Had a brain fart, so I thought I'd ask....  Has anyone used the Cortland Sylk fly  lines?  They are synthetic, but much smaller in diameter and have more suppleness in cold water than standard  fly lines. Thought they might be the cat's azz for winter (less freeze ups). I've used real silk before that was given to me, but that's on parr with staying in Jailwater and having the butler/ghillie clean, dry and store your line for you.  Sometimes it pays to have old friends. No, not ones you've known for a long time, just OLD.  I bought some Cortland trout lines a few years ago for a hefty discount and they are excellent and holding up WELL.  I thought Lucky might have tried one.....  I also see the Sylk on sale at a few places and I might visit there store sometime on a cold, slow mid-day.
Fish USA has a 7 WF for 54 bucks. Reasonable.

Charlie- It appears that the Sylk lines are designed specifically for bamboo rods. 
What lines to use and the where to's and why for's would be a good topic line. 
Too bad most companies have discontinued production of double taper lines, perfect for roll casting in limited or tight quarters.

Gerry, yeah the small dia. fits through the small agate eyes of boo, but MAYBE also has the benefit of less icing, along the lines of CandD running line. Cortland still has the 444 Peach DT, that's an awful lot of people's favorite.  I remember cutting them in half, as you only needed 20-30 feet at most for small streams. 2 for 1.

Charlie I'd imagine it would work well but I'm thinking a good loose mid belly rod would be ideal overloaded a weight or two

Don't know anything about it but your reasoning seems solid unless the line itself would hold more water and freeze.
Smooth plastic surface like most lines?

I take what I can find, and lately, when I go to the big box, it is 3M and Rio at 95.00 a pop, and if I am looking for sink tip or full sink, they have floaters, and when I want a floater they have the sinkers, ands usually in every weight but the one I need.  So, once again, I bought an Orvis line, I got one for 69.00 WF, it took about a half day to get used to the difference from my old line, which was also an Orvis.  If I can find 444's when I need a line I like them just fine, and I like Double tapers even for steelhead fishing because I can roll cast longer with less fatigue, and I can turn the line around
when the working section starts to crack up.   But lines and waders are the two biggest drags in fly fishing, the greens fees that you keep on paying.
 
I am going to be a little gun shy about exposing that backing knot for quite some time now!
 
L13

As far as I can tell, yes. The fact that they sit lower in the water may make them a little wetter on the retrieve though. More research needed. Andy, I have a old Orvis 6 wt. mid-flex  rod that would fit that bill. They make them up to a 7 and that's what I was looking to get. I also have a Winston 7 that ain't a very fast rod either.  I'll report back if I do the testing.

Lucky13
 
 
I am going to be a little gun shy about exposing that backing knot for quite some time now!
 
L13

Duder its not like you have much say in it.
10# and that hen took 15 feet of backing.
I might have set the drag a little tighter but have been trying to leave my have off the line (senior moments not dropping the slack) so they hit a tight line and the drag gives a bit as they turn.
Been pulling it away from way to many fish.
 

Charlie, I find minimizing strip in and physically making an effort to shake line off when picking up to cast helps tremendously as I assume you do. A longer rod towards 11' helps as well. I'd be interested to see and feel the presentation one could get from this line though

Andy, I went to  an 11' 8 wt. , but to tell the truth my oversize Recoil guides on the 7 wt.  10 footer really does pretty  well on the icing. I do shake 'em like a wet dog  I just hope we can walk in this winter and find space and peace. My fondest memories still revolve around days with few to no people or just a few friends. A lot to ask and hope for, but I'll keep on....
I've lost 2 Orvis Depth Charges to stripers . One wrapped the whole fly line around a huge boulder, the other hit a cross in the backing about 100' in and snapped it like a rifle shot. I've come close on Kings, but broke off before they got too dangerous. I've let a lot of backing out for steel, but it seems once they're out that far, they never come back for me.  I had one big chromer a good 200' out  in Pineville last winter that I managed to get the line back on the reel with and then  it was over. I **** near cried.