Crew Positions:
Quite often I find myself explaining crew positions and duties on the way to a starting line. Most boats are laid out differently however, the tasks for each position are about the same in most keel boats around 30 feet. Your first time on a boat you usually get great positions like: Left out, Wrong Rail, and Assistant to the Gofer. Having the knowledge of what to do at mark roundings, tacks and gybes will greatly enhance your chances of getting a good position on a boat. 
There are Seven Critical Functions on a racing Yacht:  Ideally, there is one crew assigned to each function, but often functions are combined as we seldom have a crew of seven. 
Helmsman / Skipper
Tactician
Maintrimmer
Port Trimmer 
Starboard Trimmer 
Pitman
Bowman

We will discuss most maneuvers with 6 to 7 crewmembers in mind. In sailing there are a lot of terms that describe the same thing. The upwind headsail may be called the Genoa, Genny, Jib, L1, M1, H1, 2, 3, 4, Blade, 150, 130, etc. If you hear any of these terms they refer to the Headsail of choice. A spinnaker can be called a chute, a 3/4 or 1/2 oz. depending on the weight of the material, or even the big pretty colorful sail. On large asymmetricals they are commonly called Frankenchutes due to the many repairs required after dropping one overboard. A line or rope can be called many things depending on their usage. Lines to pull sails up are called Halyards, and lines to pull booms or poles up are called topping lifts or uphauls. Lines to pull sails in are almost always called sheets. Any line to pull the luff of a sail down tight should now be called a cunningham because downhaul was far to easy a term to understand. Tacking can be called coming about, changing tacks, or you might hear We're going to lee bow. This means the boat will tack slightly to leeward of an approaching boat to gain tactical advantage. Gybing is always called gybing, but no one actually knows how to spell it; including me. Now that you have the terms, let's go through the maneuvers.
The Start (typical starboard approach)
Helmsman - Get a good position in the fleet with room to duck and come up 
Tactician - Check wind shifts and determine the favored side of line and course. Call Time. 
Maintrimmer - Keep main trimmed fully unless told otherwise. Be ready to dump the entire sail if necessary. Trim hard and fast on final approach giving the boat full power. 
Port Trimmer - Let Helmsman know of leeward boats. Grind for Starboard Trimmer on Port Tack. Trim to full speed unless told otherwise. Call Genoa skirt on final approach.
Starboard Trimmer - Let Helmsman know of leeward boats while on port tack. Trim to full speed. Grind for port trimmer. Wrap starboard winch. Get to rail. 
Pit Man - Call Time, Double check all sheetstoppers. Get to rail. Watch for obstructions, shallow water, and other boats..
Bowman - On bow calling approaching boats and distance to the line. Don't forget genoa skirting.

Tacking to Weather 
Helmsman - Call "Tacking". Start to tack slowly to maximize weather gain. Then quickly find opposite tack angle after crossing head to wind. 
Tactician - Look for a clear lane. Make sure there is breeze where you are heading. 
Maintrimmer - Ease main per boat stability to allow boat to tack easier. Then trim as the boat accelerates. 
Existing Trimmer - Release Sheet as boat gets head to wind. Grind for New Trimmer. Get to Rail.
New Trimmer - Tail sheet. Trim in till sail is a few inches off spreader. Trim as boat accelerates. 
Pitman - Adjust Halyards or Cunninghams if needed. Get to rail. Look for obstructions, shallow water, and other boats.. 
Bowman - Help Genoa across. Skirt genoa. Get to rail.

Windward Rounding - (standard port bearaway) 
Helmsman - Watch traffic. Find new course angle. Fill chute before bearing away completely. 
Tactician - Determine favored side of the course. Help find optimum VMG angle. 
Maintrimmer - Ease Mainsail and it's controls. 
Port Trimmer - Ease Genoa 2 to 3 feet. Over easing the genoa causes problems for the spinnaker hoisting. Cleat, and then trim Spinnaker. Do not over trim as the chute is going up.
Starboard Trimmer - Pull back afterguy. Trim afterguy as if it is a sheet until the course is set. Most spinnaker raps are caused because the afterguy is late in coming back allowing the chute to twist behind the genoa. Make sure the pole is square (perpendicular) to the wind. The helmsman may tell you to over square or under square the pole according to the wave angle. The angle of the pole directly affects the heading of the boat. 
Pitman - Make sure that genoa halyard is flaked out. Top the spinnaker pole and hoist the spinnaker. Drop the Genoa, tend the Foreguy, and then adjust mainsail controls. Raise staysail if required. 
Bowman - After Spinnaker setup; which is different on every boat; top the pole. Jump the spinnaker halyard, secure the genoa on deck, and prepare for a gybe or staysail hoisting.

Gybing 
Helmsman - A book can be written on the subject of driving through the gybe. A good helmsman develops a feel for the boat in every sea and wind condition. If the helmsman can call the gybe in a puff, on the roll of the sea he can accelerate during the maneuver and gain time on his opponents during the gybe. The trip should be called by the helmsman just as the boat rolls to windward.
Tactician - Look for clear air to gybe into. Make sure that you won't have to duck or head up around any boats just after the Gybe. On many boats, the wind speed is as important as the wind angle; so avoid holes if possible. 
Maintrimmer - The safest way is to bring the main to center and then ease it out on the other side as the pole is made on the new side. The fastest way is to wait for the trip call and throw it around as the boat rocks to windward. If done properly the boat stays at full speed the entire time. If done improperly on a boat with a tall fractional rig and runners, can result in the total annihilation of the rig, the boat, and all life as we know it. 
Trimmers - There are a number of setups for trimming chutes and poles.  We use the most common setup today, a single sheet with tweekers.  Tweekers are set for the sheet that becomes the afterguy, and is usually fully eased for the sheet that is not serving as the guy. On larger boats, there are separate sheets and guys for dip pole gybing or end for end gybing. On any of these setups, the only important thing to remember is to keep the spinnaker full and trimmed at all times. On the single sheet setup, the pole should be squared before gybing so that the pole can come off the mast. Trim through the gybe and give a slight ease of both sheets as the Bowman secures the pole on the mast. Remember to adjust the tweekers during the gybe. The sheet and guy dip pole arrangement is common on boats from 36 to 100 feet long.  Depending on the setup, one trimmer can handle both sheets.  As the new afterguy is made, ease the sheet slightly to allow the pole to come back quickly. The new afterguy must be pulled back as fast as possible to avoid wrapping the chute, but don't over square or pull before the bowman calls "made". 
Pitman - Tend the topping lift and tweakers through the entire process. 
Bowman - Timing, speed, and agility are required for this daring maneuver. On the end for end gybe, the pole should be tripped from both sides at once; freeing the pole to move to the new side. Grab the new guy with your outboard hand and shove it into the jaw of the pole that you are holding with your inboard hand. Then slide the pole through your hands and push it outwards with all you have till you can make the jaw onto the mast ring. Call  "made" and prepare for the next gybe or mark rounding. Don't worry about the genoa sheets until the final gybe to the mark. 
Leeward Roundings 
Helmsman and Tactician - It is critical to call the drop at the appropriate time. Too soon and you might lose an inside overlap. Too late and the spinnaker can be left flailing in the breeze as you're trying to go to weather. Once you have called for the genoa up and the spinnaker drop, the Helmsman should give all attention to driving properly around the mark. The Tactician must start looking up the weather leg before getting to the leeward mark or gate to determine what side of the course will be favored. If the crew work goes well the Tactician can sit back and do his job. If something goes wrong on the takedown, the Tactician becomes the extra hand to access the problem and help with the solution. There are no tactics when you can't tack.
Maintrimmer - Set your controls before you get to the three boatlength circle. Trim well because the main is the driving force during the sail transition.
Trimmers - Each boat and each rounding require different techniques for dropping the spinnaker. On Rebecca J, we do a standard leeward drop into a basket in the companionway.  It is best to ease the pole to the headstay and then release the afterguy so that the chute can be pulled around to the companionway hatch.  They guy will be stuffed into the basket along with the chute so it is ready to go up on the next set.  The sheet should be eased as the chute starts to drop.  Sometimes tactics require that we set or drop the chute to windward, floating without the pole, because we must immediately jibe.   On floater sets, the chute is set flying, then the pole is set after the jibe.  On floater take downs, the pole comes down first, then the sail is hauled around to windward and stuffed in the companionway.  Whenever the spinnaker is floating,  ease and tend the sheets. A sheet that is let go will try to go overboard and wrap on the prop or rudder according to Murphy's Law. The rule of thumb for trimmers is to trim the spinnaker to full speed whether the pole is attached to it or not. Prior to takedown, make sure that the genoa is ready to trim in at the mark. Trim the genoa to full speed through the entire rounding. 
Pitman - You must go with the flow of the foredeck crew. Make sure that your spinnaker halyard is flaked and ready to run free. Unfurl the genoa as soon as it is called for.  Lower the spinnaker halyard as fast as the crew can pull the spinnaker aboard. As soon as the spinnaker head hits the basket, slowly ease the topping lift to the deck. This allows the Bowman to start cleaning up the foredeck immediately for a tack. Once the pole is stowed, get to the rail and watch for obstructions, shallow water, and other boats.. The leeward trimmer can help with cleanup if needed. On floater drops, the pole comes down before the spinnaker making your job easier as you approach the mark. 
Bowman -  Make sure that the genoa sheets will be clear for a tack. Get spinnaker lines ready for the drop.  Once the spinnaker is down, secure the pole and do the minimum cleanup required to get the boat heading quickly to the next mark. Double check the windward genoa sheet for tacking ability. Do the rest of the cleanup when the boat is in clear air and sailing at full speed.
There are different quirks on every boat that need special attention, and Rebecca J has a few. You will identify them in a few practice sessions. Remember that boatspeed is the key to 80 percent of racing. Boats with good maneuvering ability will be able to capitalize on smaller windshifts. Also, nothing read in a book can equal the time out on the water experiencing the maneuvers first hand.  I try to schedule practice sessions and you should try to make them.  Once we learn to work together to keep the boat going, we can relax and enjoy the beauty of this sport and the exhiliration of competition.
Note:  Major parts of the above have been excerpted from an article by Steve Steiner, Managing Editor, YachtRacing.com.