Home made radar dome mount

SENSEI · Posted: Wed Aug 22, 2018 9:52 pm Post subject: Home made radar dome mount

Several years ago thataway Bob posted a tutorial about using toilet flanges to build a radar dome riser. I cannot find it and am asking if Bob could do it again or help me find the thread

Wandering Sagebrush · Posted: Wed Aug 22, 2018 10:41 pm Post subject:

This? http://www.c-brats.com/viewtopic.php?t=10014

thataway · Posted: Thu Aug 23, 2018 11:09 am Post subject:

Hi Roger,

The "Commode mount" is illustrated below:

The basis is two 3/4" "water closet" PVC plastic flanges, which hold the toilet to the floor. The center post can be 3 or 4" PVC Schedule 80 pipe. I have made at least half a dozen of these, and the original was on a trawler almost 20 years ago and is still in service. The design came about as a friend was visiting and we went to the local scrap metal yard to find materials--nothing suitable in Aluminum, so we tried the plastic.

I bolt it direct to the cabin roof. All bolts are machine screw flatheads, so that the surface is smooth. The upper mount the machine screws heads are counter sunk into the Starboard, and Nylox nut on the bottom. You can prepare a flat surface, on the C Dory roof, but the PVC is flexible enough to accommodate the C Dory camber. I used 5/16" bolts and fender washers under inside the cabin on the lower mount, as I recollect. The top platform is either a thick cutting board of high density polyethylene from Walmart, or Starboard 1/2". The more recent ones have used the Starboard.

The height can vary, but the one shown is 12" for the radar beam to clear the air conditioner and loud hailer (also a GPS antenna on the Tom Cat). I probably would not go more than 18". You can put a "down slope" to the beam, if you wish--I have used stacked washers or Starboard wedges to give a 3 to 4* down slope to account for the bow rise when gong faster. However most of the time I am going slowly when under radar, and don't need a wedge.

The extra grooves in the base can be filled with 3m 4000 or the similar Loctite Marine PL adhesive / sealant. Paint is any of a number of "plastic" spray paint. I have used Rustoleum all purpose or Krylon Fusion. Both will give a good finish.

South of Heaven · Posted: Thu Aug 23, 2018 2:08 pm Post subject:

Wow, that looks nice too! Doesn't look like a commode mount! Very cool.

croakz · Posted: Fri Jan 14, 2022 10:37 pm Post subject:

thataway · Posted: Sat Jan 15, 2022 2:20 pm Post subject:

I know that John Highsmith's (Cat of Mine's) mount gave up after a few years. I don't know if it was painted or not (Painting will help prevent any UV deterioration of the PVC plastic and mine was painted. We don't know where the 255 I owned is, so we cannot query the current owner.

For a small dome, it would probably be OK--but if you go to the 24" dome, I would try and find the Schedule 80 pipe.

gulfcoast john · Posted: Sat Jan 15, 2022 3:50 pm Post subject:

Mine was painted with Krylon gloss plastic paint and looked good. The failure point was just above the roof flange.

I couldn’t find any schedule 80 PVC pipe or fittings either, even special order. If you decide to go with the regular PVC, you might consider just replacing it every couple of years considering how cheap it is to minimize any fatigue issues.

If you’re not putting anything else up there (the roof looks bare in your album photo) you might consider mounting your radar to the roof without a post. The post wouldn’t add much to your radar range. You may need to experiment with shims for the best result. Keep any GPS antenna out of the beam (at least for old magnetron units, I’m not sure about the newer broadband/digital radars).

I eventually found the most varied choices (I needed a 16” mount with a 15” rooftop Coleman) at Hodges Marine.

https://www.hodgesmarine.com/boat-accessories/antennas-47-mounts-mounting-solutions.html?brand=481&utm_source=bing&utm_medium=cpc&utm_campaign=Search%20-%20Antennas%20%2F%20Mounts&utm_term=SEAVIEW%20RADAR%20MOUNT&utm_content=Mounts%20-%20Seaview

Good luck with your project!

John

ssobol · Posted: Sat Jan 15, 2022 4:12 pm Post subject:

What about doubling up the PVC pipe? Get a size that fits inside the desired exterior pipe size and glue them together (just run some acetone down the join).

colbysmith · Posted: Sat Jan 15, 2022 5:52 pm Post subject:

croakz · Posted: Sat Jan 15, 2022 11:27 pm Post subject:

Thanks all. Not much room to mount on my roof anymore. We put a Thule roof rack on there to put a Sea Eagle kayak and temporarily our camping stuff when we use the v-berth for sleeping instead of storage.

http://www.c-brats.com/modules.php?set_albumName=Jolly-Blue&id=c_dory_roof&op=modload&name=gallery&file=index&include=view_photo.php

I'm thinking of mount a DIY or premade radar mount in the roof rack now. My Furuno DRS4W doesn't weight a lot and I think I can secure it to the roof bars. Hopefully this frankenstein project works out!

- tom