Basic Vessel Control
Keeping a vessel under control depends on the type of vessel being skippered. Nothing can compare to real life experience, but covering the basics can give some understanding of maneuvering. Take every opportunity to practice maneuvering in calm water. Understanding how a vessel handles can help when conditions are not perfect.
Types of Vessels
The two types of boats discussed here are twin engines and single engine. Twin engines, or dual screws, have two drive shafts and can be operated in forward, reverse and independently to maneuver more precisely. Twin engines are more common with planing hulls which require greater horsepower to reach optimal speeds. Single engines, or single screws, are common on trawlers and sailboats that do not need as much horsepower or speed to be economical. Twin engine rudders tend to be smaller, requiring more water to move across the surface to steer. At slower speeds the rudders can often feel useless. Single engine trawlers have a slightly larger rudder, and sailboats have an even larger rudder allowing for larger swings in maneuvering at slow speeds.
Basic Docking Control
The most important thing is to take it slow and know how the boat responds to the environment. Call ahead to the dock master or other boats at the dock to find out about the wind and current. Getting close to the docks, around 500 yards, put the boat in neutral and see how the current affects the boat. Once near the dock or inside the marina, take it slow. Pulse the engine by putting it in gear and then out of gear. Just enough to give motion and direction to the boat. If it doesn't feel doable, move out and try again. It doesn't matter how long it takes to dock as long as it is done safely. It should be the mantra of every boat skipper docking, "take it slow, don't rush".
Single Engine
Single engine vessels rely mainly on a rudder to steer when not equipped with a thruster. This can make maneuvering in tighter spaces more difficult when there is current pushing the hull. With the rudder straight, the engine in forward moves the boat forward, with the engine in reverse the boat moves backward. Even light current can make staying in a straight line difficult.
While moving forward, turning the wheel in one direction steers the boat in that direction. Most steering systems on boats are set up the same way as cars except for tiller steering. Tiller steering is found on smaller sail boats and outboard engines. With tiller steering, pushing the tiller arm away from the intended direction steers the boat in that direction.
For single engine boats, there is one other factor that can make maneuvering in reverse more difficult, prop walk. This occurs because the shape of blades cause a difference between the up stroke and the down stroke. The up stroke generates more thrust on that side pushing the vessel in the opposite direction. It is very important to know if a boat has right or left hand props when reversing. This will help to anticipate the movement when the boat is put into gear and can be compensated for with the rudder if needed.
Knowing how the rotation of the props affect the maneuvering at slow speeds is vital as it can be exaggerated by turning the rudder to much trying to compensate. It can be easy to forget as while driving forward it can take a larger rudder swing to move the bow. Moving forward the rudder is basically steering the bow, but in reverse the rudder is steering the stern and in combination with prop walk, it take far less rudder swing to move the stern in the direction affected by prop walk.
Twin engines
Twin screw vessels have an easier time maneuvering. Usually equipped with a clockwise prop on the starboard engine and a counterclockwise prop on the port engine, mitigating much of the prop walk. Larger vessels are usually equipped with a bow thruster as well. This is not say there are not challenges to overcome but overall, twin screw boats can compensate easier than single screw boats.
The basics are the same for general propulsion, engines in forward gear the boat moves forward, engines in reverse and the boat moves in reverse.
The same is also true for how the boat steers as well. Most twin screw boats steer the same as a car, turning the wheel right steers right (starboard) and turning left steers to left (port). The difference is in close quarter maneuvering and sitting still, like waiting for a bridge to open.
Maneuver through a marina by putting the rudders in a neutral (centered) positions and use only the engines. Using short pulses of the engines the boat can be steered in the direction it needs to go. To go left, pulse the starboard engine forward while leaving the port engine in neutral. The forward force from the starboard engine moves the boat in opposite direction. To go right pulse only the port engine in forward while the starboard is in neutral.
Reversing an engine pulls the stern in the opposite direction of the engine that is being pulsed. The starboard engine in reverse pulls the stern to port and the port engine in reverse pulls the stern to starboard.
When this is used in conjunction with a bow thruster, the boat an be eased laterally into position. Again using pulses to get the boat into motion to create a smooth path.
Where the twin engine boat excels in the ability to pivot with little to no movement off the center axis. This enables the boat to approach a space and then pivot in either direction to get a good line on docking or moving out in a tight alleyway. In combination with a bow thruster can increase the spin effect or slow it down.
Even though maneuvering can be easier with twin screw engines, it is just as important to practice these techniques in an area with plenty of room to move, calm water and out of the way of boat traffic.
Thrusters
In combination with the engines and rudders, some vessels may be equipped with a bow thruster, a stern thruster or both. The thrusters are designed to provide thrust to either the bow or the stern to help maneuver the vessel into place. Using the combination of thrusters and engines can allow for large vessels to be guided into tighter spaces with less chance of collision.
Thrusters should be sized for the weight and length of the vessel. Heavier boats will need larger thrusters to be effective. The controls for the thrusters are usually located near the throttle controls at the helm station. The thruster forces water in the opposite direction than the controls are pushed. If you push the lever to starboard, the thruster forces water from the starboard side to the port side, pushing the boat to the starboard. While it can be tempting to just run the thruster continuously, they are intended to be used in short pulses. Overusing the thrusters can cause the motors to overheat and shut down until the temperature fault circuit on the unit cools and resets. An improperly sized thruster can cause excessive current, and can result in a blown fuse, damage to the batteries, damage to the wiring or all three.
If the vessel is equipped with both bow and stern thrusters, the boat can be spun in either direction or sideways by using only the thrusters.
Boats that only have a bow thruster can use the thruster to assist in maneuvering while using the engine(s) during docking.
Practice Etiquette
With the basic understanding of a boat movement, as mentioned many times, it is time to practice. Regardless of the location or if permission has been granted to practice, you still need to let other boaters know what is the intention over the radio. If within a marina turning basin, always get permission first and ask for the marinas working channel. This will eliminate confusion and the marina will know what kind of traffic they are expecting and if it safe to proceed. Once the marina has given their permission, use the vhf radio to make a broadcast on both channel 16 and the working channel for the marina. The message should be the same for both channels but make sure the radio is switched to channel 16 after the announcement in the event another vessel needs to enter or exit the area:
Sécurité, Sécurité, Sécurité, This is (vessel name) at (marina name) conducting practice maneuvers in the turning basin, all concerned traffic contact on 16, (vessel name), out.
When you are done practicing state on both 16 and the marina working channel:
Sécurité, Sécurité, Sécurité, This is (vessel name) at (marina name) cancelling practice maneuvers in the turning basin and clear, (vessel name), out.