Grilled Shrimp with Rosemary

4 or 5 large shrimp per person, (12 to 15 count) shrimp, remove legs, vein and leave the shells on.
½ cup olive oil
2 tablespoons fresh rosemary, minced
2 tablespoon lemon zest
¼ cup lemon juice
1 tablespoon red pepper flakes
Marinate shrimp 2 to 6 hours in remaining ingredients. Soak skewers or rosemary stems, if you are lucky enough to have them, in water for several hours. Drain Shrimp. Using 2 skewers for each serving, to keep them from twisting on a single skewer, thread shrimp onto skewers. Grill on medium hot fire about 3 minutes per side.