It is imperative to crack off the mainsheet when the boat goes head to wind. A tight mainsheet will weathervane the boat into irons. Start by cracking off a lot (3-4 feet). As your technique improves or in flat water you can let out less. On the new tack, trim the jib and main together or the jib a little faster (the main on the H16 is very powerful relative to the jib).
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<br>This is explained much better in Rick White's book "Catamaran Racing".
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