Rigging a Spinnaker on a Catamaran

[dougweibel]

Originally Posted by Epicurean

Thanks. Actually I have to take the screecher down because I only have the one halyard for that or the spinnaker. But I want to leave the furler attached.

Do you have the ability to rig another halyard? That is really ideal. We have a screecher on our bowsprit and also attach the asymmetrical spinnaker tack there. We are cruisers and dowse rather than jibing the spinnaker. We have not run into any problems having the screecher rigged and raised while flying the spinnaker. Leaving the screecher up also has the advantage of allowing you to fly both the spinnaker and screecher wing-on-wing when you are running deep in light winds.

[Epicurean]

to theDangerz: A parasite with a parasail. Haha Just kidding. Glad someone else is getting useful information, too.

[Epicurean]

Originally Posted by dougweibel

Do you have the ability to rig another halyard? That is really ideal. We have a screecher on our bowsprit and also attach the asymmetrical spinnaker tack there. We are cruisers and dowse rather than jibing the spinnaker. We have not run into any problems having the screecher rigged and raised while flying the spinnaker. Leaving the screecher up also has the advantage of allowing you to fly both the spinnaker and screecher wing-on-wing when you are running deep in light winds.

I don't but wish I did. That's a LOT of sail area! Can you keep them both full?

[Epicurean]

Originally Posted by Palarran

With the Wichard it is super easy to douse the sail in the sock either with or without crew. All you need to do is head downwind, take your down hauling line in hand, walk up and pull the shackle release, and pull it down. If your in a fair amount of wind, you really want it to be easy. But we release it every single time we douse the sail, it's just what we do.

Maybe I missed it, but you have a screecher and a downwind asym in a sock? It really doesn't matter, every boat is a little different and you will have to figure it out in the end. But to answer the question of tack placement, in general the further downwind you sail the more you want the tack to be on the windward hull. The further upwind, the closer to centerline or leeward and tighter for the tack. With my North A4 we have sailed it from 70 degrees apparent to (this is the odd one) 170 degrees IN THE LEE. The more downwind I go, the more the spin sheet needs to be controlled, which is why I use the barberhauler.

One thing I'm curious about is the tack should be well forward of the crossbeam and prodder/bowsprit. How do you actually reach the tack Wichard to release it? Aren't you stepping into thin air?

[dougweibel]

Originally Posted by Epicurean

I don't but wish I did. That's a LOT of sail area! Can you keep them both full?

It often works great. Having the two headsails wing-on-wing seems to stabilize both of them. Little gusts that might go around the luff of a single sail are blocked by the second sail. As the wind drops very low the fabric weight of the screecher becomes the limiting factor, but the spinnaker holding pressure from escaping laterally allows the screecher to fly in a bit lighter air than it could by itself. If the wind increases we dowse and drop the spinnaker and unfurl the genoa in its place.

[Happ]

Originally Posted by Epicurean

I have some questions about setting up a spinnaker on my 47' catamaran. After watching a bunch of Youtube videos it looks to me like I should get a trigger release shackle for the sheet. How do I determine what size should I get?
2. I assume the sheet should be long enough to go from the clew fully extended through whatever blocks, etc. to the winch. What size? I would think Dyneema to keep it light so the weight doesn't pull the clew down in light airs.
2. Where does the tack attach? I've seen a) Windward bow - Catamaran Guru, b) end of bowsprit - a sailmaker I know, and c)two lines, one to each bow, joined at a shackle at the tack - Cat Impi. I kind of like the latter but I've never flown one on a catamaran.

You have asked great questions. Attaching the sheets can be done many ways. Trigger Shackles are the best IMHO as there is nothing to catch on. For size ask your sailmaker. He will know for sure.

Dyneema while pricey is again IMHO the way to go. However you will want to use a Poly cover on the areas going through blocks and around winches. It will make the line much thicker thus easier to to use going around a self tailing winch not to mention easier on your hands. This will also reduce the cost as you can use smaller diameter Dyneema.

I have seen all the system you have mentioned and the simple answer is what type of sailing are you going to do? Are you sailing port to port on weekends? Are you going to be making long passages? How precise are you in your trimming? If you are sailing port to port or anchoring every night then a sprit with a top down Furler should work just fine. Easy to deploy and furl at the end of the day. Easy to put up and down. If you go that way the Reflex system by Harken is the best IMHO. Their cable system is virtually flawlessly. It also has 3 different sets of attachments for the Head and tack. So you can use the Furler with many different types of sails. If you will be offshore for days at a time then having a system that you can move the tack from hull to hull is preferable. The reason being is you can have a flatter asymmetric for reaching and move the tack to weather when you want to go more downwind. One sail for many purposes. Of course you will need to have a sock on the chute which requires going to the bow to deploy and snuff it. If y9ou are really creative you could put a top down Furler on a track system but you will need to have the means to ease the furling line when moving the tack to weather. More stuff to deal with.

IMHO I would go with a Reflex with a Code sail (Code Zero) and if you feel later you want to add a mor downwind sail it’s easy to swap between the two sails as you desire. You could also add a Drifter and still use the same Reflex Furler.

I hope this helps.

[jleeglenn]

Originally Posted by fxykty

Well, a few things to consider.

First off, is the spinnaker symmetric or asymmetric? That fundamentally changes how it’s set and handled.

Second, based partly on answer 1, what is your deployment/dousing system: sock, furler, or nothing? That determines some of the finer points of the rigging.

For a symmetric spinnaker with or without a sock, the traditional set up (as per Cat Guru):

• 4 control lines: two sheets and two guys (alternatively called braces)
• Lines, if covered dyneema, should be minimum 8mm diameter for decent hand grip. Guys should be one size larger if you go for minimums
• Length of each sheet is two times your boat length plus beam plus the distance to your sheet winch on one side
• Length of each guy is one and a half boat lengths plus beam plus distance to your guy winch on one side
• On each side, connect the outboard end of a sheet and a guy to a snap shackle that has a nice big ring. A sailmaker or rigger can advise on the size of the shackle, based on sail size and expected wind range
• On each side, each guy leads from the tack and through a block on the bow, then back to its winch. When the sail is set, the guy attached to the leeward tack (the clew now!) is the lazy guy and is loose
• On each side, each sheet is lead outside everything to a block on the outside of each stern, then back to its winch. When the sail is set, the sheet attached to the windward tack is the lazy sheet and is loose
• When the spinnaker is set, keep the tack and the clew at the same height, and keep the windward luff vertical. Ease the sheet until the luff just curls
• To reach, ease the tack, but not further than the centreline
• Gybing is simple, just pull on the lazy sheet until you’ve taken the pressure off the (now old) guy, then let the old guy go. Take up pressure on the new windward guy until the tack is in position, then let off the (old) sheet

For an asymmetric spinnaker on a top down furler or a sock or nothing, the standard set up:

• Two sheets for the clew, each two and a half times the length of your boat plus beam plus distance to sheet winch on one side
• If furled, then no guy needed - the bottom furler will connect to the end of the bow pole or to a tack line
• If not furled, then one or two guys, depending on whether you want to fly the tack from a bow pole or from the windward bow. For two guys, each guy one boat length plus beam plus distance to winch. For one guy, pole length plus boat length plus distance to winch.
• Sizes same as for the symmetric
• Each sheet can be tied to the sail, no need for shackles, but each guy is shackled independently to the tack
• If two guys, each guy leads from the tack and through a block on its bow, then back to its winch. When the sail is set, the guy attached through the windward bow takes the load and the guy attached through the leeward bow is the lazy guy and is loose. I think this is the Cat Impi setup you referred to
• If one guy, set through the end of the pole. Lead it back to a winch so you can adjust the height of the tack
• Similar to genoa sheets, each sheet is lead outside everything to a block on the outside of each stern, then back to its winch. The lazy sheet is lead around the front of the forestay and depending on gybing method, inside the tack (if furling) or outside the tack (if Gybing inside out). In the latter case have something on the end of the bow pole that will keep the lazy sheet from falling under the pole
• Gybing can either be done by furling the sail, then unfurling on the other side (only if it has a furler of course). Otherwise, with or without a furler, you can let the sheet go completely so the clew goes way forward, then haul in the new sheet like crazy until the sail is trimmed on the new side - effectively turning the sail inside out

Hope this helps.

With the description above what is the purpose of running guys....?

[theDangerz]

Originally Posted by Epicurean

to theDangerz: A parasite with a parasail. Haha Just kidding. Glad someone else is getting useful information, too.

Id like to deny... but that's spot on!

[JamesPNW]

I was interesting in the same setup as Impi as well. My take is why paying for almost $10K for the furler with complicated lines setup when a $200 Tylaska snap shackle can do the trick to get the sail down with a sock and avoid trawling or back wrapping.

[Epicurean]

Originally Posted by JamesPNW

I was interesting in the same setup as Impi as well. My take is why paying for almost $10K for the furler with complicated lines setup when a $200 Tylaska snap shackle can do the trick to get the sail down with a sock and avoid trawling or back wrapping.

Could you explain "trawling" and "back wrapping" please?
My asymmetric is on a sock. I'm trying to picture in my mind, the dowsing process. If the trigger shackle is on the tack then how do you get to it to release it because it should be in front of the boat? If the shackle is on the sheet it's still outside the boat but maybe it's easier to pull inside where it can be released. Then the clew goes way forward which I guess isn't a problem unless you're pitching and/or have large waves. Or. I guess the third way is to let out a lot of sheet to depower it. Need a long sheet. All these before socking.
I like the first if I could figure out how to walk on air.

[fxykty]

Originally Posted by jleeglenn

With the description above what is the purpose of running guys....?

Not sure which you mean?

If you mean a symmetric spinnaker, it needs a guy to connect the tack to a windward bow or bow pole end. The other guy is lazy, only needed if you plan to gybe the spinnaker, in which the tacks swap roles.

If an asymmetric, then the guy is another name for the tack line. Or use a tack bridle to either bow instead (the Cat Impi setup).

[fxykty]

Originally Posted by Epicurean

Could you explain "trawling" and "back wrapping" please?

My asymmetric is on a sock. I'm trying to picture in my mind, the dowsing process. If the trigger shackle is on the tack then how do you get to it to release it because it should be in front of the boat? If the shackle is on the sheet it's still outside the boat but maybe it's easier to pull inside where it can be released. Then the clew goes way forward which I guess isn't a problem unless you're pitching and/or have large waves. Or. I guess the third way is to let out a lot of sheet to depower it. Need a long sheet. All these before socking.

I like the first if I could figure out how to walk on air.

Trawling is when the spinnaker falls into the water and drags behind the boat like a trawling net, with some combination of extended halyard, sheet and/or guy (tackline) still attaching it to the boat. Solved by releasing either the sheet or guy and dragging the heavy wet sail back on board with the other line.

Back wrapping is a spinnaker twisting around the forestay. Not much fun.

If you’re using a sock I don’t see the point of releasing the tack line shackle - just ease the tack line sufficient to allow the luff to fall back over the tramps. Release the sheet enough to de-power the sail enough to allow you to pull down the sock. Yes, you should have long sheets - after spending $$$$ for the sail, spending $$ for longer sheets is surely not a big deal?

But if you do want to release the tack shackle, simply releasing the tack line will bring the tack closer to the boat, probably enough to reach the trigger. You could also attach a release line to the shackle release.

[JustMurph]

Another Mumby 48 owner here. In the year and a bit I've had the boat, I've made a few changes to make flying the Code D and asymmetric spin a bit easier. The previous owner had managed to bend and crack the tang on the top of the prodder that the furler or tack would attach to, so in repairing that we made a few more modifications. The prodder now has a clutch for the tack line at its base and two pad eyes at the end, so now the tack line now has 2:1 purchase and runs back to the clutch. This makes swapping between the Code D and asym a whole lot easier. Just open the clutch and haul the tack onto deck. Some other Mumby's I've seen just run the tack line through a block on the end of the prodder back to the cleat at the windlass. With the extra purchase I can adjust the tack by hand in light air, or just run the tack line back to one of the primary winches if it's loaded up.

I have no snap shackles anywhere in the system and it hasn't been a problem so far. I run a single extra long sheet, so that you can let it fly well forward when dousing....and provided you do let it go well forward, it comes down easily. If I did need to release the tack, then I could just pop the clutch.

Generally I fly the asym from the end of the prodder, but if I'm running DDW, then I'll either attach it to a bow, or let the prodder tack line go a bit at haul it across to the bow, or anywhere in between. Flying the asym DDW seems to work pretty well, but I'll usually run angles instead and make far better VMG. I don't think you'd ever bother with a symmetric spin on a Mumby. You don't need to crack off far before you start generating a lot of apparent wind.

I'm sure the setup could be improved upon, but it's proven easy to use and effective so far.

[capn_billl]

Originally Posted by fxykty

Trawling is when the spinnaker falls into the water and drags behind the boat like a trawling net, with some combination of extended halyard, sheet and/or guy (tackline) still attaching it to the boat. Solved by releasing either the sheet or guy and dragging the heavy wet sail back on board with the other line.

Back wrapping is a spinnaker twisting around the forestay. Not much fun.

If you’re using a sock I don’t see the point of releasing the tack line shackle - just ease the tack line sufficient to allow the luff to fall back over the tramps. Release the sheet enough to de-power the sail enough to allow you to pull down the sock. Yes, you should have long sheets - after spending $$$$ for the sail, spending $$ for longer sheets is surely not a big deal?

But if you do want to release the tack shackle, simply releasing the tack line will bring the tack closer to the boat, probably enough to reach the trigger. You could also attach a release line to the shackle release.

What's "wineglassing"?

[fxykty]

Originally Posted by capn_billl

What's "wineglassing"?

Looking at your host through the bottom of an empty wine glass!

Seriously, it’s when your spinnaker decides to wrap around itself into an hourglass shape, with a filled pocket above to the head and the lower section filled between sheet and guy. Usually caused while raising the sail and not enough sheet tension, such that the upper part fills but no sheet tension and a fortuitous roll of the boat sets the top to spinning. Not likely when using a sock, but be mindful of pulling in the sheet as the sock goes up.