Weekly quiz: reading your sail’s telltales
They may be simple wool strands. But it’s the best technology out there. At least when it comes to trimming the sails. Meet the telltales.
Question of the day
🔹 In this situation, what should you do at the helm or with your headsail?
And bonus question
🔹 What does this tell you about the air flow on your sail?
👉 Reply on one of our social media below. We’ll post the solution right here next Sunday!
Answer
Thanks to all who have taken part in this quiz.
First a clarification: the red telltales are seen thanks to semi-transparency of the fabric, and the red line shows how the headsail is curved. We are therefore on a starboardRight side of a boat when looking forward More tack, the green telltales being on the inside and the red ones on the outside.
This situation means we are pinching slightly: either the heading is too far up the wind or the sail trim is slightly too loose. If the heading is fine, then trim in the sail slightly. Otherwise, bear off a few degrees at the helm.
To have a deeper understanding
The pictured air flow is fine on the outside, but the forward green telltale shows it isn’t entirely on the inside. There is a slight pocket of stalled air just behind the luff of the sail. We don’t want that pocket to grow further and contaminate the rest of the air flow, either going aft or up and down the sail. Having several rows of telltales would help us understand if that situation is the same up and down the sail, but this is not shown in the picture. If there is some vertical difference, we will need to play with the rollers and barber haulers in order to enhance sail trim.
A final note, however: the outside flow contributes more to our speed than the inside flow. Therefore, the most important is for the air flow on the red telltales to be correct, which is the case here. So in the end, our sail trim is almost fine. We’re almost there.
The next quiz is now live and all yours!
