The boom is intended to support two vertical loads, $\mathbf{F}_{1}$ and $\mathbf{F}_{2}$. If the cable $C B$ can sustain a maximum load of $1500 \mathrm{N}$ before it fails, determine the critical loads if $F_{1}=2 F_{2}$. Also, what is the magnitude of the maximum reaction at pin $A ?$