$ 8.95


In stock

Product Information


Ronstan TellTails are small, lightweight flags used on sailboats to visualize airflow over the sails.

They are crucial for optimizing sail trim, which is the process of adjusting the sails to maximize their efficiency in different wind conditions and sailing points.

Packet Set of 3:

  • 3 Green -starboard
  • 3 Red -port

Tell Tails are used as an essential guide for proper sail trim.

The Ronstan TellTails have high-resolution fabric tails for maximum visibility.

They are made from stabilised nylon woven tape attached to adhesive patches to ensure a permanent bond with the sail.

Whilst most sails begin their sailing days with telltails, they often become damaged and require replacement.

There will often be additional requirements to fine-tune the reading of your sails or shrouds.

Wipe the surface of the sail or surface with alcohol to ensure secure attachment of the self-adhesive tab.


  • Several Telltales can be strategically placed at specific points on the sail, typically near the leading edge.
  • They will enable airflow visualization. As the wind flows over the sail, the TellTails will flutter or deflect, indicating the direction and strength of the airflow at that particular point.
  • By observing the TellTails, you can adjust the sails by tightening or loosening the lines controlling sail shape (sheets and halyards) to achieve optimal airflow.
  • These TellTails are easy to use and are simple and intuitive to understand for sailors of all levels.
  • They provide real-time feedback giving instantaneous visual feedback on sail trim, allowing for adjustments on the fly.
  • They will assist with improved performance. Optimizing sail trim using TellTails leads to improved boat speed, efficiency, and overall sailing performance.
  • TellTails are a relatively inexpensive tool compared to more complex sail trim instruments.