Interesting sail design... got me thinking

[rgranger]

Hello all.

Yesterday, I stumbled upon this interesting concept video for a sailing trimaran canoe. I could not get it out of my mind. Note the interesting sail design and traveler system...

http://www.iqwoodwork.com//assets/images/gallery/trimaran/TrimHDVideo.mp4

I am really intrigued by this design. Its simplicity is what has my attention. The "main sheet" is essentially the "out haul" and the trim is controlled by the traveler. If you put a "true" traveler system on this boat, you would have great sail control. A roller furler would finish the picture. My question(s) is/are this... I am wondering about a small modification to this design along the lines of what has been done to a pivoting crab claw sail. The pivoting crab claw sail allows for "reefing" with the added benefit of lift on the boat....

For example, I found these pics of the pivoting crab claw in a google search.

by tilting the sail "horizontal" you reduce the lateral pressure on the sail and some of the "lift" of the sail is actually lifting the boat up out of the water... thus reducing the drag of the boat in the water (in theory).

So back to this sailing trimaran, ... what if you simply put the mast on a hinge and set up a system where you could control the athwart tipping of the mast... something like what I have in this crude diagram...

Would that make sense? Worth the trouble?

 

[dlochner]

The second sail plan, the Trilobyte, looks similar to the sail plan on a wind surfer or Polynesian voyaging canoe.

http://www.hokulea.com/voyages/our-story/

 

[jssailem]

Would that make sense? Worth the trouble?

Perhaps technically and NO practically.
The mast transmits the power of the sail to the hull of the boat. First to accomplish tipping the mast you would have to have a structure that can control all of the sail force and multiple angles. It would make the mast base unmanageable. The forces needed to adjust the mast would be significant in any breeze. Where would you get that type of power source. Hydraulic?
Note once the power of the sail has been transmitted to the hull the hull tries to slide sideways. The dagger board or keel sits in the water and resists this force/motion. The effect of the sail force and the resisting keel - squirts the boat forward - or backwards based on the hull shape and the angular forces on the sail.

 

[JohnShannon]

Canting rigs are done on some fancy cats also a good book written in the 60's "the 40 knot sailboat" sketches out more or less feature for feature what would prove to be a 60 knot sailboat https://www.yachtingworld.com/news/lhydroptere-hits-61-knots-10400

 

[rgranger]

The second sail plan, the Trilobyte, looks similar to the sail plan on a wind surfer or Polynesian voyaging canoe.

http://www.hokulea.com/voyages/our-story/

Yes... it is a modification of the proa sail plan. Nice article!

 

[DrJudyB]

Canting rigs can be found on several Farrier/Corsair and other trimarans that owners have modified. The masts are rotating, and are mounted on a ball that resembles a trailer hitch ball. Because the mast rides on top of a ball, it’s not prohibitively expensive nor mechanically complicated to modify the rig to be canting.

Tilting the rig is accomplished via adjustable length shrouds that go from the top of the mast to the amas. Some canting rigs use 24:1 tackles; others use hydraulic backstay adjusters to control the tilt.. Adjustment is usually about 12-14 inches. That’s all it takes on a 40 foot mast.

It’s interesting that a canting rigs greatly reduces heeling, and actually lifts the leeward float up, greatly reducing wetted surface and increasing speed.

Here is a recent thread from Sailing Anarchy
http://forums.sailinganarchy.com/index.php?/topic/81259-canting-rig-on-regular-orvairs-and-f-boats/

 

[dlochner]

Yes... it is a modification of the proa sail plan. Nice article!

The boat has an interesting story. Here's a photo of her and the Draken on the Erie Canal a few years ago. The Hokulea is a fiberglass boat navigated by traditional methods. The Draken is a wood boat built from traditional materials and traditional skills with state of the art modern electronics.

The Hokolea was not sailing on this leg of her journey. She was being towed.

 

[rgranger]

Canting rigs can be found on several Farrier/Corsair and other trimarans that owners have modified. The masts are rotating, and are mounted on a ball that resembles a trailer hitch ball. Because the mast rides on top of a ball, it’s not prohibitively expensive or mechanically complicated to modify the rig to be canting.

Tilting the rig is accomplished via Adjustable length Shrouds that go from the top of the mast to the amas. Some canting rigs use 24:1 tackles; others use hydraulic backstay adjusters to control the tilt.. “Throw” at the tip top of the mast is usually about 12-14 inches. That’s all it takes on a 40 foot mast.

It’s interesting that a canting rigs greatly reduces heeling, and actually lifts the leeward float up, greatly reducing wetted surface and increasing speed.

Here is a recent thread from Sailing Anarchy
http://forums.sailinganarchy.com/index.php?/topic/81259-canting-rig-on-regular-orvairs-and-f-boats/

Very nice thread... thanks.

I am very much intrigued by the sail plan in this trimaran. I have never seen a boat that essentially is a reverse catboat. The mast is almost all the way aft and you fly a really big genoa. As I imagine this rig with a true traveler and a roller furler, you would have only three lines to deal with

1. Traveler (to adjust sail trim and twist)
2. Main Sheet (essentially an out haul)
3. Reefing line for roller furler.

Talk about a lazy go-fast sailboat. I think I'm in love. If you go to the website the builder did not follow the sail plan in the original concept design. The mast is in a more traditional place.

http://www.iqwoodwork.com/

I can imagine the mast secured to the rear ama and maybe using carbon fiber for the mast material.

 

[Meriachee]

There are a number of people around these parts that subscribe to the opposite of this theory. The masts in question do move, but away from the wind when pressed.
This falls into the "tuning" (or lack thereof) category.

 

[philwsailz]

Canting rigs can be found on several Farrier/Corsair and other trimarans that owners have modified. The masts are rotating, and are mounted on a ball that resembles a trailer hitch ball. Because the mast rides on top of a ball, it’s not prohibitively expensive nor mechanically complicated to modify the rig to be canting.

Tilting the rig is accomplished via adjustable length shrouds that go from the top of the mast to the amas. Some canting rigs use 24:1 tackles; others use hydraulic backstay adjusters to control the tilt.. Adjustment is usually about 12-14 inches. That’s all it takes on a 40 foot mast.

It’s interesting that a canting rigs greatly reduces heeling, and actually lifts the leeward float up, greatly reducing wetted surface and increasing speed.

Here is a recent thread from Sailing Anarchy
http://forums.sailinganarchy.com/index.php?/topic/81259-canting-rig-on-regular-orvairs-and-f-boats/

Judy, can you get in touch with me please?