Characteristics of twin-engine boats
To maneuver a two-engined craft effectively, one must first know the basics and the different forces that act on it. It is then necessary to translate the acquired knowledge in adapted actions according to the conditions of navigation. This kind of boats is just the opposite of square stern canoe. You can have a look at the Best Square Stern Canoe for Fishing Reviews to choose the best one.
The ability to maneuver a twin-engine boat is an aptitude that requires not only a good knowledge of the characteristics of the boat but also a lot of training. If you know how to run an outboard motor for a dinghy, then you can easily run it.
Propulsion and steering on a twin-engine boat
The propulsion and steering systems on a twin-engined boat are intimately linked. Indeed, it is useless to apply a thrust if one can not control the direction of the boat entirely. This explains why, in most cases, the drive system is also used to steer the boat. Generally, there are three configurations to ensure the thrust and control of the direction of movement of a twin-engine boat:
- Two propellers and two separate rudders.
- Two propellers and two rudders combined and steerable (outboard motors and geared motors).
- A steerable mechanical pump mechanism (turbine / jet).
On a two-engine boat, the two propellers are often counter-rotating. They are propellers of similar characteristics, but which turn in opposite directions. In the forward direction, the starboard propeller often turns to the right (clockwise) and the port propeller rotates to the left (counterclockwise).
Most maneuvers on a twin-engined boat are done through the clutch and speed selectors.
In addition to rudders, the steering can be controlled by acting on the speed and direction of rotation of each engine. For example, when both propellers rotate at the same speed and in opposite directions, the lateral forces exerted by each propeller are canceled by the other.
This feature can be used to facilitate maneuvering the boat in a narrow area with a low angle of rotation, especially when docking the boat in a saturated harbor.
The steering of the boat can be adjusted at any time by acting on the speed and direction of rotation of the engines. If you want to go to starboard, increase the engine speed on the port side and vice versa. To change your direction at reduced speed, engage the selected engine for one or two seconds, just enough time to turn the propeller, then move the selector to neutral (N).
In marine navigation, the pivot point designates a point that plots the rotation curve of a boat, that is to say, the place where the boat will pivot during a turn. This point is located in the forward part of the boat, but its position varies depending on several factors such as hull shape, boat speed, acceleration, etc.
The pivot point generally moves in the direction of movement of the boat both forward and reverse. Moreover, its displacement is one of the factors that make it challenging to maneuver boats, especially in reverse.
As the boat turns on its pivot point, the stern moves in a turn. To evaluate the displacement of the boat, it is, therefore, necessary to monitor the stern rather than the bow. Besides, when backing up, pay attention because the bow can swerve under the effect of the wind.
When steering the drive system to port or starboard, you apply a pushing force in the chosen direction. This causes the stern to move around the pivot. The boat makes a turn. Outboard engines are usually equipped with a small fin placed below the propeller. This fin helps maintain the direction of the boat, including high speeds. That said, the maneuverability of the boat and control of the steering depend primarily on your ability to direct the thrust of the discharge current created at the propellers at an appropriate angle to the longitudinal axis of the boat.
Generally, the propeller on the outside of the turn has a better thrust angle than the helix on the inside. When turning in a narrow space, you can put the throttle on the engine outside of the turn arc. This will help you get better-directed thrust, as the engine farthest from the pivot becomes an effective lever and provides better steering control. This maneuver can be applied both in forward and reverse.
As its name suggests, lateral thrust is a lateral force produced by the propeller. When the propeller rotates, the water is pushed between the blades, thus producing forward thrust. That said, some of the water is thrown aside by the edges, creating a slight lateral movement.
Unlike a single-engined boat where lateral thrust can occasionally impede reverse maneuvering, in a twin-engine propeller with counter-rotating propellers, it is possible to take advantage of the lateral thrust of each propeller to turn the stern, whether left or right. To the right. If you use the forward thrust of a propeller and reverse the direction of the other, you can almost do a full turn on the spot, which is very difficult with a single-engined boat.
If the propellers are not counter-rotating, you can turn the boat with one motor running in reverse and the other in reverse, but in this case, you will have to use the bar to adjust the direction. This maneuver is always useful in confined areas.
- When the starboard propeller is in forwarding gear, and the port propeller is locked and the rudder is in the neutral position, the boat will make a wide turn on port while slowly moving forward.
- When the starboard propeller is in reverse, and the port propeller is locked and the rudder is in the neutral position, the boat will make a wide turn on the port while slowly moving to the rear.
- When the port propeller is forward, and the starboard propeller is locked and the rudder is in the neutral position, the boat will make a wide turn on starboard while moving slowly forward.
- When the port propeller is in reverse, and the starboard propeller is stuck and the rudder in the neutral position, the boat will make a full turn on starboard while moving slowly backward.
Mooring a two-engine boat
Mooring means keeping the boat against a dock or raft using cables or ropes (mooring lines). This is one of the most delicate port maneuvers for a boater. On the one hand, the ports are often saturated and the proximity between the ships leaves little chance for the error. On the other hand, many factors tend to make maneuvers more complex: wind, weather, gusts, currents, water features, fatigue, etc. This explains why almost all boat incidents occur when approaching ports, especially at anchorages and moorings. Besides, once moored, the boats are subject to the rhythm of wind and swell, which can put them at risk if the mooring is not done correctly.
Mooring a twin-engine boat is more comfortable than that of a single-engine boat. That said, the principles are generally the same:
- Go slowly (at minimum speed) to minimize risk.
- Take the time to adapt to the characteristics of the mooring port to choose the most suitable technique.
- Choose the most appropriate location; refuse a place if the maneuver is too delicate.
- Never improvise in case of difficulty, it is better to come out and start again to secure the mooring.
- Protect the boat by setting up appropriate equipment (fenders, fenders, etc.)
- Always plan a “B” plan.
To begin, you must prepare the mooring in advance and open water. Learn about the weather conditions and characteristics of the mooring port: wind force and direction, current, maneuvering area, water depth, obstacles, a radius of rotation, port traffic, etc.
Of course, the mooring techniques vary depending on the mooring support (dock, fixed pontoon, floating pontoon, catway, dangle, etc.). In the Mediterranean, for example, mooring a boat is most often perpendicular to the dock on a dangle. Generally, regardless of the type of boat, the principle is almost the same, whether it is an in-board, an outboard, or a sterndrive.
For docking perpendicular to a dock or pontoon, move slowly into the port. Once you are in the entrance channel, pay close attention to three main elements to better anticipate the behavior of the boat:
- Keep an eye on the wind vane to strictly follow the direction and strength of the wind.
- Locate the strength, intensity, and direction of the water flow.
- Evaluate the current traffic in the port and identify any obstacles that may impact the mooring.
There are several methods for mooring a twin boat against a dock. For a beginner, the simplest way is:
When approaching the dock, the direction of movement of the boat must be parallel to the boat. Once you are in front of the dock, stop the engines and center the bar. Then reverse the direction of engine rotation on the port side. The engine on the starboard side must maintain the same direction of travel. This maneuver allows the boat to move towards the dock in reverse. During this operation, be careful not to use the steering wheel to change the direction of the boat.
Mooring can only be done using the engines. To stop the rotation and keep control of the boat, you can briefly reverse the direction of rotation of both engines. If the bow is too far from the mooring location, you can tip slightly backward to starboard and then to port. Once the boat is in place at the dock, all you have to do is attach the front and back end to complete the mooring.
Departure from the wharf
The exit method usually depends on the technique used for docking. However, the most straightforward technique to leave a berth at the dock is to go out in reverse. The idea is to rotate the stern outward by acting on both engines gradually. Be careful because the presence of another boat or obstruction of any kind often complicates the exit of the berth. Current and wind can also affect the level of control of the boat.
Maneuvering a twin-engine boat: what to remember
Moving a two-engine boat is usually more comfortable than that of a single-engine boat. Here are some tips to help you:
- Always plan your maneuvers.
- Never improvise in case of difficulty or problem.
- When maneuvering your boat in a narrow area, always use the engine on the outside of the turn arc to control the direction.
- Never take a maneuver lightly and always pay attention, even if the sailing conditions seem favorable to you.
- When mooring, always drive your boat at minimum speed, especially in a saturated port: the less you go fast, the less you hit hard!
In the end, we hope that the information provided in this article will help you better maneuver your twin boat. You now understand the importance of the ability to handle both engines to adjust the speed and direction of the boat. So take the time to practice in a bright space to adapt to the characteristics of your boat and evaluate its behavior (engine power, acceleration, the radius of rotation, etc.). Remember that the key to the success of the various maneuvers is the time and effort you will spend on learning and training!