Long Shaft vs Short Shaft Outboard Motor
When choosing the right outboard, there are several factors to consider, such as your boat’s size, intended use, and the environment in which it will operate. Among these factors, the shaft length of the outboard motor plays a significant role.
The three main outboard shaft lengths available are short, long, and extra-long shafts. Each type has advantages and limitations, depending on your boat and specific needs. This article aims to comprehensively compare these different shaft lengths, helping you make an informed decision.
Short Shaft Outboard Motor
- Maneuverability: Short shaft outboards offer enhanced maneuverability and stability due to their smaller size.
- Affordability: These engines are typically more budget-friendly
- Ease of Transport and Storage: The compact size makes them easier to transport and store.
- Compatibility: Suitable for inflatable boats, tenders, and smaller runabouts with transom heights of less than 20 inches.
- Performance: Short shaft outboards provide slower speeds, acceleration, and limited handling in rough waters.
- Safety: The propeller’s increased exposure and reduced operator visibility pose potential safety risks.
- Boat Compatibility: As mentioned, these are best suited for smaller vessels such as small fishing boats and inflatables.
Long Shaft Outboard Motor
- Improved Performance: Long shaft outboards provide better speed, acceleration, and handling, especially in rough waters.
- Enhanced Safety: The increased distance between the prop and the water surface reduces the risk of injury or damage.
- Better Visibility: Greater distance from the propeller to the water surface improves visibility for the operator.
- Suitability: Ideal for larger boats, pontoons, and center console boats.
- Compatibility: Suitable for boats with transom heights of 20 inches or more.
- Cost: They are typically more expensive than short models.
- Size and Weight: The larger size and weight can make storage and transport difficult for some boaters.
- Compatibility: These outboards require a longer transom height and may need additional upgrades or modifications for specific boats.
Extra-Long Shaft Outboard Motor
- Superior Performance: Extra-long shaft outboards offer enhanced speed, acceleration, and handling in demanding conditions.
- Deeper Water Operation: These are designed for boats that operate in deeper waters, providing better propulsion and safety.
- Reduced Cavitation: The extra-long shaft helps keeps the propeller submerged deeper underwater, reducing cavitation and improving performance.
- Suitability: Ideal for sailboats, large center console boats, and boats with bracket-mounted outboards.
- Cost: They are generally more expensive than short and long models.
- Size and Weight: The larger size and weight can make storage and transport more challenging for some boaters.
- Compatibility: These outboards often require specific boat designs or configurations, such as a taller transom or bracket-mounted setup. Suitable for boats with transom heights of around 25 inches or more.
- Limitations: Limited availability and may require modifications to some boats.
Shallow Water Considerations
Short shafts are typically more suitable for navigating shallow water, as they have a higher propeller position, reducing the risk of hitting underwater obstacles or the bottom.
In addition, boaters who operate in shallow waters may benefit from using a jack plate, which allows for vertical adjustments of the outboard.
Outboard Sizes and Engine Power
Engine Power Ranges
- Small Outboards (2.5 – 25 HP): Ideal for lightweight boats, tenders, and inflatables. These outboards provide sufficient power for basic recreational activities and short trips.
- Mid-Range Outboards (25 – 100 HP): Suitable for small to medium-sized boats, such as pontoons, runabouts, and fishing boats. These offer a balance between performance and fuel efficiency.
- High-Power Outboards (100 – 300+ HP): Designed for larger boats and demanding activities, such as deep-sea fishing, water sports, or extended cruising. These engines deliver maximum performance and speed.
Engine power is typically measured in horsepower (HP).
Factors to Consider
- Boat Size and Weight: Larger, heavier boats require more engine power for optimal performance.
- Intended Use: The activities you plan to engage in, such as fishing, water sports, or long-distance cruising, will influence the engine power required for your boat.
- Fuel Efficiency: Smaller engines consume less fuel, while high-power engines require more fuel to deliver top performance.
- Budget: Higher-powered outboards tend to be more expensive.
Matching Engine Power to Boat Size
Underpowered boats will struggle to reach top speeds and may have difficulty handling rough water conditions. On the other hand, overpowered boats can be hard to control and may exceed the manufacturer’s recommended limits, compromising safety and stability.
The Effect of Outboard Weight on Boat Stability
- Balance: Ensure the weight is proportionate to the boat’s size to maintain proper balance and prevent tipping. At the same time, an engine that is too light may not provide enough power for your boat and may cause it to sit too high, resulting in instability.
- Performance: A lighter motor may result in faster acceleration and better fuel efficiency, while a heavier engine can increase stability and control in rough waters.
- Maneuverability: A lighter outboard can improve your boat’s maneuverability, making navigating tight spaces and shallow waters easier.
Adjustable Mounting Brackets
Adjustable mounting brackets can help boaters find the optimal balance and stability for their boats by allowing them to fine-tune the position of the outboard. By adjusting the height and angle of the engine, you can ensure that the boat remains level and stable, providing the best possible performance and handling in various water conditions.
Deciding between a short, long, or extra-long shaft outboard can be challenging. Carefully considering factors such as your boat’s size, intended use, environment, and transom height is essential for making the right decision. Moreover, it’s crucial to evaluate the compatibility of an outboard with your boat and determine if upgrades or extra features are necessary.
Long shafts offer improved performance, maneuverability, and safety features compared to short shaft outboards but may require a longer transom height and a larger fuel tank, raising costs. Short is more budget-friendly, compact, and easily transported but provides lower performance levels. Extra-long shafts cater to boats with higher transoms offering additional advantages in specific situations.
Q: What is the difference between short, long, and extra-long shaft outboard motors?
A: The primary difference is the shaft length, affecting compatibility with boat sizes and transoms.
Q: How do I determine the appropriate shaft length for my boat?
A: To find the correct shaft length, measure the vertical distance from the top of the transom to the bottom of the hull, also known as the transom height. Match this measurement with the manufacturer’s specifications for each shaft length.
Q: Does the shaft length affect the performance of the outboard motor?
A: The shaft length can impact the outboard motor’s performance depending on the boat size and transom height. Choosing the correct shaft length ensures optimal boat performance, stability, and fuel efficiency.