Alex,
Here's a more detailed description of what I did to add a secondary mast support.
Here's a picture of the final rig;
http://odendahls.com/SecondaryStrutRig.JPG
The forward support strut came with the boat. When I bought the boat, the screws that hold the base of the strut to the cabin top were stripped. Also note that the black plastic clip that holds the strut when not in use is broken. It's possible that the screws stripped and the clip broke when a previous operator accidentally grabbed it as a hand rail, or possible they worked loose under load when trailering. I don't really know.
The set screw in the part that attaches to the mast is missing, perhaps intentionally to allow the post to slide into the receptacle that is part of the mast without the use of a hex key. Therefore, the only thing holding the mast down is gravity. I originally tied it down with some line between the mast and the hand rail, but this still allowed some movement and the support strut slipped out on a bumpy road, and the radar antenna contacted the cabin top. I saw the problem in my truck's mirror and stopped at the next exit. I replaced the line with the orange tie-down that you see in the picture. This worked for a couple of hundred miles by putting the base under a compressive load. I repaired the stripped holes with some marine epoxy putty, but I wasn't sure that I had really addressed the root cause of the problem.
I wanted to be confident in the strength before driving cross-country, so I went to Custom Canvas and Awnings in Henderson, Nevada to fabricate the secondary support strut. Coincidentally, there are pictures hanging on the wall in the shop of David and Maureen Baker's former R-25 Solitude and the bimini that Custom Canvas built for it.
The additional bracket is a split clamp that is attached to the mast just above the original.
http://www.odendahls.com/IMG_1354.JPG
The base of the secondary strut is a quick release swivel that releases with the push of a button.
http://odendahls.com/Strut%20Base.JPG
The top of the secondary strut attaches with a clevis pin. The strut is removed and stowed below when the mast is up.
http://odendahls.com/ClevisPin.JPG
I've added a little gorilla tape to secure the clevis pin from road shake, but am considering replacing it with something that is secured with a split ring.
http://odendahls.com/ClevisPinwithTape.JPG
You can also see that I've just tied off the extra length from the orange tie-down rather than cutting it off.
I have about 2000 road miles on this rig and it is working well.
The parts were around $100.
Hope this helps.
Rich
