Figure out if you want to gate early, gate middle, or gate late. Gating early is like starting near the pin on a line start.... you think you want to go leftish, while gating late is like starting near the RC boat end... you can control the boats that start earlier.
Typically, you can figure out from the sailing instructions the minumum and maximum times the gate will be open (you would prefer not to start after the gate launch stops and drifts)... Consider the fleet size, and figure out where on the gate start line you want to be in terms of time.....say two minutes in a large worlds fleet if you want to gate late, or maybe 45 seconds in a small fleet if you want to gate early, round the pin that the rabbit will round, and sail close hauled on port. You are sailing the same course the rabbit will be sailing. Sail up the line the appropriate time (this means that if you wanted to gate 45 seconds up the line, you would sail (45+20) (the rabbit is supposed to get to the starting point at 20 seconds or something like that), up the line, all the while checking below you for how traffic is stacking up. Be opportunistic... If there is a great hole earlier or later, go for it. In any case, when you get to where you want to be, bear off, and reach away from where the line will be. By now boats will be stacking up on starboard, luffing slowly towards where the line will be...either bear away and gybe, or bear away and then tack into a good hole. Try to leave room to leeward and pin a boat to weather. Try to start near slower boats. Sheet in enough to maintain steerage way, and carefully watch your bearing to the rabbit and gate launch. You want to be approaching the line such that you could sheet in and hit the rabbit if you wanted to (of course you don't), but if you fall too far back, you will sheet in and go, and be late for the gate launch. Do not get caught too high, you do not have rights to bear off and get room from a boat to leeward. Think in terms of "waiting your turn"... let the boats to leeward sheet in and go, try to keep space between you.... maintain course and speed so you are just going to miss the stern of the gate launch...final approach is ideally on your fastest angle - a close reach... skipper just misses corner of gate launch and hardens up while crew and skipper sheet in... The idea is to plane through at maximum speed and be close hauled. You have of course, set the boat up perfectly before you did your final run, so you don't need to adjust anything... just sail close hauled as hard and fast as you can.
The people who were a little late, or a little early and had to take drastic avoiding action, or who are a little off the pace get squeezed out of the first row pretty quickly... if you are one, consider what it would take to get clear air... if you are close to the right of the fleet, you may be able to tack, take some sterns, and emerge into clearer air... if you are one of the first few boats through the gate and are rolled, you may have to duck most of the fleet to find a lane with clear air.
Here are a few tips from the mind of SPOT.
1. Very important to be sailing on a close hauled course when you pass the guard boat. Do not reach in and round the guard boat like a leeward mark - instead sail a little lower and head up to a close hauled course. You do not want to be in a big steering / sheeting / trapping transition for the 5-10 seconds just prior to passing behind the boat. Time your crossing such that your bow passes within an inch or so of the guard boat's leeward corner / engine/ or whatever is sticking out. Smile for the camera. As you pass, steer just a little above close hauled for a few seconds to space you away from others to leeward and to put the squeeze on those to windward. This takes a bit of practice. do not hit the guard boat - a guaranteed DSQ!
2. Surging. a 505 in moderate to heavy air will sail at about "hump" speed for a planing motorboat - that is the speed which is just barely too slow to plane, the motorboat driver will have to constantly adjust his throttle to maintain position. This means the guard boat will be surging relative to the rabbit. By watching this you can sometimes set up a little high and grab a few extra feet to windward, passing the guard boat right after a surge. conversely, beware of the opposite and having to dive at the last second...
3. Clumping. for some reason - which I can not figure out [Ed. chaos theory?] - sailors tend to clump together during gate starts, leaving long periods - 10 or 15 seconds or more where no boats will pass behind the rabbit, followed by tightly packed groups with definite winners and losers. Watch the boats setting up and do not commit to a place on the "line" until the last 30 or 40 seconds. You do not want to find yourself with boats to windward barging - with no place to go but either into your weather rail or into the guard boat. Hitting the guard boat means gar-un-teed disqualification - and so you are forced to let them in to not smash up your boat. Sure, they do a 720 - but your start is hosed in the meantime. It is better to set up in a vacant spot on the line and start all by yourself. Look at the 98 505 worlds web site's intro sequence and you will see TEAM SPOT very charitably "letting in" a boat who was barging - we're such nice guys!
4. I prefer to to be the first boat out of the gate for three reasons first, I like to think we are pretty fast to windward [a delusion I have...] and want to sail at my speed, as opposed to the rabbit's. If it turns out that we are not the fastest thing out there [usually the case], we can drive off to maintain clear wind and not fall into anyone else's bad air. Second, there are usually very few people at the extreme leeward end - so we can focus our limited mental powers on nailing the transition to passing the guard boat, and finally it sets us up to take best advantage or at least break even on the first shift after the start: if the wind heads, we are first to the shift and tack and likely cross the fleet - if the wind lifts, the rest of the unstarted fleet effectively sails the same header the rabbit is on... and we are first to and furthest inside the next shift.
I have found being the rabbit is a terrifying experience. After a lifetime of mental conditioning to watch out for and avoid starboard tack boats, you are sailing along on port with a WALL of yelling and screaming starboard tackers all lined up, perfectly positioned to tbone you! Sure, there are guard boats and draconian penalties for those messin with the rabbit - but it still freaks me out. Just pretend they are all in their underware.
If you think you are faster than the pathfinder go early if slower got late, if the same speed watch the shifts and pick the end acordingly.
If the pathfinder (rabbit) is headed go early, if lifted go late.
You should be careful to protect your lee.
In fact if possible, you want two boat lengths minimum between you and the next boat to leeward. This enables you to bear off if necessary to foot faster to get clear wind if someone getts a better start than you to weather. It also prevents you from being lee-bowed to a standstill by someone with better pinching ability out of the start.
Being able to pinch up and lee-bow the boat to weather can have dramatic effects. You can have the entire fleet stalled behind you and falling off into yours, and each other's, backwind.
Protecting your lee requires great discipline, there is always a tendency to dive into the space you have been creating and start earlier, but resist it.
Also don't sit up close to the start line, hang back and take a run at it, it takes judgement and practice to get it right, but it is doable.
Those that hang up close to the line with sails flogging get picked off by the others who come in with speed and dive it the holes they have been guarding.
Having said that, there is some merit in diving off a little. the technique I have found to be most successful is to aim, closehauled, at the CENTER of the guard boat. This discourages would be bargers-in that try to come down on you, as they see there is clearly nowhere to go. Just as you are almost to the guard boat, you bear off and ease sheets, then round up gradually so you almost clip the guard boat's rear corner. You should be so close that your crew has to take evasive action to avoid hitting himself on the guard boat. If you do this correctly you will "pop" out of the gate with extra speed into clear air and you will have a massive advantage.
The difference between a good and a bad start out of a gate can be as little as one or two feet, get slightly ahead, you sail over people or lee-bow them to death, be back a couple of feet and you will become a victim, and you will be passed from boat to boat backwards down the fleet.
Will: excellent comments on protecting one's lee, however I differ on one point--
Having said that, there is some merit in diving off a little. the technique I have found to be most successful is to aim, closehauled, at the CENTER of the guard boat. This discourages would be bargers-in that try to come down on you, as they see there is clearly no where to go. Just as you are almost to the guard boat, you bear off and ease sheets, then round up gradually so you almost clip the guard boat's rear corner.
SPOT SAYS: This is the last second transition which, i believe, should be avoided. I believe that the boat should have no component of velocity in a direction opposite to the guard boat when within one boatlength or so, i.e that a starter should be sailing at right angles to the guard boat for several seconds and pass behind with no course alteration - except for perhaps a slight climb to weather on the shift from the rabbit. Making this last dive to pass behind the boat will get some extra speed - but it places you a few feet below the highest windward position....
Barney is right in that you do not want ot be transitioning, as you come out of the start, - a turning boat is a slowing boat.
However, the trick is to be able to carry some of the speed obtained by sailing freer with you out of the gate. That is why a delicate rounding up is required just before you go through the gate, the idea being that the speed lost in rounding up is less than the excess speed ( sailing free v sailing closehauled) you have in the first place.
It is difficult to achieve and requires practice, however, if it shoots you forward just a quarter of a boat length before you settle into normal upwind speed, it will give you a massive, yes massive, advantage.
If you come out of the gate fast, and right on the guard boat, you will not have to worry about being sailed over to windward, no one can get there to do it. You just need to worry about boats coming up from below. So if you have space to leeward, and no one to weather, you can sail fast in clear air and start looking to pick your route upwind just the same as a line start.
Now, whether or not you can capitalize on that is another story............
I'm still close reaching as my bow clears the aft corner of the gate launch, but I am heading up as I sail, trying to keep the rail close to the gate launch. Provided the gate launch is low enough, the crew on the wire goes over the top of the gate launch.
If you are close hauled the last boatlength or two, you don't have any "reserve" if the gate launch surges, and you are also decelerating from your close reaching speed down to your close hauled speed.
I think sailing through the prop wash slows the boat down, but I want to be going as fast as possible when I hit it. I'm pulling the main in hard as we round, and hiking very hard. Crew may have been high on the trapeze to clear the gate launch... immediately drops low as soon as he is clear... Then sail REAL FAST without looking around much for some seconds to try and get punched out (don't even check the vang/leech tension, you should have set it perfectly 2 minutes earlier). When you do have to look around, the crew does it without leaning in, skipper just drives... crew assesses the situation, decides what should be done, and tells skipper. Skipper is 100% focused on close hauled speed and height, not looking at any boats or positioning, unless the crew tells skipper they need to check something (like, can we clear the boat on our hip if we tack? or we are falling down into the boat to leeward).
In really light air, everything happens more slowly, with much less prop wash... I still close reach in, but turn a little more slowly, trying to get one pump as I sheet the main in and flatten the boat.
In large fleets, you may have to sail high at first.... and then once you have punched out, and have a little room, foot off to your normal max VMG to windward angle.