Asymmetrical Trim

[Ken Prichard]

I was looking at a thread where Alan mentioned in his reply that he wished there were more sailing related questions, so here goes:I just received my new asymmetrical with an ATN Sock and Tacker. I'm hoping a day will come when this bloody rain will stop and I'll have an opportunity to fly it but I may as well use the monsoon profitably, so I have a few questions re asymmetrical trim. I've been on other peoples boats when we've flown both symmetricals and asymmetricals but I've always had a "position" that involved only one responsibility. I've never had to run the whole show. In my research I've found bits and pieces of info here and there but never the concise, step by step process I'd like. There seems to be a lot more info re symmetricals. I realize the answers will be different for different points of sail and I know the sail is not designed for a straight downwind run. Here's my questions:What tack height am I looking for and how do I know when it's right?When trimming am I looking at the curl of the luff or the leach? Am I looking at the amount of curl, the position of the curl, or both?Should this sail be gybed between the luff and the forestay or outside the luff? I've read advocates of both. I think I'm leaning to outside.Looking forward to the answers to these questions and any other info anyone may be able to provide re asymmetricals.

 

[novelman17130]

asymetrical trim

Ken,What make and size boat do you have? With my 22' Venture (mast head forestay)I use mine in this way.When pointing as high as possible, to about a beam reach I run the block for the sheet to the back of the boat. Using the asymetrical sail just like a large genoa. When on a beam reach I run the sheet to behind the jib blocks.When above a beam reach I use the blocks for my genoa.I also tack down the foot of the sail by running a line from a deck tie through the tack gromet, back down through a deck mounted (at the forestsy connection) block attached at the forestay connection then through a block or eye and then through my cam cleat mounted on the top of my deck. In this way I am able to let the tack out so the bottom of the sail goes foreward of the headstay and flys just like a spinaker. I always "tack" the sail inside the headstay. When I hdd this set-up on my 24' Windrose sailboat and tried to tack outside of the forestay it would sometimes wrap around the headstay. It works for me.Duane "novelman"

 

[Alan]

Ken

I didn't mean anything bad by the comment but it seems that many of the posts on this 'sailing' sight have very little to do with real sailing and lots to do with TV's and A/C.I'll kick in with a few of my thoughts on setting up your akite. Use a tack line that runs all the way back to your cockpit so you can make the necessary adjustments. Set your sheets up at the back of the boat. Later you can add twing lines very easily if you would like.Trimming is all about the luff. Ease the sheet till the luff just starts to flick in and out. The deeper you sail the higher you raise the tack. On a beam reach the tack is all the way down. On a deep run the leading edge of the sail should float out to weather of the headstay. At this point your tack should be 8' off the deck. The further you can keep the sail to weather and forward the deeper you will be able to sail and keep the kite out of the windshadow of the main. It will take a little practice to play your sheets but that is half the fun of controlling this sail.

 

[Rick19382]

I had a H285 and here's how I did it

I used to single hand it this way and it worked great. I also had an asymetrical with a sock.1. I put a block at the base of the forestay and ran a tackline from the tack, down through the block and all the way back to another block just 6"8" forward of the aft-end of my toe rail and then cleated it to my Stbd stern cleat.You want the LUFF of the 'chute to curl just a bit..just like you would want a symetrical chute to do so.2. I had two sheets that I ran OUTSIDE of everything and then back to blocks I added to my toe rails (port and stbd) as far back as possible. The sheets were 2.5 times the length of my boat.3. I'd roll up my genoa and trim the chute tack so the tack was just above my bow pulpit. (I experimented a few times at the dock and marked the tack line ith permanent marker so I'd know just how much it needed to be trimmed for the initial setting.)4. Then I'd engage the auto pilot on a broad reach, move to the mast and raise the chute (in the sock) and then raise the sock while trimming the sheet (with a couple of turns around a winch) so as to get the chute to fill. Yep, I raised the chute, raised the socl and trimmed the sheet while standing at the mast.)5. Then I'd move back to the wheel and either trim or ease the tack a bit (the more aft the wind, the more easing I did) and then trim the sheet so as to get that curl in the luff. (of course, I'd also trim the main accordingly).6. I was told NEVER, NEVER tack a chute or bring it through the forestay. When/if youwant to gybe, ALWAYS, ALWAYS do a controlled gybe and ease the sheet as you are truning the boat and, once the chute has passed in front of the headstay, trim the new sheet and keep sailing. I did this for 4 years and never had a problem, never worried about my chute getting caught/torn on a spreader, never was overpowered. I REALLY didn;t like the Tacker thing used to keep the tack of the sail attached around the headsail. It was more of a pain than anything.I'm sure others will have other experiences and methods, but this worked for me.Good luck!

 

[Ken Prichard]

Thanks

I appreciate your input. I'm looking forward to playing with the sail. Alan - Don't appologize. I took your comment to be a positive thing. I'm always looking for sailing related threads and skip the TV stuff.

 

[Harry]

Pronunciation

While we're on the topic of this sail....which is the correct pronunciation? Is it "A"sym....or "AH"sym...I've heard it pronounced both ways and always wondered.

 

[Maine Sail]

The word..

is pronounced no differently when it's a sail..asymmetricalPronunciation: ˌā-sə-ˈme-tri-kəl Variant(s): or asym·met·ric Function: adjective Etymology: Greek asymmetria lack of proportion, from asymmetros ill-proportioned, from a- + symmetros symmetricalDate: 16901: not symmetrical2usually asymmetric of a carbon atom : bonded to four different atoms or groupsClick the red speaker in the link bellow to hear the pronunciation.http://www.merriam-webster.com/dictionary/asymmetrical

 

[Carl]

Gybing

Ken, Unless you have a sprit, I would stick to the outside gybe. Usually these things don't pass thru a narrow slot very well. And make sure your tack line is run inside your bow rail otherwise you will probably loose your lazy sheet under the bow and that my friend can get really annoying.

 

[Keith Willson]

Asymetrical Trim

UK Halsey has an excellent 4 pager available on thier website re setting and flying their asymetrical.I have one which was built by UK Halsey for my H 33.Keep the tack slighly lower than thw clew - never higher.With the ATN tacker you should gybe the sail outside the forestay.Trim it so that the luff is just not curling.The sail is a real powerhouse and makes off wind sailing lots of fun.

 

[DanT]

ATN Tacker

On the ATN Tacker Ideally as the wind moves aft you'd like to fly the Tack higher. It has been my experience that as you ease up on the tack line to allow the tack to fly higher, the Asymetrical tack likes to moves further away from the wind. I'd like to know how the one commentor can get his asymetrical to: "float out to weather of the headstay". That has not been my experience, but I am always willing to learn. I find the Asym likes to move into the shadow as you ease up on the tack line. At least the Tacker keeps in the tack on the headstay as you raise it higher.

 

[Alan]

DanT

Think of the asym as you would a big genoa. Easing the sheet as you sail deeper moves the luff of the sail further forward. A component of that vector wants to move the luff to weather. Raising the tack allows the luff to move further away. The ATN makes the tack of the sail captive to the headstay and in fact as the tack is raised it gets closer to the wind shadow of the main. For this reason I would never use anything that would restrict the movement of the luff away from the main. The asym then begins to collapse and becomes 'sucked' behind the main in the low pressure area that the main creates.

 

[RichH]

All depends if you have a spinnaker mast crane at the top of the mast.

What tack height am I looking for and how do I know when it's right? ****** The optimum trim of an asymmetrical will occur when the sail 'starts' to luff (curl) at the just above the middle of the luff - somewhere near/above the horizontal dividing seam (or just a wee bit higher) in a radial cut asymm. . precise trim will be that the sail continuously luffs (slowly curls back and forth) and in a distance of a few 'feet' of 'curl length' - the rest of the luff will be 'quiet' and not luffing. Simply raise/lower the tack so that the sail is not luffing at the head (tack too high) nor luffing towards the tack (tack too low). Plus, it all depends on how 'stable' the spinnaker is for the 'days' present wind conditions - at stable wind flow conditions the higher you can carry the curl; squirrely/unstable winds need the curl to be further down. A good spinnaker set will help to 'slightly raise' the bow of the boat out of the water!When trimming am I looking at the curl of the luff or the leach? Am I looking at the amount of curl, the position of the curl, or both? ******* Just a few 'inches' of slow curling of the luff is perfect. see above. Should this sail be gybed between the luff and the forestay or outside the luff? I've read advocates of both. I think I'm leaning to outside.****** OUTSIDE. If the spinnnaker halyard is run through a 'spinnaker crane' - a small cantilever arm that extends in front of the mast top (to keep the spinnaker from being 'gobbled up' and tangled in the top swivel of a genoa roller furler), then the easiest is to gybe 'out and around'. Be sure to let the spinn sheet and clew go 'well in front of the boat' before you begin to pull in the other sheet - this will prevent forming 'bubbles' in the sail, which tend to 'wrap' onto the headstay. The CLEW of the A-spinnaker 'leads' the out-and-around gybe - use lightweight spinnaker sheets so that they dont go 'under' the boat. If you're just learning spinnaker handling, do all the gybing slow and measured - so you dont get a the spinnaker wrapped/bubbled around the headstay. Even if you do get a wrap ... DO NOT pull on the clew or sheets to get it loose as that will only tighten the bubble on the headstay !!!! Instead, quickly put a preventer on the boom and begin to sail the mainsail on the lee, 'scalloping' back and forth to redirect the on-the-lee flow from the mainsail to 'reverse the flow over the bubble' --- just using the air flow from the prevented mainsail to unwrap the bubble. The airstreams wrapped the spinnaker around the headstay - use the (reverse) airstreams to unwrap the bubble - you may have to go through up and below DDW several times to unwrap. DONT PULL THE BUBBLE TIGHTER by pulling on the tackline or sheet!!! ***** INSIDE. All depends how BIG the foretriangle. If the boat is a fractional rig, forget inside gybing. If the spinnaker halyard is direct from a sheeve on the mast and that sheeve is a few inches below the mast top (AND there is NO mast spinnaker crane). Then an 'inside' gybe is OK for short LP Asym-spinnakers. You dont want to be gybing 'inside' with an asymm that has an LP of 160% or larger through the 'inside' -- but you 'can'. But, be absolutely sure all the rigging is smooth so that the spinnaker cant get snagged/ripped on any protrusions, sharp edges, etc. Inside gybing direct from a mast sheeve will create a lot of chafe on a spinn halyard. **** Dont mix or alternate between inside and outside gybing ... or you'll wrap the spinn halyard around the top of the headstay. Always remember where the halyard is "ON" (which side of) the headstay.

 

[Mike M16608]

Carl - Tack Line Question

Terrific discussion, especially for guys like me who have not used an asymetrical but am considering it. Carl - you said to run the tack line inside the bow rail (on boats without a sprit)or you will probably lose the lazy sheet under the bow. It seems to me than the lazy sheet will always have the potential to slip under the bow...why would the location of the tack line affect it? For a newbie like myself, the whole setup is hard to get through words - the UK site was excellent (thanks Keith).

 

[Ken Prichard]

Awesome Stuff !!!

Rich - This is a fractional rig, not masthead, with no sprit. Your step bye step reply is great. When I'm asking about an inside gybe I mean passing the leach inside the luff of the sail, between the luff and the forestay, not inside the forestay as I think some have iterpreted.Alan - Are you saying you would not use the Tacker? Just want to be clear because I intend to fly this the way you do, at least initially.I've followed this site for a number of years and I know it reaches a lot of very knowledgable and experienced sailors, so feel free to jump in. Picking up just one little point makes it all worth while and you gotta admit - it is interesting. I'm starting to hope it rains a little longer.

 

[DanT]

That all sounds good

I understand that ought to be what happens, it just hasn't happenned when I have used an Asym. Everytime I slacked of on the sheet We would then loosen up on the tack to try to get the sail higher and shaped better for the wind direction. but then as we did it the luff whould duck to leeward. Believe me we even ran a sort of a "guy" to the tack and ran it aft to try to get the luff to stop ducking. Do you have to raise the tack first? Doesn't make sense to me.

 

[RichH]

DanT

Simply allow the tack to rise until you get a curl/luff in the upper middle of the sail. Then slack the sheet until the sail again the luff begins to curl, then pull in a few inches. If the luff is collapsing to leeward the angle of attack is too great (so pull in the sheets) or you're sailing too deeply down wind and the Asymm is becoming blanketed by the mainsail.

 

[Carl]

Tack line

Mike There is always the posibility of the lazy sheet sliding under the bow, but if you run the tack inside the bow rail it has that every so small area to rest when your trimmers attention span lapses. As far as rotating the a-sail around, trimmer and driver need to be on the same page with the rest of the crew weight to windward trying to sail these big dogs like dingys.

 

[ruedi ross]

I use my sock

To gybe my asym. I hesatate to post this so please don't flame me for it. This works well for me when I have someone to handle the helm I just go forward, douse the sail with the sock, gybe the boat, toss the sock around the outside of the forstay and redeploy the spinnaker. Fractional rig, no crane, spinnaker halyard exits the mast just above the forstay. I have tried the ATN tacker, but didn't like it. I couldn't get the tack low enough when closer to the wind, and as alan said, when you go deeper on a run the tack wouldn't move to windward as far when let out.

 

[Joe]

I'll agree with alan.....

in that the tacker is not necessary, and in some cases it is a nuisance. The main reason I don't hook it up is that it forces me to go all the way forward to set or douse.... and I don't like to go up there too much when I'm single handing. Like Rick from Venice, I'm set up to do everything with one trip to the mast after much consideration and experimentation to get what works. So.... Have a cleat for you spinnaker halyard at the mast, and one for the sock control line also. It helps to have a vee cleat in that area for the tack line so you can set it at the mast, then snap it out and reset to a cleat in the cockpit. Sometimes I take the sheet up also, but usually I can preset it for hoisting, and reset when back in the cockpit.I suggest you practice tied up to a dock (downwind of course) to practice. Or wait for a flat water day. As far as jibing, the clew will come across ahead of forestay but behind the rest of the sail. The secret, just as with a symetrical, is to slowly steer the boat under the sail rather than trying to pull it across. Let the sheet out till the clew is flying in front of the forestay and steer the boat under it keeping both sheets under control.Dousing is pretty much the opposite, especially if you don't have to go forward to unhook the tacker, just ease the tackline, go to the mast and pull down the sock, then uncleat the halyard to drop the sail on deck. Oh... don't forget to check the JIB sheets to make sure they're clear before you put the headsail back up.