Ljungstömare, or Twin-Wing [Archive]

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Dr.Spoke

11-05-2009, 06:20 AM

Winter season is upon us, plenty of work to do on Dobra... I also want to get working on the blog for the boat. With that end in mind I'm looking to make contact with as many owners of Ljungströmkryssare as possible.
These were unusual boats built from the mid '30s to late 50s. Many were exported to the US as "Twin-Wings" in various sizes. And with the international nature of the forum I hope to find many that are not in the "local" waters for them... But even if you are in scandinavia please respond
Thanks,
Phil

Hwyl

11-05-2009, 06:33 AM

Do you mean boats in general with the Lungstrom rig, or a specific type. I know at least one forum member has a trimaran with such a rig

Dr.Spoke

11-05-2009, 06:37 AM

I'm interested in any boat that has a Ljungstöm rig, but specifically in the boats built with Ljungströms "cirkelbågs" hull-form theory.

JimConlin

11-05-2009, 07:31 AM

http://www.conlin-boats.com/p1050080d.jpg

The breadth of a multihull allows better sheeting angles.

Dr.Spoke

11-05-2009, 07:34 AM

http://www.conlin-boats.com/p1050080d.jpg

The breadth of a multihull allows better sheeting angles.
Without a doubt! Can you explain the assymetric vertical battens?

JimConlin

11-05-2009, 07:49 AM

For the sake of simplicity, only the port side ply of the sail has roach and battens. The starboard leech is slightly hollow. Upwind, the two plies lie together OK.
The battens are vertical because the sail furls and reefs by rolling around the mast. Just above the deck, there's a spool on the mast. A winch on the cabin top pulls a line which rotates the mast.

Dr.Spoke

11-05-2009, 08:02 AM

Thanks Jim, just intrigued why only one sail with battens.
My spool is below decks, and I've got a nice little handle in the cockpit to rotate the mast.
http://www.dobrakusa.blogspot.com/

Thad

11-05-2009, 09:35 AM

Can you roll your sail on the mast like the Ljungstrom rig, Jim?

JimConlin

11-05-2009, 10:23 AM

Yes. The sail rolls up on the mast. The mast has a bit of 'bulge' in its taper, so the sail stays reasonably flat.
The mast-turning line is led to a self-tailing winch under the dodger. Reducing sail is done by cranking on the winch. The neat things about the rig are that reefing is done from the safety of the cockpit and that, being a cat-yawl, as the main is reefed, the rig's center of effort stays in about the same place.