The sliding bolt, in a a slot on the shank of the anchor, allows one to have a locked and fixed point of attachment at the end of the shank in most anchoring conditions. If you are in an area with rocks, cables, and trees on the bottom, the anchor may be hung up. Then you put the bolt at the point in the slot near the crown of the anchor. By going over the anchor at a course of 180* opposite to the setting course, you then are pulling the anchor up near the crown, and an anchor stuck under a rock, cable or tree will then be pulled free, by pull in the opposite direction.
Normally keep the bolt at the point near the end of the shank. I consider this a great advantage. You could put a second bolt in, and leave a trip line attached at a point near the crown also.
The disadvantage of allowing the slot to be open, and trip the anchor with a pull opposite of the setting force, is that if the wind or current suddenly shifts, it may pull the anchor out, and not reset.
Normally if the wind or current changes, the chain drags slowly across the bottom, and the pull remains at the end of the shank. The anchor slowly pivots to face the point of the new pull, without tripping.
What size Boss did you get? You may also want to put the bow SS shield on to prevent gel coat dings from the point of the anchor. See my album for details:
