I dont know if this is question with an easy answer or not.

Just wondering, for training purposes if there are handheld GPS units that will calculate your speed towards a mark. What I mean by this is that you predesignate your destination (could be any mark on the course). The GPS calcualtes your speed to this.

Speed towards the mark being different from forward speed. Going directly at the mark, forward speed is equal to speed to mark, but if you are going forward at any bearing off the mark, your speed to mark will be less than forward speed.

This ultimately could help determine the ideal bearing toward the mark, and will give the fastest bearing to mark.

Anyway... just wondering if there are GPS units that will do this.

Thanks