In a way, this project is like an open-ended catamaran design tutorial because many views are open to suggestion and subject to change. The final version may be different from this account and also include more design concepts from named persons who care to share their experience with this project.
At the completion of this project, I would like to finalize a textured 3ds model of this concept catamaran design using a great free CAD software program called "Anim8or" and post it at my website. For those who would like to virtually explore this sailboat when it becomes finished, there exist a computer simulator program called "Virtual Sailor" in which any user should be able to examine the catamaran model in a very realistic real time aquatic environment.
Before we study the basic three design areas of a catamaran sailboat, a quick overview of myself and other sailors that may be involved should be understood.
Experience Sailors
For nearly three decades I've sailed aboard about a dozen different catamarans ranging from the classic 14' Hobie to a 62' Peter Spronk offshore cruiser. As an active boat Captain, I see new catamaran designs sailing the Intercoastal Waterway almost every week -- and as a sailing instructor at a local resort, I use the latest Hobie catamarans during lessons.
I once lived aboard a wooden 37' Chesapeake Skipjack ketch at anchorage for about 14 years and have been responsible for a fiberglass 20' Mirage sailboat kept offshore at anchorage since the late eighties. I have read many catamaran sailing adventures in books and magazines -- such as Cruising World and Multihull magazines, that reveal the latest catamaran designs in the market.
My younger brother has owned a 27' Stiletto Catamaran for years and my older brother owns a 45' Corinthian power fiberglass catamaran -- which is a popular dive boat design here in the Florida Keys and other shallow reef areas. For nearly two decades, both brothers have also experienced many types of rental marine craft as owners and operators of separate watersport concessions at major resorts. And for nearly four decades, my father has always had a family power boat in which to explore the waters of Southern Florida.
I know of friends who have lived on multi-hull sailboats for years and one that is currently a salesman at a major catamaran brokerage company in Ft. Lauderdale, Florida. Another longtime friend -- who owns a local boatyard, has taken some courses from the Westlawn Institute of Marine Technology and, although he is not a certified Naval Architect, I remember many of our conversations regarding boat designs wherein important concepts in marine engineering were reviewed.
For the last few years I have corresponded with other friends over the Internet to learn how to build textured 3d computer models. One particular good friend from the United Kingdom with offshore experience is known for his quality catamaran models -- in fact, it was an email to him that inspired this Concept Catamaran Project.
3 Basic Design Areas of a Catamaran sailboat
There exist three basic design areas of a concept catamaran that we will cover in this project -- the hull & rudder, the bridge-deck & cabin, and the sail & motor propulsion units. The following design concepts include views that favor my opinion -- but are not final because new concepts are always being discovered.
The friend with Westlawn experience once suggested that a boat design should not be limited to the handling characteristics of certain building materials -- for example, the designer should not restrict the design to conventional forming materials like wood, metal, fiberglass or even reinforce concrete, because most all materials can be modified to accommodate a design. In other words, don't make the design fit the building materials -- make the building materials fit the design.
Having said that, I still like the ideal of using a common building material characteristic -- such as plywood or metal, to build a simple catamaran design with flat surface areas because building a complex curvature hull is very difficult to scale, translate, replicate and manufacture. Using complex curvature hulls in any marine craft can be good when built from fiberglass or other plastic-like materials -- including reinforced concrete, because the perpetual curvature of the hull shell spreads surface loads evenly.
However, startup cost to build the mold and the general complexity of the design can be too great for most builders with low budgets who only want one copy of the boat. So, in trying to keep this design project as simple as possible and to keep cost and building time down, the minimal flat surface areas at the right angles will be preferred as opposed to complex curve surface areas favored by filler materials such as fiberglass or reinforced concrete.
The classic Wharram catamaran design is a good design shape made from plywood that has large flat surface areas -- but would not be as good if made in fiberglass because the perpetual surface curve form needed in fiberglass construction design does not lend itself easily to large flat surfaces. Although very popular in small boat construction, fiberglass material is a relatively strong substance with low maintenance that can be formed to fill many shapes -- but is not always the best material for building boats.
An unconventional method of boat construction using scalable tubular spars as framework for fiberglass cloth skin is also a unique building concept that could be used in this design project -- as are perhaps a few other new building concepts -- but, for now, let's stay with known conventional building construction methods that use a collection of composite materials and focus on the best design based on our years of experience.
Before the three modular design areas are presented in detail, let's also choose a length -- say, just big enough to call home (with accommodations for visitors) at between 40 to 50 feet. It would be nice if we could develop a simple scalable modular design that could be dismantled and transported on the road if need be in several major parts -- but strong enough to sail safely into a stormy inlet on a windy day without falling apart in strong swells or surf.
Designing a catamaran layout wherein the need to accommodate flexible joint areas that come apart during breakdown and assembly is harder than designing a fixed version that "stays in the water" all the time, but in choosing a transportable modular design, the craft can be much more versatile in the way it is used as mobile home.
Even if our catamaran design is only assembled together once in its lifetime, having the ability to transport a modular home overland by road great distances or being able to place it into a standard seagoing shipping container, is a design option I believe worth attempting because sometimes people like to move their homes to places not easily attainable by water pathways. Moreover, some boat owners like to visit or vacation to areas not easily explored with a large liveaboard catamaran and would like the option to store their homes ashore safely and economically.
Also before we explore these three design areas of our catamaran design project, I should make a quick comment about the need of reinforcing certain stress joint areas where the bridge-deck meets the hulls. Perhaps the most difficult design challenge in this project is to make a strong connection that is simple to put together and take apart for overland transportation -- yet has minimal flexibility when in use.
Because a catamaran design is trying to bridge two hulls together over open water, flexing will happen no matter how the boat is built -- so, locating the major stress joint areas and understanding how to restrict their flexing under stress is important in our project.
1/ The Hull & Rudder
First up is the hull & rudder design. In considering the hydrostatic relationship between hull and rudder surface areas -- together with locating the center of lateral resistance with respect to the center of effort within the sail plan, a simple design that provides for good buoyancy using modest curved flat surface areas to form a six-sided "V" shape hull bottom profile is better in my opinion than a rounded "U" shape hull bottom profile with complex curve surfaces.
Also, by making the hull bottoms out of flat surfaces instead of just rounded tubes of buoyancy, they can become foil-like to provide lift and should not have a tendency to "squat" down in the water when traveling fast . A "U" shape hull profile may give better buoyancy and draw less water at anchor than the standard "V" shape hull profile, but the planning abilities of flat surfaces on the bottom of a "V" shape hull design version should be able to perform better under sail.
Regarding the best way to steer our concept catamaran, let's review some popular designs -- such as the rudder layout option used by small Hobie Cat sailboats. They use the removable swing rudder concept -- which is nice because, if the boat is ever beached in shallow water or run aground in reverse, the rudder can adjust or flex enough to keep from breaking. Whereas a fixed rudder post design that protrudes from the stern bottom area found on many charter and luxury catamarans can be exposed to strong forces that can seriously jam the steering. If the transom was designed to accommodate a removable swing rudder -- similar to many small catamaran sailboats, perhaps a "flush" transom layout would be a safer design than the popular "stair transom" designs found on many new cruising catamarans.
Now I should add that the popular "stair transom" design found on large catamarans do provide for a great way to access the water from the rear deck area of the boat -- and the extended transom design also helps in better pitch stability within heavy seas, but the idea of a fixed rudder post protruding from the bottom found on these transom designs has other problems. They tend to snag fish trap or anchor lines -- which can be dangerous in certain situations. However, before we decide on a design, perhaps we should study the history of rudder designs on boats and learn how they were developed over time.
Actually, before rudders were invented, early boat designers used a long "steering board" device that once was attached to the outside starboard stern area of the hull that trailed a flat area of wood which could rotate with the axis of the board and turn the boat -- hence the word "starboard" or right side of the boat, leaving the left side of the boat free to load cargo when in "port".
Maybe just one well designed rudder board station mounted on the starboard transom would work. I was told once by a catamaran racing expert that sailing with one rudder up causes less water drag -- yet still provides good steering off-wind. Perhaps an asymmetrical steering system could provide a simple way to control the catamaran instead of making a symmetrical set of rudders and tillers. On the other hand, two rudders are very useful when sailing to windward on a catamaran because they also act like underwater wings and help prevent sliding to leeward.
How would you design this section of this project?
The hull decks should accommodate some support space for the bridge-deck and provide for a strong rubrail area to protect the boat from hard docking. Some flat deck space next to the bridge-deck area would allow important walking space around the cabin and should be high enough to take big waves without swamping. This concept -- together with the idea of 6.5' headroom within most of each hull, suggest a high freeboard to the design project that can result in some windage problems during stormy weather.
Unlike small boats that are beached all the time, larger boats have expensive bottom paint to consider and are not designed to touch bottom -- but because they do go aground sometimes, a good hull design should at least consider the safety aspects of how the bottom is shaped if or when it goes aground.
Our hull bottom design could have a broad "keel-wing" shape area so the sailboat would not slide sideways while climbing to weather -- or it could have an adjustable "wing board" located within or outside the hull to perform the same action, but for reasons of simplicity, let's look at the idea of avoiding any protruding wings and go with a small "fin area" near the stern which minimizes the boat from "crabbing" or sliding off wind while sailing upwind. Although this design choice will not help the boat during tacking by being able to pivot on a "wing board" -- but, if beached or run aground by accident, there is no protrusion from the hull to get caught on the bottom and cause more serious structural problems.
The width concept of each hull -- as well as the general beam of this concept catamaran will be discussed in a moment when we better understand the overall proportions of the project.
Shape of the bow design has three primary options -- an upper forward line, an even "flush" line, or a lower forward line.
The upper forward line design can be quite a safety concept because if the boat is ever running fast in dark weather and hits a hard object -- like a log or a cargo container, it has a better chance than the other two concepts of rising over the object without major damage. The upper forward line design also allows for a little more deck space -- and a better turning radius in small harbors which can be helpful in close maneuvering events.
The even "flush" line or lower forward line designs will give good longitude stability and better course control in cruse mode -- which can add to safe handling over time, but, like I said earlier, are more dangerous when sailing fast in dark weather.
Some new and very large power catamarans now sport bulbous bows that apparently seem to help carry the main bridge-deck out of the drag of big waves by providing more forward buoyancy -- but, it seems to me that an extended bow design would be more of a liability than an asset for reasons already explained.
How would you design this section of the project?
2/ The Bridge-Deck & Cabin
The bridge-deck & cabin design can have several aspects from which to consider. There are four basic views -- ratio of length to width, the clearance between deck and water, the height of the deck cabin, and the connection mount area to the hulls.
Knowing this, experience aboard my older brother's 45' Corinthian power fiberglass catamaran -- which has a 14' wide bridge-deck covering the entire hulls from stem to stern, has shown some relevant views to this subject. Because the Corinthian has a very narrow beam ratio to length proportion when compared to conventional sailing catamarans, it would not be the boat one would want take on long ocean voyages because of the poor latitude stability in big waves. However, it has great utility value as a working boat on shallow waters in fair to moderate weather conditions.
In deciding on the best or safest ratio of length to width regarding the bridge-deck & cabin area and the hulls, I have discovered a mathematical formula found in nature called the "Golden Section" or "Golden Mean". It measures at the 5/8 or 61.8% proportional mark of the cord and, take my word, it can be used to design nearly perfect designs with a very strong balance between subdivisions within any object. Take the time to read up on this very important proportional concept when you can -- you will be amazed how it is found throughout nature (the number 5 is 62.5% of the number 8 -- however, the more detail number value of 61.8% is closer to the true value of this important concept).
Anyway, using this 5/8 proportional concept, if the hull length is -- say 48', then the bridge-deck length could be measured at 30' (48 X 61.8% = 29.7) -- while the width could be measured at about 18' (30' X 61.8% = 18.5). This formula gives the value of about a 18' beam to a 48' catamaran.
Now, if we choose a forward bow line design, the deck and waterline length of our hulls will be different -- and because the keel cord line between the hulls measure differently from the total beam of the catamaran, some skewing of this 5/8 ratio proportion concept will take place. Moreover, because the width of each hull will effect the total beam formula if the 5/8 ratio is to be kept -- the final proportional numbers are not yet known.
Next is defining a safe clearance between the waterline and the bottom of the bridge-deck. If we want good 6.5' headroom within the cabin that sits on the bridge-deck -- and also want good clearance in rough waves so the bridge-deck doesn't keep banging into and over large waves under sail, then deciding on a safe distance between the waterline and the bottom of the bridge-deck should give us the general height of our catamaran project.
So -- let's say the bridge-deck cabin is 6.5' tall and the clearance under it to the waterline is 2.5', then the general height our catamaran project would be about 9' above the waterline. With roughly a 18'beam and a 48' overall length, is a 9' high bridge-deck cabin above the waterline safe enough in very rough seas?
Should there be a watertight pathway between the bridge-deck cabin and the hulls? Do we even need a permanent enclosed cabin on the bridge-deck? How exactly does the bridge-deck attach to the hulls safely as a removable module? Is a 18' wide bridge-deck too wide for long distance overland transportation -- and if not, can it be subdivided into two smaller modular sections? If the bridge-deck covers only about 5/8 of the hull decks -- how are the remaining hull deck areas connected together? Can the bottom of the bridge-deck be designed in such a way as to part a high wave efficiently without causing too much drag?
Of course some of these answers depend on the severity of what is considered a very rough sea. Trying to find the best compromise in nautical design is what this project is all about.
How would you design this section of the project?
3/ The Sail & Motor Propulsion Units
The propulsion units of any boat includes sail and/or motor units that provide movement by the action of redirecting energy. Motor propulsion units can get very complicated in how they work in pushing water to move a boat, so let's start with the sail propulsion unit -- which can also get quite complicated in how it uses the torque-pushing power of the wind as energy to move a boat into the wind.
Many light gauge built sailboats like sport catamarans use the sail rig to tie everything together and add stability to the craft -- but in general, a good boat design should not have to rely on rigging cables to keep its shape. So, perhaps the sail rig design in our project should be self standing -- or at least not rely on too many stress points to support the mast.
Although there exist many ways to reach up from a boat to support moving sails, it seems that the most popular design of choice today is to use the fully batten sloop sail rig. The batten concept within a tall sloop rig that sports a roached mainsail can be traced to the Oriental Junk rig that once used bamboo battens to add rigidity to the sail -- and world sailors can thank the Hobie company for first developing this concept on their catamarans about four decades ago.
World sailors can also thank Mr. Marconi -- who invented transatlantic radio communication with the help of his tall metal radio towers supported by steel cables, because all tall modern sailboat metal mast that use steel support cables follow the same support structure as his metal radio towers. In fact, the classic Bermuda rig is also referred to as a Marconi rig if the mast is made from metal.
Over the years there also seems to be a challenge among boat designers to build the highest sail rig possible because the high-aspect ratio concept of the popular design captures the torque-pushing power of the wind very efficiently when compared to shorter sail rigs. Moreover, the fully batten sloop sail rig is relatively easy to reef if strong winds are predicted in time -- and the sloop sail rig uses forward support stays for other sails that can be changed to accommodate weather conditions.
However, high sail rigs come with high cost to the boat design -- not to mention the monetary cost involved or other cost factors soon to be covered. Accommodating the stress points that support a tall mast aboard a multi-hull sailboat can significantly modify how it is designed.
Now it is true that some motor versions of certain popular catamaran designs without a sail rig look much like the same boat design with one -- but, unlike most mono-hull sailboats, many sport catamaran designs need their sail rig to safely hold their wide shape together during operation in rough seas or they will flex too much and come apart.
Another cost involved in living aboard with a tall mast is the threat of lightning strikes. Yes, that very dangerous electrical event that happens near tall spires during stormy weather cannot only kill people and destroy property, but can make for a very scary time aboard during stormy weather. The incredible atmospheric concussion and electromagnetic pulse that a tall mast invites during bad weather can be very costly indeed. Just the threat of them can change some attitudes about calling a sailboat a home.
So, instead of just choosing the conventional sloop sail rig design that needs support stays or cables to stick on our boat for propulsion, let's explore other sail rig options. Perhaps instead of trying to build a high sail rig that towers extremely high above the sailboat to capture the torque-pushing power of the wind, maybe we can modify a simple sail rig design that needs no stay support and can still efficiently use the energy of the wind to safely drive our concept catamaran.
In my opinion, the sail rig design that is capable of meeting this challenge is the first sail rig design in history that allowed sailboats to sail up wind efficiently. The Lateen sail rig used by the Phoenicians to sail great oceanic pathways is a design that modern sailors should know more about.
Now I'm not suggesting that the same triangular Lateen sail rig found on a small Sunfish sailboat can be enlarged to fit a large forty-something foot sailing catamaran without modifying something -- but I am suggesting that it is a design that can be used efficiently and safely if redesigned properly.
What a catamaran sailboat with a Lateen rig may lack in speed when compared to a tall conventional sloop rig version of the same sailboat, it may make up in cost and safety -- besides, most any multi-hull sailboat is still faster than a comparable mono-hull boat. If I could move aboard a new 48' catamaran and save about half the cost of a conventional sail rig price while only loosing a few knots in speed, I would do it.
If we were designing a small catamaran and enjoyed great speed while "raising hull" occasionally, I would go with the tall conventional sloop rig design, but this project is trying to build a safe sailboat that holds lots of "stuff" that makes a home a home -- and it would be catastrophic if we were to capsize. So, perhaps a huge topside propulsion unit that adds unnecessary risk is -- well, unnecessary.
Now -- of course, it would be much easier for some who have lots of money to just go out and buy "off the shelf" conventional sloop sail rig parts that match and stick it on this catamaran design project -- but let's try to learn more about how old simple sail designs can be made new again.
It is believed that the very earliest catamarans used Lateen rigs to sail great distances throughout the Pacific Ocean. These offshore catamaran designs were apparently capable of long windward voyages that safely delivered cargo between many tropical islands. All large proa's of the South Pacific used the Lateen rig -- and there is a sailboat term referred to as a "flying proa" wherein such multi-hull watercraft were able to sail extremely fast.
In fact, the very first American navel police action against the Barbary Pirates off the north coast of Africa used Lateen rigs on their boats to sail the Atlantic Ocean. And like I said, the Phoenicians -- the inventors of the Latin Alphabet, used the Lateen rig to power their boats.
It is interesting to note that the first letter of the Latin Alphabet is shaped like a Lateen rig design -- perhaps these historical seafaring natives believed the arrow shape of their sail rigs represented a powerful aeronautical design concept of how to capture and use natural wind energy. Perhaps the Phoenicians used this important arrow design concept as the first "letter logo" symbol of the Latin Alphabet to help teach others the science of aeronautical design. Are the graphical logos of NASA and "Star Trek" related to the aeronautical design concepts found within the historical Lateen rig?
What makes the historical Lateen rig so interesting is the simplicity of how it redirects and twist wind energy into pushing against itself. Together with the lateral force resistance movement of the boat shape through the water, the sail becomes a foil to funnel wind energy out of its normal path and creates a high pressure zone area of compressed twisting air on the windward side that pushes against the sail foil at relative angles toward the source of wind energy while trying to fill the low pressure zone on the leeward side.
A conventional sloop rig with a tall mast does much the same -- however, the spinning high pressure area is much longer in shape and is allowed to push at angels higher along and near the mast during upwind sailing -- thus giving more leverage to the lift action. This spinning action of pushing energy that is trying to fill the low pressure area out of the direct wind path on the leeward side of the sail can turbo-lift the propulsion unit of the sail rig in ways not fully understood by many sailors.
There even exist a theory that when sailing downwind some sail rig designs can generate an invisible column of twisting air that can "grab" more wind energy beyond the sail area and take advantage of extra turbo power to go faster. In aircraft wing dynamic concepts, sometimes this invisible vortex wake of air that projects from the wing tip becomes visible and are called "wing-tip vortices".
Because the mast design of a Lateen rig is much smaller in height and needs no stays, it can be removed easily and stored on deck while maneuvering in waters with low bridges or foliage. If one is expecting a major lightning storm, the quick ability to lower a smaller mast is also an advantage.
And speaking of mast and lightning events again, there is a new engineering concept that has been understood for some two decades regarding how to prevent -- or at least not to invite, a lightning bolt to a sailboat. Unlike the conventional method of creating a lightning rod down a mast that allows for a pathway from mast to ground/water connection, this new concept supports the idea that a "brush area" of stainless steel wires or carbon fibers mounted at the top of the mast will not allow the bolt to focus and will disperses most of the electromagnetic charge from the boat mast -- which therefore will prevent Mr. Sparky from visiting the boat. This concept has worked on my 20' Mirage sailboat for over 15 years -- and it sits out by itself away from other sailboats near a Florida anchorage which is a realm known for many lightning strikes.
If one is expecting a major storm event while flying a large Lateen rig, one could simply change to a smaller sail stored nearby on deck in a matter of a few minutes -- in fact, it may be possible to have two Lateen rigs aboard a catamaran. One could be large and the other small -- and because a catamaran is a wide boat, these rigs do not have to be restricted to the bow and stern axis. If two Lateen sail rigs were placed on each hull there would be a need to prevent the booms from colliding -- so some kind of "boom bar" could be designed that would synchronized movement between booms.
However, before we get too unconventional with the use of Lateen rig design, let just place the largest one we can safely use somewhere forward near the front of the cabin on the bridge-deck -- relative to the boat's center of lateral resistance, and see how that looks.
Also, lets modify the standard "Sunfish" Lateen sail rig design by subtracting some of the triangular sail area that lies between the outer boom ends. In doing this modification we have created an arrow or claw shaped sail that allows for a better balanced shaped pocket of high pressure area within the windward area of the sail which will push the rig better toward the wind source. Without this modification, the high pressure pocket of air created by the sail foil will be distorted by the unnecessary broad area of trailing sail material along the leech line that can interfere with the turbo-pushing power of the high pressure area trying to meet the low pressure area on the backside of the sail.
While speaking of areas that interfere with sail performance, the Lateen rig does have a "blind side" aspect wherein on one tack it works great while on the other tack the mast blocks the sail from forming properly and therefore does not perform as good. While this asymmetrical performance problem exist during short tacking maneuvers, during long tacks between long distance targets, the sail can be quickly mounted on the proper side of the mast. I know this because I have used a Lateen rig on my 17' sailing canoe for over forty years and I can attest to the simplicity and power of the rig.
So -- just how big should this new experimental Lateen rig design be relative to a 48' catamaran? If we use two sail rigs, the size can be more manageable than just one large one. Should we experiment with a new concept of sail propulsion or just accept the standard tall mast sail design for this catamaran project?
How would you design this section of the project?
Regarding motor propulsion units for our project, let's cover the conventional designs first and then explore some new theoretical techniques in moving boats on the water without wind power.
There are the readily available "off the shelf" fossil fuel burning machine engines that use combustible diesel or gas explosions within a very complicated vibrating set of devices to turn a metal shaft and prop -- which in turn, pushes water in a spiral fashion near the stern of a boat to cause a counter reaction of moving said boat in the direction desired.
Because conventional engines do get the job done and are relatively reliable, they are the popular choice of propulsion in most all types of power watercraft. They are also very available and have a huge industry ready to service them. When they work fine, they are a great choice to push boats through the water. However, they can be very costly, noisy, smelly, oily, and heavy. The gas fuel versions -- even the hydrogen gas adaptation of some engines, can also get very dangerous during certain situations. Apparently, most people who use them get accustom to these problems.
And then there are the much simpler electrical motor devices that perform the same force action of propulsion with very little or no sound -- but need a source of electrochemical energy that currently uses heavy batteries to store the energy. The weight factor of technically holding this electrochemical energy -- together with the mechanical problem of efficiently generating it on demand, is perhaps why this option has not become a popular source of propulsion for medium sized watercraft.
Although some of the largest and smallest marine vessels use efficient electric motor propulsion units, it seems that medium sized watercraft do not -- why is that? Perhaps because current battery and generator technology is not efficient enough to compete with current engine technology at that scale.
For over a decade, I have used a small portable electric trolling motor on my 20' Mirage sailboat with no problems -- maybe a larger version of the design could work on our boat project. The motor needs no cooling device because in operates in the water and, like a gas outboard engine, can be steered in the water and tilted or raised out of the water using a long composite shaft that is resistant to marine corrosion. It is extremely light for transportability and very dependable -- providing the electrical source is sufficient.
If there were a fast and easy way to generate electrical energy on demand then half the problem of providing propulsion to our project would be solved. The other half of the problem is the weight issue of current battery technology.
Now, I should point out that some new technology such as the "Electric Wheel" concept from Solomon Technologies look promising in how it generates electrical energy for future use during sailing and then uses the same device as an electric motor unit for propulsion.
It would be nice if modern technology could create a light weight capacitor type device to store electrical energy -- that would help with the weight problem. Capacitors have the capacity to store lots of electrical energy -- but apparently cannot release it slowly like batteries do. Perhaps a "flux capacitor" device -- like the one portrayed in the fictional movie "Back to the Future" is what we need to store lots of electrical energy.
Another problem I should mention in choosing electric motor propulsion is that bad things happen if water ever meets raw electricity aboard a boat. Bad things like dangerous sparks and the quick destruction of the electrical network that makes motors work. But because electric motors are relatively simple machines, if such accidents do happen, like a dead battery -- just have several spares and stick a new one on or in the housing to fix it.
Other methods of propulsion also include steam or nuclear power units to turn a prop shaft -- but these options are way too complicated to use in our catamaran project. The only way a small steam engine could work aboard our boat would be that it used nuclear fuel to heat a small steam chamber -- but finding a source of nuclear fuel would be a real challenge.
Some time ago I theorized a method of propulsion that involves gyros -- wherein a pair of spinning gyros, if mounted properly and directed or "walked" against each other by causing short timely moments of alternating drag events, may create a balancing torque-like force of movement that can move a boat over water in a desired direction. If this propulsion theory could ever be proven true, it would have the potential of moving any object over land or water without the need of an external power wheel or spinning prop. Many marine animals would love to see this type propulsion come true because boat props have and continue to destroy much marine life every day.
Even if this theoretical gyro type of propulsion unit worked, it would still need some sort of electrical energy to power the gyro motors. Where can we find or generate lots of electrical energy to power our motors?
Current solar power technology only creates very small amounts of energy -- at least not enough energy to the drive motors to push our boat any significant distance. New hybrid cars -- like some large modern ships, use gas engines to generate electrical motors to drive shafts on demand. Perhaps some kind of hybrid propulsion unit could drive our boat design.
How would you design the propulsion unit for our concept catamaran project?
This ends Version 3.28 of the Concept Catamaran Project.
Any comments can be emailed to me or posted at the boatdesign.net forum site.
These Cat5 images are working examples of this project as of 2/12/05.