Theta 26 Mono Rig on Tiki 26

[Jesse Walker]

Can a mono hull rig with the mast be used on a Tiki 26.

This rig for a Theta 26 Mono has become available at a very good price.

It would save me buying new sails for the Tiki 26 I am refurbishing.

My main concern would be the strength of the mast and how to configure the stays 

to handle the loads on a catamaran.

Could I run the back stay to the top of the mast and the second stay to the top 3rd

of the mast instead of using spreaders?

Or even better if anybody has a simple design to turn this mast into a rotating mast.

With Spreaders and stays running to the foot of the mast.

Would there be any serious performance gain on a Wharram by doing this.

Since they don't sail that well to wind. Would this extra complication be worth the effort?

The bonus to buy this rig would be all the extra's I get with it. Maybe even a spinnaker.

Please if this is a big No No, some body please let me know.

[Galway Bay]

Jesse - I sail a P31 not a T26 also I do not know the details of this rig. But I like the idea of used sails / rig. Only my working sails were new my mast and other sails were bought used and I have been very happy with them.

You will have to do some sketches. Monos tend to have taller rigs for the same length boat. You have I think plenty of wind in RSA so consider safety ie sail area x mast height should not be much more than present [if at all]. You may have to move the mast foot / tabernacle to balance the rig fore / aft. Also if the mast stood on a cabintop the boom may be very low .

I would copy the present staying arrangements but I would expect to be able to eliminate the spreaders, but without full details this is a guess. 

Hopefully some T26 owners will add more advice.

[boatsmith]

This can most certainly be done. BUT  The rig loads on a 26' cat are greater than a 26' mono. This usually means that the section is larger. Usually there will be a set of spreaders with diamond shrouds to help keep the mast in column. And usually there are upper and lower shrouds. Themast for a marconi rig will have to be taller to hang an equivalent sail area to the shorter gaff rig.If you are without suitable experience with sailing and rigging, this may not be a suitable change to make in the plans. jmo, David

[Ann and Neville Clement]

My own rigger/sailmaker agrees with what Boatsmith said above.  But you can look at similar sized old classic Wharram designs and look carefully at the pics and see what worked back then.   That would give you an idea of what you can and cannot do.   I really think you need a pro to help you with this kind of modification so the result will be safe.  Perhaps Hanneke and James would guide you too.  Keep us all informed of your progress and be sure you are safe!   Ann and Nev

[andy solywoda]

Ahoy Capn Jesse,

     It makes sense to recycle an alloy mast and good sails that approximate the sail area needed.  In my case, the original design was ignored and someone in the WIB Crealock office helped design a rig, but I suspect he was a monohull expert.  The boat had lee helm, which is bad.  I moved the mast aft a couple of feet (not a Tiki 26) to something I saw in an early Ariki cutter study plan, plus it was also depicted in an AYRS article about Wharram cutter rigs.  I added a headsail and the boat performed well.  With just the original jib as a staysail and the new mast position, the boat now has a lot of weather helm.  All this has to do with balance, and how you are going to sail the boat in different wind speeds. 

     Monohulls put their rigs forward a bit because they heel and the driving force of the rig goes outboard, tending to cause weather helm.  Moving the rig forward helps offset this, which gets pretty complicated when the angle of heel has to be considered, etc.  A catamaran is more sensitive to changes in pitch such as when the sails try to drive the bows down or when they try to cause the boat to squat. 

     If you go ahead and use this recycled rig, try to line up the center of effort of it to the center of effort of the design sail plan.

     Boatsmith is exactly right about shock loads on a catamaran compared to a monohull.  Going up in rig wire specification may be enough, but you have to also consider the tangs on the mast, etc.  Most monohulls are rigged very tight, tensions that are unwanted and impossible on a Wharram cat. 

     It is a good idea, if you go ahead with this, to make the rig adjustable to move the mast base fore and aft so that you can find the sail balance that suits you.  I like to have just a couple of degrees of rudder to counteract weather helm. 

     Lastly, you can go the archived issues of Sailorman and Seapeople and scan through them about any rig modifications. 

     If you can match the center of effort of the original rig, find sensible sheeting angles and places for your blocks and cleats, you probably will be OK.  Think through the operation of the rig, what they call ergonomics.  Ask "What if" about loose sheets, an unplanned gybe, sail handling in high winds. 

     A lot of thought went into the original design, and it seems like all the problems occur when we change things.

    

[Jesse Walker]

Thanks for the feed back. Seems the consensus is stick with what I have.

The slight saving in cost is not worth the risk and extra effort.(re-stepping the mast)

A new set of sails will just have to be my Christmas present.

Last night I spoke to our local rigging expert and he owned a 40 ft Wharram in Madagascar.

He said it was a beautifully simple rig and never had any problems and even on a boat that size he had no winches.

He has sailed many boats and done countless deliveries and races.

[paul anderson]

mate i think you have made the right decision, the timber masts are not hard to build, just source good timber, ask me why... These boats are simplicity personified, that includes the rigging, sails, why not consider dyneema rigging too as you can do it yourself?

[Jesse Walker]

Hi, I'm back making some good progress, I'm still a way off from putting up the mast. However I would like to put this out there so long.  How do I work out how long my fore-stay must be?

I'm sticking with the original rig, since I have the mast, gaff and roller furler but the cables running to the bow anchor point's is missing.  I need to know what angle the mast needs to be.

Or even better the distance from the top of the mast to the bow.  (I have no plans)

Then I can put the mast up tie it in place and then get the cables made to match.

[kim whitmyre]

Use a tiki wingsail...Tiki 26's go to windward just fine, Jesse.

[paul anderson]

4 degrees.The length of the forestay is 7.62 m. This is the length from swage to swage and doed not include the loops.The mast loop is 56cm.

[laurent]

tsss tsss ... here is the solution :  http://www.leboncoin.fr/nautisme/561488552.htm?ca=13_s

i cant download the photo , the announce will disapaired when the boat will be sold 

i called the owner , he explained me the tiki was used in a program of reserch and development on the kite sail

applied to boats . It is very interesting .

And very good price ...