Thanks Loren! This is very helpful to know what the system configuration is and what is behind the panel. It sounds like the panel is not required for the seat back, and you have elected to just leave it off for simplicity. Have you ever heard of corrosion issues at the interface of the steel rod and aluminum bar?
I am sorry not to be clearer, but I do keep the teak-face seat backs in place all the time. The first time I removed them to see what's back there I did take out the teak plugs over the screws. Since the the upholstery covers the whole panel except for a couple inches along the top, there was never any reason to have those screws plugged in the first place, IMHO. This way I can remove the screws and the seat backs in under 5 minutes.
See the first picture in this blog entry, after the cushions have once again been moved home for the winter.
http://www.ericsonyachts.org/infoexchange/entry.php?664-Lee-Cloth-quot-Quick-Connect-quot
Corrosion? Yes, but only if a seepage around the deck fitting is ignored. And if water runs down onto that bi-metalic interface (say that three times quickly...) it will indeed cause some corrosion.
Note that the SS Navtec rod has a couple of "flats" machined somewhere in the center of the span. It is threaded opposite-threading on each end, like a turn buckle. When the standing rig is set up, that rod can be turned to keep the side deck flat and not stressed downward or upward. This adjustment is kind of a once or twice ajustment in the life of the boat, IMHO.
This whole rigging and mast support system was very well done for its day - and even for today, and I am glad that all of the 39 Olson 34's constructed by EY were designed this way. While I have not done HI trips like several sister ships, I have had a (arrival time miscalculated by idiot skipper) rough crossing of the Columbia Bar and nothing moved/creaked/groaned on our boat when we spent a very long couple of hours doing the "up 6, down 6, 5 to the left, and 8 to the right... rinse and repeat.
Brion Toss' excellent
Riggers Apprentice book really explains how the whole rigging "gang" works and how the force is carried from shroud to hull to mast base to top of mast and back into the 'circle'. I believe that Bruce King and (for our Olson) George Olson must have also studied and understood this stuff when engineering these boats.
*Unrequested opinion: While there are some reasonably OK sailboats designed by committees of marketers and accountants.... The EY line shows the engineering and artistry prowess of a
real Naval Architect.
ps: when you replace any (!) hoses, write the month and year on the side with magic marker.... I heard of this idea from a surveyor. Replace them every decade. Cheap insurance.