| Author | Message | ||
     David Sheriff Board Administrator Username: Admin Post Number: 66 Registered: 01-2004 |
If I understand this, what we called "preventers" on Pilgrimage are kicking straps. With a decent angle down to the rails they exert a downward force on the boom and, together, function as a vang too. | ||
| Ted Lavino Moderator Username: Tlavino Post Number: 7 Registered: 01-2006 |
Greetings Folks, from Blue Water Sailing: Three ways to tame the mainsail Cruising boats seem to be getting larger every year and with the extra LOA we are also getting bigger sails to manage. The mainsail on a 50-footer, even if it is a roller furling sail, is a lot to handle for a normal cruising crew in normal conditions. In a blow, the big sail can be a bear. The boom is the culprit in most mainsail debacles—crash jibes being the single most unhappy event on any cruising boat running in rough seas and blustery winds. So, here are three techniques that veteran sailors use to keep their mainsails under control. 1. Kicking straps or mid-boom preventers: Most of us have rigid vangs on the mast and boom to control sail shape and to keep the boom level while raising and lowering the sail. But a rigid vang won't prevent a crash jibe. The simplest way to control the main and boom when the sail gets back winded and wants to jibe is to rig stout kicking straps or mid-boom control lines to both port and starboard. You will need heavy duty pad eyes bolted to the toe rails or decks just aft of the after shrouds; you'll need a strong attachment point on the boom just after of the rigid vang attachment (or you may be able to use the top end of the vang); and you will need non-stretch control lines that run from the boom, through a snatch block on the side deck and aft to a cleat or line stopper near the cockpit. Use the leeward line to cinch down the boom when running and use it as a way to control the boom during a planned jibe, aiding the mainsheet as the boom passes through the wind. On boats over 45 feet or so, you should rig each control line or kicking strap with a two or three-part tackle to give you the power to handle the huge forces in the sail. 2. Boom brakes: You can achieve the same control of the main sail and boom as above with an off-the-shelf Boom Brake (sold by Dutchman in Connecticut). The device attaches to the main boom with control lines led to both side decks as in the kicking strap rig. The neat thing about a Boom Brake is that it controls the sweep of the boom during a jibe without a lot of work by crew in the cockpit. You need a hand to release and control the leeward line as you jibe, but a well-coordinated soul can do this and steer at the same time while someone else cranks in the main sheet and then releases the sheet during the jibe. A lot of veteran singlehanders and short-handed sailors have found Boom Brakes to be very effective. 3. Preventers: You will hear kicking straps or mid-boom vangs called preventers, since they do prevent the main from uncontrolled jibes. For our purposes here let's call them vangs and use the term preventer to label a control line that runs from the end of the boom to a block at the bow, with a continuous line running aft to the cockpit. When you are running hard down wind in the trade winds with the main strapped out to one side and the genoa poled out to windward (we'll cover this headsail rig next week), you use the preventer on the boom to immobilize it. If you plan to be running with this rig a lot, then mount blocks forward and set up line stoppers on either side of the cockpit. Run a non-stretchy line with a shackle on the forward end through the blocks and line stoppers so you can control it from the cockpit. The line needs to be 1.7 times the length of the boat. On the boom, splice up a stout, non-stretch line to run from the end of the boom to the top attachment point of the rigid vang when not in use; that way you will always have an end handy inboard to attach the running preventers when you jibe. Just snap on the preventer from the bow, trim the mainsail and then tighten down the preventer and voila, mainsail debacles eliminated. |
