Thread: GIS sail tweaking

This is how I have mine rigged. I like it a lot, as I can adjust it at any point of sail, without taking my hand off the tiller, or otherwise slowing down. The purple line is 4mm Spyderline. The only thing I have changed from these photos is sliding the forward boom attachment towards the tack a couple of inches. This operates very smoothly, even under full load. It may be 3mm spyderline, I don't remember, and I used up the whole spool, but I don't get the impression that it stretches at all. I've beefed up and rearranged my downhaul now that I have a boom that can stand the tension without bending too much.
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Ok guys--

I love Bruce's setup, but it proved complicated with the fact that I often am reefing and un-reefing and reefing again in heaving seas off Maine. The clew progressively goes inward with each reef which necessitates a longer outhaul and the whole thing was becoming a spiderweb of line. So I did this, instead:



As you can see, same attachment as Bruce at the end of the boom, I put the fixing point and the first block in opposition of each other to keep the sail tracking straight back. Then, forward to a cheek block, back to a trucker's hitch! and then forward to the jam cleat.

This allows me to get super tension on the foot of the sail when I'm running full sail which is exactly when I have foot tensioning issues. Then, when I reef I can lose the trucker's hitch, because I get enough tension by hand if I want anyway on the new reefed foots. So lots of mechanical advantage for full sail, all on one line, with minimal parts and minimal complication when reefing at sea.

I haven't finalized positions of things yet, as in, where to put everything so it works perfect, but it's pretty close right now.

Also, I cannot tell a lie. BobWes totally called me out. I put in my burly outhaul a few weeks ago late at night, perhaps enjoying some maltiness maybe, and I thought I was being quite clever about getting a 3:1 or whatever on my fixed blocks. I went to bed, forgot about it, and didn't think about it again until BobWes pointed out the glaringly obvious. I am a fraud! I hang my head in shame.

Very tough looking - it appeals to my manly nature. What's reefing?

Very clever. You have redeemed yourself for the not-so-3:1.
In your experience do you feel the need to adjust the outhaul when reefed or since it's presumably blowing hard you just want a flat sail so the outhaul is a set tight and forget control? The reason for my question is I'm trying to set up a civilised way of reefing on the water and was thinking about combining the reef and outhaul functions into one permanently rigged line that would pull the sail down to the boom and back to flatten. Running this line forward along the boom to a clam cleat would eliminate the need to reach for the clew while reefing which I find tricky when it's rough.

Originally Posted by woodeneye

I'd recommend at least 4:1 for the GIS foot. A small cascade like this is quite elegant and makes adjustment very easy. Use a nice thin Spectra line as the loads are quite low, and the smallest, cheapest blocks you can find. My little blocks cost about $4 (see pic, actual size). The line you pull and cleat can be 4mm, but the other can be 2mm, for example SpectraSpeed which is cheap too.

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Cascades are absolutely the way to go. My tendency would be to go for blocks one size up from this, but the thin spectra that Bruce uses compensates. If using thicker rope you need a bigger block. Not sure why in the image the attachment point (the deckeye/saddle) for the second rope is not more in line with the purchase. Just need a very small lateral separation.

I would also tend to use a clam cleat rather than the cam type - half or third or quarter the cost.

This cleat doesn't work with line larger than 4mm. Which is perfect size for outhaul. With the outhaul you really don't need anything larger diameter than this.



And you don't need the deck eye as you can tie or seize a loop in the rope around the front bar of the cleat itself. Saves a fitting and two holes.

MIK

Originally Posted by SimonLew

Very clever. You have redeemed yourself for the not-so-3:1.
In your experience do you feel the need to adjust the outhaul when reefed or since it's presumably blowing hard you just want a flat sail so the outhaul is a set tight and forget control? The reason for my question is I'm trying to set up a civilised way of reefing on the water and was thinking about combining the reef and outhaul functions into one permanently rigged line that would pull the sail down to the boom and back to flatten. Running this line forward along the boom to a clam cleat would eliminate the need to reach for the clew while reefing which I find tricky when it's rough.

I totally understand your want to keep things simple with reefing, however I have unfortunately foregone the jiffy-reefing for my boat because of my fattybaggy high-maintenance Duckworks sail which is all sorts of finnicky. I find that a tight foot when reefed has adversely affected my pointing ability. So a little bit of medium belly helps this. Sometimes, when it's super choppy and lumpy and chaotic (I'm talking 15ktsG25 with a 10mile fetch down the Egg Reach against a current) I need a big baggy belly, so not a lot of outhaul. Mik has often pushed a 1:10 on the foot when in chop. So, I like to keep fiddling with it.

Your mileage may significantly vary since you actually have a professionally cut sail.

Trying something new. On my last video, I set the camera position to line up with my leech, so I could do some upwind diagnosing of my sail set on the dirty tack (boom to leeward of mast). I noticed a few things. Particularly, I noticed that my leech was curved/cupped - not flat at all. That explains the sail stalling when too closely sheeted. I'm now thinking that my original hypothesis of the dirty tack pointing having everything to do with the entry angle of the leading few feet of luff being somewhat mistaken - it's the leech. To flatten the leech, I'm going to take advantage of my DW sail having full length batten pockets, and have cut two shorter two foot battens which now support the leech alone, and are held there with line. That and a bit more outhaul. If all goes well, I may add an additional upper batten pocket to permanently eliminate flogging, and flatten the leech there as well.

I could not get out to test last weekend, as camping got in the way, but in my mind, the alterations are currently working perfectly. I'll report back whether that it is factual.

Good luck with the experimentation and problem solving.

I thought the "bad" or "dirty" tack had the boom/sail to windward of the mast. I mean, the wording isn't really all that critical - it won't change what you are doing - but it might help others understand what you're up to... Or am I all wrong on this?

^^Ditto what Bob said...

I thought the same, until I saw knowledgable folks referring to the "dirty tack" with the sail on the leeward of the mast. Dirty, in that the mast is acting to shadow the wind from the forward half of the sail when pointing. (This shadow and turbulence being dependent upon how much sail is forward of the mast, and the apparent wind angle.) So as to avoid confusion, I'll create a new acronym "bolsmokatdt" - (boom on the leeward side of the mast otherwise known as the dirty tack)

Posted by keyhavenpotterer (post #103) in a WBF thread discussing, in part, lug sails, masts and turbulence:

The mast turbulence lowers negative pressure development on the leeward side of the sail at the powerpoint a third of the way back when working upwind, when the mast is to leeward of the sail. More turbulence further reduces the force pushes it further back towards the tack, so the forward vector moving you forward is lower.

Link to the thread: A fishing, cruising, racing birdwing SCAMP - Page 3

Not sure I understand (or need to or want to) the fine points being made but it seems to me he is saying turbulence is greater, and power is lost, when going upwind with the mast to leeward of the sail.

Oh, and while your efforts to avoid confusion are appreciated, that acronym is quite confusing - amusing but confusing! (And I worked with a lot of acronyms in my working years PR (Pre Retirement).

Ha, I think you're right! I went back and looked, you are correct I think. Correct unless, I push for a change to the "dirty tack" label being attached to the opposite tack, because that's the tack that sails the dirtiest for me. Either way, I'll check how the battens affect both tacks - the dirty and the not as dirty. Yes - I am trying to at least crack a smile.

Sorry guys, I have only just got notifications of all the activity on this thread. Looks like you are on your way to solving your outhaul arrangements. There are many ways to use the cascade principle, so a few ideas are all you need to rig one up that suits you.

Here are some YouTube videos. I use the McLuvin system on my Laser as it is low friction. (hehe, didn't know the system had a name!) The only difference is that I use 2mm Spectraspeed, except for the final line that runs forward to the cleat. I get a few looks at my use of the thin 2mm line, but it lasted all last season through some big blow sailing and shows no sign of wear (still looks new), so rest assured it is tough stuff and totally up to the job. Rather than the shackle, I use an outhaul hook with a small block attached. You could dispense with the small block, but it helps to reduce friction. The hook is much easier and quicker to unrig with tired, cold hands, and the bungee works in two ways to both hold the hook in the clew and act as the inhaul.



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Very cool. thanks Bruce

Does the velcro clew strap have any effect holding the clew leech flat in relation to the boom?