I replaced my anchor with the rockna last year. Had to replace the bail on the roller with a larger bail and the anchor has worked out great on my 2000 mk ii (1896)

I have a Rocna 44lb (20 kg) on my bow. It rests just fine, but the problem is clearing the furler. I think want to experiment with a roller above the anchor, but I'm not sure how this will work. I videoed the anchor deployment and retrieval so that I could study the motion on my computer. Maybe I can figure something out. I'll tell you, 44 lbs plus over 100 feet of chain is one helluva load for a single hander to deploy, not to mention retrieve.
 

Haro, thanks for that photo. Yes, that's along the lines of what I was considering. I'll try that out. And I am hoping to add remote windlass control as well. 

If you're still reading, Ron, how did your Rocna 15 work for you, and did it fit with the C36 II bow arrangement?  What are your ground conditions, and do you find the Rocna 15 adequate?

I put a Rocna 15 on my 1993.  It rests fine with no modifications.  It's a little difficult to get under my furler drum, but really no more difficult than the Danforth it replaced.  The anchor itself has set perfectly every time so far.

I installed a 15kg Rocna this spring.
I replaced the original bail with a larger one - then moved the original bail to just under the furling drum (where it lines up with the point where the Rocna just begins to narrow...   this keeps the anchor shank from banging into the furler (which the CQR always did...).
I am posting the original CQR along with the new Rocna (before installing the original bail under the furling drum...)

I'll begin by saying that the fellow we bought Southern Comfort from at the very end of 2014 was smart, experienced, meticulous, and researched everything that he did to the boat.  He bought a Rocna 15 and used the Delta as a secondary anchor.  That, by itself, gives me cause to recommend it.
 
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There was a hellacious storm on the East Coast on June 23, 2015.  We were returning from a short cruise down the Chesapeake Bay and had tucked in at Lewisetta (Coan River) on the Virginia side of the Potomac River.  I had set the Rocna before the storm hit, but as I was setting the Delta, the lightening began and quickly became severe.  I didn't take as much time on this second anchor.
 
Reports claimed that the storm was 100 miles wide, and it was clear that there was no chance that it would miss us.  It was traveling at 30 mph  with winds of 70 mph.
 
Let's say that we were concerned.  We donned our best life jackets over foul weather gear, put on hiking shoes, packed a few water bottles, a little food, our cell phones, and wondered silently why the hell two Medicare recipients were on a boat in the middle of such a storm.  The water depth was about 8 ft, and we were only a few hundred yards from the lee shore, a sandy beach with a low cliff leading to what appeared to be uninhabited farmland.  We figured that if we dragged, we would wait until we were aground then stumble onto the beach and make our way to civilization, using the phones if we had towers.  We had matches and a couple of those aluminum blankets.  In other words, we would have drown in two feet of water, dragged down by our supplies and excessive clothing.
 
We sat up until almost midnight at which point the wind had died down and we were still afloat.  The next morning, we found that the Delta had dragged [may have been my fault], but the Rocna had held fast in the clay bottom.
 
I've never been able to learn just how fast the wind was that night, but the experience has given me confidence in the Rocna. 

Oh yeah, it fits fine, but bangs the furler drum if I'm not careful.  I have some 1/4" bungee that I tied loosely below the drum in hopes of leading the anchor home without a crash, but it sometimes catches on the swivel.  My plan this year is to raise the anchor so that it is just on the roller, and then lean over with a boat hook and bring it up the last bit manually.  
 

Thanks for the feedback, guys.  I love the pictures.

I contacted CMP/Rocna to ask for a recommendation and they suggested the 20 Kg, but said that the 15 Kg was acceptable if not planning to anchor in 50 kt of wind (who plans on that?). Based on their sizing chart, and the feedback from this group, it appears that 15 kg is acceptable. I'm going to the boat tonight to measure the distance from the roller to chain locker and under the roller to the bow. Howard & Lin's photo seems to indicate that there is plenty of room for one inch more on both measurements.

As preparation for my Inside Passage cruise I upgraded to a Rocna 20kg. That's 44 lbs! My total rode included 100 feet of chain and 300 feet of rope. Somewhere in the cockpit locker I had a secondary anchor, but never had any reason to think about it.

In my 4 1/2 month trip covering almost 3000 nm, (May 16 through Sept 30, 2017), I anchored numerous times. And NOT ONCE did I have to re-anchor because of a bad set. And NOT ONCE did I drag.

In the Pacific Northwest, Alaska, and Western Canada waters this Rocna did yeoman service. Un-damn-believable hooks with my 19,000 lb boat. Several times I had to anchor in 90+ foot depths, and rarely did I anchor in anything less than 50 feet. Only when I returned to the Columbia River getting near to home was I able to anchor in a sand bottom.

OK, it hits the furler drum, which means that every deployment and retrieval I have to get out there and carefully lift it around the drum. Also 44 lbs is certainly a tough load for an old fart to schlep around the furler. Yes, it's even tougher when you're solo on the boat (I was solo for 2400 miles) anchoring in wind, because that can cause a lot of scampering between the bow and the helm.

But I love my Rocna. Love it. Love it. Love it.

[PS: I have never in my life slept the whole night through when on anchor. I always set an alarm to do an anchor check at least once or twice a night.]

Good to know, Larry.  BTW, I have this photo of how a 20 kg Rocna sits on the the bow roller of a C36 Mk II.  No problems with fouling the deck, but I do have the same issues Larry has with the shank hitting the bottom of the roller furler drum on recovery.  Also, it invariably comes up backwards which causes some maneuvering with the boat hook as it's hanging by 6 feet of chain from the front. I don't have a swivel due to fears of swivels breaking that I've read about - perhaps an excess of caution.  Anyhow, I'm very happy with the anchor, and am happy to hear that it performs so well under very difficult circumstances.
 

I don't use a boat hook for retrieving the Rocna anchor. 

I use the windlass to bring it up to the bow roller where the anchor hangs vertically. From that point, if necessary, I twist the anchor chain to cause the chain to rotate (to 'jump' in 90 degree increments) until the shank is aligned properly. Then I lift the chain to 'wrangle' the shank past the furler.

I lead the chain straight back to the windlass. The chain fall from the windlass is wrapped around the cleat inside the locker. That's the stowed position. Finally, if going out in the ocean for a passage I use a short piece of line to make doubly sure the anchor doesn't go walkabout at sea.

I use my trip line that is attached to the anchor to twist the anchor to the correct orientation then using the windlass I pull in the shank. The roller that I have installed prevents damage to the furler. See the image above.

There is a survey on the site that may be of use to some members when making the New Anchor decision.  https://www.catalina36.org/sites/default/files/legacy/Catalina%2036%20An...
Only available to members though.
Would be nice to update that document to keep things more current.