Arwen's meanderings

Hi everyone and welcome to my new blog. My name is Steve and I am the lucky owner of a John Welsford designed 'navigator' named Arwen. I built her over three years with the help of my father, father-in-law and two children. She was launched in August 2007 at Queen Anne's Battery marina in the Barbican area of Plymouth. This blog is a record of our voyages together around SW England.
Arwen has an associated YouTube channel so visit www.youTube.com/c/plymouthwelshboy to find our most recent cruises together.







Tuesday, 13 March 2018

Using a standing lug sail with sprit boom part 2


In a recent blog post https://arwensmeanderings.blogspot.co.uk/2018/03/setting-up-standing-lug-sail-part-1.html I shared my mistakes in rigging Arwen (my John Welsford designed ‘navigator’) which have over the years caused me problems when using the sprit boomed standing lug sail yawl rig. Essentially these mistakes arose from two issues. Firstly, I deviated from the plans and these ‘adaptations’ had consequences for sail setting and trimming. Secondly, to be frank, I knew very little about sail dynamics, sail shaping, and lug sails, so much so that I often considered it a wonder that I ever got Arwen to move!
Not all is lost however, for in the last year or so I have started to gain some ‘limited’ understanding of the standing lug sail which I now share in this second follow up post for anyone using or considering the standing lug sail on their navigator. I am indebted to other navigator sailors such as Joel Bergen, Robert Ditterich, John Welsford himself and my good friend Dave, along with some members of the UK Dinghy Cruising Association and subscribers to my blog and YouTube channel ( www.arwensmeanderings.blogspot.com and www.YouTube.com/c/plymouthwelshboy ). Without their advice and kind constructive observations I would not have developed any understanding of the sail configuration on my boat. As I reflect on this last sentence, I have to confess, it is pitiful that a sailor has to rely on others to explain the dynamics of his own sail plan! 
More adept sailors will find the standing lug sail a simple, easy to use rig. If you have any observations and constructive advice about my observations below, please do share them via the comment box on this page. I am very keen to improve my knowledge further for this sailing season so that poor Arwen doesn’t feel further embarrassed when out with her skipper.

So, let’s get started straight away with the simple stuff – how I raise and then set my sails.
Arwen’s standing lug sail has, I think, four points where adjustments can be made to the sail trim and shape – the tack (luff) downhaul; the sprit boom snotter ; the mainsheet attachment on the aft end of the boom; and finally, the halyard tie on position on the upper yard, each of which I will comment on in more depth later. 
Based on what I was taught in the RYA 1 and 2 courses I completed in the Med, I’d normally come head to wind using the sheeted in mizzen to hold Arwen bow on to the wind, prior to raising the sails. However, I believe that in a small boat, you should be able to raise or lower the sails safely in any situation or on any point of sail; and that turning head to wind each time should be unnecessary if the rig is set up correctly. Thus, this season I will be trying to abandon this ‘habit’ as much as possible. In addition, I should note that Arwen’s trim is rapidly altered just by shifting my weight around in the cockpit, so maintaining a head to wind position when I am clambering over the thwart to release sail ties is normally a ‘hit and miss’ affair to say the least.
So, the procedure I go through runs like this: 
1.      I loosen the snotter on the sprit boom so that it moves forward of the mast
2.      I then haul up the topping lift slightly lifting the sprit boom and the sail yard furled on top of it; I then release and stow the sail ties (note I added in a topping lift/come lazy jack arrangement on Arwen which over the years has worked a treat. It is the only adaptation I did off my own bat which actually worked!)
3.      The main halyard is hauled thus raising the sail yard upwards. At this point I make sure it is aft heavy and that I have secured the halyard rolling hitch in the correct place on the yard (between 30 – 40% up the yard from the throat end seems best on Arwen); I also check that the parrel bead loop that runs from yard around mast and back to yard is moving smoothly and that the yard attains its correct position and angle.
4.      Having cleated the main halyard, I release the topping lift so that the sprit boom lowers and then I push the sprit boom snotter end higher up mast to just past the first reefing points line on the sail so that it is angled correctly
5.      I then check that the tack parrel beads loop is attached around the mast before then tensioning the tack downhaul.  Similar tensioning is applied to the snotter to move the boom aft until any creases disappear.

(Notes: (a) The tack downhaul and halyard in combination put tension on the sail from tack to peak. With the sprit snotter eased, there should be a crease from tack to peak and I am tensioning the snotter until this crease disappears. Too much tension, by the way, will form a crease from throat to clew.  I’ll go into more detail about sail tuning later on in this article. (b) I have arranged the snotter halyard to drop vertically through the deck to a block alongside the mast on the port side of the front thwart top, from which it then runs back aft to the cockpit. This allows me to adjust the snotter and thus the sprit boom from within the aft cockpit, eliminating the need to go forward periodically to retune the boom position).

Having raised the sails (it is far simpler than it sounds from the above description) I then set about setting and trimming the sails to gain a good and efficient sail shape and hull speed. 
And this is where I get confused due to differing sets of advice I have received.  Remember, I know little about sail dynamics or lug sails!

What I tend to do in winds of up to ten knots, when reaching and running, is to tension mizzen first (by sheeting mizzen in hard but keeping sail snotter loose for a slightly baggier sail) and then use this to set the mainsail and jib correct angles/positions. I aim to get a little weather helm on the tiller and if I have understood all this, it is the mizzen that sets the sheet angle for the other sails and the pointing angle for Arwen.

 In ten to fifteen knots, John always advised me to ease the mizzen sheet, then ease the main if exposed, by checking the degree of weather helm on the tiller. To sail for speed in ten+ knot winds, I ease all the sails a fraction and adjust the mizzen to gain a small degree of weather helm. (If the tiller pulls hard, ease the mizzen; if the tiller seems too light, sheet the mizzen in a little. Pressure on the helm is what tells me whether Arwen is over pressed or not; and whether it is time to reef – for reefing see later section).

Someone also once told me that when easing sails, I should ease jib first, then main, then mizzen. This same person, quite an experienced sailor in Salcombe, also told me that when using all three sails – I should trim the jib and main for best angle of attack and get all their tell tales streaming aft and then trim the mizzen to get a few degrees of weather helm, which for those of you still paying attention, is the reverse of other advice I’ve been given. Consequently, I remain confused as to which it all is!

(Over this last sailing season, I did try, on the advice of an experienced dinghy cruiser, to play about with the sails. Leaving the tiller, I discovered that easing the mizzen meant it caught less wind and as a result Arwen pivoted gently away from the wind. Sheeting mizzen in meant it caught more wind and thus Arwen’s bow turned into the wind. Having never learnt to sail with a mizzen, this was a revelation!  I was starting to learn how Arwen balanced and the effect of her sails on this. I tried similar tactics with the jib and so began to make simple course corrections using the sails rather than rudder, thus maintaining a more constant speed. Sadly, I don’t recall this being taught on the RYA course I did all those years ago. Maybe it was and I forgot!)

So, what about the fine sail tuning?

I hinted earlier that I would look at this aspect of using the standing lug sail in a little more detail. I stress once again, I am not expert in this rig, consequently, what I say next may be wrong in places and I therefore welcome constructive comment and observations.

The basics – if I want to tighten the luff and ease the leech, thus removing a crease from tack to peak, then I move the forward end of the sprit boom down the mast a little OR I move the halyard securing point on the yard forward slightly.  If I want to tighten the leech and ease the luff, thereby removing a crease from clew to throat, then the directions of movement for sprit boom on mast and halyard on yard are reversed i.e. boom position up a little and halyard attachment slightly further aft.  
Halyard position on the yard is critical as I hinted at earlier. For a standing lug sail to work I think there needs to be imbalance, if I have understood some people correctly! This is achieved by the halyard being tied onto the yard at a point far forward enough to make the yard aft end really quite heavy. Without doing this, the sail rotates in such a way that the boom and aft end of yard end up lying in the boat and the forward end of the yard just points upwards. On Arwen, as I said, somewhere between 30 – 40 % up the yard seems about right.


Another key aspect is sail luff tension. The tack downhaul is tensioned hard to pull the luff straight, prevent sail rotation, stop the boom moving forward of the mast and to get the yard upwards to its designed angle. At the same time this also tensions the leech thus lifting the aft end of the sprit boom into the correct sailing position. I rarely ease tension on the downhaul once set since all that does is lower the peak angle and drop the aft end of the boom into the cockpit.  (note: also crucial to all of this is tying that halyard on at the correct position on the yard. As mentioned earlier, if the yard halyard is bent on too far aft it reduces yard tail heaviness, which whilst making the sail easier to raise, does lead to less luff and leech tension. A phrase I do remember from the sailing course in the Med all those years ago, ‘a floppy sail is an unhappy sail’!  In addition, sail shape will be poor, the yard bounces, the boom bounces and all is not well!)
However, a note of caution about this luff downhaul tension. Too much applied and I think it causes other problems. The sail shape is fixed and it is this that determines the angle of the yard to the mast. Correctly applied tension raises the yard until the sail attains its correct shape. Over tensioning ruins sail shape and requires more fiddling with snotter and boom angles and leads to new tensional sail creases along the yard area of the upper sail.
A delicate touch is required in tuning the standing lug sail!

Of paramount importance is ensuring the tack parrel loop is secured around the mast and that it doesn’t restrict luff downhaul tension being applied (see first article to how I managed to mess that one up).
Alan, a blog subscriber of mine summed it up beautifully. “Whilst three of the four sail corners are attached to fixed spars, the fourth isn’t. That tack corner can float forward or aft if not secured and tensioned correctly and that affects the setting and tensioning of the lower part of the sail below the boom position. As the snotter is applied, pushing the boom aft, the lack of fixing of tack to mast means the tack is also pushed aft as well and so tension to remove any throat to clew crease is not applied and the lower sail shape doesn’t set correctly”. As we will see later this lower sail shape below boom is critical as it acts as a vang).

Finally, I was also given a cautionary word of advice from John Welsford himself too. “One of the things that can affect the set of the sail is having a yard which is not stiff enough”. He went on to explain that if the yard was flexing too much then any crease from throat to clew would be impossible to get rid of. He suggested that ideally there would be around 70mm of flex in the yard in a 15-knot wind. “any more than that and you lose control of the shape, any less and the sail won’t twist off to reduce the heeling effect in a gust

And so, we come to the sprit boom.

I’ve made several points about the snotter on the sprit boom and have already hinted at its main purposes. As I understand it, if I have this right, it acts as a vang and boom in one and eliminates the need for an outhaul on the sail/boom. The sail below the boom prevents the sail and aft end of boom from moving up when the mainsheet is eased and the vang, boom and lower sail bit stop the sail from twisting off to leeward. (Note: in such a scenario, sail twisting to leeward, I assume that the sail would spill wind thus reducing speed and power. The vang on Arwen is always tensioned and on a windy day this can be a disadvantage. I think, if I remember correctly from sailing lasers all those years ago, by easing vang tension, I could induce some upper sail twist and thus spilling of wind, which depowered the sail and prevented me from heeling or capsizing. On the sprit boom standing lug sail, I haven’t really found a way of getting upper sail twist to spill wind short of going forward to move the boom position down a tad on the mast.  In a sudden gust I merely ease the main sheet or head up into the wind a little more to reduce heeling effect. My only other thought, probably way off base, is perhaps altering downhaul tension at different times. Perhaps it needs to be a medium tension in light winds, firmer when the boat is moving along nice and flat and really full on when the boat starts to heel over, so that the sail flattens and thus depowers. I feel I read this somewhere but can’t remember where; and part of my brain sounds a warning that this may not be right at all!)

If I tension the snotter to bring the boom aft, the sail will flatten and tension will be applied to leech and foot and thus the main sheet merely hauls in or eases out the sail and has no other role. Of course, it does also allow you to play the main sheet more easily in a breeze as well. As I said above, I assume that flattening the sail is a good thing to do as the wind increases in strength. Conversely, I assume that easing the snotter during lighter winds is best to make the sail baggier. If I have this bit wrong, please do drop me a comment. Light wind sailing, for example, is one of the things I am struggling with in Arwen and its irritating to say the least!

Positioning the boom angle is critical. I start with its forward end positioned on the mast level with the first reef line and then adjust accordingly as outlined earlier. When set too high, the sail shape seems wrong. When set to low, the boom bounces. I remember reading somewhere that it is a matter of finding the ‘Goldilocks – just right’ position!

In summary, I like the simplicity of the sprit boom although with fairness I think I should point out it doesn’t give the sail control, performance and adjustment potential offered by a normal boom with a vang attached. I am sort of beginning to understand better how it works though. For me, the sprit boom brings ease of use and extra headroom. But yes, getting that position on the mast right is fiddly and may necessitate some adjustment during the first few minutes of sailing (which affects boat stability as you move fore and aft); and yes, a sprit boom is tricky to reef and can when hauling up or collapsing belly outwards to leeward. I am conscious that I am careful to sail in conditions where I won’t be suddenly overpowered. I haven’t fitted any foot straps on Arwen. I didn’t see the need. I don’t intend hiking outwards on her. If I am beginning to feel overpowered, I’ll furl the jib as the first reefing. At worst, I collapse the main and sail under jib and mizzen.

So, what about reefing a standing lug sail with a sprit boom?

When I have read up on standing lug sails with sprit booms, it seems that a major point of debate is how to reef a sprit boomed sail. Many people seem put off by this aspect of the rig. Now maybe I am doing it wrong and I do have a video which shows me doing it in a horrendous fashion when I had a silly slab reefing system set up. I have since removed that and so procedurally I now
1.      Heave too or turn head to wind, furling the jib and sheeting the mizzen tight
2.      I ease the snotter and then tack downhaul and lower the main sail halyard by the same amount as my reef depth
3.      I then move the downhaul up to the first reef grommet along with the loop of parrel beads around the mast.
4.      I then raise the mainsail again until the tack regains its original position.
5.      Tension is then applied to the downhaul to raise the aft end of the boom where I then unclip the clew from the boom and reattach the boom at the first reef point on the leech.
6.      I then tension the snotter correctly and finally tie up the reef lines to braille the loose sail below up. (note: I have found that tightening the snotter before applying tension on the downhaul leads to the formation of several sail creases – so be warned!)
7.      Finally, I unfurl the jib and bear off to fill the sails
In this way I have reduced sail area and power in the sail, hopefully reducing any heeling effect. I tend to reef earlier if I am heading upwind and especially if I am not carrying extra ballast in Arwen. Other thing I have noted about reefing the sprit boom is that on occasions after reefing, the sprit boom extends further forward of the mast thereby catching the leech of the jib. So, at times I have sailed without the jib after reefing the main. Consequently, when reefing, rightly or wrongly, I tend to consider furling the jib as my ‘first’ reef. Reefing the main for the first time is then my ‘second’ reef. During this winter’s refit I have attached a second deck eye for the sail reef clew on the boom. It is 30cm or so further forward than the normal clew aft end eye. I am hoping that this season the excess sprit gained after reefing will now hang over the aft cockpit rather than in front of the mast.

Using the mizzen
I am still getting used to having a mizzen. I know that under skilled hands it has many purposes and can be used to great effect in tight anchorages for sailing off buoy or anchor in different directions. I have yet to master that stuff! So far, I have used the mizzen to help me come about when tacking. Instead of backing the jib, I have on occasions reached over my head and used the front of the mizzen boom like a tiller, pushing it hard to port in conjunction with tiller to move me from starboard to port tack. When tacking I avoid sheeting the mizzen in tight until I have moved onto my new tack. Sheeted in tight, the mizzen points Arwen head to wind and helps her stop. It is all basic stuff I know but I am beginning to get the hang of it.

When sailing under jib and mizzen I have discovered speed is essential. I bear off a little, build up speed, wait for a gust, move the tiller over and keep it there. I then back the jib rather sharply as Arwen comes about.  She has on occasions stalled at this point and someone shared a lovely tip with me about using the mizzen. In such a circumstance, I should ease the mizzen, through the tiller over hard in the other direction, grab the mizzen boom and pull it in, thus sailing backwards slightly which apparently pivots the boat around. One to definitely try this season.

Of course, the big problem is memory. Out on the water, I can never remember any of this stuff!!

Although a lengthy piece, I hope I have most of this right and that it will help people in their future considerations of what rig to use on their navigator. At the very least, I hope it generates lots of discussion and comment, for I have much still to learn and understand. If you feel there are bits wrong, do please drop me a comment below.
Similarly, if any of you have tips about light wind sailing with a standing lug sail and on a different topic, what procedures I should be following to sail onto and off a mooring buoy or anchor using this sail configuration, I would love to hear from you too.

Thanks for reading this far and sticking with it. Take care; enjoy your next time out on the water.
Steve
www.YouTube.com/c/plymouthwelshboy

POSTSCRIPT:

My good friend made some useful observations regarding the above blog post. Bless him, he went though some of my videos and looked at other navigator videos as well. He made these observations/raised these questions


1.      Had the sail stretched any during the last eight years of sailing?


2.      Was the mast the correct length?


3.      Studying the videos and when out of the boat with me, he has noted that the sail is very baggy and that there seems to be a permanent crease. As I said in above post, he comments that there should be a small crease from tack to peak when a lug sail is hoisted; but that it should fall out once the sail comes under pressure from wind, downhauls and snotter.


4.      He reminded me that a standing lug sail is a four cornered piece of fabric, under tension from the four attachment points (see above post). I should check how I have attached each of the four corners because it affects sail shape. So check lacings and how it hangs when aloft. The four tensioning systems tension the sail along the sides and diagonally. Pull on opposite corners and the diagonal between will crease. Too much tension between these opposite corners causes the crease which must be balanced out using the other opposite corners.


5.      Observing the videos my clever friend noted that the sail area below the crease and around the sprit boom and below is very baggy and with a clew to throat crease, he suggests I look at the downhaul system and position. He noted that the tack and attached downhaul is at least a foot away from the mast in some of the videos; and so ‘adds’ a foot or so to the foot of the sail. This can be taken up with the sprit boom snotter being tightened and the boom moved aft but it would be better to reposition the tack downhaul so it is closer to the base of the mast.


6.      The sail clew is wrongly attached as well. It has 8 inches or so of lashing and a snap hook link; and it the attachment on the sprit boom isnt completely at the aft end. Altering the sail clew so that the sail attaches directly to the very aft end of the sprit boom would help enormously. In addition, if the sprit was then further forward it would allow greater control of sail shape. As I indicated above, the sprit can alter the curve of the sail; fuller in light airs and when running; and flatter in stronger winds and when close hauled.


7.      In terms of setting sails he comments that he always sets jib flying cleaning, then adjusts main to maximise air flow and uses mizzen as a balancing sail. He reminds me of the need to go through the whole cycle again after every wind shift or course change. I should avoid using the rudder where possible and should remember that too much lee or weather helm will slow the boat down. “.  Letting go of the rudder completely and balancing the sails onto your chosen course will provide the maximum speed”.



In a nutshell, my friend suggests I should


a.      move the crease from throat/clew to tack/peak, before any sailing takes place by increasing tension on the tack/peak diagonal, (or reducing the tension on the throat/clew diagonal); including moving the tack forward to the mast. 


b.      The sprit should be moved forward and the clew attachment made much tighter and moved further aft on the boom thus giving more control.  The height and angle of the sprit can be successfully then adjusted as it is my outhaul and vang.

Comments from the Duckworks Magazine site are below:

From Tom 


Steve,
I’ve been studying all forms of lug for a while, and have personally built and used both a chinese lug and a balance lug on my boats, and absolutely love them. I intend to try a standing lug with sprit boom on my current boat, so It’s with great interest I’ve been reading this. Here’s my input for what it’s worth 🙂
Generally if you attach the halyard at the 40% back point, that makes the mast cross the yard @ the 35% point, which is usually pretty optimal for either a balance lug or a standing lug. A few % adjustment fore or aft is perfectly fine, but if you get the yard too far aft of the mast, you end up with too much sail twist. If you get it too far forward, you can’t properly tension the luff.
Generally luff tension is increased with the wind strength to flatten the sail.
A balance lug is self vanging. the yard pivots on the halyard as a fulcrum as the boom pivots on the downhaul as another fulcrum. If the aft end of the boom tries to lift, the front end past the downhaul and mast tries to drop, which is prevented by the luff tension. Wit a standing lug you need some way to vang down the boom off the wind as you don’t have the “teeter totter” effect of the boom on the balance version. This is what the sprit boom is so good for, provided your snotter attachment is far enough up the mast. If it’s too low, the geometry doesn’t give the foot of the sail any leverage to hold the boom down, and you end up needing a vang anyway. The perfect angle for a sprit boom is usually bisecting the angle of the foot and the leach, but this is often unobtainable as it puts the snotter attachment to far up the mast to be practical.
Traditional adjustment of the snotter is looser in light winds for a fuller sail shape, and tensioned in higher winds to flatten the sail, same as with the tack downhaul.
The Yard advice from Welsford is critical. I made my first yard much too thick and heavy, and as a result I’ve had too much bag at the top of the sail in all conditions, and it doesn’t bend off and de-power the sail in a heavy gust as it’s supposed too.
Lastly the mizzen. I wish I had one. Raising and lowering the main is much easier head to wind, especially in heavier winds. full drop your centerboard, raise your rudder and sheet that baby in tight, and the whole process of raising and lowering the main is much less dramatic. Secondly, it absolutely lets you dial in the helm balance for whatever sails you have up, sheeting in for more weather helm or out for less/lee helm. I agree with whoever told you to trim the jib and main for best performance on your bearing, and then sheet the mizzen to adjust the helm.
Thanks for the article!
Tom



2 comments:

Anonymous said...

Steve! Greetings from NZ. I have skimmed this article and here are two small points:- 1. Always raise/lower sails head to wind - for safety and ease of sail handling especially single-handed. 2. I do not think the comparison between the standing lug sail and the Laser is valid when you write about easing the 'vang' to spill wind. The cloth tensions in a standing lug sail are not as high as the Laser (triangle sail) so it is never as flat and 'stiff', therefore it spills wind in circumstances when the Laser sail will be tending towards being over-powered. If you watch the ubiquitous yachts sailing upwind in a gusty breeze they tend to do a lot of heeling. Watch a standing lug sail or a gaffer in the same conditions and you will see that there is less heeling going on and it is more moderate too - the sail is spilling the gusts, by virtue of the design. One time last year I had to sail in unpleasant, gusty, wet, very lumpy conditions and was surprised that in this far-from-ideal situation the boat was still easy to control. Apart from the hull design, the main contribution to control and safety was the lug sail - when a gust arrived the top of the sail spilled it, instead of trying to lay the boat on it's beam. People under-estimate these sails. I know mine has kept me safe. Having said that though, I have been trying to get my standing lug sail to set to my satisfaction for over 2 years now. I am analytical by nature, and it took me all that time, trying all the adjustment permutations and combinations, to conclude that perhaps the sail itself was not correct. I took it to the sailmaker to check it was made as per plan, and it turns out it isn't - significantly so. I shall get it back this week, so will have to do the setup again. When I get it to my satisfaction I will know that the boat and rig are far more capable and safe than most people appreciate. Hang-on in there - the best way to gain knowledge is by having to solve problems (back to first principles!). I know I have learnt a lot, with more to come no-doubt. That's part of the beauty of this sailing lark.... Cheers, Alan H.

steve said...

happy Easter Alan. Your comments are really helpful - thank you so much for taking the time - deeply appreciated. I had never thought hard enough about analysing the cut of the sail but actually the sailmaker who made mine is very famous over here in UK and he would have naturally made some alterations if he thought they were necessary. However, it doesnt mean to say his alterations would have necessarily been right, so I'd better check that. You have given me so many pointers above - I'm really grateful - thank you.

I guess you are heading in to autumn now; so I hope you have a good final bit of the summer when you can get out and test the newly cut sails