When I had a Gemini 105Mc I could back up to a tree and anchor in 2 feet. Not that we did all that often but...
I've held up to 17 boats (over 150k pounds) on my 25 lb danforth the trick is to give it time to settle in and dig.
Even the 'next gen' anchors that are deep diving designs need time. If you aren't actually drifting, just wait.
Now on the Irwin 38, I have no windlass. I typically wander up to a cruising boat (like Xort's who posted above), throw out a fender and dock to them. Of course if you don't know them before doing this it might be cause of a slight problem, or it might be a spontaneous party. Hey, it's not your fault they weren't listening on the VHF when you asked for permission to raft up