Inboard engine series#

You may need to add weight to the bow of your boat to prevent it from porpoising or having water splash over the transom in the back. This will most likely change how your boat handles – and usually not for the better. The first thing you’ll need to consider is how the telemetry of your boat will change with a heavy motor added to the back of it and the effective length increased with the addition of a setback bracket or offshore bracket. Here are all the things you should consider. Now that you’ve figured out if you can do an inboard to outboard conversion, it is time to ask yourself if it is worth it.

Inboard to Outboard Conversion: Is It Worth It? And on top of that, you may end up with a boat that performs significantly worse than before. While these steps don’t sound super complicated, it will be an expensive proposition. You may need to adjust or make new bunk brackets on your trailer as well.Īuthor Note: After these steps, you’ll need to buy an outboard motor and mount it to the transom. You’ll need to add a new steering system to the boat since the old inboard prop or jet pump steering won’t work anymore. And because the engine(s) face aft service access is compromised because the drive belts, water pump, and alternator will probably be very close to the transom.Next, you’ll need to make sure there is room for glassing an I/O plug in the transom and mounting a hydraulic steering system. The added complexity of the V-drive transmission results in more power loss than a direct-drive transmission. The aft placement of the engine is great for wake-boosting weight distribution in a watersports boat, but on larger boats that weight aft can make it harder for the boat to get on plane. On larger cruising and sport fishing boats, the space that would be occupied by direct drive engines is now available for that mid-cabin or other uses. In a watersports boat with a V-drive system the engine is usually covered with a padded sundeck, so the boat’s cockpit is very similar to that of a sterndrive, with the middle of the cockpit open.

The advantage of the V-drive is that the engine is placed aft.

Inboard engine series#

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. 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.

On the other hand the engine(s) in a direct-drive system are usually easy to access for service. On larger boats the engine(s) are taking up space below deck that could be used for a mid-cabin, storage lockers or fish wells, or tanks. On a smaller watersports boat the engine resides under a “dog house” cover right in the middle of the cockpit, great for weight distribution but also in the way. The disadvantage is the location of the engine(s) near the middle of the boat.Very little horsepower is lost in the direct drive transmission.

The advantage of a direct drive system is its simplicity and its energy efficiency.

This angle means some of the energy from the prop thrust is always lifting the boat, rather than pushing it forward. 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. 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.Ī direct drive system places the engine or engines near the center of the boat. However, the sterndrive can be trimmed, which results in superior speed and efficiency on small to mid-size boats. 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. 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. 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. 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.