lift 32 is being used the length of swing arm 26 is adjusted by sliding the upper arm portion 42 farther out of the base arm portion 41 or farther into the base arm portion then securing the upper arm portion in place within the base portion the port hydraulic cylinder 34 has a lower end pivotally connected to the port side rail 30 or another frame member of the boat lift 32 and an upper end pivotally connected to the port swing arm 26 the starboard hydraulic cylinder 34 has a lower end pivotally connected to the starboard side rail 30 or another frame member of the boat lift 32 and an upper end pivotally connected to the starboard swing arm 26 to deploy the cover 22 the hydraulic cylinder 34 may move from an extended position shown in fig1 to a retracted position shown in fig3 the retracting movement of the hydraulic cylinder 34 causes the swing arms 26 to move from a forward position to a rearward position the roller 24 allows the cover 22 to unwind and extend over the boat while the swing arms 26 move from the forward position to the rearward position to retract the cover 22 the hydraulic cylinder is moved from the retracted position shown in fig3 to the extended position shown.