No time penalty for a course change, until you tack or gybe.
The same time penalty below also applies for a sail change though.
The penalties normally depends on the boat (they are coded in the boat characteristics), but so far, they always have been the same, which is:
For a Tack, a Gybe, or a SailChange, the penalty is a 50% speed during:
- 300 seconds if you don't equiped you boat with the Pro Winch,
- 75 seconds otherwise.
If you happen to have 2 or 3 of these penalties at the same time (you tack + change the sail at the same time for instance), they are cumulated, which means that your speed falls to 25% of its normal speed for the same amount of time (which is better than having 2 full penalties of 50% overall).
Here is an extract from the boats raw polars data:
   "winch":{
      "tack":{
         "stdTimerSec":300,
         "stdRatio":0.5,
         "proTimerSec":75,
         "proRatio":0.5
      },
      "gybe":{
         "stdTimerSec":300,
         "stdRatio":0.5,
         "proTimerSec":75,
         "proRatio":0.5
      },
      "sailChange":{
         "stdTimerSec":300,
         "stdRatio":0.5,
         "proTimerSec":75,
         "proRatio":0.5
      }