Originally Posted by thenzsea
Thank you and 3 questions?
1. Jumpers? You mean wires like stays at the top?
2. Even if I put Permanent backstay, wouldn't it be helpful for making rig
3. Openning up the top of the main means that when I pull the backstay
it just help to twist (=open) the main. isn't it related to move the
draft back of sail that help for beating?
The masthead backstay on your rig primarily serves as a mast bending tool. Bending the mast flattens the mainsail. Bending the mast will also twist off the top of the sail if you don't compensate with more sheet tension. The permanent backstay will prevent your mast from falling down in the absence of the runners, but it will not make it stronger. In strong wind a serious mistake on the running backstays could still break your mast!
The running backstays control your forestay tension, and your check stays limit the amount the mast bends, and prevents it from "pumping" through waves.