The Concept Catamaran Project

Hi Bob,

Yes, thanks to you, both mast placements and size now look right for the C5. I have enlarged the base of both mast by a third to give them better strength. And yes, aluminum for the mast and perhaps Carbon Fiber (CF) for the booms -- although aluminum could also be used for the booms without much of a problem I believe.

How to attach the sail material to the booms is still uncertain -- creating a sail track or a simple rope and ring design are some options. An aluminum sail track may even give support to CF booms -- although I've never seen a Lateen boom use a sail track. The Sunfish Lateen sail rig uses simple sliding plastic rings like shower curtain rings to attach the sail to the booms. Any ideas?

Yesterday, I redesigned the cross supports between the hulls -- there are two main square telescoping beams at or near the base of the bridgedeck with three smaller beams that tie the hulls together. They all tie into support vertical beams of the keel frame. The idea that the bridgedeck of the C5 can be dismantled and the hulls can collapse into a 12' wide trailerable overland home is quite a concept -- and a challenge in design.

BTW -- your sea story about sailing your Super Snark with a Lateen rig reminds me of an event onboard the family 17' sailing canoe back in '65. It came with a Sunfish rig -- but with part of an old parachute as the sail. My brother and I went sailing in the bay just as an afternoon storm blew in -- and yes, like your experience, a rooster tail appeared as we rode the squall line.

The canoe also came with a rudder -- but I discovered that all you needed was a good paddle to steer with -- much like the old steering oars that once were used on early sailboats. Last year I refurbished that old canoe and built a temporary Lateen rig out of blue plastic tarp material -- using wood booms and the old aluminum mast from my old Snark sailboat. The whole design works great -- and on a calm day, a small electric trolling motor helps to speed over to explore the nearby mangrove creeks.

The Lateen rig design is a great option for any sailboat if one wants to sail safely in rough weather. Check out these links to some of my website pages and see how I've used it on some other multi-hull boats.

http://ourworld.cs.com/duanekmccullough/vst3.htm

http://ourworld.cs.com/duanekmccullough/tri4.htm

http://ourworld.cs.com/duanekmccullough/atlan002.htm


And again -- thanks for your help Bob.

Duane

 

C5v28

Ok -- after creating the C5 model using the free Anim8or CAD program by Steven Glanville, I splashed it into the $25 Virtual Sailor (VS) simulator program by Ilan Papini to see how it looks on the waves. The sails, rudders and helm move independently from the boat with great looking action.

I will now "paint" the model with some JPEG images and design more interior items such as a galley and computer workstations. Each VS boat uses a configuration text file from which it draws numerical data from so that the boat performs accordingly. VS is a great way to test any boat design if one has the time to learn the program and can create 3ds CAD models.

Check out these programs when you can:

http://www.hangsim.com
http://www.anim8or.com

I also found an interesting set of links about solar powered catamarans last night which some may find a good read -- check these out:

http://www.solarnavigator.net/
http://www.solarnavigator.net/solar_panels.htm

 

renewable energy

Hi Duane,

I have read about your concept.
I like the lateen sail solution. Do you have any scientific or other figures about it's abilities to point to windward?

I have serious doubts about the generator/electric motor configuration.
As a sailor, one of the most fun things in sailing is the use of mother nature i.e. the wind as a means of mobility. This is free, renewable energy at it's best.
I like the idea of an electric motor, since this is clean energy, as long as it's energy source is produced by renewable energy, not by fossil fuels.
This can be photovoltaic panels, windchargers, drag generators, ...
But definitely not fossil fueled generators.
The efficiency of an electric motor may be reasonably high, the transformation through a generator obviously isn't (to my knowledge, an efficiency of 60% is a wishful thought.
So by taking the intermediate step of transforming fossil energy into electric energy before you apply it as a means of propulsion, you are simply throwing away quite a big percentage of valuable fossil fuel.
To me that is only acceptable as an unforeseen error (even I sometimes spill some petrol while filling my outboard engine), but not as an installed system.
If you use fossil fuels (which I myself do, but only when there is no wind, or to get in or out of a lock), every care should be taken not to waste any more than the striclly unavoidable.
Explosion motors are transforming expansion into a rotary movement, which is then transferred to a propeller. To move a car, this may be an efficiënt way to make the weels turn. Thanks to rubber and it's intimate contact with a concrete road surface there is little loss from the rotating movement into the forward one.
A boat propeller is far less efficiënt.
Why that intermediary step to rotation is done to propell a boat, is a mystery to me, I simply don't know. Maybe for generating the spark?
It seems to me, that with today's knowledge in electronics and of virtually friction free materials, it should be possible to simply use this expansion to directly propell a boat (and create a very simple and reliable system at that).
In my simple mind it is only a question of having a controlled explosion - expansion, which would expel water out of an underwater vessel in a controlled direction, thus propelling the boat to where you want it.
The heat generated by the explosion would also benefit the expanding movement rather than having to be diminished by a mostly problem generating cooling system.
Of course a rotating propeller gives a smoother, constant movement whereas the system I have in mind would resemble more the action of a team of oarsmen.
I'm sure this effect could be eased out by a crafty technician.

greetings

 

Hi vouwcat,

Thanks for your input on this project.

The Concept Catamaran Project uses the Lateen Rig Design (LRD) not only because of the easy ability for the entire rig to fold down onto deck level without any stay rigging, but also because I believe certain issues like cost and safety can be important in a cruising boat. The LRD could be exaggerated for racing reasons, but I tried to place safety over speed in this project.

As to any scientific data that could prove how the LRD performs to windward, I'm not aware of any specific data -- but I do have empirical data that tells me it is the rig of choice for the project.

Regarding the idea of a nonpolluting motor propulsion system for boats, I see a day in the not too distant future that the prop method of pushing boats will seem very inefficient. Perhaps theoretical onboard electric gyro-propulsion systems (EGPS) will be used to move boats over the water in the future and not need to grab and push water like props do today. Imagine if two strong gyros could be taught to "walk" against each other in a timely fashion aboard a boat, wherein the boat, as a payload, would move progressively in a desired direction -- that would be a radical non-evasive propulsion system which could revolutionize marine transportation.

However, until any new theoretical propulsion system is proven true, boats like the Cat-5 should be able to safely and efficiently provide a way to cruise the islands.