Author Topic: Spinnaker sheets  (Read 13543 times)

Gridrat

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Spinnaker sheets
« on: July 23, 2016, 11:35:09 AM »
I am preparing to rig my asymmetric spinnaker on my 323. I'm trying to decide on the line and line size (5/16 or 3/8). This is new to me so any suggestions would be appreciated. My boat has a spinnaker halyard so that is not an issue.

Dolce_Vita

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Re: Spinnaker sheets
« Reply #1 on: July 23, 2016, 12:56:50 PM »
Generally with spinnakers, you want the lightest line that will do the job, so I would go with the 5/16.

I'm interested in the rest of your spinnaker rigging, because our boat came with a spinnaker (built from a Sailrite kit by a PO) that was never used.  We have a spinnaker halyard, but no other rigging to support it, so its sat in the garage for the last 7 years.

In particular, I'd like to know what you have for
  • Turning blocks for the sheets
  • Winches (dedicated or shared with the jib? size?)
  • Deploying/dousing (halyard with clutch, hand-raised sock, code-zero furler?)
  • Downhaul (fixed, adjustable, parrel beads?)
« Last Edit: July 23, 2016, 01:10:30 PM by Dolce_Vita »
@(^.^)@  Ed
1977 P-323 #42 "Dolce Vita"
with rebuilt Atomic-4

selene

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Re: Spinnaker sheets
« Reply #2 on: July 23, 2016, 09:13:12 PM »
This is a great topic.  I continue to experiment with my asym and would be happy to learn from you, and exchange ideas!

My setup: Selene had no provision for the spinnaker, and all the lines are at the masthead (which complicates the process).  I have only a single pair of winches in the cockpit. With some advice from Ed, I installed the spin halyard as a first step.

The spinnaker tack I currently attach to one of the loops on the anchor bracket.  I have a block with a becket on the loop, leading to a block with a snap shackle which connects to a soft shackle on the sail - that way when I release the snap shackle there is nothing hard to wack me on the head (except the sail).  This setup gives barely acceptable mechanical advantage. Currently I just cleat off to the bow cleats; I intend to bring it back at some stage. Note that this means I fly the spinnaker forward of the forestay. I do worry of that steel loop is strong enough, but so far so good.

My asym is about 415 sq ft, i.e. 150%.

As for the sheets, I have a pair of sheet blocks which attach to sliders on the toerail track - again with soft shackles to make it easier to remove them when not in use.

The process is currently a bit tortuous as it is not ideal for the jib and the spinnaker halyards to share the same masthead winch - or the same cockpit winch - but it does work. So right now I only fly the kite in light winds.

Deploy/retrieval: If the jib is up, I feed the kite out of its bag behind the jib (to blanket it), then furl the jib, moving the spinnaker lines onto the winches. A bag which opened full length (a turtle) would sure help...  The other way I have done this is to feed the kite out of the forward hatch - this is what I do if the jib is furled. It has the advantage that I can set the spinnaker up down below do it deploys smoothly.

Dousing generally unfurling the jib (blanket), blowing the tack, then with somebody below as a squirrel to pull the sail down the forward hatch. Getting it quickly out of the wind and down below seems like a good idea to me; on deck there is always a chance of it getting away.

Other thoughts:
- The sheets need to be long, as the lazy sheet curls around the sail (so you can jibe) . . . I think I used 60' 3/8 sta-set each side - too small for the winch tailing, but that is okay, personally I never want the spin sheet to lock up - no cleats, stopper knots, etc.  If that sail gets away from you, I want the sheets to run free!

- Opinions on socks go both ways.  I have an old sock, which has the interior lines loose (modern socks have the control lines in their own sleeves, to prevent tangles) and have not tried it yet.  In general, when they work, they make things way easier.  When they don't work, they make things way harder.  Having said that, if I was single or double handed, I would use a sock.

- I have an ongoing debate with an experienced skipper/instructor about the optimum number of crew to manage the kite.  I have done it single handed in light winds (with Otto the autopilot!); but if moderate winds (10-15kn) or racing a minimum of three - foredeck, sheets, helm. With Selene, 5 is ideal: Helm, jib sheet, spin sheet, 2 foredeck.

- Initially I ran the sheets to the stern block, but an asym is really like a big genny, and so the blocks work better (for me) on the track.

Phew.  Quite the dump. Over to you guys!

Gridrat

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Re: Spinnaker sheets
« Reply #3 on: July 23, 2016, 09:58:39 PM »
I'm going to take this one step at a time as this is new to me. I have a 150% Tru Radical Asymmetrical Spinnaker. My spinnaker has a turtle with a steel ring that is rigged inside a sleeve so the lines won't foul. I don't have spinnaker winches so I will have to use the jib winches they are sized for 7/16" rope. There is a ratcheted sheave attached to the railing that should give me control for the tack line.

I thought about attaching the tack block to the anchor bracket. I wondered if the tension was within parameters so that the anchor bracket would hold.

I have a pair of sheet blocks that are adjustable within the sliding track, dedicated to the spinnaker sheets. In the past I have run my jib sheets to the windward winch to make it easier to adjust trim when sailing alone. I can adjust everything from the high side. The leeward winch acts as a change of direction block. I thought about rigging this way and taking the spinnaker sheet to the leeward winch.
I'm just thinking through this process on paper at the moment.

I am leaning toward using a 3/8" braided polyester line for the sheets. I think the heavier line would work better for my old arthritic hands. As to Ed's question, I have parred beads for the tack.

I appreciate the response Selene an Dolce_Vita. I will post my progress as I prepare my boat for the spinnaker. Wayne

Dolce_Vita

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Re: Spinnaker sheets
« Reply #4 on: July 24, 2016, 11:34:03 PM »
Thanks Guys for all the detailed info.  A couple of questions and comments:

...The spinnaker tack I currently attach to one of the loops on the anchor bracket.  I have a block with a becket on the loop, leading to a block with a snap shackle which connects to a soft shackle on the sail ...

I forget if you have the bowsprit option or not. I'm not sure exactly about the "loop on the anchor bracket" you're referring to.  Could you put up some pictures?

...Initially I ran the sheets to the stern block, but an asym is really like a big genny, and so the blocks work better (for me) on the track...

I have no "stern block".  Where is yours placed?  Agan, a picture would be helpful

... There is a ratcheted sheave attached to the railing that should give me control for the tack line. ...

Are you sure the railing is strong enough for that?  Spinnakers can generate some really tremendous force.

... In the past I have run my jib sheets to the windward winch to make it easier to adjust trim when sailing alone. I can adjust everything from the high side. The leeward winch acts as a change of direction block. I thought about rigging this way and taking the spinnaker sheet to the leeward winch. ...

This should work.  I used to do the same thing on my San Juan 21 when single-handing.  But I think I would be chicken to single-hand with a spinnaker.  I've seen some epic spinnaker takedown fails with a whole foredeck crew available.

I am leaning toward using a 3/8" braided polyester line for the sheets. I think the heavier line would work better for my old arthritic hands....

Yes, the bigger line is always easier to handle.  But gloves help solve this problem.  When I converted from wire/rope halyards to all rope, I went down to 3/8" VPC because that is the biggest I could get to fit well in the masthead sheaves.  It's still way stronger than the wire was.  I could have gone even smaller if strength was the only consideration, but handling the 3/8" is tough enough as it is.  I always have to wear sailing gloves.
@(^.^)@  Ed
1977 P-323 #42 "Dolce Vita"
with rebuilt Atomic-4

selene

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Re: Spinnaker sheets
« Reply #5 on: July 25, 2016, 11:09:21 AM »
Like both of you guys, I am taking this slow, one step at a time, so I am only partially through understanding and optimising the setup and process.

Loops: Yes, I do have the anchor platform (which I also call a bowsprit, 'cos real sailboats have bowsprits). Will take a photo.

Stern blocks: Initially I used soft shackle to secure blocks to the stern cleats. This meant very long sheets were needed!  However, I did not like the shape of the sail, so moved the blocks onto the track.  I later learned that, whereas with a sym spinnaker sheets should be led as far back as possible, and asym acts more like a very big genoa (makes sense) so the sheets are often further forwards. So now the sail shape looks better - fuller, fewer creases.

Forces - yeah, I worry about that.  But the track is through-bolted, and like I said, I limit myself to lighter winds. I have seen a fair share of broaches and one dismasting from a spin at 20-25kn. My favorite discussion with a friend of mine in a larger boat: "We were racing well, spinnaker up, but the wind crept up and we had difficulty bringing it down". "So what did you do?""Left it up until it exploded"."What did you learn from this?" "Well, I really need a range of spinnakers of different weights - 3 at least". <ahem>. Not on my budget....



Dolce_Vita

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Re: Spinnaker sheets
« Reply #6 on: July 25, 2016, 01:13:01 PM »
Oh my!  If you're talking about that tiny little loop that's welded down and used to tie down the anchor then I would be concerned!  That weld is small, and I'm sure that it had less attention given to it's fabrication than a "mission-critical" weld would have. And then there's the matter of the off-center and un-opposed force applied at the end of a long lever arm.

My bowsprit has a small vertical hole drilled through the SS platform just aft main tube at the farthest forward point which suggests itself as an attachment point for the tack.  But again, I was unwilling to use it without installing a bob-stay to offset the large upward force that would be applied at the end of that long unsupported lever arm. And that SS sheet didn't seem thick enough to not flex and fatigue crack over time.

Instead, I've been considering somehow using the bolt that attaches the bowsprit to the stem fitting.  This is already anchored to support the full force of the forstay and jib.

@(^.^)@  Ed
1977 P-323 #42 "Dolce Vita"
with rebuilt Atomic-4

selene

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Re: Spinnaker sheets
« Reply #7 on: July 25, 2016, 09:55:55 PM »
Agreed on all points.  I also noticed some other boats have a bridle from the back of the stem fitting to the front of the forestay (sometimes just a long u-bolt).  We have 3(?) holes in the top of the stem fitting, so that could work...

rbrtfeld

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Re: Spinnaker sheets
« Reply #8 on: July 27, 2016, 03:53:22 PM »
Great Posts everyone. You might like to see the web site for the  ATN Tacker and Sleeve. This is what I use and it works great. Here is the web site you can copy and paste, they have a short video showing how it works. Fair winds to all.

Bob

http://www.atninc.com/atn-tacker-sailing-equipment.shtml

Dolce_Vita

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Re: Spinnaker sheets
« Reply #9 on: July 27, 2016, 11:11:01 PM »
I like it!
@(^.^)@  Ed
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with rebuilt Atomic-4

Gridrat

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Re: Spinnaker sheets
« Reply #10 on: July 28, 2016, 05:50:56 PM »
I like the tracker also. Thanks for posting the website.

selene

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Re: Spinnaker sheets
« Reply #11 on: August 01, 2016, 12:24:36 AM »
I hope, dear colleagues, you will excuse a bit of a ramble.  I have been reflecting on my spinnaker setup after reading some of the points in this thread - but with summer winds here at 20-25kn every day, I am not going to experiment until the fall, when the winds die down a trifle!

Ed - that small bolt is intriguing, thank you for pointing it out. Looks like a potentially great anchor point - perhaps with a small tang of some kind? Incidentally, I do not have a hole in my anchor platform steel sheet, but I would be worried about deflection of the sheet.  I am less concerned about the long lever arm, as the anchor platform seems to be pretty solid; and I know that the spinnakers generate a lot of lateral force, but vertical force? Don't know.

I had a good chat with a friend who has a new (few years old) Catalina 34 who frequently uses an asym.  Many of his learnings are relevant to us.

- Tack: He had a bracket fabricated above his anchor track. It is a few inches forward of the forestay, close to "Ed's Bolt" location, and inside the pulpit.  He said he was surprised - initially he rigged it forward of the pulpit, but the tack line always seemed to pull aft (and snag on his running lights), so he moved it inside the pulpit, where it works well.

- Tack line is run though blocks on the stanchions (http://garhauermarine.com/ProductSpecs.cfm?pid=290) to a clutch installed on the jib track (http://garhauermarine.com/ProductSpecs.cfm?pid=186). He runs the furler control line on the port side, the spinnaker line on the starboard side. (we're big Garhauer fans around here...)

- He raises and lowers the spinnaker, like me, forward of and blanketed by the jib; he uses a sock.

- Winches - like us, he has a single pair of main winches. But he installed turning blocks (as Gridrast mentioned) so the working spinnaker sheets run across the cockpit to the windward winch. 
We have cleats in that position; I will try lashing (snatch block?) a block to each cleat, which should allow the spin sheet to run to a block on the jib track back to the cleat turning block, and across the cockpit to the windward winch. Have not tested the geometry yet.

Like I said...just thoughts...