Blue is sailing to leeward of Yellow. Both boats have spinnakers set. Blue luffs Yellow. What are the obligations on Blue and Yellow?
Yellow is required to keep clear and Blue is required to give Yellow room to respond to her luff. While Yellow is able to keep the majority of her spinnaker filled and drawing she is not entitled to additional room to drop her spinnaker.
If Blue continues her luff so that Yellow, in order to keep clear, has to luff beyond the point where she can keep her spinnaker filled and drawing, then Blue must give Yellow room to drop her spinnaker.
Whether or not Yellow drops her spinnaker at that time, she is still required to keep clear. If she does not drop her spinnaker at that time, then Blue is not required to give her additional room to drop the spinnaker later in that luff.
If Yellow does not drop her spinnaker and passes head to wind to keep clear, is Blue giving Yellow room to keep clear in a seamanlike way?
Yes. Blue may continue to luff as long as she has previously given Yellow room to drop her spinnaker.
Does either answer change if Blue does not have a spinnaker set, or if Blue has a different type of spinnaker set?