Inboards are primarily automobile and truck engines, slightly modified to fit the marine application. They supply power to the prop via a shaft through the bottom of the boat.
The inboard power system allows the use of engines much larger than those available in outboard power, so they're the universal choice for big sportfishing boats and yachts.
The disadvantage of inboards is that the prop and shaft are fixed in place, straight ahead. They can't be adjusted or trimmed to improve the running attitude of the boat, and they require more draft, or water depth, to operate without touching bottom. Also, steering is less positive at lower speeds because a rudder is used for directional control, rather than moving the prop thrust to one side or the other as in outboards and I/Os.
Bet You Didn't Know
Got a noisy inboard or inboard/ outboard motor? You can quiet it by adding a high-density foam to the inside of the engine box. Standard material for this job includes a soft foam sheet sandwiched between Mylar metallic outer skins. The stuff can be gluec or stapled into place. It acts like the insulation in the hood of your car to trap noise and heat inside.
Inboards like this Crusader are modified versions of auto and truck engines. They provide lots of power for larger boats.
(Photo Credit: Crusader Corporation)
Was this article helpful?
Lets start by identifying what exactly certain boats are. Sometimes the terminology can get lost on beginners, so well look at some of the most common boats and what theyre called. These boats are exactly what the name implies. They are meant to be used for fishing. Most fishing boats are powered by outboard motors, and many also have a trolling motor mounted on the bow. Bass boats can be made of aluminium or fibreglass.