Why do outboards not have gears?

Boat engines don’t have transmissions because they add a lot of undesired complexity for a minimal speed gain. Usually, the propeller doesn’t turn at speed equal to its engine; if it does, it cavitates & reduces its life span. Adding gears increases speed, which increases cavitation, so no gears.

Do boats use gears?

Every boat has gears, but they are not the same as gears in cars for increasing the speed. Boats have reduction gears. Before going into reduction gears, let’s see the basics first. The propeller shaft drives the propeller, and the engine drive shaft drives the propeller shaft.

How does an outboard shift gears?

The pinion gear is permanently engaged with the forward gear and the reverse gear, so when the driveshaft is rotating, the pinion gear is rotating, and the forward and reverse gears are rotating. If you hear grinding as you shift the outboard into gear, it’s usually a worn dog clutch.

Does an inboard outboard have a transmission?

Inboard and inboard/outboard boats basically use two different applications of drive systems. An inboard application, figure 1, normally contains a transmission mounted on the back end of engine, then transfers power to the propeller via a long slim drive shaft.

Do boats have multiple gears?

Have boats not got gears because the medium of water has traditionally allowed designers to get away without having them (you can still get going from standstill due to prop slipping, but prop of planing boat is designed to work most efficiently at point where engine is producing max power, so until it’s got to max …

Do boats have reverse gear?

Small ships and boats does nor really reverse the engine to reverse the propeller motion. Instead they use gear box assembly with a reversing gear fixed with an idler. The shifting between the gears are many a times achieved by using reversible hydraulic coupling or by using friction clutch.

Is an inboard or outboard better?

Inboard motors generally last longer than their outboard counterparts. You can squeeze roughly 1,500 hours out of an inboard before necessary maintenance. Outboards, on the other hand, last about 750 hours on average. So, the inboard option means less maintenance (nearly half) even though they cost more initially.

What is the difference between inboard and inboard outboard motors?

What’s the difference between inboard and outboard motors? As the names imply, an inboard motor is mounted inside the boat and usually at the hull. The outboard motor design means the engine is placed outside the boat, typically in the back or stern of the craft.

Does a boat have a clutch?

The propeller automatically slips enough to get your boat underway. Another is to provide reverse rotation so that you can back your boat into your slip. These two functions are accomplished by a series of internal clutches, which when moved via the gear lever at the helm, engage different gear sets.

What is a marine gear?

A marine transmission — or marine gear — is a wondrous thing. It couples all the torque a big diesel or gas engine can deliver to the shaft that spins the propeller, so it must be built like a tank.

Do boats have transmissions?

Boats can have transmissions with gears, usualy with 2 ratios, though some very high performance racers have more than 2. We are talking about boats like some Cigarette models, or the offsore racers which use 4 speed gears.

Is a 2-speed drive good for a planing boat?

A 2-speed drive can be useful for a planing boat during the transition from displacement to planing mode if you have props optimized for high speed, but its benefits have to be evaluated against the increase in weight and the need for an additional space in the engine room, besides the mechanical complexity.

What is the gear ratio of a ship propeller?

Commercial ships, bulk carriers and tankers, for example, which are designed to deliver their load with minor fuel consumption possible, have their props mounted directly to their slow engine’s shaft – 1:1 gear ratio and very high efficiency.

What are the advantages of a two-speed gearbox?

If you look at the Volvo Penta sterndrives made for larger boats in Europe, there is an option of having a two speed gearbox. The main advantages are fuel efficiency and slow speed handling. Without the 2 speed the creep speed is too high for docking and the engine revs at cruise are too high for economy.