Twin Engine Boat Handling: A Step-By-Step Guide

Operating a twin-engine boat is a challenging task that requires a good deal of practice and preparation. While twin-engine boats offer better maneuverability and performance than single-engine boats, they can be tricky to handle, especially when docking or turning. One key difference is that the motors on a twin-engine boat are off-center, which affects the balance and turning radius of the boat. When docking a twin-engine boat, it is important to consider the type of boat, such as twin inboards, sterndrives, or outboards, as each has unique handling characteristics. For example, twin inboards have propellers and rudders under the boat, while sterndrives have them out behind, which affects the thrust and leverage of the boat. Additionally, when operating with only one engine, it is crucial to tilt up the non-operable motor to reduce drag and trim the running outboard to enhance its ability to lift the stern and keep the boat on a plane.

Characteristics of Driving a Twin-Engine Boat

Steering with the wheel vs. shifters

When it comes to steering a twin-engine boat, there are two primary methods: using the steering wheel or relying solely on the shifters. Both have their advantages and specific applications, and understanding them is crucial for effective boat handling.

Steering with the Wheel

Using the steering wheel in conjunction with the twin engines can be beneficial in certain situations, especially when quick and responsive manoeuvres are required. This method allows for faster adjustments and is often necessary when dealing with wind or current. The wheel can be used to make quick turns, and by putting the wheel hard over and utilising the outside drive, a more efficient and tighter turn can be achieved. This is particularly useful when docking, as it provides better control in close quarters.

However, one must be cautious when using the steering wheel with twin engines, as even a slight turn of the wheel can change the angle of thrust, making the boat's movement confusing and unpredictable. It is important to pay close attention to the wheel position, especially when shifting into gear, to avoid unintended movements.

Steering with Shifters

Steering with shifters alone is often recommended for twin-engine boats, as it provides more manoeuvring control than a single engine boat. By adjusting the thrust from both corners at the stern, you can perform standing turns, manoeuvre in a straight line, or make small directional changes without touching the wheel. This method is ideal for calm conditions and when you have ample space to manoeuvre. It gives you more time to make adjustments and fine-tune your course.

When using shifters, it is crucial to understand your boat's handling characteristics. The port and starboard drives should push or pull the bow and stern in the opposite direction when in forward or reverse gear. However, some boats may have slightly unbalanced stern drives, resulting in one side turning better than the other. Practising in safe, open water is essential to familiarise yourself with your boat's steering behaviour.

Additionally, when using shifters, it is important to use short shifts and allow some drifting in neutral to control the boat's momentum effectively. This technique takes practice and a good understanding of how your boat responds to different throttle and shifter inputs.

In summary, both steering methods have their advantages. The steering wheel is ideal for quick adjustments, tight turns, and dealing with external factors like wind and current. On the other hand, shifters provide more precise control over the boat's movement and are excellent for calm conditions or when you have ample space. Knowing when to use each technique and practising them in a safe environment will make you a more confident and skilled twin-engine boat handler.

Docking with twin sterndrives

Docking a twin-engine boat can be intimidating, especially if you are attempting it for the first time. However, twin sterndrives offer more control than single-engine boats, so you can push or pull from both corners of the stern, allowing for easier manoeuvring in a straight line or when making small directional changes.

Prepare for Docking:

Before approaching the dock, ensure that you have deployed fenders and lines as necessary. Also, check for wind and current conditions to anticipate any challenges they may pose during the docking process.

Trim Your Engines:

Use the tilt-trim switch at the throttle to trim your engines slightly upwards. This ensures that the propwash goes under the boat, where it is most effective. If not trimmed correctly, the propwash may hit the transom, making the boat harder to manoeuvre.

Approach the Dock:

As you approach the dock, try to plan your path so that wind and current work in your favour, guiding the boat towards the dock. Pull slightly past the dock, and then begin backing into the slip with both engines. Ensure that your rudder is amidships during this process.

Pivot and Adjust:

As you near the point where you need to pivot, pull the starboard engine in reverse and slide the port engine into forward. This will initiate the turn. As you move parallel to the dock, enter with both engines in reverse, making adjustments as needed. Counter the thrust and bump the engines in and out of gear to control your movement.

Final Adjustments and Tying Up:

When you are ready to tie up, put both engines in forward briefly to stop the boat's movement and bring it alongside the dock. Make any final adjustments by shifting the engines accordingly (starboard reverse, port forward, or vice versa) with light thrust to bring the boat into the perfect position.

Additional Tips:

• Practise docking in open water with one engine running and the other off to familiarise yourself with the different handling characteristics.
• When using twin sterndrives, it is generally recommended to keep the steering wheel centred and rely primarily on the engines for manoeuvring. Even a small turn of the wheel can change the drive's angle of thrust and make things confusing.
• In calm conditions, you can take your time and use only the shifters with the wheel centred. In wind or current, you may need to use the wheel along with one or both drives to act more quickly.
• Learn your boat's handling characteristics. For example, a port drive should push the bow to starboard in forward gear and pull the stern to starboard in reverse. The opposite applies for the starboard drive.

Remember, docking with twin sterndrives becomes easier with practice and familiarity with your boat's unique characteristics.

Docking with one engine

Docking a twin-engine boat with only one engine can be challenging, as the thrust is off-centre and unbalanced, making it very different from docking with two engines or with a single-engine boat. Here are some detailed instructions to help you dock a twin-engine boat using only one engine:

Lessons Out on the Lake

Start your practice in open water.

Exercise 1:

• Assume your starboard engine is running, and your port engine is dead, so you will be turning to port.
• Execute a hard-over turn with the running motor on the outside of the turn.
• The bow will start to curve towards the port side gradually.
• To make this curve tighter, give a short burst of throttle, then slow it down and shift to neutral.
• Watch as the boat rotates and continues its turn to port.
• If you want to tighten the rotation even further, pull the running (starboard) motor into reverse.
• For a Twin Sterndrive or Twin Outboard, turn the wheel hard in the opposite direction, and then reverse to pull the stern further.
• For a Twin Inboard, when reversing the starboard (outside) engine, use no or very short reverse to prevent killing the swing or rotation from forward gear.

Exercise 2:

• For this exercise, keep the starboard engine running and turn hard over to starboard.
• You will notice that the boat requires a much larger radius to turn when the throttle is in forward, as the thrust is now on the inside of the turn.
• When approaching your dock and turning within a narrow harbour, remember to allow enough space for this larger turning radius.

Exercise 3 and 4:

Repeat the first two exercises with the port engine running and the starboard engine off.

Lessons for In the Harbor

Once you are comfortable with the exercises in open water, it's time to move to tighter spaces.

Exercise 5:

• Repeat the previous exercises within the confines of the harbour.
• Approach a large gas dock or service dock, as there is more space and fewer boats.
• It is preferable to have your "live" motor away from the dock and your dead motor closest to it.
• Have your lines and fenders ready, with your First Mate at the aft corner near the dead motor, ready with the FLIPP Line.

Exercise 6:

• Approach the gas dock with the shutdown engine closest to it.
• Regardless of the drive system, forward gear will swing the bow in, and reverse gear will draw the transom in.
• Remember that the wheel position and the effect on the bow will differ depending on your drive system, as explained in Exercise 1.

General Tips:

• Practice makes perfect: spend time with only one engine running to familiarise yourself with the feel of the boat.
• Know your boat's handling characteristics: understand how your boat responds to different engine and wheel positions.
• Be prepared: print out and keep these lessons on board for quick reference.
• Keep the other engine in neutral: this allows for full control of the vessel and quicker response in case of an emergency.
• Trim your engines: depending on your drive system, trim the dead engine up or down to reduce drag or improve steering.

Preparing for docking

Docking a twin-engine boat is easier than docking a single-engine boat. However, it can be a bit intimidating, especially if you haven't tried it before. Here are some tips to help you prepare for docking your twin-engine boat:

• Get to know your boat's handling characteristics. Practice handling and docking your boat with only one engine running, and then repeat with the other engine. This will help you understand how your boat turns and manoeuvres with the thrust coming from different sides.
• Learn how to use the wheel and shifters effectively. When docking with twin engines, it is generally recommended to keep your hands off the wheel and use only the shifters to steer. Turning the wheel, even slightly, can change the angle of thrust and make things confusing. However, in some cases, you may need to use both the wheel and the shifters to manoeuvre effectively.
• Understand the impact of wind and current. Check the wind direction and current strength before docking, as these factors can affect your boat's movement. Use the wind or current to drift sideways into your berth, and be prepared to adjust your approach if a gust of wind knocks your boat off course.
• Deploy fenders and lines in advance. Before approaching the slip, make sure you have deployed fenders and lines as necessary to protect your boat and secure it in place.
• Trim your engines. Adjust your engines slightly using the tilt-trim switch at the throttle. This ensures that the propwash goes under the boat, making it easier to manoeuvre.
• Approach the slip at a 90-degree angle. As you approach the docking area, maintain a perpendicular angle to the slip. Once the middle of your boat is even with the middle of the slip, stop and centre your steering wheel.
• Be prepared to adjust your approach. Docking a twin-engine boat may require some trial and error. If you encounter challenges or misjudge the current, don't be afraid to pull away from the slip and start over.

Using the wheel to dock

Docking a twin-engine boat can be a stressful experience, but with practice, it can be done safely and smoothly. Here are some detailed instructions on using the wheel to dock a twin-engine boat:

Prepare for Docking:

Before approaching the dock, there are several steps you should take to ensure a safe and controlled docking procedure. Firstly, deploy fenders and prepare dock lines as necessary. Check for wind and current conditions, as these factors can influence your docking approach and require adjustments.

Approaching the Dock:

As you get closer to the dock, drive up close to your intended slip or berth, maintaining a slow speed to give yourself ample time to react to any changes. It is recommended to approach the slip at a 90-degree angle, and once the middle of your boat is aligned with the middle of the slip, stop the boat and centre your steering wheel.

Using the Wheel to Turn:

At this point, it is generally best not to touch the steering wheel, and instead, rely solely on engine manoeuvring by shifting one engine into forward and the other into reverse. This will cause the boat to spin. Remember, the bow will move in the direction of the throttle shifted into reverse. For example, shifting the starboard throttle into forward and the port throttle into reverse will spin the bow to port.

Completing the Docking:

Ideally, with no wind or current, you would have enough room to spin the boat until it is parallel with the finger pier. From there, you can simply shift both engines into reverse idle and back into the slip. However, space constraints or unfavourable wind/current conditions may require additional manoeuvring. If you need to reduce the rate of spinning, you can take the forward throttle out of gear, allowing the boat to continue backing up while still spinning. As you move into the slip, you can make final adjustments by briefly reversing both throttles to stop any spinning motion, and then slowly back into the slip, adjusting as needed to align the boat alongside the dock.

Additional Considerations:

It is important to note that the specific procedures for docking a twin-engine boat may vary depending on the type of propulsion system. Twin inboards, twin sterndrives, and twin outboards each have unique characteristics that influence the docking process. For example, twin sterndrives have articulating steering systems, meaning the wheel turns the twin drives, which redirects thrust. Additionally, the positioning of the propellers and rudders can differ between inboards and sterndrives, impacting the thrust and handling during docking.

In conclusion, while docking a twin-engine boat can be challenging, with proper preparation, a good understanding of wind and current conditions, and a well-practised technique that suits your boat's propulsion system, you can confidently and successfully dock your boat.

Frequently asked questions