CNC Plans not Included

The rig was designed to a max load of 18 tonne meters.
Your 60ft cat @ 12 tonne displ will have a RM of approx 54 tonne meters so its going to need to be alot stronger and alot more expensive.
The ballestron rig will be heavier than a standard rig and you will have also created many months more work for yourself.
Dont be afraid of sailing- its a peice of cake

 

Im not scared of sailing even though the most memorable sailing experience I have is hanging off the back of a boat like a piece of bait, acting as the rudder since ours was broken, in half moon bay Saudi Arabia lol!!

I hope I can keep it under 12 tons. My boat is going to be very much like the MC2 Banuls 60 with even less fitout so 9 tons light ship will be my goal. My hulls can be narrowed another 3-6 inches without affecting current layout.

So far, from what I am seeing, material wise, I should be able to do quite a bit of carbon. The mast, bulkheads, beams, daggers and rudders for sure, the roof and roof supports as well.

How is RM calculated?

The MC2 60
Dimensions
LOA 18.28m (60ft)
LWL 18.28m
Beam 8.60m
Draft 1.40/3.20m
Displacement (light) 9.3t
Displacement (max load) 11.5t (max 100% RM) 13.5t (CE)
Bridgedeck clearance 1.25m / 1.10m
Mast 10m2
Mast Height 25.10m
Mainsail 118m2
Solent 56m2
Staysail 35m2
Code 0 120m2
Gennaker 165m2
Asym Spin 235m2

 

The rig is designed to the max displacement of the boat - not lightship.
For a cat it can be simplified to; RM=0.5*max displacement*overall beam

The other problem with aerorig - which puts off most propective buyers - is that it cant be easily re-rigged if you want to change the rig back to a traditional rig. The reinforcing in the boat is all for compression in a normal boat wheras its all in bending for the aerorig. So you cant just change your mind at a later date and drop a normal rig on it - the structure isnt there for it. This puts off most buyers and leaves you in a very small niche. The Kurt hughes boat we talked about earlier sat on the market for years... If the aerorig has a problem and needs repair - your up for a very expensive excercise unless you do it all yourself - again this puts off prospective buyers.

If you dont want to sail - then why not build a full solar power boat? Massive full solar array with fold out arms which essentially doubles the solar area from stern to bow. Spend the extra money on the solar and batteries not a rig? Motor everywhere...? Prove it works, and youll have commercial buyers lining up everywhere...

 

Thanks for that formula, I was typing same time you responded. No I don't believe solar can do it alone.

Good points! The aero rig also lacks beauty. I can see it on industrial ships but it does seem out of proportion when you put it on something sleeker.

You know I keep on thinking that unstayed masts like WylieCat uses and stayed masts should be combined. So far as I understand it the only complication is hooking up the stays? I have the structural support for downward force and I have the bury, building a stubmast or hole with bearing at top of mast beam would not be difficult.

The stays would stay connected up the mast and I would release them at deck level. They would run down the mast and clip along the side of my roof. It's not like you are going to be connecting and disconnecting them that often.

What I like about this idea is that most of the time you can run unstayed with only the main sail. I have read so many threads where everyone is reefing and alert for that sudden gust of wind. Who needs that, you can go faster safer and be less tense if you run unstayed. Most of the time ocean conditions aren't going to allow full speed comfortable travel anyway.

You get the peace of mind from many standpoints mentioned, less wear and tear on the stays, no chaffing, no need for spreaders (I don't think) and yet when you need to run upwind or want to launch a spinnaker, it takes a couple of minutes to connect the back stays.

An extra connector a foot or so above end of stay could be used to winch from. That is not complicated to me. Okay it costs a bit more but not much more considering you now have so many more benefits!!!

I tell you this is what makes the most sense to me.

 

Lowering one's rig height makes a LOT of difference in overturing moments, and can create sail sizes that are more easily handled. Divide those big sloop rigs down into 3 sails in a ketch arrangement. Have a look at this arrangement, and take note that I included the option for the owner to revert back to a sloop rig if he ended up not liking the new design. Also note the difference in the height of the two rigs,...the original design and my new suggestion.

 

Hi Brian, 20 foot difference! That is quite a bit! That means more complexity though, or not? What about shading of my solar roof? Have you ever seen temporary back stays used on an unstayed mast?

good info I want to refer back to
What about free standing rigs? http://forums.sailinganarchy.com/index.php?/topic/129717-what-about-free-standing-rigs/&page=2

Backstays to the Future http://www.cruisingworld.com/how/backstays-future

Rig for a Staysail http://www.cruisingworld.com/how/rig-staysail

 

Seems like another completly at odds design scenario- why build a 65ft high performance trimaran then put a low aspect ratio rig on it?

All the exepense and effort to build such a beast with huge righting moment, high build complexity and little accommodation space. Great for performance - why ruin it?
If you dont need such performance and put a low aspect rig on it- why build a trimaran in the first place?

 

There are some folks that are just predisposed to the trimaran form rather than the catamaran. This fellow figured he could build a big tri and get some sort of the accomodations offered better by a big cat. He was not into racing or big perfotmance.

This vessel was going to be a boat primarily for he and his wife to sail live aboard a substantial portion of the year, and that BIG, TALL full batten mainsail was a REAL concern of his. I gave him the same sail area in a much shorter height rig, with 3 sails that all roller furled. With that original rig he was going to most likely have to have crew onboard, which he was not excited about.

I've often though that were I single-handling a big multihull vessel in the ocean, I would prefer the trimaran form. It really can give you much better warning as to being overpowered than the cat form does.

As for performance do you really think the lower aspect ratio vessel is going to be that much disadvantaged to tall sloop?, .... perhaps upwind, but doubtful on reaches and running. In fact you just might keep more sail up and maintain a higher average cruising speed if you were less concerned about the overturning moments of that big tall rig.

 

More complex?, not necessarily
Shading, I don't have an opinion

I used a few unusual rigging stays on this freestanding design concept....
Dynarig Motorsailer

 

I bet it was a concern Brian That main sail as designed is enormous...

I just dont understand the owners needs and wants for a big trimaran that uses a low aspect rig... If he didnt want performance he could have build a much more comfortable boat for less effort and expense, and using a low aspect rig for ease of handling/less stress... why you build an enormous trimaran to meet those goals, performance not being one of them, is beyond me? thats all im saying...

 

So it's been done then? Your explanation on your drawing was very informative.

One sail with over 2000 sq ft. That would be all you need I would think )) why haven't more Dynarigs been used, is that the realm of mega yachts and super deep pockets? I like the idea of 2 pivoting, asymmetric centerboards on your motorsailer. If it can really achieve those speeds under sail that is quite impressive.

 

Yep, i would also like to see the cost of such a rig including its required structure on the boat to hold it.

A rig to propel this boat at 48,000lbs at 20 kts - under sail alone, call me a skeptic...

 

I was VERY fascinated with the development of the 'modern Dynarig' on Maltese Falcon. I followed and contributed to at least 2 long forum discussions on Maltese Falcon. I had hopes that some financially well of client would come along that had an interest in going forward with this much smaller vessel employing a Dynarig.

I also was thinking of some alternative designs to build a Dynarig type rig somewhat more simple and less costly than the one on MF. here is one subject thread were I started making some contributions:
Square rig variation
I developed some sketches , but never posted them as I wanted to refine them a bit more. Then I got distracted onto other subjects so never got around to refining sketches nor posting them.

John Shuttleworth designed and engineered the support structure on interesting free standing mast on a 50 foot cat. I incorporated a portion of that support structure on my Dynarig cat design:


Here is one posting I made to that square rig variation discussion:

 

Here is another excerpt from that subject thread. Have a look at the Youtube link !

 

I saw that video, it's a beauty of a sail. Do I understand correctly that each section of the Dynarig furls into those cross arms?

some cool stuff coming