Why would a jammed mainsheet mean they could not STEER away? We are obliged to take any action to avoid loss of life. Anything they risked by not bearing away is trumped by avoiding a collision. One, minor, wrong move for a crewman could mean death in even a slow speed collision. The impact of two vessels weighing tons will crush whatever comes between them.
If the mainsheet jams many boats will be overpowered, and the rudder will not have any effect turning the boat down. It sounds like in this case they wanted to bear away, but there was just to much weather helm.
As Davidsailor said, there was too much weather helm and the boat didn't repond to the helmsman. The wind had picked up from less than 10 knots to around 20 on that leg of the race so they were over powered. A more experienced person on the helm may have thrown it down and come about if they realized early enough but it would need to be quick thinking to avoid making it worse than it was. By the time we realized they weren't going to duck it was too late for our boat to avoid the collision. As I said before, racers tend to push the rules and shit happens because of it. No hard feelings between the owners and both boats were brought back to fighting form fairly quickly.
