~ Sustainable Seafaring from Oceania. History, Design, and Relevance ~

A Working Crabclaw Sail

Having tweeked the mock-up rig a litte more this weekend, I'm now officially declaring it workable!

 A "workable" single-hander`s crabclaw sail is what I've been after all along.  As written in the sidebar:

"Why tinker with a good thing?

The Micronesian Proa rig is already an exceeding good thing. Why even mess with it? Because single-handing the rig during the shunt can become a daunting prospect as boat size, wind strength, and/or sea state increase..."

Well, a good simple solution is just to move one piece of the rig at a time.  To recap, here is an earlier post of mine titled, The New Tack:

"This latest approach to rig shunting has ultra simplicity in its favor.  Simple is best.

The problem is simply that I can't always handle the whole rig, mast and sail, at one time in order to move it the length of the boat.  The solution is simple - move one piece at a time!

BTW, thanks to Craig O'Donnell and the Proa Page at his Cheap Pages http://www.thecheappages.com/proa/commodore.htmlfor his excellent article with illustrations about Commodore Munroe and his proas.

The Commodore used a bridle on the yard, allowing it to travel vertically while at full hoist.  His mast was fixed amidships and that geometry would have caused the heel of the yard to dip down into the water while shunting the sail if not for that bridle arrangement which allows for the yard to be lifted up as it passes amidships.

The permanently centered mast, however, IMHO is lousy - the sail sets down at too low of an angle.  But here comes the good part: I discovered that after securing the yard at the new bow, I can then tilt the mast forward to where it should be, and thanks to the bridle arrangement, the whole sail slides up to the proper attitude!

Commodore Munroe's 1900 proa.
The bridle can be seen at the top of the yard.
The mast simply needs to be able to belayed at the centered position while the sail only is shunted.  Then the mast can continue tilting toward the new bow.  I can easily move just the sail or just the mast, one at a time!

The mast is controlled by a single continuous backstay line run through a block at either end of the boat.  The line can be belayed when the mast is at center position. 

In order to shunt:  First bring the mast upright to its centered position and belay it.  Then free the sail from the old bow, swing it the length of the boat and secure it at the new bow.  Then tilt the mast the rest of the way forward.

It's all as simple and clutter free as it sounds...

BTW, also in use on the sail are "spilling lines" (a unique set of reefing lines which are used on traditional micronesian sails - more on this at another time). These spilling lines are utilized to brail-up the sail during the shunt.  Strictly speaking, this is not necessary but does help keep the sail out of the water.

The Shunting Sequence

Bear off onto a reach and then:
Free the mainsheet completely and the boat will lose way
     (one can actually backwind the sail to stop the boat quickly).
"Brail-up" the sail, (optional) this will help keep it out of the water.
"Center-up" - tilt the mast back to amidships and belay it.
Shunt the sail from the old bow to the new bow.
Tilt the mast to the new for'd position.
Unbrail the sail, free the quarter rudder and affix it to the new stern.
Sheet in and go!

I'll be getting photos and video of this as soon as possible.

More later...