A 3/8 -in.-diameter bolt connects the marine propeller to a boat’s 1 1/4 -in. driveshaft (Figure P5.30). To protect the engine and transmission if the propeller accidentally strikes an underwater obstacle, the bolt is designed to be cut when the shear stress acting on it reaches 25 ksi. Determine the contact force between the blade and obstacle that will cause the bolt to be sheared, assuming a 4-in. effective radius between the point of contact on the blade and the center of the driveshaft.

Figure P5.30

Obstacle impact point 4 in. Driveshaft Section A-A