See full version: Marine Engines and Power Systems: The Basics Behind What Powers Your Powerboat
TIP: As a recreational boater, what’s important for you to remember about this issue is that a boat should be designed specifically for the power system you’re getting with it. In some cases a manufacturer will modify a boat to sell it with inboards when it was originally designed for outboards, or vice-versa. If great care isn’t taken to mitigate the resulting changes in weight distribution, the boat’s running characteristics may be sub-par. here
Strictly speaking, the engine is what creates power and the drive system is what transfers that power into thrust. So logically, you want to distinguish between the two. There’s just one problem: many power and drive systems are integrated. The term “outboard engine,” for example, commonly describes both the powerhead and the lower-unit drive system that's attached to it. On the other hand, a “jet engine” comes in both outboard and inboard varieties. So let’s start off by dividing engines and power systems into their most basic forms: outboards and inboards.
Propellers? Who needs propellers? This Yamaha jet boat gets by just fine, without them.
Runabouts often have stern drive propulsion. On this Cruisers bowrider, the engine is located under the aft seat, just forward of the swim platform and transom. [links]
There are, of course, some significant down-sides to inboard engines. Handling is rarely as good as with an outboard (though there are exceptions, most notably inboards paired with pod drives); their power-to-weight ratio isn’t as good as it is with outboards; they’re more difficult to work on and replace; and in many cases they eat up a significant amount of room inside the hull which could otherwise be dedicated to seating, cabin space, or stowage. here
The Mavi Deniz engine driven Hydraulic Power Pack designed to convert a primary drive source into a hydraulic fluid flow for supplying the hydraulic . more
. styles, types and sizes of Hydraulic Power Pack, using Petrol engines, Diesel engines, and Electric motors. Most engine . here
. exceptional low-end torque and power with reduced emissions and increased fuel efficiency. For safety reasons, the hydraulic power pack is equipped with an automatic . more
ScorPack 7.5 kW POWER SUPPLY HYDRAULIC POWER UNIT The ScorPack 7.5 kW (Hydraulic Power Unit) is a compact hydraulic .
Do that two years running and you are down to 60%.
For instance the Sterlings give you more Ah for your money, but the Victron, Super B Epsilon, Mastervolt and Relion 100HP give you higher continuous currents.
The Lifos is new onto the market, and while it was below our target 100Ah, we included it as it could be of interest to the smallest trailable boat, or as power for a small electric outboard. The company has larger models in the pipeline. [links]
A direct drive system places the engine or engines near the center of the boat. Power passes from the engine to a transmission that enables forward-neutral-reverse shifting, and then to the propshaft, which passes through the boat bottom at a 7- to 12-degree angle. This angle means some of the energy from the prop thrust is always lifting the boat, rather than pushing it forward.
A V-drive and a direct drive are both inboard propulsion systems, which means the engine drives a propshaft that passes through the boat bottom, with the propeller positioned under the boat and steering accomplished by a rudder. These days inboard power is most popular on watersports tow boats designed for wakeboarding and wakesurfing, where placing the prop deep in the water under the boat produces a clean wake and keeps the prop away from the person behind the boat. But inboard power can also be found as an alternative to a sterndrive or pod drive system on some cruising and sportfishing boats, where its chief advantage is its simplicity, reliability and ease of repair.
Inboard power–either direct drive or V-drive–is less complex and requires less service than a sterndrive, and is also less prone to corrosion in saltwater. However, the sterndrive can be trimmed, which results in superior speed and efficiency on small to mid-size boats. Pod drive systems feature a steerable prop and are a hybrid of an inboard and a sterndrive, but pods require twin engines and are available only for larger boats.
In a V-drive system the engine is placed further aft in the boat, almost as close to the transom as the engine in a sterndrive. The engine “faces” aft with its output shaft facing forward and mated to a V-drive transmission that uses a series of gears to reverse the output direction 180 degrees and mates to the propshaft, which is in about the same position and angle as it would be found on a direct drive inboard system.