I'm finally back "on" so I thought I'd post on the topic of "snuffing" since I've had questions from various folks about it and there were some negative comments made about the experiences in the Keys. First let me say I'm NO expert in the topic BUT I do have experience so I want to share that and get others input. I made a decision about a year ago now to try the "skunk" midpole snuffer based on my (unsatisfactory) experience with a pole end snuffer and the fact the Tornado class was almost unanimously going to snuffing and some sort of midpole snuffer was working well for them. I sail a Taipan with the "stock" ~1.5" diam. aluminum pole (as "stock" from AHPC) and mounted the skunk ala the Tornados- with the back of the skunk lined up with an imaginary line drawn down the forestay to the pole. I wanted the skunk as far "back" as possible to keep the weight back and windage down (bag is both farther back and lower). Since I generally solo sail I also wanted a system I could handle solo with as few lines to "pull" as possible.
Now that I have thin, flexible snuffer patches on my chute and have worked out most of the "bugs" I think I can launch and snuff quite quickly- (Not sure how it relates to rolling a Hooter but probably within few seconds of the time?), I KNOW faster than I can bag drop (maybe slightly slower than perfect hand "launch" but you don't have to go low or "prepare"). I ended up with my bag atop my tramp for wave drag and ease of rigging issues and a Tornado style double halyard arrangement and it all works.
Gotta go to work now but please post specific questions or others comment-

Kirt

I have attached a picture of my boat with my home-made snuffer.

http://www.kcc.ozehosting.com.au/Photos/T099spin.jpg

The opening or gate is out of carbon fibre. A kayak oar was cut up and fibreglassed in the right shape. The bag is light dacron. Goes under the tramp for about a foot.

Works really well with 2 lines for up and out.

The other alternative which works really well is fibreglassing an alloy hoop (available from Redhead Sails) to the pole. Very sturdy and light.

JC

Thought I'd post some more now that I have more time with some specifics. My pole has the tack line led internally though a back-to-back double block so the halyard also tensions the tack line (allowing a single line to hoist/douse the spi w/o need for a separate tack line). With the midpole snuffer one only needs about 4-5 feet of "slack" to snuff the tack so I shortened this line to take the un-needed excess line out of the system. I have the SS "gate" on my mast and settled on using a short bit of SS wire w/ thimbles as a sort of "pigtail" between the mast padeye (that supports the vertical loads) and a small Ronstan block with becket for the upper halyard. The upper halyard is 1/8" Spectra deadended on this becket, runs down through a back-to-back small Ronstan double block, back up through this block and down to head of spinnaker. The "conventional" halyard- which exits a through block at the back of the spi pole now runs up the side of the mast and through the other end of the double block then back down to a swivel Ronstan block mounted on the rear of my mast via the sail groove (I drilled and tapped a bit of Aluminum rod which slides into the track and then the block screws into this). The lower halyard then runs the length of the trampoline to a block with becket (use a larger block here than a micro to reduce friction/snarls) I shackle/clip to the padeye that holds the port hiking strap. A short bit of Spectra extends from the back of my snuffer bag to the becket on the block- holding the bag back and the block aligned. The lower halyard then runs along the hiking line into the bag and through a small loop in a short bit of line that extends from the lower snuffer webbing (make the loop small enough a large stop knot tied in the halyard will not slide through it) and ends on the upper snuffer patch webbing. I tie the stopper knot in the lower halyard line about 6-12" from the upper webbing so when snuffing the lower webbing point is pulled into the skunk this far ahead of the second patch. By pulling what WAS the original halyard end (which exits the spi pole and cleats on the pole) now you can take all the "slop" out of the halyard/snuffer line you want (don't want it snug when fully snuffed but with just a bit of slack). I actually took off the heavy, rotating cleat and just put a light jam cleat in it's place to keep from "snagging" it with the jib sheets, etc. and to save weight. Also- tie a bit of bunji from the swivel cleat on back of mast to the rotator to keep lines from "falling" into this cleat (spi sheets tended to get trapped there). If you pass the spi sheets between the forestay and spi luff (so you jibe the spi through the foretriangle rather than around the outside) they won't end up wrapped around the pole (very easily) and when snuffed (if you have the right length) the excess sheet is drawn into the snuffer as well so there's no extra sheet flopping around! I have small Holt-Allen snatch blocks I shackle to a sail slug and slide into the front beam as turning blocks for the spi sheet so the sheet just runs along the back of the front beam when snuffed (and I don't use the barber haulers when spi sailing) and stays out of the way. I have the Ronstan autoratchets shackled to the shroud adjusters as my "main" blocks and they seem to work quite well. Since the "skunk" is mounted on the side of the pole it wants to "rotate" and to prevent this I simply tie a line from the pole, along the back of the skunk and under it, to the port bridle wire- trapping the skunk between this line and the stabilizing line from the pole to the bridle tangs on the hull. Now- if only I had a selftacking jib like the Tornados sailing sloop with the spi would be a snap!

Kirt

Kirk,
Is it possible to have a self-tacking jib on the Taipan? I thought there was too much jib overlap. Would the jib have to be redesigned? I've seen a tornado with it and saw the Stealth F16 pics with it. Since my "crew" are ages 6, 8 and 11, it would be a nice element on my next boat...heck sometimes I'm just happy if they don't fall in.
Regards,

Eric-
It's definitely possible but it would require some changes including the addition of a jib track, strut from bridle to spi pole (or solitary pole ala the P 19MX) and a new jib (shorter in the foot but longer in the luff and leach, potentially with full battens if you wanted overlap- it would HAVE to be smaller than the "stock" 4.9 jib to be F 16HP compliant since the "stock" jib is too large [but grandfathered as long as the 4.9 is stock]). On our "small" boats I really think this would be a big blessing and I am going to pursue this possible option.

Kirt

I'm working on the same issue and for the same reasons as Kirt. As my boat has the same triangle as the standard taipan 4.9 I'm faced with the same problems.

Answers are simple. Selftacker possible ? Yes and Greg Goodall of Goodall Yacht sails will help you in designing one when requested.

Taipan sized jib as selftacking possible ? No, simply doesn't fit. Alternative is to sheet it of the trampoling right behind the mainbeam instead of far back on the trampoline. Is not a selftacker but will move jib sheets and blocks out of the way of crew and spinnaker. I might go that way as a cheaper soloution to the selftacker. I have some ideas on how to make this setup work like a selftacker downwind even though that is really isn't. Extar items needed an extra line and two little blocks.

F16 size jib ? It will be a feat to get the max allowed area in the Taipan triangle but some sailmakers think it can be done or at least come very close to the 3,65 sq. mtr actual area. No definate answers has been found that although it is required to have the bridle strut setup like the stealth and teh Tornado's

I will keep you informed when I have more answers.

Wouter

How important is jib overlap for airflow on the main? Maybe less is more. Seems like a trend. The Hobie 18 had jib overlap; the big Nacras have huge jibs and overlap. But now more cats are going to non-overlapping setups. My N5.0 (with stock jib) has overlap, but it looks like the new N5.0s don't; instead, they have a fat head main but smaller, non-overlapping jib. Could the same thing be done with the Taipan--Smaller, self-tacking jib but bigger main? Or, maybe the loss of sail area wouldn't be missed.

Eric,

What you describe is exactly the way you would go when ordering a F16 package for a Taipan 4.9.

The F16 main is slightly larger but, more importantly, has a larger squaretop. The jib is reduced in size by some 12 % but gets a larger luff length as higher aspect ratio. At the same time one moves the jibsheet to the (far) front of the trampoline where the out of the way. In the old days this required the fitting of barberhaulers to pull the crew to the proper sheeting point for downwinf sailing but with the introduction of the gennaker the sheeting points don't move about that much any more. Ergo, you can get away with less distance between blocks and clew.

I questions a few sailmakers about the non ovelapping jib and several indicated that airflow theory has changed a bit. It seems that it is not the jib which is important with respect to the airflow over the mian but rather the other way around. The main is important in determining the airflow over the jib. Ofcourse for the last ; having an overalp is far less important as it becomes a suction situation instead of a slot / ventury situation. It seems that a NASA aerodynamisist whose name I can't remember now has proven that the old theory of the slot ventury was incorrect and he did that back in the 60's.

And the theory is more detailed than I want to write down in this reply.

However this "new' theory is confirmed by experiments in "High Performance Sailing" by Julian Bethwaite and he even shows some wind tunnel pictures of it.

Now, ofcourse a bigger jib will always produce more power but it seems that overlap is more linked to having more power because one can than fit a bigger jib than that the overlap itself is the cause of more power.

With respect to powering up a sloop rig in respect to a uni rig. It is found that the power increase is more than can just be accounted for by the extra area. In sailboat sailing that is ofcourse. Landyachts behave differently because, well, they go 2 to 3 times as fast as catamarans. So what is the reason why more power is developped ? One reason it that a sloop rig can skew the airflow (wind) over a larger angle than a uni rig can. This is especially productive on reaches and shy reaches. In the old days also when going on broad reaches and downwind but we mostly have the gennaker for those courses now. But even upwind it seems to work. Just like with the flyer A-cat catamarans are increasingly found to be better footed off than pointing high. The Flyer was found to be faster to A by pointing slightly lower and moving faster than by pointing high and moving less fast. Same comments are heard over and over again with respect to the Taipan 4.9.

The cat rigged Taipan sailors typically move their traveller about 4 to 5 inches from the centre. The comment is that with the mainsheet centred the boat just doesn't seem to drive as well. By placing the jib in front of the main and centre sheeting the main the whole rig can now fully bend off the airflow to the centreline when going upwind and be more efficient is harvesting energy than the extra area of the jib alone can account for. The cat rigged mainsail alone can not bend off the airflow to such a large angle on its own. Ofcourse this aspect is not influenced by having an overlap or not. You will have this effect by having a jib or not and not by having an overlapping jib or not.

Than we have the extra effect of have a slot between the jib and main. But this is a different effect than the overlapping slot effect we just discussed. In general an airfoil wing devide in to parts with one in front and one behind the other in more efficient than the same area in one undevided airfoil.

In leemans terms the decellerated airflow near the surface of the jib is preventing from continuing near the surface of the mainsail and detaching there by a flow of fresh and undecellerated air coming from the slot between the jib and mast. This fresh boundery layer is instrumental in assuring attached flow over the mainsail resulting in good power. Or at leadt more than would be the case when the area placed in the jib would simply be have added to the mainsail.

Several people are often quickly to refer to the cat-rigged C-class catamarans but often overlook the fact that in that class teh slotted sails are by long the prefered rig. This slotting of the rig is also at work between the jib and main although less effeciently due to the triangular shape of the jib and the fact that it only properly interacts with the lower halve halve of the mainsail instead of the whole mainsail. Ofcourse by slotting the whole mainsail as done in the C-class the principle of slot effect is far more optimized than would be with a jib and mainsail configuration, however it is still the same process at work albeit to a different magnitude.

All this can be researched and discovered by anyone making an effort in rig designing and has been know for some time. Although I must admit that it something is more beneficial to leave several people in the dark about these issues. But that time has ended.

So the main conclusion from this reply is that :

Two of the main processes at work that result in more power being produced are unrelated to having an jib with an overlap. -1- bending off airflow over a bigger angle and -2- Slot efect which replaces used up boundary layer by a new fresh and high on energy boundery layer.

1 proces directly linked to power production by the jib is linked to having an overlap and that is the total amount of jib area. However this can be counteracted by using the bridle strut and adding the removed area below the current jib. With respect to teh F16 rules some of the Taipan 4.9 jib can be moved to the mainsail and be used to make the larger squaretop. All this while clearing up the trampoline.

Goodall Yacht sails have expressed that they will supply a Taipan 4.9 with a fully optimized Formula 16 rig when requested. This may include a selftacker.

With kind regards,

Wouter

Do you know if anyone has tried an F16 optimized sail plan (smaller jib, bigger square top on main) on the Taipan as opposed to its stock "grandfathered" sail plan? If so, any benefit other than being able to rig a self tacker? Otherwise, why would you want to give up the grandfathered sail area? I'm not crazy about the jib blocks on the tramp of the Taipan. I guess the rope loops that act as the block "traveller" are better than a bunch of cables. But blocks/cleats on the crossbar are a lot tidier.

Eric,

>Do you know if anyone has tried an F16 optimized sail plan (smaller jib, bigger square top on main) on the Taipan as opposed to its stock "grandfathered" sail plan?


Sorry to have to butt in again but I think I have the first optimized mainsail for the Taipan design. And it was tested when fitted to a standard Taipan and reference checked against a Standard taipan with a new Taipan mainsail from the same sailmaker.

Both sails were new, so we didn't compare it to a blown out old sail.

Results : We didn't get eveything we hoped for, but very got we expected would be the case. Please remember that this F16 mainsail was optimized for a doublehander crewweight of 150 kg's = quite powerful.

The gust response of the redesigned squaretop was superb, even the seasoned Taipan sailors doing the testing were very impressed. I is already a well documented fact that the Taipan would rapidly accelerate in every gust but with the quick action of the self adjusting squaretop the boat jumps up and drives much more and heeling in noticably reduced. Result is that less active sheeting, to produce the same result manually, was needed.

From the few tests that have been done in both light air and heavy air the allout topspeed doesn't seem to be noticably faster than the Standard rig. Ofcourse the changes to the F16 mainsail are to small for that. It is mostly a refinement of the old excellent mainsail shape. However, having said this, gust response is very important, especially when flying a spinnaker. When the spi is but it is unwise to sheet out the main to much as that will put your mast in danger when the wind is sufficiently strong. With this squaretop it is intended that to automatic and unsheeted asction of the top of the sail still retains good gust control while flying a spinnaker.

Also, when single handing and the lone skipper has his hand full than a rig that reacts to onslaughts like gusts in a more automatic manner is much prefered. I'll be singlehanding myself halve of the time.

Also, a automatic adjustig of the rig is always faster than manual gust responses. In gusty conditions this would easily constitute "having an edge".

In short, the F16 mainsail rig for the Taipan 4.9 mast was found to be a good further refinement of the well performing standard Taipan 4.9 mainsail. With respect to more all-out topspeed in steady windconditions ? The two rigs seem to perform equally.


>>If so, any benefit other than being able to rig a self tacker?

See my comments above. To this I would like to add that I will be very happy to move the jib sheets to the front of my boat leaving more room for the crew to manouvre and allowng faster tacking even when no selftacker is fitted. Remember, the crew has one hand less now with the spi sheet in his hand. I personally think the selftacker is sexy nice to have and the last refine to the rig but I also have not decided on getting it yet. Last time when I spoke To Greg Goodall he suggested that simply moving the loops to the front of the trampoline right behind the mainbeam and redesigning the jib would be a very effective low cost modification which would still allow good finetuning of the sheeting angle. I might go that route myself.


>Otherwise, why would you want to give up the grandfathered sail area?

The Taipan 4,9 has 16,66 rated sq.mtr. sailarea, the F16 has 16,5 sq. mtr. rated sailarea. Difference is not even 1 %. When taking the real sailareas the difference in sailarea is just shy of 1 % with the F16 having less. As we all know 1 % sailarea difference roughly translates in 0,5 % speed difference (taking the square root) which is 18 seconds per hour racing. My reasoning is :"how many gusts and improved tacks/gibes does one need to win back those 18 seconds?"

Clearly the few tests we did indicated that the standard taipan has a competitive rig in the F16 class but this doesn't mean it also has "the edge".


>>I'm not crazy about the jib blocks on the tramp of the Taipan. I guess the rope loops that act as the block "traveller" are better than a bunch of cables.


Well, the sheeting of the jib differs somewhat when flying a spinnaker. I used to have barberhaulers on my P18 which uses fixed sheeting points for the jib. And thos barberhaulers works, the improvement in downwind sheeting angle was easily translated in more speed. Quickly after I fitted the boat with the spinnaker , I removed them from my boat. I never used them while sailing with a spi and the upwind setting point seem to be acceptable for downwind spi sailing. Not optimal but optimal enough.

This less moving of the sheeting point with respect of sailed courses allows the distance between clew and block to be much reduced. And to retain some finetuning, because windstrengths still have a influence on the sheeting angles; a line of loops near the mainbeam would still be very handy for on beach tuning of the rig.

I hope this answers the questions you may have.

Wouter

Wouter,
Thanks for the info.