Finishing Touches on Big Gate

I bought a 2 ton chain hoist to open the big gate.  The gate only weighs about 500 lbs. … however when the forebay or headrace is full of water there will be a lot of force pushing against the gate.  I designed the system so the hoist and controls would be indoors.  The exterior portion in the photo is made of white oak and has a pully on the top.