Final answer:
The two destabilizing forces that cause the boat conformation are steric strain and torsional strain.
Step-by-step explanation:
The two destabilizing forces that cause the boat conformation are steric strain and torsional strain. Steric strain occurs when bulky groups on the boat conformation come into close proximity and experience repulsion. Torsional strain occurs when adjacent bonds on the boat conformation are eclipsed, leading to increased energy.