Anchoring a boat using a stern tie is a bit of an art. The procedures change with each location. Therefore, it is important to understand the overall concept and then adjust as needed for the particular anchorage.
The reason to use stern tie is to reduce the amount of room needed to anchor. This might be driven by the size of the anchorage or the desire to provide space for as many boats as possible at a given location.
There are five things needed to in order to have a successful stern-tie.
1. Enough water under the keel at low tide that is near enough to shore to accommodate the amount of stern line available.
2. Suitable bottom conditions at the location where you want to set the anchor for good holding.
3. An appropriate place to secure the stern tie to shore.
4. Enough crew with sufficient experience to accomplish the procedure.
5. Winds and current favorable for the deployment and securing of the stern-tie.