M8 hoist Heavy Duty, Vibration-free, Self-contained Hydraulic Hoist. WESMAR's rugged hydraulic hoist system extends the soundome up to 125% deeper in the water providing maximum performance, free from vessel noise. The soundome tube on the M8 sonars is more than twice the size of other systems and at 4 inches in diameter it provides stable, vibration-free performance. WESMAR is the only manufacturer of scanning sonars to offer this option in this price range. If you are installing the sonar on a side of the keel, the M8 hoist is the way to make sure the sonar will see on the other side of the keel. Hydraulic power pack assembly requires no Maintenance and comes fully assembled from the factory. Only an electrical connection is required, no complicated plumbing. The M8 hoist can also be supplied with an emergency lift screw system.