the radar barcket is attached. The wiring is run inside the roof above the liner and comes out of the roof over the cockpit, not the overhang. Tthe monitor is mounted in the upper right corner.

[WillieC]

Nice adjustable mount you have there, Kelly. There you go, Joe!