The best reason
Oday didn't put vangs on their trailer sailers so they could save money. I think vangs are especially important on the 22 (and 23 and 25); they are not only good sail-shaping tools, they are important for comfort and safety. Because the mainsheet on all three models attaches to the backstay, Oday did not provide a traveler, nor is there an easy way to retrofit one. A boom vang is really the only way to adjust mainsail twist on these boats without making the semi-serious modifications necessary to fit a traveler. I also think a vang is good for safety reasons. These boats are tender, and in a blow a vang will keep the boom from raising up and increasing sailpower and angle of heel. You can buy a decent soft vang and all attachment hardware for about $100. Install it so that the vang is at a forty-five degree angle to the boom and mast.