The following describes an alternative to a tripline and anchor buoy.
Alchemy anchor float
I generally abhor anchor buoys/trip lines (unsafe and un-neighborly) and feel that getting one’s anchor trapped on the bottom is partly technique, but mostly bad luck. (Part of the technique element is to always initially use plenty of scope so the anchor sets with a minimum of dragging around the anchorage before getting a stick: dragging an anchor around hoping it finds a stick is a recipe for a fouled anchor). I use trip lines only when I know of reports of a foul bottom, and (hopefully) a night with steady wind direction and an uncrowded anchorage: rarely in other words. That said, I also wished for a plan for when the anchor does become stuck and there is no trip line.
In friendly waters I usually dove on the anchor and realized that it was a regular occurrence that all I saw was chain: the anchor was buried. Recovery is dependent on getting to the end of the anchor, attaching a line and pulling the anchor out backwards. It is also possible the anchor is tangled in a stump or some discarded appliance and getting at the end of the anchor could be difficult or take time. In warmer waters, I would be doing this free diving and only had seconds to attach the trip line, so I wished to make the finding and attaching quick and easy. Even if I put on a tank, and dive gear (if quite deep) I would want it easy to attach the trip line.
To get a line attached to the end of the anchor quickly, I attached a shackle on the end of my anchor to which I tied 6-8 feet of nylon 3 strand with an eye on the end and a brightly colored small commercial fishnet float (shaped like a small football: the US game). The float “floats” the eye high above the anchor and accessible and easy to find. In clear water, I can often see the float (bright orange) from on deck if not too deep. If the anchor is fouled, it is far more likely and easier just to dive to the float and attach a spring-loaded shackle/carabiner with a line taken back to the boat. Then from deck it is easy to pull the anchor up backwards.
The 6-8 foot line serves a secondary purpose when stowing the anchor of always being there to tie the anchor off on the roller.
My best, Dick Stevenson, s/v Alchemy
Note: With effort, I have found that most anchor foulings get free with some creative boat maneuvering. First, I let out lots of scope while moving away from the anchor in the opposite direction from initial set and slowly attempt pull it free. Next, I might try a short scope, attach a stout snubber (here you do not want stretch, but you do not want to load up the windlass) and then power in various directions taking up slack as it occurs. Pay attention as it is not likely to make things worse, but certainly possible.