code zero loads

[flee27]

I am trying to figure out if/where I can tack a code zero on my boat. I don't have room in front of my normal furler the way my bow/stem fittings are set up. Selden says I can't use one of their removeable sprit for a code zero. They say the upward loads are too great which I get because of the high tension needed for the luff.

My question is what are the side loads like? I see a way I could add/extend a bracket up from my stem fitting. Looking for experienced opinions.

Thanks
Foster

[GordMay]

I wouldn’t expect that to suffice.
Not exactly what you’re looking for, but this might help you visualize the magnitude of sail loading.
➥ https://www.harken.com/en/calculator...ng-calculator/

[flee27]

Thanks GordMay. I know I am trying to talk myself into a solution and I fully keep that in my mind as I process this. I am at the point of reaching for a solution that most likely doesn't practically exist. But I hold on to hope and am searching the outskirts of the box.

Saying that and running some loads on the attached calculator it doesn't seem out of the realm of reasonable as long as I really stick to some strict wind velosity rules for flying said code zero.

My headsail at 100% is 376 sq ft. The proposed code zero is 950 sq ft. The loads are about the same flying the code zero in 15 knots (971 lbs) as a 100% job in 25 knots (1013 ibs). Both of these wind ranges for the sail are realistic.

I really appreciate everyone's experience and opinions. Thanks again.

Foster

[flee27]

A concern I didn't mention in my original post is that added load to the stem fitting. I would be increasing the load by adding the code zero loads to the forestay loads. I can't figure out a way to know the answer to this. Practically their probably isn't a way to know this answer.

Starts to look like I have my answer to the question...

Foster

[Rucksta]

Consider running the coded sail inside the forestay with the tack on a hard point close to the prow.

Yes the furled headsail will interfere with the air flow and you will have less available sail area but there are a number of mitigating factors that make this less horrible.

I can go on at length if you're at all interested.

[wingssail]

Originally Posted by flee27

Thanks GordMay. I know I am trying to talk myself into a solution and I fully keep that in my mind as I process this. I am at the point of reaching for a solution that most likely doesn't practically exist. But I hold on to hope and am searching the outskirts of the box.

Saying that and running some loads on the attached calculator it doesn't seem out of the realm of reasonable as long as I really stick to some strict wind velosity rules for flying said code zero.

My headsail at 100% is 376 sq ft. The proposed code zero is 950 sq ft. The loads are about the same flying the code zero in 15 knots (971 lbs) as a 100% job in 25 knots (1013 ibs). Both of these wind ranges for the sail are realistic.

I really appreciate everyone's experience and opinions. Thanks again.


Foster

In the first place the tack and halyard loads are very significant and the sheet load calculator does not properly address these in my opinion. Code Zero sails are often used in close reaching situations. In my case, after breaking a halyard in 22kts of true wind (ahead of rhe beam) I calculated the loads. For my 1175 sq ft A3 the halyard loads came in at over 3000 lbs by one calculation, and I broke a 10,000 breaking strength, 3 year old dyneema halyard.

Whatever you build, make it strong if you are going to use a code zero on it.

Having said that, see my next comment for how you can do it.

[wingssail]

I added a new "tack point" ahead of my forestay inside of the pulpit for the asymmetrical spinnakers. The tack of the sail is held by a tacking line which goes through a block on a swivel ahead of the forestay and then shackled to the ring on the sail. The entire tack system is inside of the bow pulpit. This works well.

You will have to build an attachment with the following considerations.

• sufficent strength to suport vertical and side loads (this can be very significant in windy conditions)
• no obstructions within the bow pulpit which might restrict the movement of the tack system
• sufficent width within the pulpit to allow sideways movement when reaching
• clear lead aft for the tacking line to clear the forestay

Just one point to add to this topic: Your Sabre 42 has a longish overhang at the bow and you can carry a large genoa. With these characteristics you have in my opinion little need for a code zero sail. The code zero is critical to provide sail area for close reaching for those boats which have smallish, non-overlapping, headsails. Some boats even try to use a code zero for upwind work. But a genoa is far superior.

What will give a lot of benefit is an asymmetrical spinnaker (or cruising chute) which, BTW, will also need a tacking point, so make your new tack attachment point, but consider carefully what your offwind sail needs are.

[flee27]

Rucksta. I would be interested in hearing what you have to say. Thank you

wingssail. Thank you very much for the information. Your suggestions are the direction I am leaning based on others info also. Getting a light weight genoa around 150%. And a asymmetrical for off the wind. Looks like tack loads are way less for an asymmetrical vs. a code sail.

If its not too much trouble could you be more specific about how you attached yours. The pictures don't show me well. Thank you for your experience/opinions.

[flee27]

On another note. The sailmaker I have been talking to is suggesting make a light weight genoa out of Challenge MCZ6P code zero laminate. What are your thoughts on this type of material over a light weight dacron?

Foster

[Rucksta]

flee 27

What I want out of a Code 0 is to restore light air performance that I loose from running a 100% flat cut headsail on a furler.

Large free flying sails (without a top down or bottom up furler) are difficult to handle and retrieve for a short handed crew.

With enough luff tension to make a top down furler reliable the rig needs some consideration.
If the forestay starts to go slack care must be taken to not allow the mast to become inverted (masthead forward of base)
Swept spreaders may need assistance from running back stays.

Without sufficient tension the luff will fall off to leeward badly affecting the draft in the mid sections and reducing any windward ability it may have had.

OK not all doom and gloom here.

By cutting the luff to a concave shape much of the negative impact of leeward fall off can be reduced.
This allows for reduced loading on the rig.
The loading on the luff is dependant on wind pressure but you can control the luff tension so the forestay is still doing it's job.

By moving the tack aft of the forestay you gain a hard point without additional engineering.

Once the tack is aft you have the whole fore triangle to tack the coded sail in much the same way you tack a genoa.
You may need a crew member at the mast but not one on the foredeck. Gybing is a bit trickier .

You will be using the spare genoa halyard to hoist the coded sail.
Hoist and retrieve can be done with the genoa unfurled to either shadow the coded sail (outside peel) or
bring it down onto the deck and flake into a bag (inside peel)

Launch can be a single handed operation but retrieval usually requires two hands on deck.

More good news.

In very light air try free flying your big genoa with another sail on the furler.
You will get the idea of how this works on your boat with minimal if any expenditure.

You can also gauge how much luff fall off to expect. Chances are your big genoa is already cut to allow for some leeward fall off.

I have headsails including coded sails made from Kevlar Spectra blends. (ancestors to the cloth you are considering)
The construction allows for some structure to be built into the luff improving the leading edge and possibly doing away with the bolt / torsion rope.

They are difficult to handle and do not like creasing or sunlight.
they hold their shape right up until the time they go off with a bang (literally)

I hope the modern blends are more forgiving and the skins are more robust.

When I dream of replacement it's with a 4D sculptured fabric .
I also dream of an engineered retractable bow sprit and a top down furler and a couple of newer A sails.
Carbon mast and standing rig are also in the dream.

It is a dream in the meantime I have a coded sail that gives best VMG at 40 plus degrees true in light air that compares favourably with the 40 degrees maybe minus I get out of a #1 light genoa under the same conditions.

Good luck hope this makes some sense.

[wingssail]

Originally Posted by flee27

Rucksta. I would be interested in hearing what you have to say. Thank you

wingssail. Thank you very much for the information. Your suggestions are the direction I am leaning based on others info also. Getting a light weight genoa around 150%. And a asymmetrical for off the wind. Looks like tack loads are way less for an asymmetrical vs. a code sail.

If its not too much trouble could you be more specific about how you attached yours. The pictures don't show me well. Thank you for your experience/opinions.

Originally Posted by flee27

Rucksta. I would be interested in hearing what you have to say. Thank you

wingssail. Thank you very much for the information. Your suggestions are the direction I am leaning based on others info also. Getting a light weight genoa around 150%. And a asymmetrical for off the wind. Looks like tack loads are way less for an asymmetrical vs. a code sail.

If its not too much trouble could you be more specific about how you attached yours. The pictures don't show me well. Thank you for your experience/opinions.

I am attaching a photo which does not show it very well, and every boat is going to be different.

I had a bar welded between two parts of thebow roller assembly (1). Then I shackled a low friction ring to that bar with a short piece of line (2). My tack line, with the tyleska shackle (3)is what goes on the tack of the sail, and the other end of it leads back to the cockpit(4).

As for the choice of cloth for a genoa, If you are racing the laminate will be good, for cruising, you could also use dacron, but the life and shape won't last as long.