How do you design a Crab Claw rig for your boat?

[Budget Boater]

I have seen tons of photos and videos of various types of rigs on different types of boats, but unlike the junk rig Bible - Practical Junk Rig - I have yet to find anything that exists for the oldest known sailing rig, the Crab Claw. In fact, I have yet to find any "How to" articles for designing your own crab claw rig.

Anyone have any resources or ideas?

[Budget Boater]

Mathematically:

The Tiki 46 is 9 tons fully loaded. At 60sqm sail area, you have 30% less sail area than the designed 1000' sq/91sqm sail area. This equates to about 71.7' sq/6.7sqm per ton displacement.

The Narai MKIV is 7 tons fully loaded. My design has 600' sq/55.75sqm, or 13% more sail area than the designed 529' sq/49.1sqm working sail area. This equates to about 85.7' sq/7.97sqm per ton displacement, or nearly 20% more power to weight ratio than your Tiki 46.

I did draw the design to scale. Because of this, I do not feel that I will have any issue tacking since the majority of the sail area is forward of the CE. If I ease the mizzen before starting the tack, this moves the CE of the foresail between beams 1 and 2, which should be more than adequate to push the bow around. Will I be able to point to 45-50 degrees? Who knows, but my previous ketch/cutter rigged Tangaroa couldn't either, and my beloved Colvin Gazelle junk schooner certainly did not, and I could have cared less.

Since my foresail design is only about 11% smaller than your mainsail, I should be able to get by with laminating 1"x4s" to create 11m long, 3.5"/89mm diameter spars, which is exactly 11% less than your spars.

Thanks. You have helped more than you realize.

[Alex]

Hi BB - what changed your mind to a crabclaw?
Simplicity?
Very interesting that cc rigs can be smaller, especially as Wharrams are considered under rigged anyway.
Always thought Aluna looked under canvassed. Seems to go fine tho'.
Pity Glenn Tieman doesn't post more on his ketch rig here....
Tons of experience there!

[Budget Boater]

I'm cheap (and poor.) The Junk rig will cost at least 5 times more than a Crab Claw.

Alex said:

Hi BB - what changed your mind to a crabclaw?
Simplicity?

[wakataitea]

hallo BB,

 to tell you the truth. the CC on you tiki 46 is maybe 10% slower than the original tiki46 soft wing schooner. we sailed side by side with the original tiki46 ("grace" from south Africa) in Madagascar. it was 10-15 knots of wind and he  was under full sail and we too. we sailed as him up to 45 degree apparent wind. downwind, the CC is faster, the soft wing needs a spinnaker then to keep up with us. we tack as the original or even better through the wind. even at 3 knots of speed. ( of course, waves are the enemy for every tacking boat. after all this miles we did, i still love our rig. it is very good (with one reef in the mail even better) on our courses around the world. the soft wing rig is a very good rig too and i believe, that in stronger wing conditions, you have better options to change to different sail set ups and when it is really beating, i would like to have a soft wing rig.
yu have to be aware that the CC sail has a lot power and pressure on the back top area. even you reef, the pressure will stay there. we to not use our main in higher then 25-30 knots of wind. reefing it down as we do ( in second reef) will give you a very long slim sail. and still a lot pressure in the back....
 we sailed although side by side with the lapita boat. ( the same like glenn tiemanns design). they do well put shit in there pens when the wind gets strong. this CC sails are not real made to get reefed down in strong winds. we sailed with the navigators from the island Satawal on board our boat from island to island. this are great seaman and they know there trade. everybody is fascinated from there sailing experience. if you sail with them, you will fast figure out, that this guys are only sailing in the right time of the year. they never start a passage if the conditions are not suitable for there boat. and if the wind picks up to much, they take down the sails and wait and drift along... these flying proas can not sail like us and can not be reefed like our boats. they can ease the sail is a squall passing by but if shit comes up, they start praying and bailing water.
if you look up the lapita voage from james and hanneke, you will see that it was a battle most time of the trip. Klaus hympendahl, he was the skipper of lapita tikopia, is a friend of us and we talked a lot about the trip. he said that it was the worst trip in his life and he sailed with a monohull around the world already.
want i  want to tell you, is that this CC rigs are very sex and a lot fun. they work great (for us) but a total different story to any bermuda sail. the tiki 38 aluna has not sailed as much as hans or us with the CC rigg i just checked there blog and see that the last entry is DEC 2013...???? the same with glenn, we meet him in ponepe island in the north pacific. already hanging on a mooring since one year. this was 2012. he did not stop on may place since he left the USA and where is he now??? i thing he left to the Philippines in 2013. but not sure about this. talking to him told me, that if the real wind is coming up. he is heabe to under besan sail only and having a cup of tee till the wind drops....
we meet and sailed although side by side with this nice looking voyaging canoes (dieter paulmann project) in Tonga. they do nice and long passages too AND I RESPECT THIS A LOT  but when they go out , they change from there CC rig to a bermunda rig... what the fuck????? only the traditional painting and some exotic looking maoris and Tahitian guys with a nice counch shell around there neck is left on board...
we are not sailing like this traditional sailors500 years ago. we do not have the time like them and don't want to waste so many people an the way. We have better weather forecast. we risk more that this guys but use 1000 times better materials and navigation equipment.   we do not know how many of them died on sea when they had real winds. going from the west to the east. we only see the success of there great voyages.
for sure they did amazing stuff and i pull down my heat fro what they did and still do. especial the guys in the Caroline islands.
 we load up some pics of books we have on board. you will maybe find them in second hand stores.... this books are nice to look at but will not help a lot... all this wind chanel test are a story for it self. Chris Dowie ,  Marchaj or this german guy...  very theoretically...
sailing a dingy or and 40 feet boat is very different.

i can only tell you, that it will be the best for your boat to combine new and old. use the best materials, make it strong . use a sail ( jib) that pulls you through a storm. think about the strong wind performance more than the lite wind performance. forget about the costs. it will cot you a lot. it does not matter if it is a junk, crab or bermuda rig.
 ok, have fun ... hans

[wakataitea]

[wakataitea]

some more i found on my hard drive... A study from  Chris Dowie ...

i put it up on drop box...

A CFD investigation and comparison of 3 traditional Sailing Rigs wi...

or

crabclaw_analysis

internet is full of stuff... just google...

http://en.wikipedia.org/wiki/Crab_claw_sail

or

http://www.multihull.de/technik/t-slotboom_gb.htm

[Alex]

http://manuleleblog.wordpress.com/2014/06/30/tiny-islands-through-w...
Rather than reef, he takes the main down and replaces it with the mizzen - and replaces that with a smaller sail.
With mizzen only , it weathercocks the boat.

[Budget Boater]

Thanks for all of the information wakataitea.

Yes Alex, that is my basic plan. I will have an extra main and mizzen that will each be about 40% smaller than the working sails.

[wakataitea]

BB,

this will not work. i want to see you changing a set of sails in strong wind on a moving boat on the ocean. maybe you are traveling with 10 people on board but for 2 or 3 person, that's very very difficult. a 40% smaller sails sounds good up you still have to put the main (big)sail down, rap it up and put on the side and store it away. you have to have the smaller sail already attached to shorter spars.... or do you plan to fidle them on on he way????  it will take you at least 30 -40 minutes. you will drift around losing control and being a ping pong in the waves. fighting with all this canvas.

you shoud go out with a boat and change a genua1 against a storm jib in conditions of 20 knots plus....

the problem is, that is CC sails have all the sailarea in the back. if you do not drop it pointing direktly into the wind, it is a hell of a mess on board. you have to have leasy jacks and this will help you only a little.

it will work on a  drawing or  in the habour. on an ocean crossing you will have big trouble.

it sound for me that you have then only one ref option. that is not much too... don't forget that glenns boat is 30 feet, half the weight and a nut shell against a Narai. his sails are a little bigger then a "blanket".

have you ever though about when you plan to put a ref in a sail? at what strengs of wind. most boat do this at 18 knots (first ref). at 25-30 second. and 35 plus they use strong jibs.

please tell us how you disgn your sail plan to set up the canvas in a way that you still can sail propper.

running downwind with a jib is easy. but sailing in strong conditions and still be able to go windward because the deadly shore is getting closer is a differnet story.

looking forward to read your ideas...

 cheers hans

[Budget Boater]

Hans,

I certainly do not have all the answers. However, I have owned, built, crewed, and cruised on a multitude of boats with a variance of rigs:

Cal 30 (fiberglass): sloop (engineless)

Tayana 37 (fiberglass): custom triple headed cutter

Wharram Tangaroa (plywood): Ketch Cutter (engineless)

Colvin Gazelle (steel): Hasler-McLeod Junk schooner (10hp diesel)

42' Charter Catamaran (plywood): Rotating wing mast sloop

82' Charter Catamaran (foam core): Rotating wing mast schooner

90' Charter Catamaran (aluminum): Sloop

30' Baba (fiberglass): Cutter

Tiki 30 (plywood): Wingsail sloop

Morgan 38 (fiberglass): sloop

I have ridden out heavy weather on a lee shore, hove too, deployed and retrieved a parachute anchor, sailed through dense fog on a lee shore, taken two direct hits from tornadoes while sailing, and suffered through 10 hurricanes while moored. During the delivery of the above Tayana 37, I had to go to the end of the extended bow sprit to retrieve the Yankee, where every wave plunged the lower half of my body under the North Atlantic water in the winter.

With all of this various experience, I can tell you that I would never intentionally go sailing in heavy weather. And if I somehow find myself on a lee shore in heavy weather, I have made a serious mistake. As for when I plan to put a reef in the sail, I don't plan to do that. I plan to change the sails:

1. point to wind

2. release halyards

3. secure sails in place (main will land on a boomkin.)

4. disconnect sheets and halyards (attached via snap shackles)

5. attach reduced sails (on their own spars) to halyards and sheets

6. raise sails

7. turn to heading and adjust sheets.

This is not much different that dropping the main, and jib, then raising the storm trysail and storm jib on a sloop, which I have done in heavy seas in the Gulf Stream on a monohull, which should be much easier on a catamaran from my experience.

I am not that familiar with Glenn or his boat. However I am more familiar with Beat and his Tiki 38 Crab Claw rigged Aluna, which is far more comparable to the Narai in both displacement, length, and anticipated rig design. I have not read much in the way of complaints for his rig, which is little more than $200 white tarps laced to bamboo spars, and he has since crossed the Pacific with it.

Hans Klar, with whom I believe you are familiar, also seemed to have been successful with his previous Wharram Tehini with a similar Crab Claw Ketch rig.

Wharram also seems to endorse the Crab Claw Ketch rig design as well

[wakataitea]

hey BB. don't get me wrong. i am not questioning your capability of being an good seaman or boat builder.
 i am sharing my experience and concern about this CC rigg.
when you invited me to join you blog here i was number 26 i think. since then i am following your projects too.
 looks like you have way more experience with bad weather then i do. i life and sail the oceans  since august 1999 non stop.
i never counted really but i guess i have 40000 plus miles behind me.  so, it looks like we both know what we are talking about.

aluna: i followed this blog and we had email contact when he was planing to sail down to NZ. i never reed some ready detailed stuff about his CC rigg and its performance. actually i miss him on this page too. they all talk about there island experience but never about there boat experience. that's a pitty. even a container can make it down from north america to NZ with a 200$ sail.  i would love to know , learn, from his experience.
hans klaar: yes i know his guy and this very well. we are kind of brothers and believe me, i has a smile on his face every time when people think or plan about having a CC rigg. he is the CC rigg guru, thats for sure. there is nobody (still alive) who sailed more miles then him under a CC rigg. even the islanders in the not pacific do not have his knowledge.
his tahine was a nice looking boat but a shit rigg. i meet him in Tahiti when he came ones again after a passage, out of the bush with a bamboo stick on his shoulder and a machete in his hand. look were he is now. in all this years he developed a CC rig which last and has good performance. his tahine was a trail and error boat. 
him and us build the boats in the same time and we stayed in contact all the time. he helped us, working out the best performance of this CC rig, regarding to the size of boat we have.
the last to ontong javas and us have the exact same typ of CC rig. and if we throw or our miles together in one pot it will be close to 50.000 NM sailing a CC rig in open ocean.
james wharram wrote ones on his web pages about hans boat that they would never be able to build (design) a wharram cut this size with a CC rig. and they never did. vaka moana and his outrigger canoe are in a size of boat, were everything is possible.  you can see on the development on there page that it is not in there faivour that that wakataitea sails with this rig. they took us of his page because peoople start asking question they can not answer. anyway. they ignore your page too. a pitty.
this model is a nice pice and a had a picture hanging on my wall to when i build wakataitea. but look it is a model. look at the size of the top front spare.  but you will figure it out i guess.
maybe you will make it happen. and show us how it works best.
i would love to see more CC rig on the water.
 cheers hans

[Budget Boater]

Well, one way or another, I will get it rigged. If it works, great. If it doesn't, I will adjust it until it does, even if that means scrapping it and starting over at some point.

For now I am going to stick with the Ketch until something specific points me in another direction. If I eventually need to reposition it and add a jib, then I will cross that bridge when I get to it (that might even be before I launch it, who knows....)