Knowing the boat's accurate dry and motor weights is crucial in choosing the correct lift capacity. Most manufacturers state that they only want 80 percent of the capacity used. If you have a 4,000 lb. lift, we only recommend putting 3,200 lbs. on it. Remember, overkill is never better, as you want to find a lift that has the correct lift power. Having the boat appropriately positioned on a lift is crucial. If you have a 4,000 lb lift, it was designed for 2,000 lbs. on the front beam and 2000 lbs. on the rear. To avoid your weight shifting with liquid flowing around, keep ballast tanks full when lifting a boat! One that isn't will overload your lift and void your warranty.