[kennethspindola]

Interested on opinions and how a sanderling performs with a loose main.

[Tim Lund]

Ken,

The sanderling, like any sailboat, will perform differently based on the relative shape of the sail. When going upwind or in heavier winds, you typically want the sail to be flatter/tighter in order to act like a foil (similar to wing on a plane). When going downwind or in lighter breezes, you’ll want it to be looser. On a typical sloop (or sailboat more aimed at racing) the outhaul is readily accessible for tightening and loosening depending upon the point of sail. Similarly, the aft stay gets adjusted as well as the cunningham and boom vang. I’m sure there’s an article in an old bulletin about this, but am not sure where it is.

Tim

[nrx500]

Tim Lund’s explanation of sail shape is accurate, and a good starting place for you.

The purpose of the boom vang is to tighten the leach of the sail, thereby making it more powerful. Vangs are frequently fitted to boats where the boom is high enough so the vang forms a 45 degree triangle at the base of the mast and at the attachment point on the boom. You will see vangs on open cockpit cats such as the Sandpiper. But the Sanderling has a cabin and the boom is low, making a boom vang relatively ineffective because of the shallow angle. For this reason, gaff rigged boats like the Sanderling over peak the gaff by lifting it higher with the peak halyard. This also tightens the leach and makes the sail more powerful. Easing the peak halyard will soften the leach and depower the sail. This is what the term scandalizing refers to.

Now to your question about a loose sail. The looseness of the mainsail is adjusted by easing or tightening the foot of the sail and the luff. The outhaul is used for the foot and the throat halyard for the luff. Cunningham cringles are seldom seen on catboat sails. Easing the outhaul is done on reaches to add curvature or draft to the main, thereby creating a more powerful sail. Tightening the outhaul is done upwind to flatten the main and streamline the airflow. Tightening the throat halyard, or Cunningham if fitted, moves the belly or draft in the sail towards the mast. Doing so moves the center of effort of the mainsail forward and decreases weather helm, an important consideration in catboats. Typically, draft in the mainsail should be 1/3 back from the mast.

The halyards on a Sanderling come back to the cockpit and are easily reached for adjustment. The outhaul is typically cleated on the boom, therefore less easily reached. Most catboaters set the outhaul at the beginning of the sail and forget it. If you plan to adjust it, consider creating a 2:1 or 3:1 mechanical advantage with small blocks (pulleys) and lead the outhaul line to a cleat at mid boom so it can be reached when the boom is out over the side of the boat.