Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 14-04-2010, 01:15   #1
Registered User
 
svstrider's Avatar

Join Date: Apr 2003
Location: back on Gold Coast after sailing north to Thailand then east to Pacific via Irian Jaya, PNG & Solomons
Boat: Tennant 47ft Catamaran
Posts: 310
Tack Point/s for Asymmetrics

Any thoughts from the Brains' Trust on the pros & cons of controlling the tack of an assymetric spinnaker by running control lines between both bows and then back to winches in the cockpit? I saw photos of it when previewing greg Tajan's book on cats on Amazon.

I have a central prodder so attach the ass. tack there and don't tend to adjust it when the sail is up as there is usually too much tension on the tack line. I have not run the tack line to a winch but am considering doing so, EITHER by
1. using anchor windlass rope gyspsy or
2. using blocks down one side or
3. new sheet leaders on the bridge deck top.

Ideas on pros & cons of that plan would also be appreciated.
__________________

__________________
Paul & Kaspar de Wonda Dog
S/V "Pelican V"
"Trust not a living soul and step warily around the dead"
svstrider is offline   Reply With Quote
Old 14-04-2010, 01:41   #2
Senior Cruiser
 
Talbot's Avatar

Cruisers Forum Supporter

Join Date: Jun 2004
Location: Brighton, UK
Boat: Privilege 37
Posts: 3,579
Images: 32
I am not sure that I entirely understand what you want to do. My assumption is that you want to stop using the central prodder, and instead control the position of the tack by use of lines to each bow, thus being able to move the tack position . If I have this right, it will enable use of the assymetric at a much deeper angle on the wind, when using the normal central prod would lad to a collapse of the assymetric.

If this is correct, then the best way to set this up is entirely dependent on your deck layout, thus I would recommend that you add a few photos.
__________________

__________________
"Be wary of strong drink. It can make you shoot at tax collectors - and miss."
Robert A Heinlein
Talbot is offline   Reply With Quote
Old 14-04-2010, 03:40   #3
Registered User
 
svstrider's Avatar

Join Date: Apr 2003
Location: back on Gold Coast after sailing north to Thailand then east to Pacific via Irian Jaya, PNG & Solomons
Boat: Tennant 47ft Catamaran
Posts: 310
Quote:
Originally Posted by Talbot View Post
I am not sure that I entirely understand what you want to do. My assumption is that you want to stop using the central prodder, and instead control the position of the tack by use of lines to each bow, thus being able to move the tack position . If I have this right, it will enable use of the assymetric at a much deeper angle on the wind, when using the normal central prod would lad to a collapse of the assymetric.

If this is correct, then the best way to set this up is entirely dependent on your deck layout, thus I would recommend that you add a few photos.
Thanks Talbot. Yes, I was wondering if controlling the tack point off lines from both bows had any advantages over setting it off a single point on the centrally situated prodder. So being able to keep it flying on deep downwind angles with the main up as well would certainly be a positive.

I will dig up some pictures of my fore deck setup.
__________________
Paul & Kaspar de Wonda Dog
S/V "Pelican V"
"Trust not a living soul and step warily around the dead"
svstrider is offline   Reply With Quote
Old 14-04-2010, 04:38   #4
Senior Cruiser
 
Talbot's Avatar

Cruisers Forum Supporter

Join Date: Jun 2004
Location: Brighton, UK
Boat: Privilege 37
Posts: 3,579
Images: 32
There is no doubt that being able to move the tack point will give you significant advantages for use of the assymetric when the wind is from deep astern. It will also help if you have the mainsail hoisted as well. However, the prodder is much better than lines when you are trying to get as close to windward as possible.
__________________
"Be wary of strong drink. It can make you shoot at tax collectors - and miss."
Robert A Heinlein
Talbot is offline   Reply With Quote
Old 14-04-2010, 16:35   #5
Registered User

Join Date: Sep 2008
Location: Hervey Bay, Queensland
Boat: Spirited 380 Catamaran
Posts: 91
Another options which I am setting up on my cat is to hinge the prodder and swind it to the side. My prodder is 1.9m long so I should be able to move the tack across a fair way. I have also set up a padeye on the hull deck to move the tack across to the side of the boat.
A number of multihulls use this arrangement to run deeper if needed.

Peter
__________________
spiritcat is offline   Reply With Quote
Old 14-04-2010, 17:06   #6
Elvish meaning 'Far-Wanderer'
 
Palarran's Avatar

Cruisers Forum Supporter

Join Date: Jan 2008
Location: Me - Michigan / Boat - Tenerife
Boat: 56' Fountaine Pajot Marquises
Posts: 2,641
I don't know if this is true or factual but I thought I read that your better on a broad reach and tacking then running as your vmg is better.
__________________
Not all who wander are lost

http://www.sailblogs.com/member/palarran/
Palarran is offline   Reply With Quote
Old 14-04-2010, 17:18   #7
Registered User

Join Date: Sep 2008
Location: Hervey Bay, Queensland
Boat: Spirited 380 Catamaran
Posts: 91
That correct, with the right wind conditions reaching and gibing downwind will produce a good vmg, especially when the wind is stronger as the apparent wind moves forward and you start to run deeper.
However on lighter days there can be an advantage to moving the tack to windward and getting a better angle to run deeper. I am not talking about running dead down wind as this creates its own problems, but reaching at a lower angle.

Peter
__________________
spiritcat is offline   Reply With Quote
Old 18-04-2010, 04:12   #8
Marine Service Provider
 
Factor's Avatar

Join Date: Dec 2006
Location: Brisbane Australia
Boat: Corsair Dash MKII
Posts: 4,084
I dont have a prodder - so the only way I can fly the MPS is by two tack lines that go from tack to each bow and back to the cockpit. Works just fine. The up side is you can use the same gear for a symmetrical spin
__________________
Factor is offline   Reply With Quote
Old 19-04-2010, 14:08   #9
Registered User

Join Date: Jan 2008
Location: Fort Lauderdale, FL
Posts: 310
You can create a tack bridle using the following:

1) Fiddle block attached to the port bow via snap shackle
2) Fiddle block with becket and cam cleat attached via snap shackle to the tack of the MPS.

Duplicate the same on the starboard side.

As you ease one side out you take in on the other. Both control lines are together attached to the tack of the sail. Ease them both and the tack goes up. Very easy to control in all three deminsions. Running it all the way back to the cockpit would require a lot of extra line. With 4:1 purchase you don't need a winch.
__________________
Abaco is offline   Reply With Quote
Old 19-04-2010, 14:31   #10
Registered User

Join Date: Nov 2005
Location: Ohio
Posts: 2,313
You can use all 3 points with three separate lines, this is how we set up assy's. Center line to hold it to the bow (prod in your instance) and two guys. We jibe the pole by disconnecting the bell, sliding the pole back and then reconnecting on the weather side. Just a matter of reseting the guy in the jaw then. We use a pole, you have two other hulls for attachment points. Pull it to the center, jibe and then square it to where you want.

Bottom line: you want projection from centerline when going deep.
__________________
Joli is offline   Reply With Quote
Old 23-04-2010, 04:38   #11
Marine Service Provider
 
Factor's Avatar

Join Date: Dec 2006
Location: Brisbane Australia
Boat: Corsair Dash MKII
Posts: 4,084
Whats a spinnaker pole?
__________________
Factor is offline   Reply With Quote
Old 23-04-2010, 05:07   #12
Registered User

Join Date: Nov 2005
Location: Ohio
Posts: 2,313
It's like a multi's prodder but we also use it to lift the dinghy on and off the foredeck.

Quote:
Originally Posted by Factor View Post
Whats a spinnaker pole?
__________________
Joli is offline   Reply With Quote
Old 26-04-2010, 20:27   #13
Registered User
 
Cotemar's Avatar

Join Date: Dec 2007
Boat: FP, Helia 44 Evo
Posts: 5,717
Asymmetric chute using a bridal for the tack point

You will need a snatch block and some place on each bow to clip in the snatch block to manage the sheets. Spinnaker winches are nice but not needed if you can route the sheet to your jib winches or any available winch. The boat should have been built with attach points for the snatch blocks. Loads on the sheets can be quite high and a winch is a must. For dead down wind sailing on a cat with this rig its best to drop the main and only use the chute. Even being a assymetric it will naturally want to fly up and in front of the boat. You can let the down wind side of the bridal almost loose and the chute will rotate out front and up. If you are reaching you pully both sides of the bridal in tight and fly the chute as a big jib with the tack centered between the hulls and as low as you can get it for a tight leach. I can point to 50 to 55 degrees apparent without a sprite using this method and the mainsail up. A rule of thumb is to drop the main anytime the wind is within 30 degrees of the stern.
Attached Thumbnails
Click image for larger version

Name:	1.jpg
Views:	112
Size:	56.6 KB
ID:	15644   Click image for larger version

Name:	Asm_Bridal_1.jpg
Views:	111
Size:	58.2 KB
ID:	15645  

__________________
Cotemar is offline   Reply With Quote
Old 26-04-2010, 21:20   #14
Registered User

Join Date: Jun 2009
Location: Skippack, PA
Boat: Lagoon 42
Posts: 83
Mark,

Thanks again for the great information! Do you having any pictures of the attachment points/hardware on the forebeam?
What are you using for a port winch?
What size asym works with our boats?

Chuck
__________________
RoadRacer is online now   Reply With Quote
Old 06-05-2010, 13:07   #15
Registered User

Join Date: Jan 2008
Location: Fort Lauderdale, FL
Posts: 310
Cotemar,

That chute does not appear to be flying on a Mahe 36. Was it on a Voyage down in the BVI by any chance?
__________________

__________________
Abaco is offline   Reply With Quote
Reply

Tags
asymmetric

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
The Point of it All . . . sarafina General Sailing Forum 14 04-04-2010 15:42
Overtaking vs Port/Starboard Tack SkiprJohn Rules of the Road, Regulations & Red Tape 47 15-01-2008 13:48
Point No Point Lighthouse For Sale TaoJones Atlantic & the Caribbean 10 25-11-2007 08:14
Rigging the tack on a C-Lark davethegr8 Deck hardware: Rigging, Sails & Hoisting 1 16-08-2007 10:49
JOTD: point Amgine The Library 12 08-12-2006 23:42



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 08:17.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.