Hey guys,
I recently picked up Rick White's Cat Sailing for the 90's... I got to downwind section, don't remember the page number, but he talks about two methods of sailing downwind.
The first being set the sails for the course and then steer to keep the tell tales going.
The second was keep the bridle wind vane 90 degrees to the boat and adjust the sails.
The thing I don't get is how is the second method different, if you keep the boat 90 degrees to the wind then your sails shouldn't need to be adjusted right, you are just staying on a beam reach which is what the first method is. I know i'm missing something, been a great book so far.
Consider walking around a carpark....
Wind is North at exactly 1mph.
Stand in the middle of the car park. Where is the wind coming from ? Answer - N at 1mph
Now walk south at exactly 1mph - where is the wind - nowhere, you are walking in the same direction as the wind at the same speed. You feel NO wind.
Now turn around and wak directly INTO the wind at 1mph. where is the wind ? in your face at 2mph
Now turn east and walk at 1mph, now where is the wind? well it's now coing from NE as you have a VECTOR of the true wind (N) plus 1mph east (your walking speed) and the wind you will feel is root(2) 1.41mph.
now turn southeast and walk at 1mph, again the wind you FEEL will be shifted as a function of the fact you are walking at an angle to the wind, the faster you walk, the more the apparent wind will go east.
now do the same on your boat. Sailing southeast in a North wind, as you speed up, the VECTOR changes and the wind moves east, the more you either
1, Sheet in
2, Bear off to keep the apparent wind at the same angle....
Faster you go, more sheeting in, or more bear off....
