Thing is, a sandspike is an additional piece of equipment, in addition to the requisite anchor. If your engine(s) die 100 yds off a rocky jetty with wind and waves pushing you toward the rocks, a sandspike isn't going to help. ROBYW1 will need a good anchor, and good technique, if only for safety.

Now that is a lesson in anchoring!!!

ANCHORING LESSON 101
 

First off, I have no experience with the box anchor that ya'll are talking about and don't even know what it looks like, all my experience is with either a danforth or a Fortress.

It is simple geometry! You have to let out enough scope on the rode to allow the flukes of the anchor to embed themselves in whatever medium you are anchoring in. The angle between the anchor rode/shank and the bottom must be less than the total angle between the rode/shank and the flukes. This will allow the anchor to bury itself in the medium. You can compensate with chain to help hold the shank down while setting the anchor, but nothing helps more than enough scope. If you look at page 256 of the 62nd edition of Chapman's you will see how an anchor is suppose to be set. Once set the only thing you should see on the bottom is the rode sticking out.

On my 40' SeaRay in 20' of water I put out around 120 to 150 feet of rode with no chain, once I feel that it is set, I "back down" on it with both engines to 2000 rpm's to make sure the anchor is set. I sometimes throw a stern anchor to control the drift. I have held 12 large boats this way. On the 41, I use a Fortress FX16 with 10' of 3/8" chain. I don't have to use as much scope 'cause the chain holds the shank parallel to the bottom to set the anchor.

If I were you, anchoring a 22' boat in 3 to 5 feet of water, I would put out at least 40 feet of rode on whatever anchor I had and possibly some chain. It has been my experience that smaller boats react more to wave action than larger ones.

I hope this helps,
Robert