The start of a head race is different than the start of a sprint race because you’re rowing into it instead of starting from a dead stop. Most regattas will have the crews hanging out, sort of, in a waiting area a few hundred meters above the starting line before calling them down by bow numbers. As you row into the waiting area, you’ll want to find crews with the bow numbers immediately ahead of and behind yours and situate yourself between them. From here, you’ll want to use use your bow pair or bow four to slowly move you up the queue with the other crews.
Most larger regattas have what’s called a “chute” right before the starting line. (Smaller races might just do one single file line.) This is what everyone in the waiting area is funneled into before they cross the line one by one.
As you come into the chute, odd numbered bow numbers will line up on one side and even numbered ones on the other. Where you should go is marked by three buoys — a red one, a yellow one, and a green one. At HOCR, the odd numbered crews will line up between the red and yellow buoy (red = port) and the even numbered crews will line up between the yellow and green buoy (green = starboard).
By this point you should be rowing all eight, slightly above paddle pressure. You’ll row down towards the line in a staggered pattern and then cross at 10–15 second intervals. There will be officials on the water telling you to ease off or go to full pressure depending on how close you are to the crew in front of you. They’ll definitely tell you when to go to full pressure but if you start too early they’ll tell you to back off so you aren’t too close to the crew ahead of you when you start. By the time you cross the starting line you want to be at full pressure and at least 2–3 strokes into your starting 20 or whatever you do at the start of your race. At this point, you’ll hear an official say “on the course!”, which you should then communicate to your crew.
Coming across the line, you should already have your starting sequence figured out (and have practiced it many times) so that should be fairly self-explanatory. I called the five to build into full pressure when the officials on the water told us to bring it up and then we usually crossed the line somewhere around the second or third stroke into our high 20. From there it’s coxing as usual.
I think it’s important to not say a lot before the race because there’s going to be a lot going on and many things for you to be listening and paying attention to, which can be difficult to do if you’re trying to actively cox the crew or carry on a conversation. Same goes for the rowers. Things happen fast in the chute and it’s imperative for the rowers to be ready to go as soon as the officials/coxswain call for it.