Learning boat tuning is just like learning racing rules. You can only get so far by word of mouth. You really have to read to get past the middle of the fleet. The most helpful articles will probably come from Model Yachting, CR 914 News, and the AMYA website. This teaser is CR 914 specific and abbreviated intentionally to provide a head start to anyone motivated to learn to tune their boat intuitively.
All 914s are the same. Even yours is capable of being tuned to be the fastest on the pond. There are multiple tuning choices available to achieve the same result. So, two boats, tuned differently for one set of conditions, can have equal boat speed. As conditions change during a day's racing, without further adjustments, one boat will become faster than the other.
Tuning a 914 begins with deciding what conditions to tune for. The usual variables are wind, including fluctuations in direction and speed, and waves. If the skippers you are racing against aren't up to speed yet in the tuning department, your job is a lot easier.
Up to about 6 mph, the boat is tuned for all the power it can take. Beyond 6 mph, the boat has to be progressively depowered in a manner that retains control. In variable wind conditions, sails are sometimes twisted to alternately take power from prevailing winds and swirls.
Tuning is always for the best performance to weather. The first boat to the first weather mark always wins the race if no further mistakes are made.
| CR 914 ADJUSTMENTS AND WHAT THEY DO | |||||
|---|---|---|---|---|---|
| Adjustment | Primary Use | Secondary Use | Inadvertent Changes | ||
| Forestay | Mast Rake | Mast Bend | Jib Sag | Mast Bend,Sheets,Slot | |
| Jib Halyard | Jib Luff | Mast Bend,Sheets,Slot | |||
| Jib Sheet | Jib Slot | Jib Travel | |||
| Jib Outhaul | Jib Draft | ||||
| Jib Foot | Jib Height | Mast Bend | Jib Sag | Mast Bend,Sheets,Slot | |
| Topping Lift | Jib Shape | Jib Twist | |||
| Backstay | Mast Rake | Mast Bend | Jib Sag | Mast Bend,Sheets,Slot | |
| Main Sheet | Boom Position | Boom Travel | |||
| Main Outhaul | Main Draft | ||||
| Main Downhaul | Main Luff | ||||
| Boom Vang | Main Shape | Main Twist | |||
| Boom Ring | Boom Travel | ||||
| Diamond Stays | Mast Stiffness | Mast Reshape | Main Twist | ||
| Upper Shrouds | Mast Straightness | Main Twist | |||
| Middle Shrouds | Mast Straightness | ||||
| Lower Shrouds | Mast Straightness | Mast Reshape | |||
| Concepts | |||||
| Added draft gives more power to accellerate but holds the boat back on top speed due to greater drag | |||||
| Less draft has considerably less drag and produces the greatest top end speed | |||||
| Waves take more power to get through and will often stop a boat with minimal sail draft | |||||
| Reducing draft depowers the sail | |||||
| Twisting the sail depowers the upper portion of the sail | |||||
| Bending the mast takes draft out of the main and adds to the twist | |||||
| The greatest detriment to pointing ability is a sagging jibstay | |||||
That should be enough to get you started. The rest is up to you.
Reading traps to look out for include many authors who are not able to communicate a complex subject effectively, and who also may not have the full picture in perspective. The biggest trap concerns the reader's inclination to understand in terms of the reader's own views. Sometimes the writer can be talking about a different concept without the reader being aware.