Alchemy has a really nice
rear end, er, stern. But this leads to a problem in that we have all sorts of stuff hanging off it. MOM module, Lifesling, stern anchor, GPS, VHF, outboard mount, etc. The problem is that Alchemy’s skinny butt means that there is not enough room to mount it all on the small stern rail.
So, we contacted Atlantic Towers and purchased one of their aluminum radar arches.
The arch came in three pieces which were in a massive box. This being Vermont, our dirt road was closed and the diversion was even more of a dirt road. The 18 wheeler truck being unable to make it, we had it delivered to our local general store. They joys of living in the country!
The arch didn’t really have any installation instructions, but with the help of a couple of able crew, we muddled through. Here are the highlights of the installation and a few tricks we learned.
There was a grainy installation video for a powerboat, and it suggested measuring and gluing the arch on the ground. Here you can see that we had to squeeze the arch in between the existing stern rail and bimini fittings, and so we decided to press fit it and then hoist it up to see where it goes and what to cut.
We put the arch together while it was lying on the ground. We left all the plastic wrap on to keep the scratches to a minimum.
Another tip we figured out was to stick some socks over the ends to stop the sharp ends of the feet scratching the deck. A quick bit of duct tape to hold them on.
We also held the two side sections together with a strap. It turned out that this was not needed at all as pushing the sides into the middle platform piece made an extremely tight fit. So tight, it was very difficult to move it. Next time it would have been a good idea to squirt some kind of lubricant inside the fitting to make adjustment easier.
Getting the final placement was difficult. We had to cut several inches off one of the legs to get it “flat” and had to haul it up and down about six times to make the various adjustments.
One challenge was the idea of what is “flat and level”. The boat is on the hard, so using a spirit level isn’t much use. In the end we more or less eyeballed and measured from the lubber line (the water line) to at least ensure aesthetics. We figured when we mounted the radar, we could use shims if we had to (amazingly, we didn’t have to, it was perfectly level in the water!)
Now we had each foot marked where we needed to fix it in place. Here the Atlantic Towers video went crazy with the drill and silicone caulk. I was a bit horrified by that and wanted to use the method outlined by Compass Marine, his excellent article on sealing the deck.
First drill holes a few sizes larger than the final ones you will need for the bolts.
Then put some duct tape around (and underneath inside), we are going to fill the holes with epoxy, and then redrill the smaller holes. This seals off the deck with a ring of epoxy.
Here you can see the holes filled with epoxy.
After re-drilling, you can see a small ring is made that will seal the deck.
Use butyl tape to cover the mounting feet and seal. Don’t use silicon or caulk!
When the backing plate is tightened, the butyl is compressed. This is after cutting away the excess
At this point we had fixed the rear feet only. Leaving them just press fitted, tip the arch back and then mark and drill the front mounting feet
The exact same procedure of epoxy and butyl is used for the other feet. Once all four feet are mounted, the instructions call for gluing them in place and tapping the ends to install a locking screw.
The sail arch is now mounted on both feet. Here you can see it just after launch. We used the narrowest arch, and the one that was offset in order to accommodate our small stern. The sight lines flow quite well, as it is the same scaling from dodge, to bimini to arch.
They are easily strong enough for two men, or a small boy jumping off.
So the Atlantic Towers Radar Arch was easy(ish) to install, good looking and affordable. Highly recommended.
But there was a downside to the story.
The photo right shows what you get (instructions not included).
I figured the bolts are a few bucks. The post stock is less than $50. This implies that the curved washers are about $30 each and must be custom turned by vestal virgins who feed on caviar. I don’t know what else explains the price!
And the bolts were too short, I had to go buy longer ones anyway…