AT CAD Team/AT catamaran
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The AT catamaran is catamaran design that is locally buildable and cheap, and which allows (emissionless) transportation of a relative large amount of cargo.
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[edit] Main 2 versions and variations
The catamaran can be customised for its intented task. For this, several variations can be made on the 2 main versions. The 2 main versions are:
- Steam engine powered (using 2 Tesla turbines)
- Electrical engine powered (using 2 squirrelcage-rotor induction motors)
The options on how the catamaran can further be changed are
- adding a keel or leaving it off (depending on use at sea or on inland waters)
- making it driverless or only manually controlled
- using a different wind energy harvester (electrical version) or even 2 Flettner rotors;
the latter useful for very shallow inland waters
2 motors are always used in regards to the steering: by varying the power provided to each of the motors, the catamaran is turned left/right.
The electric powered version uses a regular sulpheric acid/lead battery. The fuel used with the steam engine powered is either firewood or ethanol and nitrous oxide (which is a emissionless fuel; see Comparison_of_alternative_ICE_fuels). Tanks with these 2 different fuels are needed since nitrous oxide won't ignite unless it is incinerated at a high enough temperature. The ethanol is thus used first to preheat the engine.
Since the logs are not that hydrodynamic nor light, a compressor is added with the electrically powered version in order to reduce drag by upto 60-70%. With the steam engine powered version, steam is injected in the log, having rougly a same effect, yet eliminating the need of an extra compressor.
The steam powered version btw uses desalinated water, to avoid corrosion of the firebox. It does this by the use of 2 alambics which are heated due to close contact with the firebox. The alambics are themselves fed by seawater from under the vessel (seawater being pumped up manually or by means of a electric pump).
There is no regular anchor since this destroys the seabed. Instead, the ship can be moored regularly (ie on jetty's), or moored using a mooring buoy, or the 2 sea anchors can be used at open sea.
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Simple control and excellent navigation are possible using the AT_ship_control_stand. Note that a additional rudder (operated electrically using a tiller) is also present, yet the turning is still done by varying the power to the motors. The rudder is simply turned to increase the speed of the turn if so required. The catamaran has an autopilot in the form of the UMPC (not present in model) which is hooked up to the control stand. It is able to measure wind speed, current speed, and steer the vessel autonomously to an entered destination, making the necessairy course corrections for wind/current. Manual control/course correction is also possible offcourse.
Note that a additional sail is also present with the steam engine-powered version. This increases the range. It can be rolled down/up, and even steered autonomously according to the wind speed/direction. Note that the sail is can rotate freely left/right but can be kept pointed at a certain direction using the electrical winches. The sail was especially made, based loosely on the Reaper's sail. It includes a manual winch on top (can also be automated) and 2 rings that fix the yards once they are winched up/down.
The electric version does not have a sail, yet has a Savonius windturbine. Power is generated using the turbine which recharges the battery. The battery in turn powers the 2 propeller engines.
[edit] Construction
The logs used for the amas are from a single tree. Thus besides easy local production for the boat's components, it also makes for a sturdy construction (sturdier than most boats). The logs can also be easily repaired using birch resin. The size of the catamaran may differ slightly depending on the region. This, as some each tree species (native to the region in question) has it's own height and width when fully matured.
The logs are also partly hollowed out. This allowed to implement the sleeping bunks (4) in the logs. The bunks are closed at the top with a glass dome, hence allowing the passengers keep paying attention to the sea and get out of the log quickly if necessairy.
The vessel is also suspended using leaf springs mounted between the logs and the metal frame on which the deck is mounted.
[edit] Safety
Satefy has taken greatly into consideration when designing the vessel. Firstly, the passengers/captain are given
- a RFID implant (allows the vessel to detect when someone has fallen overboard. If this happens, the vessel detects this (using the back loop antenna) and is automatically stopped.
- a 100N lifejacket (see http://en.wikipedia.org/wiki/Lifejacket )
- a climbing harness (for securing oneself to the vessel while on deck)
Flag F, V, W and R are also carried along and can be raised on the flagpole (see http://en.wikipedia.org/wiki/International_maritime_signal_flags ). These flags are only raised when something is wrong, when everything is OK, no flag is raised at all.
- Flag F means: I'm in trouble, communicate with me
- Flag V means: I'm in trouble, I request assistance (board my vessel)
- Flag W means: I'm injured, I request medical assistance (board my vessel)
- Flag R means: I'm in trouble, stay away
Communication is done using the UMPC. The horn and microphone allows to create sounds (maritime signals) and detect maritime signals. The meaning of the sound is then automatically translated and displayed on the screen of the UMPC.
The marine propellers are foreseen of a cage/tube around the propellers. It ensures that no people in the water can be hurt by propeller or that any marine animals are injured. It also shields the propeller from the seabed, and floating/submerged debris/plants. Finally it straightens out the outwards flow, possibly increasing the propeller's efficiency and reducing propeller-walk (see http://en.wikipedia.org/wiki/Pump-jet )
[edit] Moving the vessel over land
The carrying of the boat between inland rivers will not be possible by hand. To solve this problem, a simple rail with winch system can be designed. This works as follows: the winch would be mounted on rails, winches the boat out of the water, and is then unlocked and transported to the other river. The system can be placed on the shortest routes between rivers.
[edit] Practical execution of driverless version
For the driverless version, some hard/software can be used from other projects; knowingly:
