WHAT IS THE PROPER AMOUNT OF HELM FOR AN EC12?
When going to weather many sailing texts advise adjusting the boat for 3
to 5 degrees weather here, but this amount seems quite slow on an EC12. With
the Dial-a-Helm (Bobs term), I have had some opportunity to explore different
helm angles tuning against boats of essentially equal speed. Here are my
tentative conclusions. I hope Kelly will tell me if I am right.
Beating, light air (0 to 2 mph)
Some weather helm is a must. The keel is near stall and lowering the
flaps helps provide the required lift with less drag penalty. Because the lift
is now created at a lower angle of attack the leeway angle is reduced. Weather
helm in light air also helps the boat find the wind and will hopefully prevent
you from sailing too low for 10 to 20 boat lengths before realizing it. About
1 degree helm seems an appropriate target.
Beating, moderate to heavy air (4 mph and up)
I have convinced myself that one should aim for 0 degrees helm, but if
anything err on the side of weather helm. You will probably not notice a speed
detriment with 1 degree helm but as you approach 2 degrees a loss that is
significant on our long courses at Juanita and Coulon will be apparent. By the
way, even Jerry has given up tuning for lee helm.
Reaching
Over trimming the jib seems more effective than carrying a lot of helm.
In light air you can often balance the boat with the jib only; do so if you
can. As the wind increases you will have to add some helm to prevent the need
to sheet the jib so tight that it cuts off the slot. Up to 2 degrees helm
seems to have little adverse effect so I use this amount freely. In heavier
winds a practical maximum is about 4 degrees weather helm, beyond which it is
probably better to ease the sails to reduce heel angle and thereby reduce
helm.
On heavy air reaches you can set 3 to 4 degrees helm, over trim the jib some, then adjust the balance with the sail servo. Its sort of like power reaching on a full size boat with a good crew.
Running
In moderate to heavy air EC12s will have some weather helm, even when
wing and wing. In moderate winds about 1 degree weather helm dialed in at the
weather mark will help you keep off the rudder. I think that the difference
can be at least 1\4 boat length, maybe even 1\2 boat length at our Juanita
site.
If you use helm this way, either with your trim lever or add-on transmitter circuits, you must be meticulous about changing the setting when you tack, jibe, or round a mark. Otherwise you will give up way more than you ever gained.