A common question when purchasing or repowering a boat is whether to have inboard or outboards engines. The answer to this question mostly lies in where you will use your boat and what your personal preferences are. Inboard engines are often seen in commercial, offshore, military and water skiing applications. Outboards on the other hand are more general purpose, can be used in a variety of craft and offer a cheaper alternative with less maintenance. In design, an outboard is mounted on a transom and can be tilted up when entering shallow water. An inboard sits with the vessel and is attached to a drive system such as shaft, sterndrive or jet. Both engine forms can be in petrol or diesel versions although this will depend on the horsepower required.
”The answer to this question lies in where you will use your boat and what your personal preferences are”
Things to look at when deciding on your engine system are:
- Length of vessel – Certain size vessels just simply can’t take outboards without becoming too heavy in the transom and becoming overpriced (because of the number of outboards needed begins to lose cost effectiveness)
- Petrol versus Diesel – Over the years petrol has had some safety concerns and so the larger the boat, the more petrol required to move it. This means storing the fuel onboard safely and making sure that your maintenance is up to date
- Use of vessel – Traditionally, boats with outboards have more manoeuvrability inshore as well as at speed. Inboards require a form of propulsion and the efficiency of the system is dependent on which drive system is chosen in the end.
- Noise – Engines on the transom will generate greater noise than ones inside the boat hence outboards are noiser
- Maintenance – All engines in a marine environment need maintenance but it could be argued that outboards are cheaper due to their simpler design. However, Inboards are in a protected environment and less likely to be exposed to the elements
- Cost – Smaller outboards will generally win out against inboards for costs but once you start heading into larger boats the cost lines become more blurred. Ultimately, you have to consider the questions above first and then weigh up the costs to install and run over the lifetime ownership of the boat.