THIS NEEDS CLOSE ATTENTION. Do we mention the forestay only option? I think it adds unnecessary confusion._
To repeat an earlier thought, a great attribute of the DN is that essentially any boat can be set up to match any condition. Unfortunately, all these variables can make finding the initial setup confusing. Follow these steps to get yourself started, and through time you’ll begin to make adjustments based on how your boat is performing.
Some older boats may not have some of the adjustments mentioned below. Your set up is perfect if the boat hikes in a big puff, but keeps the weather runner on the ice most of the time. Hikes should be controlled by sheeting harder and steering (new reactions for a soft water sailor), most of the time. Easing the sheet six inches at your hands is a big ease. Your sail gets fuller but opens at the top.
Boat to Plank. A set of stud plates on the plank are inserted and bolted into one of four sets of holes on the hull. For starters, use the third set from the front. In sticky conditions with lots of wind, you may move to the second or first set of holes. The further your plank is forward, more effectively your weight keeps the boat from hiking. Light air and snow, when you want one runner up, use the back hole.
Mast step. The step location can be moved fore and aft. Set the step at about one inch forward of the maximum aft location. Once everything else is set, if the front of the boat seems to want to push to leeward, move the step back. If the back of the boat tends to want to spin out, then push the step forward.
If your boat doesn’t have an adjustable mast step, don’t worry about it. An average sailor rarely moves the mast step. The stays and halyard are more important by far. The boat changes in response to very small changes!
Halyard. The sail can be raised to a variety of heights. Multiple latches or stops on the halyard allow such flexibility. The higher the sail, the more the mast bends, but the less effective the boom is at taking rotation out of the mast. Too much or too little can be slow. So the bend can be fine tuned in part by simply adjusting the halyard a half inch at a time. Find a middle ground. On any given day, you may adjust this one or two notches, or none at all.
Forestay. The forestay adjustment changes the rake of the mast. It (along with halyard position) also affects the distance between the back of the boom and the deck. For starters, raise the sail and then adjust the forestay so the boom hangs approximately 14” above the deck, and the blocks are about 12 inches apart.
Side stays. With the sail up, and the forestay adjusted, now tighten the side stays so there are even and tight (Plank deflected slightly). In light winds, the side stays should be looser to enable the mast to bend. In higher moderate winds, the side stays are tighter. You can now see how the boat sails relative to a fast competitor.
Mast rotation. The more the mast rotates, the more it bends. Rotation is controlled by positioning of the rear pulleys. Set the pulleys on the boom about 5” forward of the pulleys on the rear deck. This is a safe starting point. When the sheet is pulled very hard, the boom and deck blocks should come together (except in very light air with the boom set higher than normal) and the boom jaw should be just clear of the mast at the front of the boom. The block relative positions should be adjusted if you change mast rake (forestay) or sail height (halyard). The mast needs to bend to flatten the sail and let you go faster while pointing better upwind.
If you sheet really hard, some rotation is pulled out of the mast. This should happen after a tack but only after you are at full speed, and wind pressure is keeping the mast bent. Mast rotation increases power but also drag. Power helps accelerate (and move in sticky conditions). Drag limits top speed and down wind sailing angles.
The minimum adjustments for comfortable sailing in a variety of conditions is: pins in the forestay adjuster, pins in the side stay adjusters.
The minimum adjustability for a newly minted competitive racing is: Pins in the forestay adjuster, pins in the side stay adjusters, three or four inches of adjustment in the halyard, and three or four inches of adjustment in either the boom blocks or the deck blocks or both.
The ultimate adjustability: A threaded adjuster plus pins in the forestay, a threaded adjuster in the side stays, plus the halyard and boom adjustments as above.
The "True World Competitor" knows how long his side stays always are, and adjusts everything with three pin locations and a threaded adjuster on his forestay, plus the halyard and boom adjustments as above. Once in a while, the mast step will be moved.