difference between inboard and outboard boat motors

Many new outboards are also more efficient and more powerful and feature-laden than the motors offered just a few years ago, all reasons outboards have become more popular on more types of boat. Many new boats may be rigged with three or more outboards that, when combined, make more power than the biggest pair of sterndrive engines available, resulting in performance that was once unimaginable.

In fact today, with the advent of Mercury’s 600-hp V-12 outboard, these engines are being put on boats 50’ (15.24 m) and larger and are replacing diesel inboard engines. Originally intended only to power small fishing boats and runabouts, outboard engines have become more powerful and have often replaced inboard and sterndrive engines on larger cabin cruisers, day boats and high-performance boats. OutboardĪn outboard is a dedicated marine engine that is attached directly to the stern of a boat, and today many family boat models are offered with a choice of outboard or sterndrive power. Today, there is little difference between the two. And, they were much more fuel-efficient than the old 2-stroke and approached sterndrive engines in terms of fuel consumption. With the advent of automobiles where owners almost never raise the hood, and new generation proved challenging for the industry.Īlso, at the same time, 4-stroke outboard engines got rid of the 2-stroke smell, smoke, and temperamental behavior. There are many reasons for this, but a major one was that they required maintenance and TLC, characteristics that take time and forethought. Indeed, 20 years ago about 75,000 sterndrives of all sizes were sold new each year, and that number has fallen to around 10,000 a year now. While the two major sterndrive makers have alloys and coatings that are less prone to corrosion, it remains a concern for many boats. All come with sacrificial anodes to protect against galvanic corrosion. Sterndrives once had a reputation for being prone to corrosion-related issues in saltwater, but manufacturers have significantly improved corrosion resistance on engines and outdrives. The newest sterndrives are for wakesurfing and have forward-facing propellers, as mentioned aboveĪ sterndrive has the engine installed inboard of the transom with the drive outboard, hence the nickname inboard-outboard. Dual-prop drives such as the MerCruiser Bravo Three and Volvo Penta Duoprop are typically paired with larger V-8s ranging from 350 to 430 hp and are used for pushing heavier cruisers and day boats. Single-prop sterndrives are for smaller boats and are matched up primarily with inline 4 , V-6 and V-8 engines. Today, gasoline sterndrive engines range from around 200 hp to 430 hp. The trimmable drive improves performance and economy, and because the drive can be trimmed out, or raised, it allows the boat to be beached. This allows for easier, more confident maneuvering at low speed. The sterndrive engine (sometimes called an inboard/outboard, or I/O) was introduced by Volvo Penta in 1957 as a power system that combined the torque of an inboard engine with a steerable and trimmable drive capability of an outboard. While some mid-range cruisers are available with inboard gas engines, they are quickly being supplanted by the large outboard engines, and they seem to be bound for extinction. Then the Great Recession of 2008 finished off the few that were left. Unfortunately, global economic conditions, foreign wars, and misguided government tax policies spelled the doom for most of the builder that made this types of boats.

Throughout the 1960s to the 1990s, inboard gasoline engines were popular in express cruisers, cabin cruisers, express fish boats, and even some small motoryachts in the 3o” to 45” ( 9.10 to 13.71 m) range. But, with experience and patience, most owners get onto it, and this issue did not keep over 13,000 people last year from buying inboard engine tow boats. Perhaps the biggest downside to a single inboard is that they are challenging to dock for the beginner. With the props no longer exposed, regular bow riders are now being used for wake surfing. Mercury’s Four S forward drive was second to market but is picking up in popularity.īoth Volvo and Mercury have introduced forward-facing lower units that put the props about 26” (.66 cm) forward of where they would be otherwise.

Difference between inboard and outboard boat motors