The secret to enhancing your outboard boat

For anyone looking to upgrade their outboard boat, extra horsepower often tops the priority list. But what if you could get appreciably more from your existing outboard, both in terms of performance and economy, both easily and affordably? Welcome to the world of outboard engine jackplates…

If you have ever had the opportunity to compete in ski racing, or on the Australian bream and bass fishing circuit, you will know that the ability to get there faster and more efficiently than your nearest competitor is crucial. To get the absolute most out of your glistening hull you need a couple of things: less drag and less turbulence. The ability to achieve both is often the difference between winning and losing.

A jackplate allows you to tune your engine’s vertical placement in relation to the water. It also drops back the position of the outboard leg and propeller farther from the hull into cleaner water less affected by turbulence created by the boat.

Now consider that in relation to how you use your own boat. While outright speed may not be a prerequisite, efficiency, and the ability to better control the engine and its depth in shallow water will be, and that is where a jackplate can help.

A jackplate is a device that bolts onto your boat’s transom, usually where the outboard would be located, so the outboard can then be bolted onto the jackplate. The design moves the engine back from the turbulent water immediately behind the hull into the cleaner water beyond. The plate also allows vertical adjustment so you can sit your outboard leg higher out of the water, or deeper within it.

There are three main types of jackplate: fixed, manual, and hydraulic. As the name suggests, a fixed jackplate allows you to move the engine a fixed distance from the hull but does not allow vertical movement. A manual jackplate offers the same option to have a fixed distance between the engine and hull but requires manual adjustment and experimentation to find the correct fixed vertical lift for maximum efficiency. And finally, a hydraulic jackplate allows a fixed distance between the hull and engine, but also allows changes to the vertical position of the engine whilst running, giving users the ability to find the most efficient location at various speeds, conditions, and water depths.

Dometic offers both manual and hydraulic jackplates. And while you can put jackplates on small-horsepower outboards, Dometic’s range encompasses outboards up to 600hp for specific models. Working out what type of setback you need will require input from the hull manufacturer or a professional. They will best be able to determine the most efficient distance between hull and outboard for your boat.

Dometic jackplates range from 4 inches to 12 inches of setback and feature a recessed slot for anodes to reduce corrosion damage in saltwater. On the hydraulic models, operation is smooth and efficient, with the transition between the highest and lowest settings taking approximately 8.5 seconds.

Unlike your outboard’s trim and tilt function, which only allows you to move the propeller clear of the water or the bottom by altering the angle of the shaft and therefore the angle of propulsion, jackplates allow vertical movement up and down without altering the angle of propulsion.

Anyone who has tried to cross a shallow bank by merely trimming the engine up knows that in doing so, idle speeds are all you can achieve as the upward angle of the outboard forces the hull of the boat lower in the water and potentially into the sandbank you are trying to cross. The faster you go, the worse it gets.

What a jackplate allows is the ability to change the height of the engine and propeller without changing the angle of drive. You can raise the engine up vertically and in doing so avoid hitting the bottom. This is particularly useful in boats that regularly operate in shallow waters, as the boat can remain at speed. You can reduce drag by having minimal hull contact with the water. In fact, utilising a jackplate, there is less hull and less engine gearbox in the water at any given time.

In normal running this comes with the advantage of increased efficiency; less drag means the engine is not working as hard, so you get better economy and speed.

But the advantages don’t just concern top-end speed and shallow water operation. The other benefits come when you are operating as normal. During hard corners, some boats tend to cavitate. Sometimes the engine trim and tilt are not enough to offset the engine cavitation in a hard turn. By adjusting the jackplate lower, however, more engine is in the water, and so you gain more bite from the propeller. This gives you better control of your vessel, not to mention a sharper turn.

Conversely, operating in rough water can sometimes require more trim. By having your outboard farther back from the hull, you can achieve more angle by using the plate in conjunction with the outboard’s own trim and tilt. This higher angle of trim can be invaluable when facing oncoming waves with a fully loaded boat; by getting the nose up higher, less waves can breach the bow.

The other advantage comes in the ability to control engine placement in relation to changing elements on the engine itself. A new propeller is a classic scenario. Manually changing engine placement to find the perfect position for that engine and propeller combination is time consuming, often requiring plenty of trial and error. A jackplate allows you to do it on the fly, simply by adjusting the position of the jackplate.

The supreme adjustability of a Dometic jackplate gives you the opportunity to take a poorly performing boat and make it a better performing boat, without costly hull alterations such as adding a pod or time-consuming engine changes.

And that brings us to our last point. A jackplate can allow you to move your outboard completely clear of the water. In Australia, where saltwater use is common, damage from corrosion and saltwater ingress is common. By removing the saltwater element completely, less maintenance saves you money over the long run.

Using a jackplate is simple if you follow a few simple rules. Higher means less hull and engine gearbox in the water, lower is the opposite. If you want to get on the plane as quickly as possible, lower the plate for maximum control and bite from the propeller. This gives you instant acceleration. As the boat comes onto the plane, lift the jackplate up so less of the outboard is in the water. This gives you a faster and more efficient plane speed, resulting in less fuel burn.

Dometic jackplates, with their 8.5-second lift from lowest to highest point, are perfect for this type of operation, allowing boats to get on the plane quickly, and then just as quickly move to a more efficient placement.

If you are looking for the ultimate performance upgrade, Dometic jackplates can deliver better performance than heavy, complicated pod additions, which have no vertical adjustment.

For more information visit the jackplate page of the Dometic marine website.