Rookie here: Cleaning the bottom of my 1993 Hunter 30T and noticed the calm shell housing, forgive my lack of knowledge of the correct terminology, that should be fastened at the top of the prop shaft has come loose and has slid down toward the prop. It appears the screw worked out and allowed it to slide down from its position at the top of the shaft next to the hull. Questions, 1) what is it called, 2) What is the purpose of the the clam shell device, 3) since I will be pulling the boat out in about 3 weeks, will it hurt anything to wait until the boat is pulled and and repair it then. The prop is spinning freely. 4) I think the calm shell device fastens tightly at the top of the shaft next to the hull and spins with the shaft - correct. Thank you for your help in advance.