Crab claw rig for Tiki 21?

[Scott Veirs]

Does anyone know of any attempts/tests of a crab claw rig for a Tiki 21?  Inspired in part -- I think -- by crewing on Aluna's trip out to Hawaii, Thomas Nielson introduced Mike and me to the idea as we were dreading building a 21.5' round mast out of square timbers (as called for in the plans).  

Thomas made this sketch a couple weeks ago...


...which I find remarkably similar to the first of Hans' drawings on the comment wall:



Glenn Tieman responded a few days ago saying he didn't think much of Thomas' sketch.  He recommended sticking to the plans, but unfortunately he didn't offer any brighter ideas about how/whether a crab claw rig could work.  What do you all think?

How cool would it be to have an efficient, family-safe, rig that utilized the 12-18' long, 2-4" diameter bamboo poles that are so cheap and prevalent here in non-Tropical Seattle?!

Fair winds,
Scott

[Boris Potschka]

Hi Scott,
under the following link http://www.multihull.de/story/st_panama1gb.htm you´ll find a very simple solution for a clab claw rig for a Hitia 17. It´s not the one you´re looking for, but it is still an interesting report.
By the way, I´m also planning to fit a crab claw rig on my Tiki 26, but I´m a real `crab claw novice´, so it will take a while to collect a the informations I´ll need.
Greetings Boris

[Boris Potschka]

Hi Scott,
I just found my study plan for the Tahiti Wayfarer, which I bought last year. James Wharram offers there three different sail plans for his double canoe. Maybe you can find some interesting informations there. The Tiki 21 is 66 cm wider than the Tahiti Wayfarer, but the boats have the same lengh.
Greetings Boris

[Scott Veirs]

Thanks, Boris, for the great leads. I've ordered up a copy of the Wayfarer study plans and will report back once I've digested them.

In the interim, here is a photo of Thomas Nielson's crab claw rig held temporarily over my Tiki 21 (during beam alignment last weekend):

(Click on the photo for more pix...)

[Scott Veirs]

And here are a few photos of Thomas sailing his 18' outrigger Ulua with the same.... Note how far forward the mast is stepped -- similar to the position of the mast shown in theWayfarer building plan photo.

Clearly, a question is: step it on the central mast over the planned dolphin striker, or up on the forward crossbeam?! Opinions?

[Scott Veirs]

This just in from Liz and sales *at* wharram *dot* eu:

"Yes, a crab claw sail can easily be fitted to the T21 and we do now sell a rig conversion package for this. It costs GBPounds 80.00 plus p&p (and VAT if applicable)."

Whoa! Maybe Thomas was right in postulating that James originally intended to put a crab claw rig on the Tiki 21, but shied away from trying to market such a "radical" departure from what was familiar to most (European?) sailors.

I can't find said package on the web anywhere, including in the wharram.com or wharram.eu domains, so maybe the master's ideas ore only now emerging?! As recently as 2008, the forums show Glenn and others discussing Tiki 21 crab claw rigs, but with no mention of this package.

I've ordered up a copy and will comment on their approach when the package arrives. Here's to testing a (first?) officially-sanctioned Tiki21 crab claw rig!

[Scott Veirs]

Well, the Tiki 21 crab claw plans arrived a while back and after digesting them I'm underwhelmed by the ideas bought by my 80 Pounds. They are simply a few pages and a sheet pulled from the Wayfarer plan book. In fact, you can see the edges of the label where they covered up "Wayfarer" with "Tiki 21." I understand that the two designs are similar in length, but I was surprised they hadn't taken the time to draw the Tiki 21 hull under the Wayfarer rig to show they'd taken some time to think about where the standing and running rigging would go.

The Wayfarer study plans were more thoughtful. The main sheet (ha!) shows a couple crab claw rig configurations. Also, the couple of Wayfarer build pages that came with the T21 crab claw plans have some nice ideas about how to step mast on a round cross beam (nevermind that the T21's are square!) with mast and spars build from saplings or bamboo.

I'm left with the impression that team Wharram hasn't experimented much with crab claw rigs on Tiki 21s, so we're gearing up to gather some real data over the next few summers. Below are the configurations we're considering (with total combined sail area in square footage; 208 sq ft is the standard Tiki 21 wing sail + jib area). Mike is excited about an unstayed mast centered on each hull (crab claw junk rig?). Scott wants to try a 12' stayed mast on the center of the center beam with jib and small main (upgrading to big main later if we like the small one -- and building it!). Thomas likes the big main version of Scott's plan, plus a little mizzen mast on a new aftmost cross beam.

Mike, Thomas, and I spent an evening brainstorming beyond that initial sketch by Thomas. The following sketch distills our favorite options, drawn to start thinking about the rigging implications for space on deck -- a key consideration, I think, on a 21' boat with short (8' to 12') masts supported by up to 4 shrouds/stays! (The two main/mizzen configuration pictured in the Wayferer study plans looks like a friggin spider web -- moving around deck would be a decapitation nightmare.)

Finally, here is a link to a gallery of more pix -- including the Tiki 21 sail plan co.... Let us know what you would recommend, base on pure aesthetics or practical reasons.

[Scott Veirs]

Hey Hans and Isabelle,

Will definitely go with your style of not overlapping the tack and the mast. Rather than a metal hinged set up like yours, though, we'll first try the forked limb over a round spar technique outlined in the Wayfarer plans.

I agree, cheaper isn't always better. We're mostly looking for an optimal solution that would be easier than the planned mast (and also inexpensive?) for others to replicate, particularly here in the NW U.S.

Cheers,
Scott

nice day "wakataitea" (tiki46) said:

hallo scott.
go for a one mast version and attach the point of the triangle on the base of the mast. use the space in the front for a jib. .... like we and hans did. our boats sail like a dinghy and yours will do it too. a 21 feet boat is to small for two masts. you will have no deck space anymore. i am not sure if a cheap solution is a better solution. use a crab claw because you like the performance. and you will see, it is reliable and a lot fun.

[Scott Veirs]

Still working on optimal combinations of mast (bamboo or Al) and sails here in Seattle.  Here's a couple links to recent experiences with the crab claw rig:

http://econscience.org/tiki/2011/09/26/breaking-bamboo-on-lake-wash...

http://econscience.org/tiki/gallery/?album=2&gallery=19

Our next steps are trying a Wakataitea style halyard system on our bamboo mast, getting a stronger (Al) 21' mast to open up more rig/rigging options, making a maststep system to experiment with mast position between center and forward beams, and making another crab claw sail with stiffer spars (wind surfer masts?).

 

 

[Scott Veirs]

Well it's been too long, but here at last is a history of the last few years of experiments with crab claws on our Tiki 21, Milagra. 

http://econscience.org/tiki/2015/02/15/performance-of-a-bamboo-poly...

The halyard and sheet attachments have worked well (no further breaks of the bamboo spars), and the polytarp and bamboo have held up.  The Race to Alaska is inspiring us to try out some new spar materials and make some new sails, so stay tuned for more data from the Pacific Northwest.

We'd love to hear from anyone who has succeeded in getting crab claws to point well (tacking through less than 120 degrees), particularly in light winds.  Follow our crab claw experiments on our race boat -- a Hitia 17 -- here:

http://searunners.net

[Steve W]

Hi Scott, I know it's been a while since you've been active on the forum, but I'd like to ask for the benefit of your experience with Crab Claw on a Tiki. I'm rebuilding a Tiki 26 and designing a Crab Claw rig. What's your take on the best way to install the rig?

My starter design is stubmast about 15' stepped on the forebeam, approx 220 sq ft sail with curved bamboo spars, hardwood yoke to the mast, but provision to experiment allowing the tack to go fwd of the mast. Possible jib.

Thanks for any help,

Steve