Best speed is achieved by ones ability to find the right combination of the following variables
Wind
Waves
Opponents action
Course steered
Sail trim
Boat balance (including rudder/centerboard
The key to boat speed is feel. Feel is achieved through a combination of sail trim, boat balance and course steered which results in the correct amount of weather helm feel for any given wind and wave condition.
To Increase Weather Helm Feel By(or decrease by using opposite of below)
Move body weight forward.
Move body weight to leeward.
Sheet boom further to windward.
Sheet tighter on mainsail leach.
Ease off outhaul for fuller mainsail .
Ease off cunningham so draft moves aft.
Straighten mast by reducing pre-bend for fuller mainsail.
Move centreboard forward.
Rake rudder more aft.
Steer a course further away from wind than the sails are trimmed for or the boat is balanced for.
The key to top speed is how you use your natural feel to mix these ingredients in the right combination. Once out on the race course this mix of course steered, sail trim and boat balance is the difference between being fast or slow.
Natural feel can really only be learnt by time spent sailing (especially in small dinghies starting at an early age). A sailor with feel will automatically make adjustments without even knowing the reasons. The late starter may have to think why a certain adjustment is necessary.
For the best results you need to combine natural feel with a good understanding of what is fast and the reasons some combinations work better than others. What is obvious is that variables – course steered, sail trim and boat balance are all completely dependent upon each other for best speed.
Light wind Boat speed 0-5 knots
Upwind: The key points are to increase weather helm and create efficient wind flow over sails. Body and helm movements must be super smooth so as not to disturb wind and water flow. It is critical to remain calm, both mentally and physically (this is not easy as you often have to remain in the same position for long periods).
Use mast pre-bend and outhaul to flatten mainsail.
Tighter rig tension will pre-bend the mast (for dinghies) or ease rig tension to power up head sail for racing keelboats.
Have both jib and main luffs eased to create a few horizontal wrinkles, allowing the draft to move aft for better light air sail shapes.
Sheet both main and jib with twist to leeward on leaches to help wind flow.
Be careful not to over sheet the boom. Use the boom well off the centre line in very light breezes and only when sure of your boat speed, attempt to sheet further inboard. Boom down for further drive.
Keep jib slot open and flowing, remember boom is further to leeward than usual.
Rake rudder aft and centreboard maximum forward to increase weather helm feel.
Position weight to leeward and forward to create more weather helm and reduce wetted hull surface. You should be careful not to disturb wind flow in the slot between the jib and mainsail.
Try to steer by watching wrinkles along the jib luff (on monotypes, the main) allowing them to be slightly back winding for best flow. Try to create correct weather helm feel by careful use of body movement. Don’t allow the helm to go dead by flattening out leeward helm. Try to balance the boat for light airs using rudder and centreboard positioning, rather than having to use too much leeward heel to achieve the desired weather helm feel.
Reaching: The same principles apply as for upwind, i.e. best wind flow by having luff wrinkles slightly backing, combined with good helm feel.
Using the variations in wind speed is critical to fast reaching legs i.e. pointing down in the puffs and up in the lulls.
Running: In very light airs running utilizes the same principles as broad reaching or low course reaches, finding the right combination of boat speed versus best course to mark. As wind increases your gybing angles should become smaller, allowing you to steer more directly downwind.
Remember a Dabbie planes even up wind,keep it flat,very flat and dont kill it
Good luck, in the words of Gary Player ” the more you practice the luckier you will get”