Code 0's and Sprits

[Dockhead]

Originally Posted by Kenomac

We use a Bamar furling system for our asymmetric spinnaker. It worked out very nice last summer, total cost minus the spinnaker was around $8000. There was no need for a bow sprint.

Oh, you have Reckmann furlers -- those are nice. My next boat will have something like that.


The other furler looks good too. I am surprised though you don't have different kinds of interference, having it mounted inside the pulpit like that and so close to the forestay.

For a Code 0, apparently, the sprit is mandatory in any case, although Uncivilized has made some comment that you need Either sprit OR pole -- which I am still trying to understand.

[Dockhead]

Originally Posted by hoppy

Prior to getting one of those bowsprits I had the Selden and either way I could not have a roll bar anchor.



on the SWL, I noticed that the SWL of most units is 2500kg covering different boat sizes. Perhaps an issue for Dockhead's size of boat?

How do you know the SWL required for a C0?

Last year I watched the VOR inshore race in Auckland in light winds and most of the yachts used their C0 for most of the race, beating into the wind and tacking and then on a deep reach.

The riggers told me 4 - 5 tons of SWL.

I have no problem with no roll bar (don't use roll bar anchors), but the addition to LOA would be unpleasant, as I'm already near 60' with davits. It gets hard to find a place on the quay; this would be even worse. I would prefer something retractable.

For getting on and off the boat when moored Baltic style, however, this would be lovely.

[Dockhead]

Originally Posted by UNCIVILIZED

The below, fill in's (in blue) explain some of the backstory behind the specialized gear & techniques for Code 0's. As well as an abridged version of how to get more out of any A-Sail (or conventional kite).
The full versions of which, are covered in some of the above posts, or via the links in them.

Concerning the "Penalty Pole" -- I guess I lucked out on that.

I have a massive carbon pole from a TP52 -- 8 meters long.

I was planning to cut it down, but now it looks more and more like the length could be a benefit. It's fully 2 meters more than my "J" dimension, so approximately the length of the foot of my 120% yankee jib or even slightly longer.

Just worried about dipping the end on the roll in large seas -- yikes.

Maybe not a problem as I would probably not use it in big sea conditions.

[Kenomac]

Dockhead,

Are you positive that you need a bowsprit? I was sure we needed one, but the sailmaker Mac Sails assured me that it wouldn't be necessary with the Bamar furling system... and they were correct. All of the other furling manufacturers thought I'd need one.

Check out my photo of the Bamar top down furling system, which is a top shelf Italian made piece of heavy duty artwork compared to any of the others we priced out. Which was all of them.

Bamar systems are mostly seen on the super yachts and not so much on boats less than 60ft. At boat shows, we mostly see the smaller stuff which is just as expensive, but.... not nearly as heavy duty. There's a big difference.

[estarzinger]

just two quick comments:

#1 we did not use 'expensive torsion ropes'. North recommended and we used dual spectra lines on the luff with some biggish polypro line as 'luff padding'. This worked well for us, was relatively inexpensive, and we never felt the need for more specific torsion ropes.

#2 we used the sail to about 45 awa. Sheeted tighter than that and it hit our jumper stays.

There is a BIG difference in the way racers and cruisers use these sails.

[Dockhead]

Originally Posted by Kenomac

Dockhead,

Are you positive that you need a bowsprit? I was sure we needed one, but the sailmaker Mac Sails assured me that it wouldn't be necessary with the Bamar furling system... and they were correct. All of the other furling manufacturers thought I'd need one.

Check out my photo of the Bamar top down furling system, which is a top shelf Italian made piece of heavy duty artwork compared to any of the others we priced out. Which was all of them.

Bamar systems are mostly seen on the super yachts and not so much on boats less than 60ft. At boat shows, we mostly see the smaller stuff which is just as expensive, but.... not nearly as heavy duty. There's a big difference.

It would save me a lot of money to not have a sprit. I haven't finish reading all of Uncivilized's links; maybe there's something in there about it.

[Dockhead]

Originally Posted by estarzinger

just two quick comments:

#1 we did not use 'expensive torsion ropes'. North recommended and we used dual spectra lines on the luff with some biggish polypro line as 'luff padding'. This worked well for us, was relatively inexpensive, and we never felt the need for more specific torsion ropes.

#2 we used the sail to about 45 awa. Sheeted tighter than that and it hit our jumper stays.

There is a BIG difference in the way racers and cruisers use these sails.

Thanks. Very useful as always.

What about halyard tension? Did you have any trouble achieving the required?

Did you use a sprit?

[Kenomac]

Contact Colin Mack at Mack sails and look into the Bamar system. The torsion line is included as part of the system.

He will design a system specific for your boat, you'll save yourself a lot of trouble and money. When I looked into a comparable system from the UK, it cost twice as much. Ended up buying Italian.

[estarzinger]

Originally Posted by Dockhead

Thanks. Very useful as always.

What about halyard tension? Did you have any trouble achieving the required?

Did you use a sprit?

2:1 dyneema 10mm halyard - no problem with luff tension.

We had a very small (fixed) anchor platform sprit - perhaps 60cm - was enough to get the zero furler clear in front of the main furler It was fine.

[Dockhead]

Originally Posted by estarzinger

2:1 dyneema 10mm halyard - no problem with luff tension.

We had a very small (fixed) anchor platform sprit - perhaps 60cm - was enough to get the zero furler clear in front of the main furler It was fine.

OK, that's good to hear on both counts.

I have 12mm racing dyneema halyards -- very strong, and 6 of them.

The sprit proposed by my riggers was a very substantial carbon tube based one, about 1.5 meters long. 60cm sounds a lot easier and cheaper.

[Dockhead]

Originally Posted by Kenomac

Contact Colin Mack at Mack sails and look into the Bamar system. The torsion line is included as part of the system.

He will design a system specific for your boat, you'll save yourself a lot of trouble and money. When I looked into a comparable system from the UK, it cost twice as much. Ended up buying Italian.

Thanks -- I'll definitely talk to them.

[TJ D]

Hi Dockhead,

Our boats have relatively similar sail areas, and we just went through this exercise, perhaps our experience will be relevant to you.

First, regarding the sprit, we have a retractable carbon pole, like on J-boats, which is deployed about 8 feet from the stem when using spinnakers, but only about 3 feet with the zero. I don't have any advice on that front, as we are fortunate enough to already have this covered.

The sail is about 1100 square feet. I don't believe that we are seeing anywhere near the loading that's been described elsewhere here. We are using a 1:1 halyard, hoisted with a manual winch. We do use runners, but I'm not by any means slacking them off, winching the sail as tight as possible, and then cranking the runner down hard. It just doesn't need it for the conditions that we're using the sail in.

However, we are also only using the sail in lower wind speeds, probably nothing over 15tws, AWA is generally between 60 and 125. The main and jib are plenty of sail for us when reaching in stronger winds.

Regarding cost, I think that you might have some luck with going the route that we did.
We had our old zero delamintate and fail last summer, and got a similar quote to yours- $10,000 without the furler for a mid-range sail. I about choked.

So, we did some looking online for used sails, and wound up scoring a lightly used Ullman carbon GPL light #1 from one of the used sail dealers. I had Ullman fit the new torque rope (basic amsteel 12 strand, not expensive), and we're absolutely thrilled with the sail. It looks pretty sexy out there on the bow, too. Not that we really care, but the carbon sails are pretty cool.

No, it's not as full as a true zero, but we're really happy with it as a reaching sail. We use the Asym's sailing deep anyway, so it was never our intent to have the sail for very deep angles. It furls just fine.

I also added a Selden 45 continuous line furler (lower unit only) to replace the old drum unit.

Total cost for sail, furler, and luff conversion- $2600, and it's about 90% as good as a loft built sail for our purposes.

I would guess if you were looking to sail deeper with it, you might not be as happy, but since you mentioned your sail budget might be a bit on the lean side this year, this is certainly an option.

Good luck. TJ

[UNCIVILIZED]

Originally Posted by hoppy

Prior to getting one of those bowsprits I had the Selden and either way I could not have a roll bar anchor.

To accomodate this (big, & or, roll bar anchors), there are several options. The most common ones being; retractable sprits, like on J-boats. And detachable deck mounted sprits. Such as on Eric Goetz's (former I believe) boat, "Katie G". And there's a link to images of her, & also her sail & hull plan, in one of the above posts.
Plus, there's the option of sprits with more offset, them being set at more of an angle, or A-frame sprits. Some of which hinge up vertically, when not in use. As seen on some of the boats made by www.rm-yachts.com



on the SWL, I noticed that the SWL of most units is 2500kg covering different boat sizes. Perhaps an issue for Dockhead's size of boat?

How do you know the SWL required for a C0?

Last year I watched the VOR inshore race in Auckland in light winds and most of the yachts used their C0 for most of the race, beating into the wind and tacking and then on a deep reach.

Regarding sprits. No they're not mandatory. But the longer the sprit is, the bigger the sail which you can fly, as it increases you J dimension. Plus, it puts the leading edge of the sail out away from the turbulent backwash of the furled jib. By a few feet at least, which is where the worst of it is.
And as stated before, the further forward your sailplan's center of effort when you're not beating, the less load there will be on the rudder, & less tendency to want to round up, or get pulled into the right harmonic to start a boat rolling. Especially downwind.
This is also true when on the wind, to a fair degree. At least up until the boat's righting moment becomes the limiting factor. And then the boat heels over enough so that again, the rudder loses it's grip, & the boat's nose (typically) spins up to weather.

Though, even without a sprit, you need to get everything for the Code 0, out in front of your headstay, & everything else. Just like with a normal kite. And you also need to ensure that whatever you attach the tack/furler to, is strong enough to handle the load.
As, from time to time, bow rollers have been ripped out... along with some pieces of fiberglass.
But usually cruisers fly these sails in lighter winds than racers do, & also tend to put less load on their hardware & sails. Unless caught by a squall, or front. Which can be pretty common in some locales.

To figure the load more precisely, you'll want to work with your sailmaker (& possibly your rigger too). Not that the math is necessarily complex. But you have to think it through, & run the numbers. Followed by adding in a safety/fudge factor.
Particularly if you'll be carrying the sail in any real breeze, & or waves. Where shock loads really start to become a real factor, too.

Though by my reckoning, the load calc's are something like this. Let's take a hypothetical 40' boat as an example:
Say you have 50:1 halyard winches, & you're running the sail on a 2:1 purchase. Then, with a big double handed winch handle, you can input 50lbs of force. And with a decent sized rig, your Code 0 is 1,200sqft +/-

With frictional losses, you're inputting about a 4,000lb load onto the anti-torsion cables. 40x for the winch x2 with the block on the halyard, & 50lbs input by you.
And in addition to that, there will be some load from the sail too. But to be safe, I'd figure on adding the full wind loading in addition to that of the winch, & 2:1 purchase. With the thought that I'd be shifting down to a different sail when the breeze picks up.
Thus, I'll use 15kts for wind. Which equates to 1lb/sqft. Or, 1,200lbs in this case. Thus, by combining the two, you get 5,200lbs.

In the real world, even with 15kts of breeze, I doubt that the system would see 1,200lbs of additional vertical load from the sail. Or not consistently anyway.
But when you figure in what happens as you sail though waves. Or anything else happens which causes the AWS or TWS seen by the sail, & thus everything attached to it, to go up abruptly. Then so do the loads on everything which is connected to the anti-torsion cables, furler, sprit, tack fitting, halyard, etc..
And all it would take for the load on the sail to double, would be for the breeze it's seeing, to go from 15kts, up to 22kts.
Plus, if the breeze is building, & you want to depower the main via the backstay...

And on a racing boat, or a cruiser which has a tunable mast, the above is entirely reasonable. As, when trimming the main, I spend FAR more time using All of the controls when the wind is in the low to mid ranges, & variable. Than I do once it's consistently well into the double digits.
And a key shaping control for the main is the backstay. Which, on a boat with a tunable rig, it's easy to move the masthead on a 40'er 18" (1/2m) or more. Albeit, that's the range of the spar's movement, from say 3kts to 30kts.

If you then scale up those kinds of loads to something like a VOR boat, where the loads on the "small things" are measured in tons. And the backstay loads are well into the double digits tonnage wise. Then the loads generated by Code 0's get Big.
As the anti-torsion cables are taking the same loads as headstay would see, if not more. And on a 40'er going upwind, sometimes thats 3-4 tons. So, yeah, Big on even mid-sized boats.

[meirriba]

My 2cents of worth regarding longer bowsprit length:
1. (already mentioned by Uncivilized) - allows larger sail.
2. Clears the sail from whatever is on bow, free air flow, no damage to anything installed there from sheets, etc.
3. Easier (more room to pass the sail) to make an 'inside' jibe.
4. Allows lower sailing angle (pressure centre further forward)

[Sysunday]

Last winter I made my bowsprit of carbon fiber with titanium hinges. Additionally I made a really good working anti-torsion rope.
I now use this with a code0 on a Karver furler. This winter I will add an asymmetric spinnaker.
Here is a YouTube I made during the project:

https://www.youtube.com/watch?v=IGSrXROzgm8