Using an Assy Spinnaker

[Dockhead]

OK, so looking at various photos for examples, I came up with this:





Relevant because of the pole setup. My pole is actually longer and will extend somewhat over the bow pulpit. The pole here is set to WINDWARD of the inner forestay -- isn't the guy under huge stress? And working at an angle which would magnify the forces? I shudder to think what would happen if that guy let loose and the pole slammed into the inner forestay.


Is the tackline attached to the pole, or to the tack?


I guess they wouldn't want to have the pole to leeward of the inner forestay because it would interfere with use of the staysail. My staysail is not so big that I think I would bother with it in light air. It would be a rounding error of power compared to a 200m2 assy so just needless complication, no?


Obviously I'm going to need more cordage. Maybe I could use jib sheets as sheet and guy -- 14mm racing dyneema. Or maybe I need to have new ones made up, maybe out of 12mm racing dyneema, maybe make up long leaders out of single braid (you can see the leaders in the photo, a couple meters worth).

[jmh2002]

Originally Posted by Dockhead

Relevant because of the pole setup. My pole is actually longer and will extend somewhat over the bow pulpit. The pole here is set to WINDWARD of the inner forestay -- isn't the guy under huge stress? And working at an angle which would magnify the forces? I shudder to think what would happen if that guy let loose and the pole slammed into the inner forestay.


Yes, the pole is always set to windward.
Yes, the guy can be under huge stress, especially as the pole moves forward towards the forestay.
A 'reaching strut / jockey pole' is normally used on this point of sail to give the guy a better angle.
Slamming the pole into the forestay is not recommended, but it happens and the forestay seems to survive.

Is the tackline attached to the pole, or to the tack?

Ultimately the tackline should be attached to the tack of the sail, even if you use a short anti-chafe strop to pass through the jaws of the pole.

The point being that if you open the jaws of the pole and detach it, the sail will continue to fly from the bow, via the tackline

I guess they wouldn't want to have the pole to leeward of the inner forestay because it would interfere with use of the staysail. My staysail is not so big that I think I would bother with it in light air. It would be a rounding error of power compared to a 200m2 assy so just needless complication, no?

Not necessarily, because it's not just the sail area but also the slot created between the asymmetric, the staysail, and the mainsail.

Your staysail cloth weight may be on the too heavy side though. As I mentioned, just try it and see. It's relatively easy for you to unfurl and furl the staysail for testing, or if conditions justify it.


Obviously I'm going to need more cordage. Maybe I could use jib sheets as sheet and guy -- 14mm racing dyneema. Or maybe I need to have new ones made up, maybe out of 12mm racing dyneema, maybe make up long leaders out of single braid (you can see the leaders in the photo, a couple meters worth).

Answers above in red (and some in the other thread too).

For your purposes you don't need to use the pole when on this point of sail and that will mitigate some of the related issues.

Just fly the sail from the bow instead.

Use the pole when you want to run deeper, and pull the sail around in front of the boat.

You have multiple options available to you, all of which will work.
Some will be better suited to different conditions and points of sail.

Also bear in mind that the photo is of a Volvo Race boat, which is much faster, always bringing the apparent wind much further forward than on a cruising boat. They rarely run dead downwind in the traditional sense, except maybe in very heavy air.

[jmh2002]

PS: A racing trick in heavy air (which can be used by cruising boats too of course):

When you are running downwind and should normally have the pole squared back, presenting maximum sail area to the wind, instead you can ease the pole forward, putting the spinnaker (symmetric, asymmetric, or otherwise) further around to the side, more blanketed by the mainsail, and therefore producing less power.

The sail may also be more stable in this mode too, and help reduce the boat rolling.

In light air none of this should be an issue though.

[Dockhead]

Originally Posted by jmh2002

PS: A racing trick in heavy air (which can be used by cruising boats too of course):

When you are running downwind and should normally have the pole squared back, presenting maximum sail area to the wind, instead you can ease the pole forward, putting the spinnaker (symmetric, asymmetric, or otherwise) further around to the side, more blanketed by the mainsail, and therefore producing less power.

The sail may also be more stable in this mode too, and help reduce the boat rolling.

In light air none of this should be an issue though.

Cool trick; thanks!



OK, pardon for the likely stupid questions, but:


So the pole should come around to leeward as you sail deeper, right? And should come forward when you head up? At what approximate angles does this happen? With an A2, how high do you think I can sail, considering I have a very long pole?

[jmh2002]

Here is a nice little graphic for the VO65. Whilst not directly related to cruising, or this thread, you may still find it interesting. Note that they have no symmetrical spinnakers, instead using a MH0, FR0, and A3.

https://www.northsails.com/sailing/e...sail-inventory

https://www.northsails.com/sailing/e...rofile-vo65-a3



There are a few other interesting links at North as well:

https://www.northsails.com/sailing/en/sails/new-sail

https://www.northsails.com/sailing/e...types/downwind

https://www.northsails.com/sailing/e...sing-gennakers
(on right select between G0 Close Reacher, G1 All Purpose, G2 Runner to see the difference in sail shape)

https://www.northsails.com/sailing/e...ing-sail-guide

Trim An Asymmetric Spinnaker On A Sport Boat
https://www.northsails.com/sailing/e...n-a-sport-boat

^^^ ok, that's for sport boats, but it gives some idea of the concepts.

[jmh2002]

Originally Posted by Dockhead

So the pole should come around to leeward as you sail deeper, right? And should come forward when you head up? At what approximate angles does this happen? With an A2, how high do you think I can sail, considering I have a very long pole?

Some things seem a bit mixed up there:

- The pole should always be on the windward side
- The pole can go from the forestay (let's call it 0deg, back to almost 90deg and touching the sidestays
- In practice, with a symmetrical spinnaker, the basic concept is to have the pole at 90deg to the wind
- The asymmetric spinnaker will effectively be used in a similar way to a symmetrical spinnaker once it is on the pole and being squared back
- As you sail lower/deeper (more downwind) the pole needs to come further to windward, as the sail is now being blanketed behind the mainsail
- As you sail higher (more upwind) the pole needs to go forward
- The length of the pole doesn't really change how high you can sail, the limiting factor is the shape and cut of the sail
- It's difficult to say to what angle you can use the A2, because they often vary from one sailmaker to the next, and from race to cruise, and of course wind speed is a factor too
- A2's are normally quite a full sail, for deeper running angles
- You'll note that the North Cruising Gennakers don't specify an angle, because the cruising sails are normally cut to cover a much wider angle and be more forgiving to trim and steering (autopilot too).
- For racing North specify an A2 as a "Medium Air Runner" and below is their angle chart
- The Racing A2 is in the 135 to 155 TWA

You also see from the chart that lighter air enables a tighter / higher angle.

https://www.northsails.com/sailing/e...ric-spinnakers



Here are some links from Doyle too, for comparison:

https://www.doylesails.com/product/a...ght%20material.

Racing A2

TWA 140 to 150 TWA

TWS: 9 – 20 knots

https://www.doylesails.com/product/c...ising-downwind

https://www.doylesails.com/product/a...ical-spinnaker

All Purpose Asymmetrical Cruising Spinnaker

TWA: 100 – 155 degrees

TWS: 6 – 22 knots

Hope that helps.

[jmh2002]

EVEN MORE INFO:

UK SAILMAKERS

https://www.uksailmakers.com/sails-o...ing-spinnakers

(click the link to see specs for other spinnakers, code zero, S1-5, A1-5 as well as "info" text which I think you will find useful for explanatory and comparison purposes)

A1 Light Air Reacher (VMG) - Racing Spinnakers
Formally called VMG spinnaker
AWA 70-110°
AWS 0-10 knots
Mid Girth approx. 90% (of foot length)
Flat Entry

"In winds under eight knots true, boats make the best progress sailing with apparent wind around 90-degrees and then jibing. A sail for these conditions is made from a .5 to .6 oz. high performance nylon like Airx or Superkote, has a flat entry for sailing closer to the wind, and has a reduced area to make it easier to fill in light winds."

A2 Light/Medium Runner - Racing spinnakers
AWA 105-155°
AWS 8-18 kts
Mid Girth 100-105% of foot length
Full entry, Rotates to windward of the forestay as the sheet is eased

"The A2 is the go-to sail on most boat. Sprit boats never run dead down wind because the asymmetrical spinnaker gets blanketed behind the main sail if they sail below 155 degrees AWA. For an asymmetric spinnaker flown off of a centerline pole, “running” is when the boat sails with the apparent wind angle greater than 90 degrees until the boat is sailing as deep as 155 degrees AWA. An A2 (light/medium runner) is used in apparent wind speeds of 8-18 knots. To help sail as low as possible, UK Sailmakers designs these sails to be full-sized with a full entry and a high clew so that the middle of the sail will flatten out and rotate to windward of the headstay to get as much of the sail as possible out of the wind shadow of the mainsail."

QUANTUM:

https://www.quantumsails.com/en/sail...downwind-sails

https://www.quantumsails.com/en/reso...hore-inventory

SYMMETRICAL Spinnakers:



ASYMMETRICAL Spinnakers:



AND:

HOW TO CHOOSE THE RIGHT ASYMMETRICAL SPINNAKER

https://www.yachtingworld.com/featur...pinnaker-68317

All that should keep you busy for a while. Clear as mud I think?

[Smokeys Kitchen]

We use a traditional sock which works well for us. Dousing with the sock when we gybe

Our tack attachment is rather simple. About a one foot lead of a dyneema loop attached to the substantial bow roller with a low friction ring in it. We just thread the tack line through the ring and run it back to a mooring cleat. This setup works for us since we are not racing and don’t adjust the tack line all the time.

You can just see the line and ring in the photo below:

[jmh2002]

This older thread might provide some different perspective too:

https://www.cruisersforum.com/forums...as-205003.html

[Dockhead]

Originally Posted by Smokeys Kitchen

We use a traditional sock which works well for us. Dousing with the sock when we gybe

Our tack attachment is rather simple. About a one foot lead of a dyneema loop attached to the substantial bow roller with a low friction ring in it. We just thread the tack line through the ring and run it back to a mooring cleat. This setup works for us since we are not racing and don’t adjust the tack line all the time.

You can just see the line and ring in the photo below:

Thanks! Interesting.

[Dockhead]

Originally Posted by jmh2002

. . .

All that should keep you busy for a while. Clear as mud I think?

Tremendously helpful, thank you!

[jmh2002]

Originally Posted by Dockhead

Tremendously helpful, thank you!

You are welcome

[wingssail]

Thanks to JMH (or someone) I get to answer here too, cool.

Originally Posted by Dockhead

OK, so looking at various photos for examples, I came up with this:


Attachment 216620


Relevant because of the pole setup. My pole is actually longer and will extend somewhat over the bow pulpit. The pole here is set to WINDWARD of the inner forestay -- isn't the guy under huge stress? And working at an angle which would magnify the forces? I shudder to think what would happen if that guy let loose and the pole slammed into the inner forestay.

Yes the guy is under stress, however, if you lead the guy aft to a turning block at the widest part of your boat (out at the toe rail, but be sure it is strong point) with a strong line for a guy it will be fine. However, just lower the tack of the sail to the stem fitting and put the pole away in this situation.

Is the tackline attached to the pole, or to the tack?

People do it multiple of ways. I attach the tack line to the tack ring of the sail and lead it directly to a block and then aft.


I guess they wouldn't want to have the pole to leeward of the inner forestay because it would interfere with use of the staysail. My staysail is not so big that I think I would bother with it in light air. It would be a rounding error of power compared to a 200m2 assy so just needless complication, no?


Obviously I'm going to need more cordage. Maybe I could use jib sheets as sheet and guy -- 14mm racing dyneema. Or maybe I need to have new ones made up, maybe out of 12mm racing dyneema, maybe make up long leaders out of single braid (you can see the leaders in the photo, a couple meters worth).

I recommend that the sheets be double the length of the boat + 3-6 mt or you run out of sheet during a jibe. No fun to go fishing for the end of the new sheet when the helm's person is hollering "sheet, sheet!"

[wingssail]

Originally Posted by Dockhead

Cool trick; thanks!

OK, pardon for the likely stupid questions, but:

So the pole should come around to leeward as you sail deeper, right? And should come forward when you head up? At what approximate angles does this happen? With an A2, how high do you think I can sail, considering I have a very long pole?

JMH2002 got it right, the pole goes forward as you reach up, and comes back as you turn downwind. The terminology is simple and important: "pole forward", "pole back".

Be sure to man the tack line when moving the pole.

We carry our A2 much higher than the graphs shown (we have to due to the reaching legs our typical races have). The AWS is often well below 90 degrees and the true wind angle is often as low as 110 degrees. We often carry an A3 on those angles if the breeze is up.

[Joli]

Reaching, we simply run the tack line through the leeward chock to the bow cleat.
Going deep we have to use the pole to rotate the tack to weather just like a sym kite.
We use a sock and will drop it for jibes, we're not racing anymore.
Our biggest fear is wrapping it around the headstay when the boat rolls.
Usually it's just my wife and I so we tend to pull it down when the breeze is around 22 true.