The components depicted in Figure CS-18 are two styles of mounting brackets used to attach outboard motors to the stern plates of small boats. The sketches show the parts as unfinished castings or forgings. Finish machining will add a threaded hole through the bottom of the short leg to accommodate a tightening turn screw. Holes will also be drilled through the long leg to permit attachment of the motor.
Since outboard motors are frequently carried to the boat, weight is a definite concern. The bracket will also operate in a wet environment, possibly even saltwater, and will be subjected to impacts and vibration, in addition to its steady-state force. The designer has recommended a minimum yield strength of 345 MPa (50 ksi), coupled with a 5% minimum elongation in a uniaxial tensile test to assure adequate resistance to brittle fracture.
1. Briefly discuss the major service requirements for these components. Which of the various engineering materials would you recommend for this application?
2. For your recommended material, what are some of the possible means of producing the desired shapes? Which of the possible alternatives would you recommend? Why?
3. Would a heat treatment be necessary to establish the required properties? If so, what type of treatment should be used?
4. Would some form of surface treatment be desirable? What type of treatment would you recommend?

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6.50 11.88 5.75 50 8.20 FIGURE CS-18