Use a Jack Plate for Shallow Water
Since the introduction of the outboard motor, it was just bolted or clamped onto the transom and that was that. This setup appeared to work well for most situations until the fishing boats became larger and the outboard motors bigger. However, bringing the larger boat with the heavier motor which protruded into the water deeper into the shallows where the fish like to hide became an ever increasing problem. Adding a small trolling motor helped mitigate this but it did not solve the problem of controlling the depth of the main motor or saving the expensive propeller from touching the bottom.
A typical scenario being when the skipper would engage the large main motor giving it lots of throttle sucking the stern down deeper and reducing the depth of available water dramatically leading to an unplanned prop strike.
Another problem is unseen debris in the water. Although outboard motors can tilt up when striking an object in the water or sand bar when in forward motion, they tend not to do it well. A jack plate can also be hinged that will allow the motor to swing up when striking a submerged object.
Along came the Jack Plate, an outboard motor jack plate made for multiple parts with two faces; the front face of the jack plate attached to the boats transom and the boat motor attached to the rear face of the jack plate. The two jack plates are adjustable and slide up or down parallel to each other. This adjustment is either done manually or hydraulically and offers precise depth control of the propeller. Adjusting the fixed jack plate
requires some effort and is done out of the water with the boat on the trailer whereas a hydraulic jack plate
is accomplished on the fly and can be done either out of the water on the trailer or while in the water even if underway. Manual jack plates are an economical option when considering an outboard jack plate but do not offer nearly the options of the costlier hydraulic jack plate.
Choosing the Correct Jack Plate Size
Sizing a jack plate is determined on multiple factors the two main ones being the size of the outboard motor and the setback. The setback is typically the length of the jack plate which will determine how far from the transom the motor is located. This distance setback will have a significant influence on the new performance characteristics of the boat. According to jack plate manufacturers, like Dometic
, adding a jack plate will only improve the performance of the vessel. In recent years Jack Plates have become available for even larger engines (up to 400HP), the SeaStar Xtreme Jackplates
. These jack plates utilize high strength materials to handle some of the strongest engines on the water.
Installing a new jack plate on a vessel might require modifying or altering some existing systems such as the steering
. If the steering is hydraulic and the hydraulic hoses
have no extra maneuverability one might have to replace the hydraulic lines or consider an alternative. The electric cables and fuel lines
will also need measuring to determine if they will reach the new outboard motor location and allow for the free movement of the motor when the jack plate is adjusted.