Most of the time you can allow the computer to handle sail trim automatically while you focus only in steering a course through the water. However, as you advance there will be times and indeed entire races when you must understand how to manually trim the sails for the desired performance.
The physics of sailing Edit
thumb|500px|right|The Physics of Sailing You don't need to be a rocket scientist (or an aeronautical engineer) to sail a boat. It does help if you can add and subtract 30 and/or 45 to and from the true wind angle displayed on the digital instrument panel. TWA] has the same 0° to 360° range that you can see on any compass.
For those inquiring minds this video may help you appreciate the similarity between the soft cloth of a sail and the rigid wing of an aeroplane. In the later part of that video the concept of sail trim is introduced and this is useful to understand when you are playing VSK in Simulation mode because you must manually trim the sail(s) to generate the desired lift from the curvature of the sail.
In Arcade mode and and Tactical mode you can let the computer take care of sail trim and all you need worry about is steering a course through the water. Tactical mode also allows you to switch between automatic and manual sail trim whenever you wish.
Usually the desired lift is that which produces maximum forward velocity however there are times when an experienced skipper wants the boat to sail slower than this and there are even some uncommon circumstances when reverse motion is desirable. While VSK does not emphasize the sail handling aspect of the sport to the degree that you can, for example, back-fill the sail and quickly accelerate in reverse you may find your boat has spawned in the pre-start area pointed head to wind and therefore, knowing how to steer her to get onto a desired tack is a major time saver.
Optimum velocity made good Edit
The game's user interface (UI) provides a wind arrow in Arcade and Tactical modes of play and the color of that arrow is an indication of the lift being generated by the sail at any moment in time.
- A green arrow is maximum lift* which translates into maximum velocity made good (VMG).
- Yellow, orange, red are progressively worse cases of a luffing sail (which sailors will refer to as a de-powered sail) and so this means that you lose boat speed very rapidly.
- Light-green, light-blue, dark blue are progressively worse cases of an over-trimmed sail (which is equivalent to a stall in aircraft terms) and when this happens the sail is being pushed by the wind in much the same way that the square rig ships of by-gone years were pushed along by the trade winds. It is a sub-optimal use of the sail.
- * Is this the case or is green indicating optimum VMG?
When playing in Simulation mode those same ranges of color are made visible inside the triangular slider at the right of the screen. Each major division represents 10° of angular position of the sail relative to the center line of the boat. When you want maximum power form the sail (for maximum acceleration) you sheet in or sheet out to cause that indicator to glow green or maybe slightly yellow-green. Just remember that as you change course by a few degrees you must also adjust sail trim by a few degrees to preserve the same aerodynamic surface to the wind.
thumb|300px|right|Apparent wind explained Similarly as you gain boat speed the apparent wind shifts in the direction of travel (AWA in the instrument panel) and so to maintain the same aerodynamic lift from the sail you must trim the sail inboard by a small amount.
Trimming your boat for maximum power and maximum acceleration can be about :
- adjusting the position of the sail for maximum lift or
- adjusting the helm to alter the boat's course through the water or
- a combination of both
When sailing close-hauled you will typically trim the boat's heading to take advantage of any wind shifts that lift your course toward the upwind side of the destination mark. Helmsmen refer to this as feathering the boat.
When running downwind you may also prefer to feather the boat because usually you want to sail as deep as you can without losing to much boat speed and if there are waves (swell) then you may be steering in rhythm with the swell to maximize power/acceleration when on the rear surface of a wave and maximise speed/minimize distance to next mark when on the front surface of a wave.
- In both cases you choose to feather the boat because it is the quickest way to maintain trim. The boat is more responsive to small steering adjustments where as the sheets controlling the position of the sails are under a very high load and much more difficult to trim.
When sailing a broad reach or a beam reach point of sail you may choose to adjust the sail trim rather than the boat trim because generally you are steering a course for the shortest distance to next mark having adjusted for any tidal stream enroute.
Of course you won't always appreciate this in a cyber-sailing situation but the game engine does a pretty good job of making the preferred trim method quick and responsive while the alternate is slow and unresponsive.