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Trawlercat Marine Designs

 

Two thirds of the earths surface is covered by water - Our power catamarans allow you to safely explore it all

GREEN TECHNOLOGY


THE FUTURE IS NOT WHAT IT USED TO BE


Not to start out on a negative note but the reality is that Marine Green Technologies are still evolving and there is no one system advanced enough to power an all electric power catamaran at a reasonable speed for a reasonable amount of time.  By this I mean replacing the power taken from the batteries using only renewable energies from the sun and the wind. The only practical solution is to use a Hybrid which requires you to at least run a generator from time to time. 

Solutions are just around the corner and I believe by the end of 2011 a reasonable all electric vessel will be a reality, but it will come at an unrealistic price as everyone is pouring millions of dollars into new research and this R&D money has to be recouped.

Most small solar powered boats can only achieve 4 knots for about 2 hours before the batteries need to be recharged. Some solar and wind power catamarans are achieving up to 7 knots for extended periods in good conditions but we don’t see this as being acceptable for long range cruising.  Hybrid systems are only viable when they burn fossil fuel; as we will see further on.

A Bad Example
A 102’ x 50’ all solar catamaran is presently (Feb 2011) on a round the world voyage relying solely on the sun.  As exciting as this seems the reality is the vessel required 800 lithium-polymer battery cells weighing in at 11.7 tons to give it a three day operating window when there is no sun. Despite its light weight carbon fibre construction, with 5,766 square feet of heavy solar panels spread over its deck and the aforementioned 11.7 ton of batteries the boat weighed in at over 60 ton.  For all this it is only averaging speeds of 5 to 6 knots and it cost well over US$10 million making it a very impractical all electric catamaran solution. 


102'x50' Solar Cat
Top View of Solar Cat
For long range cruising to be practical, a comfortable and well fitted out all electric power catamaran must be able to cruise at a minimum of 10 knots for 24 hours a day for 7 days to make a 1,680 nautical mile passage.  To do this it must be able to produce enough renewable energy from the sun, the wind and other non carbon burning sources to keep topping up its large banks of Lithium-Ion or Lithium-Ion Polymer batteries.
All our "all electric" power catamarans have back up generators and carry a minimum of five days fuel. 
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We will use some of the following technologies in our All Electric and our
Hybrid Power Catamaran Designs


Powering
Electric powering motors are available as AC or DC motors and both can be used as generators to charge the battery banks when the vessel is being powered by some other means such as a SkySail (more later).  With a SkySail pulling the vessel along the freewheeling propellers turn the electric powering motors which become a generators that charge the batteries.

AC motors are more efficient, lighter in weight and more reliable than DC motors for powering a vessel, but they require more complicated controlling.
   
DC motors may be a little heavier and may not last as long as AC motors but they are less expensive and simpler to integrate which is why most electric boat builders are using DC motors today.

Batteries
Unless better batteries become available Lithium batteries are undeniably the only batteries you should use to run an electric powered boat.

Lithium-Ion and Lithium-Ion Polymer batteries are basically the same with the polymer versions being lighter, which makes them more appealing in marine and motor vehicle applications.

Lithium-Ion Polymer batteries are still improving and being used more so they are coming down in price.  An Audi A2 ran non-stop for 600 kilometers without recharging and Hyundai has designed them into their next series of hybrids - (2011) and this is encouraging news.

Whether TMD recommends them will depend on their availability and price at that time. Therefore we are designing around Lithium-Ion but hoping for the lighter polymer versions.

Solar Panels 
Solar panel efficiency runs from 20% to 29% with military and space applications running as high as 42%.  Although this seems inefficient solar panels are still one of the best producers of renewable energy for marine applications.

Solar panels come in the form of heavy bracketed panels and thin film panels with the thin film panels not as efficient as the heavy panels.  The output from each cell in each panel is affected by shadows falling on them so it is important that the boat be designed with this in mind.  A large radar arch would throw a large shadow so consider mounting the radar on top of the pilothouse and the antennas as far outboard as is practical.
 
Solar panels lose efficiency with heat so the heavy bracketed panels are usually mounted slightly above the deck to allow cooling air to flow around them.  This requires additional brackets to be mounted on the boat and the panels mounted on these brackets.  Carrying heavy bracketed solar panels mounted on mounting brackets brings a weight penalty that should be borne in mind.  A good alternative is to fabricate the mounting brackets using carbon fibre and bond them to the deck during construction.  This will also eliminate screwing into the deck and this will prevent future deck leaks.

If you’re looking for efficiency in solar panels then the most important things to look for are the power they produce for their size and the weight of the panels; price should be the last consideration.

Wind Generators
The wide beam of power catamarans allows you to have four or more wind generators spread across the aft end of the top deck where they will be out of the way and will catch the most wind.

Wind generators come in horizontal and vertical axel configurations.  Just like solar panels you should opt for models with the highest output for its size and weight.

In 1984 I fitted three large solar panels and a horizontal axel wind generator on my live aboard cruising catamaran. In 1987 we sailed out of Sydney, Australia headed North then West for Darwin and the Indian Ocean crossing to Sri Lanka, India, Oman, the Red Sea, Sudan, Egypt, Suez Canal to Israel, Turkey, the Greek Islands, Malta, Spain, Gibraltar, Canary Islands, Atlantic Ocean to the Caribbean then North to the British Virgin Islands.  I monitored the output on a voltage meter and was able to see how easily their output varied as shadows from the rigging was cast on them. The wind generator on the other hand was great for night sailing as it ran the navigation lights and radar.  In high winds it became noisy and in really high winds I had to tether it.
33'x22' "Quiet Achiever" cruising from Australia to the Caribbean with 3 solar panels and a wind generator hanging off the port stern, 1987
Vertical axel wind generators have come a long way with new models coming on the market touting excellent performance figures.  One manufacturer quotes “Silent Operation” which they achieve by using rare earth magnets in lieu of hard bearings.  This technique suspends the rotor in air and contains it within a magnetic field.  With no physical bearings there is no wear, no surface friction resistance and no maintenance which all sounds idyllic.
This 1.8 kW Vertical axel wind generator can mount on the pilothouse roof, or six or more can mount on a full width "arch" across the aft upper deck providing over 10 kW of power
Wind Propulsion
Commercial power vessels and superyachts can take advantage of a new form of propulsion; a parachute type of soft flying wing called a SkySail.  The SkySail is launched from the bow of the vessel working at heights of 100 to 300 metres where the wind is stronger and more consistent.   Launching and retrieval is fully automated and is carried out and monitored from the pilothouse.

The SkySail is deployed while traveling downwind with a minimum of 10 knots of wind. A telescopic mast at the bow of the vessel hoists the SkySail aloft.  It can remain aloft in wind speeds up to 40 knots and operates at any angle 50 degrees off the wind.

Due to its inflated construction and aerodynamic shape SkySail generates 5 to 25 times more power per square metre of sail area than conventional boat sails and requires no large mast or rigging to contain it as it is tethered off the bow of the vessel. 

The most important factor when using the SkySail is that the boat is being pulled along by the wind.  This allows you to let the propellers spin and use the electric powering motors as generators to regenerate power and charge the batteries.

Smaller versions of the SkySail suitable for pleasure boats is not too far away.
SkySail's inflated flying wing 25 times the power of a normal sail and capable of working 50 degrees either side of the wind
Total Vessel Weight
Every pound or kilogram of weight a boat is built from or carries onboard has to be pushed through the water and this consumes energy from the batteries which must be replaced. 

The heavier the boat the more power it will draw from the batteries to move it through the water.

With solar panels, wind generators and SkySails providing free renewable energy to keep large battery banks charged it would be a shame to waste some of this energy just to push a heavy, overloaded boat through the ocean.  The weight of the vessel and what it carries is a very crucial part of the overall equation in gaining the best use from renewable energies.

Construction
The vessel must be constructed and fitted out using the lightest possible materials.  For ultimate weight saving and strength this will require it to be constructed using epoxy resin infused foam sandwich and carbon fibre. For flexible strength it will also include tri-axel Kevlar in certain areas.  The interior and exterior fitting out should also be planned and built as lightweight as possible which could include painted carbon fibre safety railings instead of stainless steel.

All the above is expensive technology; but fortunately  carbon fibre is becoming slightly less expensive thanks to Boeing and Airbus using carbon fibre for the wings and fuselages of their latest passenger aircraft.  This new  market is huge and it forced the manufacturers of carbon fibre to ramp up production and provide competitive pricing as they went after the business.  The result is that there is now more carbon fibre available on the market and this has brought the price of carbon fibre down, which is good news for the marine industry.
  
Boeing and Airbus’s use of carbon fibre in large passenger aircraft is a testament to carbon fibre’s strength and lightweight and it should be proof enough that this is the best material to use to construct our all electric power catamarans.
 
If carbon fibre sounds too exotic or too expensive all the TMD models can be constructed in ‘standard’ fiberglass laminates using hand laid methods that are less expensive than carbon fibre.
Hybrids
Different types of diesel electric hybrids are available commencing with DC propulsion motors (at least until AC frequency converters become more practical and affordable) and at least two large banks of lithium-ion batteries.  Twin diesel generators can be used to provide the necessary power to charge the battery banks.  A smaller generator is also recommended as a ‘house’ generator when not underway.

Additionally, using as many solar panels and wind generators as is practical or affordable to charge the batteries will reduce the time needed to run the generators and save carrying and burning fossil fuel, which brings a weight penalty.

Parallel Hybrids are another option where a standard diesel engine and an electric motor operate through a clutch.  The battery bank runs the electric propulsion motor until the batteries reach a predetermined low voltage point causing the diesel engine to automatically kick in turning the shaft and charging the batteries through its alternator or via a Power Take Off (PTO) to a generator.

One such system comes from Siemens Marine Solutions who have a diesel Electric Hybrid Propulsion System called Siship Ecoprop.  It’s aimed at workboats, ferries and superyachts, or any other vessels requiring propulsion motors between 100 kW (134 hp) to 800 kW (1,073 hp). 

Siship Ecoprop provides for four modes of operation and is controlled and managed automatically by its own systems.

Diesel mode: Diesel propulsion engines power the propellers mechanically through a gearbox that also has PTO’s driving generator/motors that charge the batteries

Electric mode: Onboard generators provide power directly to the electric propulsion motor/generators turning the propellers via the mechanical gearboxes.  Batteries are recharged using the same generators.  In this mode the main diesel engines are not used and are de-clutched from the system.

Battery mode: Power from the batteries powers electric motor/generators turning the propellers through the mechanical gearboxes. The batteries are charged from onboard generators.  In this mode the main diesel engines are not used and are de-clutched from the system.

Hybrid mode: Both electric motor/generator(s) and the propulsion diesel(s) supply power to the propeller(s) via the mechanical gearbox. Typically the main engines are used for higher speeds and the electric motor/generators are used for slower or cruising speeds.

The Siship Ecoprop has already been installed on two vessels; the recreational 44m Green Voyager superyacht and a new commercial ferry.
Siemens Parallel Hybrid System
Serial Hybrid
Dutch electrical equipment supplier Mastervolt and Austrian marine diesel manufacturer Steyr Motors have formed a partnership to develop and distribute a range of Serial Hybrid diesel-electric drive installations for boats.

Steyr won a Dame award in 2007 for its parallel hybrid technology, and the company is now working with Mastervolt on a range of Serial Hybrid propulsion systems.
 
In these systems, only the electric motor drives the boat, with the diesel engine effectively becoming an efficient generator set that charges the batteries for the electric motor. It is simpler than the parallel arrangement and well suited to marine applications.

Both these companies are already leaders in Hybrid technology and they will make formidable partners, bringing together STEYR’s expertise in diesel technology and its associated mechanics with Mastervolt’s highly advanced electrical power solutions.
                                                                              
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The Green Technology choices you make will depend on your cruising plans.  If you’ll be cruising locally and have the opportunity to tie up at docks with shore power available then an all electric version might work for you.  If your plans are more ambitious such as cruising the islands and anchoring out then one of the hybrid options would work for you.

The one common denominator with all new green technology is that it all comes at a higher price than a standard power catamaran, the same as it does with hybrid motor vehicles.

All our designs are available as standard foam sandwich diesel engine powered cruising power catamarans.  They are also available using any combination of construction methods and any level of electric or hybrid powering. 

When you’re ready to discuss the finer details of your cruising vessel then give me a call or send me an email with some basic information on how you would like your power catamaran to be configured and what you would like it to achieve for you.

To give you a starting point choose a design from our PRODUCTS page that is closest to what you are looking for; then we can tweak it or make major changes to it until it is exactly what you want, or we can design an entirely new power catamaran to your design concept.

 
GO FURTHER, FASTER AND
LEAVE A SMALLER CARBON FOOTPRINT
 in a TMD power catamaran using our suite of
GREEN TECHNOLOGIES


TMD Green Technology Low Profile 49’, 55’ & 65’

All Electric Long Range Cruising Catamarans

 

PROPOSED PRELIMINARY SPECIFICATION

All Models

 

The all electric models MUST be built as light as possible. This is to use as little energy as possible to move them through the water.  This means they MUST be constructed using the lightest strongest materials and everything that goes into and onto the vessel MUST also be the lightest and strongest option.

 

Structural Engineering working to ABS Rules will provide the carbon fibre and other laminates to be used to construct each model in a laminate schedule, with a built in safety margins.

 

Our refined hull form, fine entry surface piercing bows and unique low drag rudders will provide extremely efficient hydrodynamic performance.  Like all our models these vessels will be UNSINKABLE.

 

Fiberglass Construction

Pigmented gelcoat where required. Gelcoat is lighter and more durable than paint systems

Epoxy resin infused carbon fiber foam sandwich material for hulls, decks, superstructure and bulkheads

Areas requiring reinforcement will use bi-axel or tri-axel Kevlar

Decks will have a molded gelcoated non skid pattern where applicable

Molded window frames and bonded window glass

Stainless steel safety rails and hand rails will be replaced with fabricated gelcoated carbon fibre railings

Interior fitout will be honeycomb and foam sandwich construction

Overhead and wall lining will be “Whisper Wall”

 

Power and Systems

2 x DC Electric powering/generating motors, size depends on requirements

2 x Straight shaft drives with appropriately sized surface drive propellers

2 x Lithium-Ion battery banks sized to suit specific vessels intended use

2 x DC to AC Inverters

Energy Management Control System and CANbus system

Energy efficient AC and Appliances with rapid heat Halogen range

LED and Fluorescent Lighting

Maximum number of solar panels space permits

Minimum of four 1.8kW vertical axel wind generators max. 7.2kW

Optional SkySail, if required for operating powering motors as generators

 

Back Up System

2 x 40kW diesel generators

2 x 500 USG Diesel fuel tanks 

 

Speed Cruise               10 knots +

Speed Max.                 18 knots recommended but higher is available

Range                          Unlimited, depending on food supplies

 

 

Diesel Hybrid Models are available for local cruising with speeds up to 25 knots using propellers and up to 30 knots using water jets.
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Trawlercat Marine Designs

The Dockyards at Port Royal - New Westminster - British Columbia - CANADA
Phone: 1 604 495 6386 - Mobile: 1 604 329 7448
Email: graham@trawlercatmarine.com

Copyright (C) Trawlercat Marine Designs 1997 - 2011 All Rights Reserved