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How to Use Manual Jack Plates

Adding new equipment to your boat may seem intimidating at first. However, understanding the advantages and the ease with which the equipment may be used could quickly change your mind. Boating enthusiasts, anglers and hunters may benefit greatly from using a manual jack plate. Read on to find out why.

What Is a Jack Plate?

There are three main types of jack plates: fixed, manual and hydraulic. While they each have their advantages, this article will focus on manual jack plates. A jack plate is a mounting mechanism situated between the transom of the boat's hull and the outboard engine. The jack plate provides adjustable vertical positioning of the outboard engine to change the height of the engine in the water.

What Are the Advantages of Using a Jack Plate?

Utilizing a jack plate allows for more overall control of your engine height and, ultimately, performance in the water. It allows you to maximize the performance of your engine in rough waters and provide ease of use in shallow waters. Furthermore, the vertical position defines the water column that is available for use and can therefore be optimized for the performance you desire.

Adjusting a Manual Jack Plate

Manual jack plates are adjusted without hydraulic assistance before putting the boat in the water. While this requires some planning on the boater's part, adjusting before entering the water provides the flexibility that will be needed if entering shallow water (adjusting such that the boat's engine sits higher) or rough water (adjusting such that the engine sits lower, providing more control).

Adjusting the height of the jack plate is a simple process that requires only a few steps to help optimize the performance. You may need several tools, including one or more wrenches that are of appropriate size, a tape measure, a level and a pencil. To adjust appropriately, follow these steps:

  • Using a pencil, mark the current height of the jack plate for reference.
  • To accurately determine the height of the engine and therefore where the jack plate supports your motor before adjusting, make sure your boat is level and measure the distance from the pad to the floor, and then from the center of the propeller to the floor. The difference is the pad-to-prop height.
  • Loosen any supporting bolts on either side of the jack plate, as this will allow the jack plate to move vertically.
  • Supporting the engine will help take the weight off the bolts and reduce the chances of it binding in place and not moving during adjustment.
  • Begin by turning the bolt in the center, which raises or lowers the jack plate and thus the height of the engine.
  • Tighten all bolts back down and test for the performance you'd like.

The optimal height of the jack plate provides the best performance for your boat. While each engine is different, some engines operate better lower in the water than others. Additionally, if the boat will run primarily in shallow waters, adjusting the jack plate higher may be advantageous despite a drop in performance.

How Would You Choose the Right Setback?

Setback is the distance that the jack plate provides between the engine and the transom. Since one face of the jack plate attaches to the boat and the other face of the jack plate attaches to the motor, a gap is created between the two, and the setback, therefore, defines the distance in which the engine is sitting behind the boat. With increased setback, props tend to run in cleaner, less turbulent water, providing more grip.

The setback should be chosen based on the size of the engine and how the engine moves when trimming. As the height of the engine is adjusted, different parts of the engine may be at risk of coming into contact with the boat, such as when the jack plate is lowest and the engine is trimmed back. The setback should be large enough to ensure there is no contact between the engine and the boat. Additionally, if your boat is bow-heavy, the extra setback may help balance the boat, making it easier to trim out when on plane.

Final Thoughts

Vance Manufacturing has manual jack plates for engines that range from 0–400 horsepower. Manual jack plates with setbacks ranging from 3 inches to 12 inches are also available. Finally, both clamp-on and bolt-on jack plates are available, providing the most flexibility for the user. If you need the extra flexibility of vertical adjustment with your engine, want to optimize performance or need to provide height and clearance when running in shallow water, then a manual jack plate may be an ideal option for you.