I'm new to sailing and recently picked up an O'day 20. Regrettably, former owner gave little rigging instruction. I have standing rigging completed but am lost regarding running rigging. Two questions: 1. Once attached to the mast, what supports the boom (keeps it from drooping to deck)? 2. On this boat does the mail sail sheet route down inside the mast? Any help greatly appreciated!
A great guide to rigging sailboats is Royce's Sailing Illustrated. It has detailed explanations and pictures of all the different control systems.
The boom is normally supported while sailing by the mainsail. While not sailing, it can be supported by: a topping lift, a boomkicker, or a pigtail (a wire pennant that connects the end of the boom to the backstay). Boats usually have one of these, but not usually more than one.
NEVER leave the pigtail attached while the mainsail is up! Ease the topping lift when the mainsail is up. A boomkicker is super convenient because it can support the boom whether the sail is up or not! Remember to support the boom before lowing the mainsail, either manually or mechanically, but not with the pigtail, in order to keep the boom from crashing down into the cockpit when you lower the sail! Once the sail is down, you can deploy a pigtail if that is what you are using. I prefer a boomkicker or topping lift.... only because I once raised the sail with a pigtail attached and scared the heck out of myself, and a boomkicker or topping lift will not get you into trouble!
Sheets are not routed through the mast... In my experience. Don't see how or why you would, but I don't discount the possibility that someone has tried!. Halyards are sometimes routed through the mast from masthead sheaves to the foot of the mast where they exit and are either cleated off or are routed further astern toward the cockpit. Halyards are used to raise and lower sails. Internal halyards are cmmon on bigger boats. They reduce clutter around the mast.
Mainsheets, genoa sheets, and jib sheets are used to control sails by hauling them or easing them in relation the angle to the wind. A mainsheet is usually attached at some location to the boom: midboom or end-boom (the clew end). You will use a combination of blocks to sheet the boom to some location in the cockpit to allow you to control the sail. The boom often gets sheeted to a traveler that combines with the mainsheet to enhance control of sail shape. Read Don Guillette's sail trim guide! He has a specific forum here!
Control systems range from super simple: rope tied to boom, like a Sunfish... To double and triple block systems or systems employing winches on larger boats where the sail might be under too much pressure to simply hold onto a sheet (line).
Look up pictures of Oday 20s on the internet. You will see how others rigged theirs. You will also see that there are many possibilities!
Ask anything. There is about 10,000 years of sailing experience here on the forum to help you!
Oh, and get that book! I got it when I set up my own boat while in college. I got a US1 that had almost no rigging. Very simple boat, but that book helped.
Thanks,
Andrew