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Asymmetrical Spinnaker Question

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Captmorgan
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USA
220 Posts

Initially Posted - 04/13/2019 : 09:21:57

I have been buried in a bathroom renovation and just starting to think about sailing this spring. I will be working on cleaning her up next week and the following but thinking about my addition for the year. always adding something. Last year was lazy jacks and boom vang.

I have a std 25 swing keel, and I was thinking of adding an asymmetrical spinnaker to my "Gal-Way"

I have seen some tack/Jibe devices and Bowsprit rigs.
I know I need to add some winches in the rear, and a sort of downhaul in the front.

Whats the best way to do this. I saw a recent post on the Masthead modification to keep the head in front that was great.

Any advice. Total cost estimate etc

Links to good threads etc

Thanks for the advice

"The Gal-Way" 1985 SR/SK Barnegat Bay, NJ

Enjoy Sailing =) Be Safe

Happy Sailing - John

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HerdOfTurtles
1st Mate

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USA
68 Posts

Response Posted - 04/13/2019 : 18:45:16

I have an asymmetrical 'cruising' spinnaker on my boat I bought on ebay for about $250-$300 or so. It came with a dousing sock.

Then I spent another $100-$150 on 5/16" line for the sheets, some basic blocks for the sheets, a block with a becket for the dousing sock control lines, some control line for the dousing sock, some 1/8" vectran, a splicing fid for the vectran, and some waxed sail thread for whipping.

So for about $500 I was up and 'running'.

I have internal halyards on my mast - two fore and two aft. I use one fore halyard for the genoa and one for the spinnaker.

My spinnaker has a single hank at the tack which secures it to the forestay. The tack also has an eye which I attach a tack line to and secure this line to one of the bow cleats. Using this line I can adjust the draft of the spinnaker depending on whether I am reaching or running. Running, let the lack line out so the sail can get a powerful belly, reaching -> pull it down tight so I can point. The sail is usable approximately 100 deg - 180 deg TWA.

For the spinnaker sheets I use one continuous line with a figure 8 in the middle where it attaches to the spinnaker clew.

I use the existing jib/genoa winches for the spinnaker sheets and I can't think of a legitimately good enough reason to add winches to the boat for the spinnaker.

You're probably wondering about the vectran, splicing fid, and waxed sail thread. I used these items to make a number of 'soft shackles'. I used four of them: two to secure the sheet blocks to the stern cleats, one to secure the spinnaker head to the becket block in the dousing sock, and one to secure the spinnaker sheets to the clew. This has worked very well but note that if I were to do it again I would use Dyneema instead of vectran because it has better UV resistance. I like being able to make as many shackles as I need and I especially like the soft shackle on the clew of the sail because heavy metal snap shackles flogging around whipping people in the face and damaging the boat are no good.

If you have a roller furling headsail I would use 'the tacker' from catalina direct which essentially replaces/serves the same function of the single hank I have at the tack of my spinnaker(I have a hank on genoa).

If you choose to use a dousing sock, which I very highly recommend you do, you will most likely be performing 'inside' jibes such that when you jibe you will douse the sail in the sock, then move the sock to the other side between the forestay and the mast. The reason for this is the control line for the sock. If you do an outside jibe then you will have to walk the control line for the sock around the outside of the forestay every time. If you don't use a sock then you can perform an outside jibe a bit easier and in this case I would recommend you get a spinnaker crane to make it a little easier getting the spinnnaker around the outside of the forestay when you jibe. If you are using a sock and doing inside jibes the crane will be a hindrance and I would not recommend one.

I would not add a bowsprit unless you absolutely had to have the best possible performance. It's expensive and gets in the way of the anchor locker. For me the best part of having a bowsprit would be the ability to use a top-down furler and have it rigged up with a spinnaker before I left the dock. Then I could just roll out the spinnaker as easily as rolling out a genoa on a roller furler. But to be able to do this on a catalina 25 you would have to cut off a significant section of the bow pulpit. If you absolutely had to have the best possible performance then you'd probably be better off with a symmetrical spinnaker anyway.

1978 Standard Rig
Fin Keel
L-Dinette

Captmorgan
Navigator

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USA
220 Posts

Response Posted - 04/13/2019 : 19:09:09

Wow excellent detail on the reply. I do have a furler so Ill look at the tacker. How do you know how big a spinakker sq ft and the weight. Is 0.75 oz the right weight.

"The Gal-Way" 1985 SR/SK Barnegat Bay, NJ

Enjoy Sailing =) Be Safe

Happy Sailing - John

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Lee Panza
Captain

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USA
465 Posts

Response Posted - 04/13/2019 : 19:44:01

John, here's an idea that might alter your thinking. This is a system I put together a few years ago, but I wanted to use it for a while to make sure it was actually a good idea before showing it here.

I use a sail that's more of a Code 0 than an asym, but I pole it out with a whisker pole when I'll be going downwind for a while. However, I use it much more often for reaching. I can point up to something less than 45 degrees off true, and down to somewhere around 150 (30 degrees off DDW) before it has to be poled out. I had it constructed with an integral torque-rope, and I use a continuous-line furler. When I put it away I just lower the furled sail to the foredeck, with its halyards wrapped around it, and fold it up to go back into its bag. I clip the head swivel to the furler and leave them in place permanently. Whenever I want to use the sail I simply clip it in and pass the halyards through the blocks near the aft ends of the tracks. It hoists while still furled, so if I decide to use it while I'm already sailing it's easy to rig by myself while the tiller-pilot is steering, even while the working jib is still deployed. Or I can hoist it at the dock or at anchor and then deploy it from the cockpit when I'm ready.

This arrangement is much more versatile than an asym, and it's easy to use when I'm sailing solo (or with a non-sailor guest). Once it's in place it allows me to switch back and forth between this light sail and my working jib as conditions change: furl one sail up and unfurl the other, either way.

Here's what it looks like when I measured just 3 kn of breeze (flat water) and my knotmeter was registering 1.8 kn. This is pretty much the bottom end of its useful range.

At the mast head I fabricated a sturdy extension on the truck casting to provide an attachment point well forward of the jib furler:

At the bottom, I attached the furler to the bow pulpit. However, to transfer the stress to the hull I installed a cable down to the stem fitting (with a turnbuckle to adjust the tension after the cable was attached). I made the assembly at the pulpit rail for a combination bow light; it's a short piece of 1/4" SS angle stock, and the U-bolt on top of the rail anchors it to the bottom of the rail.

I've never seen this done before, but it works quite well. I had been concerned that my intuitive understanding of the stress distribution and the effective strength of this arrangement might have been incorrect, but having tested for a few years now I'm satisfied that I can recommend it to others. Under conditions that overpower the boat there doesn't seem to be any flexing of the pulpit. Here's what it looks like on a close reach when the breeze picked up one afternoon (note the position of the boom). I measured sustained winds of 8-10 kn before I decided to go back to the working jib (good decision; the breeze continued to build to over 20 kn, which is way beyond the appropriate range for a big sail like this).

The cable takes the vertical component of the load. The lateral load is angled back pretty nearly in line with either side of the pulpit, so there isn't much force wanting to bend the tubing. The load becomes a downward and shear force where the pulpit attaches to the deck, and the six 1/4" screws on either side can easily handle it.

Since this sail sits ahead of the forestay, tacking or gybing requires that it be furled most of the way up first. This is not a sail to use when frequent direction changes will be needed (ie. in an area crowded with other boats), but it's still still far more versatile than an asym. It functions through a much wider range of points of sail and in conditions that would be frustrating with just my working jib.

If this appeals to you I can go back through my records and try to come up with the prices, but the sail was a custom one-off made from a Spectra-reinforced fabric, so what I spent on the sail alone would probably discourage most people. However, the way it's mounted is novel, so this might be something to think about.

The trouble with a destination - any destination, really - is that it interrupts The Journey.

Lee Panza
SR/SK #2134
San Francisco Bay
(Brisbane, CA)

Captmorgan
Navigator

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USA
220 Posts

Response Posted - 04/13/2019 : 21:56:22

Awesome

this is a lot of detail . I appreciate it.

I will consider it. but cant you do the same with a less expensive sail?

"The Gal-Way" 1985 SR/SK Barnegat Bay, NJ

Enjoy Sailing =) Be Safe

Happy Sailing - John

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Davy J
Master Marine Consultant

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USA
1511 Posts

Response Posted - 04/14/2019 : 03:22:35

I installed the CD masthead crane. Purchased an ATN spinnaker sleeve. Then made a homemade "tacker" that I copied from Paul Alcock.

Here is my thread on that, it has a short video of the tacker in use:

http://www.catalina-capri-25s.org/forum/topic.asp?ARCHIVE=true&TOPIC_ID=27302

Here is the link to Paul's homemade tacker:

http://www.catalina-capri-25s.org/forum/topic.asp?ARCHIVE=true&TOPIC_ID=27224

If your spinnaker does not come with a dousing sock I highly recommend the ATN Sleeve. It is superior to the standard variety.

Davy J

2005 Gemini 105Mc
PO 1987 C25 #5509 SR/SK
Tampa Bay

Derek Crawford
Master Marine Consultant

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USA
3312 Posts

Response Posted - 04/14/2019 : 06:35:21

Lee you must have a PhD in engineering!

Derek Crawford
Chief Measurer C25-250 2008
Previous owner of "This Side UP"
1981 C-25 TR/FK #2262 Used to have an '89 C22 #9483, "Downsized"
San Antonio, Texas

Captmorgan
Navigator

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USA
220 Posts

Response Posted - 04/14/2019 : 13:23:35

I must admit being able to furl rather than buying a sock to douse it makes a lot of sense. I may consider this. What is a code zero sail.

How to I find the right size and type of sail.

Thanks again for this.

Lee I see the steel you used to put the load on the boat not the bow rail.

How about if you had a sort of stainless steel tub thick that went around the bow rail and then had two places to attach. Why do you need such a large plate. Just curious because I have a PhD in chemistry not engineering :)

"The Gal-Way" 1985 SR/SK Barnegat Bay, NJ

Enjoy Sailing =) Be Safe

Happy Sailing - John

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Peregrine
Admiral

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830 Posts

Response Posted - 04/14/2019 : 15:35:38

I found a very simple solution to my "drifter". It fly's free and I hoist it with the spin halyard which on Peregrine comes back to the cockpit. It tacks inside the forestay.
I have a block on the bow at the deck and a long line attached to the clew that runs all the way back to the cockpit on the port side."When I need to douse the drifter I let the spin halyard go and let the line to the clew go. That way the sail falls in the cockpit, I can stuff it in the cabin and get to the furling headsail.
With all lines led to the cockpit I can and do single hand the entire maneuver.
The same set up should work with an asymmetrical.

John Gisondi
Peregrine #4762

*

Captmorgan
Navigator

Members Avatar

USA
220 Posts

Response Posted - 04/15/2019 : 03:56:17

The spin halyard is side by side with main correct.

What makes it go inside forestay. I guess I see the forstay is outside the halyards. It seems easy to just add thr spinnaker attachment to masthead . can you explain how your run your sheets.and the block function Did you add rear winches? Thanks for your input.

"The Gal-Way" 1985 SR/SK Barnegat Bay, NJ

Enjoy Sailing =) Be Safe

Happy Sailing - John

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Captmorgan
Navigator

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USA
220 Posts

Response Posted - 04/15/2019 : 04:06:31

This seems like the way to go. I saw this video. What weight and type , sq ft would I have if I want it for running. Also why do you use it more for reaching t ha, running. Thanks again

Is thisbthe type of inline furler?

https://www.velasailingsupply.com/selden-gx7-5-top-down-asymmetrical-spinnaker-furler/gclid=Cj0KCQjw19DlBRCSARIsAOnfRei3Cbn-O3riQKFRgF4Mx1297dYX7dv_4lZcdp4b9ckMPTzrapEYhaAaAqxwEALw_wcB

quote:
Originally posted by Lee Panza

John, here's an idea that might alter your thinking. This is a system I put together a few years ago, but I wanted to use it for a while to make sure it was actually a good idea before showing it here.

I use a sail that's more of a Code 0 than an asym, but I pole it out with a whisker pole when I'll be going downwind for a while. However, I use it much more often for reaching. I can point up to something less than 45 degrees off true, and down to somewhere around 150 (30 degrees off DDW) before it has to be poled out. I had it constructed with an integral torque-rope, and I use a continuous-line furler. When I put it away I just lower the furled sail to the foredeck, with its halyards wrapped around it, and fold it up to go back into its bag. I clip the head swivel to the furler and leave them in place permanently. Whenever I want to use the sail I simply clip it in and pass the halyards through the blocks near the aft ends of the tracks. It hoists while still furled, so if I decide to use it while I'm already sailing it's easy to rig by myself while the tiller-pilot is steering, even while the working jib is still deployed. Or I can hoist it at the dock or at anchor and then deploy it from the cockpit when I'm ready.

This arrangement is much more versatile than an asym, and it's easy to use when I'm sailing solo (or with a non-sailor guest). Once it's in place it allows me to switch back and forth between this light sail and my working jib as conditions change: furl one sail up and unfurl the other, either way.

Here's what it looks like when I measured just 3 kn of breeze (flat water) and my knotmeter was registering 1.8 kn. This is pretty much the bottom end of its useful range.

At the mast head I fabricated a sturdy extension on the truck casting to provide an attachment point well forward of the jib furler:

At the bottom, I attached the furler to the bow pulpit. However, to transfer the stress to the hull I installed a cable down to the stem fitting (with a turnbuckle to adjust the tension after the cable was attached). I made the assembly at the pulpit rail for a combination bow light; it's a short piece of 1/4" SS angle stock, and the U-bolt on top of the rail anchors it to the bottom of the rail.

I've never seen this done before, but it works quite well. I had been concerned that my intuitive understanding of the stress distribution and the effective strength of this arrangement might have been incorrect, but having tested for a few years now I'm satisfied that I can recommend it to others. Under conditions that overpower the boat there doesn't seem to be any flexing of the pulpit. Here's what it looks like on a close reach when the breeze picked up one afternoon (note the position of the boom). I measured sustained winds of 8-10 kn before I decided to go back to the working jib (good decision; the breeze continued to build to over 20 kn, which is way beyond the appropriate range for a big sail like this).

The cable takes the vertical component of the load. The lateral load is angled back pretty nearly in line with either side of the pulpit, so there isn't much force wanting to bend the tubing. The load becomes a downward and shear force where the pulpit attaches to the deck, and the six 1/4" screws on either side can easily handle it.

Since this sail sits ahead of the forestay, tacking or gybing requires that it be furled most of the way up first. This is not a sail to use when frequent direction changes will be needed (ie. in an area crowded with other boats), but it's still still far more versatile than an asym. It functions through a much wider range of points of sail and in conditions that would be frustrating with just my working jib.

If this appeals to you I can go back through my records and try to come up with the prices, but the sail was a custom one-off made from a Spectra-reinforced fabric, so what I spent on the sail alone would probably discourage most people. However, the way it's mounted is novel, so this might be something to think about.

"The Gal-Way" 1985 SR/SK Barnegat Bay, NJ

Enjoy Sailing =) Be Safe

Happy Sailing - John

Photo Album

Lee Panza
Captain

Members Avatar

USA
465 Posts

Response Posted - 04/15/2019 : 06:44:33

The principal concepts that I had wanted to present here are:

a.) using a continuous furling rig for an auxilliary light-air headsail; and,

b.) using the pulpit railing, rather than a sprit, to keep the auxilliary headsail far enough away from the forestay to avoid conflicts with the working jib.

Some of the mechanics of my setup could certainly be simplified. For instance, instead of using the nav light bracket as part of the system I could have used a simple eyebolt ( with a cap nut on the other end rather than leaving the bare threaded end sticking up). I'd still recommend a U-bolt on top aligned with the upward tension of the torque rope.

Also, the crane I fabricated may have been excessive, but 1/8" angle is the lightest SS stock I could find. On the other hand, the tension developed is pretty substantial: the first block I used at the crane disintegrated. It was a Lewmar 29901401 rated at 890# WLL, so I replaced it with a Harken 6065 with a 2100# WLL. Obviously the cable down-link from the pulpit to the stem fitting is critically necessary.

I'm sure a more conventional sail could be used for this setup, but it would have to have a torque rope sewn into it for furling. The head and tack on mine are lashed to the thimbles at both ends of the torque rope, with the rope loose inside a sewn tube running the length of the luff. The head may lag slightly behind the tack when I start to furl, and the middle lags behind both ends, but this doesn't seem to matter. And the extra cost of a top-down furler is not at all necessary. Other than the addition of a torque rope I'm sure a sail made from a more conventional material would work. I went with the spectra-reinforced dacron because I believe that shape retention is more important for a reaching sail than for an asym, and I'd like this sail to last for the rest of my sailing life. I'm not sure nylon would be a good idea.

I had my sail made with the foot 16'-3" long and the leach 27'-5" long, making the LP 15'-9". This is just over 150%, and the total sail area is just under 210 SF. Because it is tacked up on the pulpit railing there is good visibility beneath it. Sailmakers use the designation Code Zero for a sail that's sort of a cross between a genoa and and asym, although there are a variety of interpretations. The important thing seems to be that it's a sail that can point much higher than an asym but can work pretty far off the wind as well. A whisker pole extends the downwind range, although it's no substitute for a true spinnaker when going deep downwind.

Regarding the furler, I went with a Facnor FX900, which was one of the lightest and least expensive available, and it has been satisfactory. As of this writing Mauri Pro is selling the FX900plus (very similar) for about $660.

In addition to the furler you'll need fairleads and a block at the aft end of the continuous loop haul-line. I put that block on a slider near the aft end of the genoa block track (although I understand that sometime after 1984 Catalina stopped running the track all the way back), which allows me to slacken the tension when I'm not using it. Continuous-line furlers need the haul-line loop to be kept tight during use or they slip when you're working against any load on the sail. For this reason they can't be used to reef the sail by partially furling it; even with a ratchet block at the aft end of the loop you can expect the drum to slip. But you can also expect the haul-line to stretch over time, so some means of adjusting it is necessary.

This was a substantial project, with a substantial cost, and it wouldn't be justifiable for most people. It certainly isn't a racing mod, and it's too expensive for a casual owner. But I'm setting up my boat for extended coastal cruising, now that I'm retired, and I expect to get a lot of use out of this system in places where the summer breezes tend to be light. I enjoy using it even just for daysailing during the wintertime on San Francisco Bay. For me this was a really interesting DIY project, and it has produced the results I had desired. Now I hope that this write-up will be helpful to anyone else who has a similar desire for the versatility of a single auxilliary light-air headsail.

The trouble with a destination - any destination, really - is that it interrupts The Journey.

Lee Panza
SR/SK #2134
San Francisco Bay
(Brisbane, CA)

Lee Panza
Captain

Members Avatar

USA
465 Posts

Response Posted - 04/15/2019 : 06:51:53

John, the link you posted didn't open for me. Also, it would be a courtesy to others to delete or truncate the post you're responding to when you post a follow-up.

I'm sure I haven't answered all of your questions (I didn't really understand what you were asking about another tube at the pulpit), so I'll try to respond (albeit more succinctly) to anything else that isn't clear in what I've posted. Good luck with your own project; I usually find the planning to bring almost as much pleasure as the execution.

The trouble with a destination - any destination, really - is that it interrupts The Journey.

Lee Panza
SR/SK #2134
San Francisco Bay
(Brisbane, CA)

Lee Panza
Captain

Members Avatar

USA
465 Posts

Response Posted - 04/17/2019 : 22:15:42

After talking about how much I enjoy using that Code Zero I took it out today for a spin. With the breeze showing 3 to 3 and a half knots on my Kestral I was getting about 1 knot at about 50 to 60 degrees off true and about a knot and a half with the breeze on the beam. There was just enough breeze to balance the warmth of the sunshine, so I'd set the tiller-pilot and kick back for awhile, and then tack off the other way. Now I've got a bit of a sunburned face. Ahhh, California.

The trouble with a destination - any destination, really - is that it interrupts The Journey.

Lee Panza
SR/SK #2134
San Francisco Bay
(Brisbane, CA)

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Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.