Early squaring can have a very significant effect on racing speed.
How significant can wind be?
"5 m/s head wind makes singles 17.4% slower and eights 12.2% slower, tail wind of the same speed makes singles 7.5% faster and eights 5.1% faster."
He briefly compares to World Championship results and suggests the research may somewhat overestimate the effect.
Perhaps most interesting is the significant effect of feathering and squaring of the blade - something we all know who have been in the boat, but perhaps not the extent:
"If the blade squared early at the middle of recovery, a crew can lose up to 10 s over 2k race at calm conditions and up to 30 s at head wind 5 m/s."