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Mast canting after sidestays are released for folding
Posted: Thu 25 Apr 13, 22:56
by EarthBM
My rough estimate is that the lenthened sidestay (when the line is released before folding) allows the mast to cant up to 13 degrees off center. In practice it's less than that because forestay tension takes up some of the sidestay slack. But still it's significant and you can see it with naked eye.
Does anyone know how the mastbase can support this movement without breaking? There is no pivoting ball that I can see, looks bolted on.
Posted: Fri 26 Apr 13, 4:42
by Double Horizon
It's just sitting on a stainless post. Compression and gravity hold it in. The 920 has a clevis pin to lock it, but the 1000 and 1200 don't have anything locking it in. Not familiar with the 28 or 35 details. Regardless, there's enough slack for it to move as you noted.
Posted: Sun 28 Apr 13, 19:44
by EarthBM
Hey Larry, looks like just the two of us on this site. Checked the mast foot better, maybe it is on a ball after all. I am just trying to figure out whether tightening the windward backstay is safe on long tacks.
Posted: Sun 28 Apr 13, 21:06
by Steve B.
Ivan,
It's fine to adjust underway.
We do it all the time.
Steve
Posted: Mon 29 Apr 13, 2:06
by Double Horizon
Yes --fine to adjust the windward stay underway. Not tighter than you can do one-handed.
DO NOT adjust the LEEWARD stay underway. If it's flopping too much you can adjust the windward side, but leave the leeward side alone. (If you adjust the leeward side, the rig will have too much tension when you tack again.
Adjusting the stays
Posted: Mon 29 Apr 13, 2:38
by Steve B.
We adjust both, but have pre made marks on the adjuster lines.
One, two and three marks for anchored, light wind, heavy wind.
Steve B.
Posted: Mon 29 Apr 13, 5:44
by EarthBM
So how far windward can the mast be canted by tightening the backstay? "In theory" (when the leeward backstay is fully slack) this seems to be 13 degrees, but that is a lot. MOD70 racing trimarans can cant the mast 8 degrees.
Posted: Mon 29 Apr 13, 17:02
by Steve B.
Just imho, but the DF1000 mast socket doesn't really allow for mast canting.
It's a square hole about 4 inches deep, made of heavy gauge stainless with several wall braces.
The whole thing is screwed to the deck with lots of fasteners.
The mast post is equally rigid.
Any canting going on would have to be something flexing.
Posted: Tue 30 Apr 13, 3:40
by Double Horizon
I agree -- DF masts aren't designed to cant.