Floating objects have some common properties with objects in space. An object floating on water appears near frictionless. The main friction is the displacement of water. With the right hull shape this displacement friction can be near neglectable.

Any motion the vessel has will continue until a force is executed on the vessel.

Unlike rockets a vessel seems not completely to follow the action equals opposite reaction rule. Vessel hydrodynamics play a significant role.

It is a Multi Vector Plot

Most propulsion systems just give a thrust in one direction, an entire system is involved in the direction the vessel eventually goes. Hull, waves, wind, current even the centre of mass of the vessel as well as side effects of the used propulsion will give deviations from the expected opposing direction.

Pick up the floating branch and use the forked end to knot your towel to it, you have just made a paddle.

Manual Propulsion

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  If conditions allow it you can jump overboard and swim, towing is more efficient then pushing when swimming. Regulations often prohibit swimming in or near locks, bridges or near other water furniture.
  

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  If the stern is low enough to the waterline, hold your hands on the stern and flipper with your feet. Again only if conditions allow to get overboard, water temperature or waves can be a hazard.
  

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  Paddle with your hands, pushing the water backwards. This requires low boards and a moderate water temperature.
  

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  Paddle with a praddle, a kind of swimming fin for your hand. This increases the surface of your hand and probably also the efficiency.
  

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  Use a bucket on a rope, throw in near the bow and drag it to the stern. This works best if you have hallway boards on your vessel and no shrouds.
  

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  Swing the rudder over less then 90 degrees, most often your small vessel will slowly move yawing forward. More to one side makes that the direction of slow rotation.
  

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  Scull with a single oar making sideways figure-8 movements. This may require an oarlock in the stern, a forcola, two pins or a rope can also give enough support. Stand wide with your face to the stern, take the oar in two hands and swing sideways pivoting in the oarlock, during the swing you keep the blade slithly tilted to create some force against the stern. On the end of each swing you rotate the blade near ninety degrees, now swing the blade to the other side. Repeat this until you feel a near constant force pulling the handle of the oar abaft. You may now notice the sideway figure-8 motion your hands make.
  After practicing for some years you may be able to look forward, sing and get a job as a gondolier.
  

  The motion of the blade:
  \  ->      Move the handle from port to starboard.
          \  The blade will move from starboard to port.
          -  Rotate the oar counter clock wise.
     <-   /  Move the handle from starboard to port.
  /          The blade will move from port to starboard.
  -          Rotate the oar clock wise.
  \  ->      Continue until destination or blisters.
          \
   ___U___   | Notice the oarlock at the centre of the stern.
  / stern \  |
  | Vessel | V Resulting direction of the vessel.
  

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  Very light vessels with near none hydrodynamic properties like inflatables or coracles can not be sculled from the stern. Use a paddle instead and holding it with two hands near vertical in the water ahead of the supposed bow. Use the blade to drag the water toward you then rotate the blade and slide it forward again. A small course correction at every drag may be required.
  

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  Put a pole to the ground, just behind the bow and push backward, if possible walk to the stern while pushing it, do not let go! This works best if you have hallway boards on your vessel and no shrouds.
  

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  Jump on shore with a line attached on the mast, drag the vessel by just walking along the shore. At least a second person is required to steer the vessel keeping it clear from the shore. A horse can do this as well, this is why barge canals have a towpath along the entire shores.
  

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  Paddle sitting with a paddle, by alternating board you can steer slightly yawing in a line.
  

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  Paddle sitting with a paddle, by only paddling over one board and giving a compensating sling outward you can steer in a straight line, just a little off of the length axis of your vessel. This is called a J-stroke.
  

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  Row with two oars, go sitting facing the stern, your most powerfull stroke is leaning backward and pulling with your arms. Oarlocks are usefull, however even a simple pin or rope attached in direction of the stern is sufficient as pivoting point. Rowing with two oars you can easily steer, a little by making shorter strokes on the intended direction. By letting the oar on the intended side run in the water you make a more sharp curve. By stroking one oar and keeping the blade of the other in position you make a small circle. By stroking one oar and backing the other you will turn on the spot. Only use backing if you have oarlocks!
  

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  Row with one oar, this only works if you are doing this in couples, another rower on the other board is required. When rowing with two or more pairs the person on the helm is in command and has to give orders for manoeuvring with any accuracy. All rowers synchronise their motion with the rower abaft, or in front of them.
  

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  A relaxed but not very efficient way to move by man power is the pedal propulsion of swan boats. Your legs are powerfull enough but the peddlewheel mainly splashers on the water.
  

Wind Propulsion

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  Use sails to propel your vessel in any direction except directly into the wind.
  

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  Use a kite to propel your vessel in any direction more or less with the wind.
  

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  Use the superstructure of your vessel to drift downwind. Perhaps using an anchor and the rudder to have any control of the speed and actual direction.
  

Water Propulsion

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  That is to go with the flow and travel down a river on a raft. Any other vessel will also go with the flow but as it will be build to have as little drag as possible you may require a drogue to catch the current. Basically you will go nowhere as the current does not park you at a quay. Even ocean currents tend to go just in huge circles known as gyres.
  

Motorised Propulsion be it Combustion Engine, Electric or Thermonuclear

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  A paddle wheel behind the vessel, propelled with a sternwheel. The major drawback is that the rotation force has to be applied on the very sides. Also hard and complex to steer. This propulsion does not require much draft and gives a lot of force.
  

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  Paddle wheels alongside the vessel, propelled with sidewheels. These give much better steering properties. Still not very efficient and adds to the beam of the vessel.
  

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  A propeller converting the rotational motion of an engine, like the Archimedes screw, into a linear motion of water is already more efficient.
  

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  An open propeller can be used in reverse, however due to maximising the efficiency for normal direction it will have several drawbacks when used in reverse. The thrust is only a fraction of the forward use and the rotating motion causes the propeller to walk, the bottom half of the propeller 'walks' sideways. This propeller walk also happens in forward direction but is near neglectable with any speed.
  

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  A tube in front of the propeller already gains the efficency as less water will be re-propelled, causing a short loop or short circuit on open propellers.
  

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  Mounting the entire propeller inside a tube, a tunnel, will also prevent the water flowing just outward, sideways, up and down, from the propeller. Though this tunnel also complicates the construction and maintenance.
  

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  More efficient still is the use of pods, the propeller is completely enclosed inside its tunnel. The entire pod hanging under the hull can be made to turn, this is more accurate in direction of propulsion. This is even more complex in construction, maintenance can however become more easy by exchanging the entire pod. An obvious disadvantage is the increased draft and the pods beeing the first to hit the rocks can be a problem.
  

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  A waterjet has a completely enclosed propeller a seperate fixed intake and a rotatable nozzle to direct the propulsion. With this construction the propeller is inside the hull and the draft is reduced compared to outboard propellers.
  

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  A Voith Schneider propeller is a set of vertical blades rotating in a circle at a constant speed. In neutral they only give a tiny rotational force, though giving a section of the blades an angle off the circle, thrust is generated. The section gives a very accurate direction of thrust and the angle gives a very high accuracy in force. This is often used on tugboats and ferries.
  

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  A single propeller is only used on very small vessels, most larger vessels have two, rotating in opposite directions at the stern and at least one probably electric under the bow.
  

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  The only exception on the single propeller vessels is the submarine, these use a single slow rotating propeller. The main target for this single propeller is not to make any noise at all. This has many drawbacks but all are to be taken for granted.
  

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  Sailing yachts may have open, folding propellers. The blades are folded together to the rear reducing draft, when not in use.
  

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  Airboats, or swamp boats have a huge air thrusting propeller on the stern. Large flat ailerons are used to give some control of direction.
  

• Hovercraft, like airboats use air-propellers for propulsion, some with ailerons some individually rotatable. They also use an aircushion to lift the hull above the water.
  

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  There are vessels running on wave propulsion. The pitching motion of a yacht is converted to thrust with an op and down going motion of a hydrofoil at the stern. Another example is a cargo boat where the engine generates the slow up and down going motion of a foil.