Here's a 22# Rocna coming up (for it's first overnight stint on the bottom) and how it fits on the old toy bow rollers.
Our old Bruce 16.5# is on the port side and "protects" the hull from the new longer Rocna. I've since removed the old Bruce and use it for a stern anchor, and moved the Rocna to port. We added a port cleat, but still kept the middle factory cleat, so a port side anchor works best for us with the two cleats we do have. I'm considering either what Craig did, or just biting the bullet and adding a small stainless plate to the bow.
We bought this at the suggestion of Maine Sail who did a terrific writeup - search for "Rocna" and read his contribution (#33 page 3 at:
http://c34.org/bbs/index.php/topic,2705.0.html) . I wrote him offline:
"I bought the 22# having experienced over 25 years sailing here that I would not require anything larger. Long story, doesn't involve windlasses or bad backs, but just the places I choose to anchor and the way the weather works here - we just don't get those afternoon thunderstorms, etc.
"Well, you were spot on right about the anchor. I haven't felt an "I gotcha bottom" like that since [forever]..." We have 30 feet of 1/4 chain, I bought an anchor connector between the chain and anchor, but still have a shackle on the rode chain joint, but will do a splice there to get rid of the big shackle. I used 3/8 chain in these pictures, but it's too much for the "system" and having Calder's "Cruising Handbook" I designed the system with the appropriately sized components - only the 3/8 rode chain shackle is overkill. 42 knot wind design with anchor, chain, connector and shackle.
A big advantage of the longer bow roller is keeping the beast on the bow. We use a line tied to the stanchion and the roll bar of the Rocna. While I don't have a picture of the latest final install, the shank does come back a teeny bit aft of the anchor locker doors, but the shackle hole is a short slit, not just a hole, so the connector ends up dropping straight down into the locker with the chain. Interesting and great physical serendipity.