It's difficult for me to pick out the nit picky stuff in these decisions, if the yellow boat had ducked earlier there would be no doubt in anyone's mind, as it is the yellow boat would have pushed me into losing concentration and focusing on them and whether I had to avoid collision. To my feeble brain the luffing decision leading to loss of rights to me doesn't stand up either as black luffed up and yellow luffed up then black came back on to it's course first therefore yellow should have kept luffing up and tacked.