Just as any other skill learned, start in light to mild conditions and slowly 'work-up' to but dont exceed your personal 'comfort level'. If you can fly a Genoa, you can fly an asymmetical. Most folks become terrorized never again to fly the kite because they exceed their 'comfort' (aka 'pucker factor').
If you can fly a genoa, you can fly an asymm kite.
Hints for spinnaker 'newbies':
•ALL lines 'outside' of shrouds, stays, pulpits, small dogs --- VERIFY prior to deploying from a 'sock'. (except for forestay if you select to inside-gybe where the spinn gybes betwen the mast and the forestay - then INSIDE the forestay) When first starting out have a crew 'recheck' your set up for 'all outside'.
• Go out in light winds and flat water (drifting+ conditions), the usual 'calm before dusk' that has stable wind is preferred.
* raise ONLY the spinn. (no mainsl)
• Set the tackline tight/close to the deck, pull in on the sheet, than SLOWLY 'uncover' the spinn while going approx 45° off of DDW. Rapidly pull in the sheet to prevent the spinn from 'wrapping around' the forestay as the sail 'uncovers' from the sock, etc.
• AT first few times out, forget about how high the tack is off the deck ... later stuff, for when you are 'comfortable', for now keep the sail 'tacked' to the bow/deck.
• Sail at ~45° off of downwind and work the sheet .... slowly ease out and stop/pull back in when the luff begins to 'curl' ... thats the 'sweet spot' that you will use for the rest of your spinn trimming life. Experiment in/out on the sheet till satisfied, then go deeper downwind and repeat until almost DDW then start working up in increment to beam reaching .... youll notice different shape in the spinn as the sailing angle changes.
• douse the sock (or HALFWAY) gybe over and repeat on the other side.
• Gybing (outside and around)
First time (no Mainsail up) - go onto a 45° off of DDW, then SLOWLY ease off the sheet until ALL the spinnaker is IN FRONT of the forestay, do this as you slowly gybe the boat .... but NO FURTHER than DDW. Once the Spinn is totally 'out and front' and the boat is DDW, THEN complete the SLOW turn as you slowly pull in the 'other' sheet .. and go back to a 45° on the 'other side'. If you pull in the 'other' sheet before ALL the spinn is in front of the forestay, you will probably wrap the spinn around the forestay. Ideally, you want the CLEW of the spinn in 'front of everything' when you gybe and begin to pull in with the 'opposite' sheet. If you pull the 'other' sheet too soon you can 'wrap' part of the spinn around the forestay .... here, later is better than sooner.
• Gybing 'inside and through the foretriangle' (no main up) sail at 45° off DDW
Pull IN on the sheet until the spinn is flat and the clew is about as far back as you can get it. Slowly gybe the boat (let its 'momentum' carry you through the gybe) and as the boat starts comes up on the opposite 45° off of DDW slowly ease the spinn, back to 'perfect trim' with the luff 'just' beginning to curl. You 'control' the rate at which the spinn 'goes through' the foretriangle with the spinnaker sheet. You may want to slightly 'pull down' the sock a few feet until you get used to this and your 'timing' gets good.
• Keep 'practicing' (with no mainsl) in increasing windstrengths (10-12kts. max) until you have a clear visual/mental picture of what is happening to the spinnaker ... and all the 'corrections' you made to 'get a good visual' set ---- remember all the 'behaviour' of the spinn so that when you add the mainsal later you will have a clear 'remembrance' of how the the spinn is 'behaving' when you cant see it hidden behind the main.
• Begin with tack-line adjustment on various sailing angles and wind-strengths (below 10-12) and see how much or how little adjustment is needed so that the middle of the spinn luff begins to 'curl' .... make your adjustment of the tack line up/down so the curl is at the 'middle' of the luff. Do this at various sailing angles and find out how 'far above a beam reach' you can go!! Then when youre confident fly the spinn with the main up (still in less than 10-12). Your goal now is visualize the 'reaction' that the main makes on the spinn. with various angles of the boom; and to time the gybing of the spinn with the gybing of the main
Other hints:
• the halyard to spinnaker connection MUST have a swivel - allows the spinn to 'cleanly' deploy without 'twists'. If you have a sock there MUST be a swivel between the sock and the spinn.
• When first starting ... take the spinnaker + sock and lay on flat ground and puil the 'sock' totally up to expose the spinnaker ..... then, as you close the sock back down on the spinn take the leech and the luff and hold them TOGETHER with your thumb between ... this will ensure that the spinn will deploy without TWISTS in the spinn.
• Do everything the EXACT SAME way each and every time you raise, deploy, douse .... When not racing I always raise, deploy, douse when on *Starboard* (gives me 'rights' over other boats) and lessen the chances of 'screw-up' because I dont have to 'think'. Sorry, good spinnaker handling is like 'religion'.
• You can REEF a spinnaker by partly pulling down the sock !!!
• Deploying and Dousing let the main/boom go forward on your 'preferred' tack to 'shadow' the sock/spinn and raise and deploy the spinn with the main deflecting the air OFF while you raise/dowse.
Before raising pull the tackline taught and the sheet 'somewhat' taught ... pull in on the sheet as you deploy the spinn from the sock.
Dowsing ... gybe over to your 'usual preferred' tack, open the mainsheet to let the boom/main go full forward to shadow the spinn, release the TACK LINE and immediately you pull down the sock - do quickly and stop any 'lines' from going into the water and under the boat. This type of 'douse' will allow you stand amidships at the rail when you douse.
• practice, practice at every possible opportunity / whim if you want to become 'good' with a spinn. When in doubt, fly the spinn.
• Ultimately GET RID OF THAT 'SOCK' ... at first a sock will allow faster confidence (got a problem, pull the sock; wind too high to gybe, pull the sock then gybe, too much sail up - partly pull the sock down, etc.) BUT the sock adds 'complexity' - more lines to trip over, foul, be on the 'wrong side', etc. etc. Consider (later) raising, dowsing without one - faster, simpler, less 'line clutter'. If all hell breaks loose, put the spinn behind the main, (and with stopknot at the halyard end) let the halyard 'fly' and pull in the spinn faster than it can fall into the water ..... OR bring the main/boom to center (or pinned to the rail), pull in the sheet as far back as it will go (may have to partly release the tack line), TACK the BOAT (turn the BOW through-the-wind) and immediately 'heave-to' and lay the spin onto the main, the wind will keep the spinn stuck to the main, then release the halyard and PULL the spinn down off of the windward side of the main. (I do the 'heave-to douse' a LOT when single-handing my sport boat with a symmetrical kite.)
.....& Saving the very 'best" ?? for last.
• Wrapping the spinnaker around the forestay is a 'problem' and eventually you WILL make an error and wrap the spinn which can also form 'many bubbles' of entangled spinn firmly wrapped. If 'bubbles' form due to the wrap .... NEVER EVER EVER EVER pull on the tack-line nor luff nor the spinnaker foot in an attempt to clear the bubble .... as that will/may cause the 'knots' to become tighter and may even JAM the spinnaker firmly attached to the forestay . (wink, wink to the racers reading this)
The wind (turbulence) causes the wrap or bubble-wrap ... and you can use the wind to 'unwind' the bubbles. Forget the bubbles, gybe the main to the opposite side and quickly apply a 'preventer' to keep/hold the boom as far forward as possible, then slowly gybe back and forth while watching the bubbles ... sometimes you have to gybe the main back and forth again and again. The wind put the bubbles around the forestay, so the easiest way is to use the wind to 'unwind them' by 'reversing' the wind. The timing of when you gybe will become apparent - just watch the bubbles when you gybe back and forth and it will become very apparent which way to go. If you pull on the edge/corner of spinnaker in an attempt to 'clear' the bubbles, you risk only tightening/jamming them (can you shinny up a mast with a knife held in your teeth?).
;-)