100 Years of Going With the Current
The late Edward Hawthorne,
former Hon. vice-president of the
Electric Boat Association, outlines the history of electric
propulsion on the Thames and describes present trends.
During 1898 electric
boat activity on the River Thames was growing apace. The Immisch Electric
Launch Co. and the Thames Valley Launch Co. each had about sixty electric
launches for hire, there were about the same number in private ownership and
most of the large boatbuilders had experience in building, fitting out and
hiring electric boats.
Advertisement for an electric canoe 1892
|Most electric boats were launches ranging in size from 15
to 45ft. in length. The largest on the river, and for a long time in the
world, was the 65ft. eighty-passenger 'Viscountess Bury', which plied on the
Thames between 1888 and 1910 when she was converted to oil and taken up to
Cambridge. The development of oil engines at the turn of the century
and the effects of the First World War proved the death knell for
electric propulsion - and steam. A few boatyards maintained electric canoes and some launches for
hire, but by the mid 1930s even these had disappeared from the river and
there was virtually no interest in electric boats on the Thames until about
The resurgence of interest was encouraged by the import of electric
outboards developed in America as trolling motors for fishermen on the
lakes, and by the practical activities of Rear Admiral Percy Gick and Lord
St. Davids. The former, supported by the Midland Electricity Board, took an
electric Trentcraft cruiser 600 miles up the Thames and around the canals
and Lord St Davids moored "Silver Sail" a small narrow boat powered by prototype Lynch
outboard motors at the bottom of his garden on the Regents Canal, whence he
cruised over 4000 miles between 1981 and 1991. The two of them also founded
the Electric Boat Association, the first of its kind in the world.
Silver Sail - electric
steel canal narrowboat
1899 Andrews river launch
|During the 1980s, Rupert Latham at Wroxham set out to develop the Frolic
electric launch using GRP construction and an advanced electric propulsion
system. To date, more than two hundred of them have been sold. The electric
boat market in general was slow to materialise but has expanded rapidly
during recent years. For example, in 1991, there were only two
electric boats on the three-mile stretch between Cookham and Marlow; today
there are more than thirty. Nine of the pre-1930s Thames launches and four
canoes are still in use or undergoing restoration.
Four of the launches have been converted to steam and one to
petrol but the canoe, 'Gena', still has
its original motor and controls. The traditional launch design with high
length/beam ratio is still the most elegant type of electric boat and the
skills of building in teak and mahogany are carried on by some yards on the
Thames and in Norfolk. However, the growth market is in maintenance-free GRP
hulls which not only cut costs but provide opportunities to design specially
shaped low wash hulls. Interest is growing in the use of cruisers up to 35ft
length. Electric narrowboats arrived in the early 1950s as hireboats but
have not yet caught on.
1903 electric canoe 'Gena'
picture: Mike Phillips (TTBR)
In Austria electric ferries carry up to 200 passengers on trips across
lakes where petrol or diesel engines are banned. It is interesting that the
original electric boats on the Thames were designed as ferry boats for use
in the Pool of London. Recently Hammertons of Twickenham opened the first
Thames electric ferry since the end of the last century.
The main components
of an inboard electric propulsion system (DIY kits are becoming available
for those who wish to do their own installation or conversion) are:
Batteries: The batteries of 1896 were lead-acid 2-volt
single cells with removable plates and with a typical capacity of 30
watthours/litre. Today's batteries store 100 watthours/litre in a sealed 6
volt monobloc containing 3 cells. Liquid electrolyte is the most common in
use but gel electrolyte cuts out the need to top up, although at some slight
loss in performance. Batteries can be the most costly item in the electrical
system and users are therefore acutely interested in the life which can be
expected. Most industrial battery applications are rated at a life of 1500
cycles equivalent to 5 years of normal industrial usage, but the lower usage
of most boats means that, if properly treated, modern batteries should last
at least seven years and lives of 10 to 15 years have been quoted. The
golden rule is never to overcharge and try not to discharge more than 80 per
cent of capacity.
Motors: Until recently, the motors used in boats were
standard industrial DC series types with axial armatures and run at speeds
at which they could be directly coupled to the propeller. A typical 1.4kw
motor would have dimensions of 11in x 10in diameter, a weight of l00lb and
an efficiency of about 80 per cent. Motor size can be reduced by increasing
motor rpm and fitting a gearbox as in the Brimbelow E drive system. However,
during the last ten years the radial armature motor reinvented by Cedric
Lynch has been developed and is increasingly being used. Not only is such a
motor much smaller (eg a 5" x 8" diameter motor will provide 1 to 8.5kw
continuously and weigh 241b) but the efficiency is 90 per cent, thereby
adding 11 percent to the boat's range. One snag is that these motors run at
2000 to 4000rpm and have to be geared down to the propeller.
Lynch DC motor
|One manufacturer is now taking advantage of the small size to
build a Lynch motor in the head of an outboard and therefore out of
the water. The brushes of electric motors inevitably make some noise
and this is usually more or less eliminated by sound-proofing. But
it is sometimes not realised that
using anti-vibration mountings can materially reduce the noise transmitted
through the hull. Gearing between motor and propeller can also produce a
surprising amount of noise and this can generally be reduced by using belt
drives. Of course, electric boat users, like steam boat enthusiasts, are so
used to very low noise levels that any increase becomes irritating!
|Cedric Lynch, the inventor of the revolutionary
Lynch motor demonstrates
the torque of his latest Indian built
Agni Motor by attempting to stop the shaft by hand while Tony Rymell
& Barry Goldring power it up by simply holding a couple of AA cells
(borrowed from Tony's camera) against the terminals.
June 2009 - Agni Motors
win the world's first zero carbon
IOM motorcycle Grand
image to enlarge
Controllers: The Curtis pulse modulated controller based
on solid state technology is fitted in many electric boats and provides
infinitely variable forward and astern speeds. This probably enhances the
reliability of batteries and motors by providing smooth changes in speed
although there are a few percentage points of loss. The traditional switch
system, usually giving up to four forward and two astern speeds is now very
reliable, cheaper and quite satisfactory for the smaller boats. There are no
losses in the switch but corrosion and arcing can occur and may reduce life.
Chargers: For dinghies and small boats fitted with only
one or two batteries it is usual practice to take the batteries out and
charge them on the land. If enough time is available, trickle charging can
be used but it is always better to use an automatic charger in order to
avoid any risk of overcharging. Traditional chargers are transformer types,
but the new high frequency switching technology can reduce charger size and
weights by up to 80%. Most boats larger than dinghies carry their chargers
onboard with a normal 13 or 15 amp cable carrying the mains supply to the
boat. Many pubs and the like are prepared to allow boat-owners to plug in -
"a pint and a charge, please", as Lord St. Davids used to say to the
landlord. Virtually any powered leisure boat can be electric but it is
important to match the electrical system to the boat's operational
requirements, the essence being to reconcile speed and range. Batteries are
limited in capacity (i.e. ampere-hours); speed is a function of power which
at a given voltage is itself a function of current flow (i.e. amps).
Therefore the higher the amps the higher the speed but the lower the running
time. A 21ft open launch may require a current of 50 Amps at 48 volts to
reach a speed of 6.5mph with a range of 36 miles, whereas at 5 amps and a
cruising speed of 3 mph a corresponding distance of about 170 miles could be
achieved. For example, the EBA 24-hour Endurance Record on a single charge
for a battery powered 31 ft saloon launch is 116 miles at an average speed
of 4.8mph. Contrary to popular belief, electric boats can go fast. Lady
Arran established the world speed record of 50.8 mph in 1989 only to have
the Americans capture it at a speed of 70.6 mph in 1996.
(The above article appeared in "The
Boater" magazine, June 1998)
Electric boating is currently enjoying a
worldwide revival, yet at the turn of the
century there were 100 electric launches on the Thames alone.
1834 IMPERIAL RUSSIA:
German physicist Moritz
Hermann Jacobi presents a paper to the St. Petersburg Academy of Sciences
about electromagnetism as applied to machines. Four years later Tsar
Nicholas I grants Jacobi enough money to design and build an electric motor
to be fitted to a ten-oared shallop.
The engine Jacobi built comprised electromagnets to drive two paddlewheels
(propellers were as yet unheard of). The general arrangement proved
successful and the electric paddle-boat began to voyage up the River Neva,
applauded by the Tsar and his Court. But the motor gave out as much nitrous
fumes as smoke from a steam train. The brave pioneers, choked and
asphyxiated by these sickening and suffocating fumes, were obliged to stop
their observations. The following year Jacobi tried another experiment with
the same boat. It was worked by a battery a fifth the size of the previous
one. Following the recent formula published by British physicist William
Grove, it was charged with concentrated nitric and sulfuric acid. The vessel
attained an average speed of 3 mph with some 12 or 13 passengers aboard.
In August 1848 an electric boat was demonstrated on the private lake of
Penllergaer near Swansea, Wales. It was propelled by a motor developed by
Benjamin Hill, sponsored by John Dillwyn Llewelyn, again deriving its energy
from a Grove cell.
Twenty years were to elapse before a certain Monsieur de Molins launched his
electric paddleboat in the Bois de Boulogne lake. Despite her strong
electric batteries (developed by Robert Bunsen and using carbon electrodes
instead of platinum) the boat started slowly, disappeared behind the island
which forms the centre of the lake, and did not reappear.
Disinterest continued over this promising form of motive power until a
Parisian electrical precision instrument maker, Gustave Trouve, arrived on
the scene. In May 1880 he patented a small 11lb (5kg) electric motor and
described its possible applications (Patent N°136,560). Trouve suggested
using two such motors, each driving a paddle wheel on either side of the
hull. Later he progressed to a multi-bladed propeller. Modifications to this
master patent date from August 1880, then March, July, November and December
1881. To quote: “It is the rudder containing the propeller and its motor,
the whole of which is removable and easily lifted off the boat…”
With this invention, Trouve could not only lay claim to the world’s first
marine outboard engine but, in taking the same motor and adapting it as the
drive mechanism of a Coventry-Rotary pedal tricycle or velocipede, Trouve
also pioneered the world’s first electric vehicle.
On 1 August 1881 Trouve made his benchmark report to the French Academy of
Sciences, stating: “I had the honour to submit to this Academy, in the
session of 7th July 1880, a new electric motor based on the eccentricity of
the Siemens coil flange. By suggestive studies, which have allowed me to
reduce the weight of all the components of the motor, I have succeeded in
obtaining an output which to me appears quite remarkable.
A motor weighing 5kg [11lb], powered by 6el of Plante producing an
effective work of 7kgm per second, was placed, on the 8th April, on a
tricycle whose weight, including the rider and the batteries rose to 160kg
[352lb] and recorded a speed of 12km/h.
The same motor, placed on the 26 May in a boat of 5.5m long by 1.2m beam
[18 x 4ft], carrying three people, give it a speed of 2.5m [per second] in
going down the Seine at Pont-Royal and 1.5 m [8 & 5ft] in going back up the
river. The motor was driven by two biochromate of potassium batteries each
producing 6el and with a three-bladed propeller.
On the 26th June 1881, I repeated this experiment on the calm waters of the
upper lake of the Bois de Boulogne, with a four-bladed propeller 28cm [11
¼in] in diameter and 12el of Ruhmkorff-type Bunsen plates, charged with one
part hydrochloric acid, one part nitric acid and two parts water in the
porous vase so as to lessen the emission of nitrous fumes. The speed at the
start, measured by an ordinary log, reached 150m [490ft] in 48 seconds, or a
little more than 3m [10ft] per second; but after three hours of functioning,
this had fallen to 150m in 55 seconds and after five hours, this had further
fallen to 150m in 65 seconds.
One bichromate battery, enclosed in a 50cm [20in] long case, will give a
constant current of 7 to 8 hours. There is a great saving of fuel and
During the 15 years that followed, it is estimated that over 100 Trouve
electric motors were installed in pleasure launches. Some of these were
fitted with his electric headlights and klaxons. There was, for example, the
Sirene, a charming electric boat which he built for Monsieur de Nabat,
arranging it so that her owner could change at will from propeller to
paddles. This boat, whose owner used her three times a week during long
periods, measured 29ft 6in long by 6ft beam (9 x 1.8m) and cruised regularly
at between 8 ½ and 9 ½ mph (14-15km/h), her propeller turning at between
1,200 and 1,800 rpm.
To show the speed with which an electric boat could move in a race
situation, on 8 October 1882 a Trouve craft was launched onto the River Aube
and steered onto the race circuit only five minutes before the start. It
left at gunfire and spectators noticed, not without astonishment, that in
this famous race the boat covered more than 2 miles (3.2km) in 17 minutes,
averaging 7mph (11km/h) and slowing down to make four turns around the
In September 1888 a Trouve boat was sent to China to fight against opium
smuggling on the China Sea. 49ft (15m) long and steel-hulled, it weighed
some 8 tons and the bronze prop had a diameter of about 20in (500mm). One
can but wonder at the electric power necessary to shift her along.
The idea had caught on elsewhere. The iron-hulled 25ft (7.6m) Electricity,
designed by the brilliant Austrian-born Anthony Reckenzaun, was built for
the Electric Power Storage Company at Millwall, London, to accommodate 12
passengers. Power came from 45 Plante accumulators, modified by Messrs Sellon
and Volchmar to total 96 volts and supply power for six hours at 4hp to two
Siemens D3 dynamos with regulators and reverse gear, belt-driving a 20in
screw propeller of 3ft pitch (500mm x 0.9m) at 350 rpm. Either or both
motors could be switched into circuit at will. On 28 September 1882
Electricity made a pioneering trip on the River Thames to London Bridge.
Two years later a race took place between Electricity and the electric
launch Australia from Millwall to Charing Cross Bridge and back to
Greenwich. There is no record of which boat won, but apparently Australia
was very slightly ahead at Charing Cross on the way upstream!
|Enter Moritz Immisch, German-born clockmaker turned electrical engineer.
Having worked on battery-operated trams in London, in 1887 Immisch teamed up
with Viscount Bury to pioneer the world's first electric hireboat-fleet. An
80ft (24m) Thames houseboat was converted to a charging station with
semi-portable steam-engined dynamo. Four other stations were set up, the one
on Platts Eyot Island near Hampton becoming the headquarters. From an
initial six launches, by 1904 the Immisch operation had grown to some 23,
all capable of carrying from 4 to 50 passengers.
The accumulators were manufactured by the
Electric Power Storage Company to drive Immisch motors
of from 1.5hp up to 12hp, at 65, 95 and 120 volts, and give with certainty a
run of 30 miles at 6mph, half upstream and half downstream, on one charge.
In 1888 there were half-a-dozen charging stations on the Thames, but by 1902
there were over 20 on land and two floating barges. At Maidenhead alone,
seven electric hireboat operations jostled for business. During the same
period, over 50 British boatbuilders are known to have built one or more
electric launches. Most of these were Thameside yards. Launches were also
exported to Venice, Ceylon and South Africa, while Eastern princes and
rajahs received sumptuously fitted-out vessels.
The Thames Valley Launch Company of Weybridge, Surrey, offered 29 launches
for hire, many of which were fitted with feathering propellers. Messrs
Andrews & Sons of Maidenhead had a fleet of 12 electric launches, each one
named after a freshwater fish, with an additional flagship called the
Angler. It was on the Angler that King Edward VII, Queen Alexandra and a
royal party enjoyed the pleasures of the Thames.
The Mary Gordon - built 1898
|Apart from these 100-odd launches on the 93 miles of the Thames between
Teddington Lock and Oxford, a number of local corporations bought electric
boats for used in their ornamental parks. In Leeds, for example, a 70ft
(11m) launch called Mary Gordon was capable of taking either 75 adults or
120 children for trips on Waterloo Lake, Roundhay Park. A similar boat plied
for hire at Southport. The English Lake District and Irish and Scottish
lakes also had a number of launches for hire.
Elsewhere, British electrical boat pioneer Anthony Reckenzaun and his
brother Frederick, emigrated to the USA and settled in Newark, New Jersey.
Using experience gained with the cross-Channel Volta and other vessels, they
built for their own use a 28 ft (8m) launch which they named Magnet, with a
2.5hp, 420lb (191kg) Reckenzaun motor powered by two banks of accumulators
made by the Electric Accumulator Company of Newark. The vessel was reviewed
by Thomas Martin, Editor of The Electrical Engineer, who described a voyage
of 50-60 miles without recharging, so supporting the Reckenzauns' claim of
60-70 miles over 10 hours.
It was in 1891 that the fabulously wealthy WK Vanderbilt became the first
American to order an electric boat. It was built at Charles L. Seabury's
yard, measured 30ft (9m) in length and was called Alva. In terms of length,
US millionaire John Jacob Astor sported the largest privately-owned electric
launch in the world: the 72ft (22m) Utopia had two motors each developing
around 25hp and was luxuriously fitted out like a miniature Titanic. The
largest electric passenger boat in the world, however, was the 93ft (28.4m)
Victory, designed by William S. Sargeant in 1904 and licensed to carry 350
passengers above Westminster Bridge.
The main reason for the decline of the quiet and clean electric launch in
subsequent decades was the development and ease of refueling of the more
powerful diesel engine. Since the late 1970s, however, there has been a
revival of interest in electric boats for pleasure boating on the inland
waterways around the world. Better underwater hull designs, lighter glass-fibre
construction, improved motors and batteries and electronic control and
recharge systems have given birth to a new generation which is already
contributing more environmentally friendly pleasure boating for the 21st
Electric offshore: time to plug in?
The past may have been electric, but electricity could
also save us from a polluted, fossil-fuelless future. In fact diesel and
petrol engines are to be banned in Friesland before too long. Electric boats
are becoming commonplace on Britain's inland waters, Broads and rivers, but
no-one seems to have taken electric power seriously as a direct alternative
to diesel engine in an offshore cruising yacht. Yet the technology,
arguably, is so nearly there.
Back in April 1998 we ran an article entitled 'The quiet revolution' about
an American invention that could just be that. Developed at a cost of $
millions by NASA to power its Mars Rover, the Electric Wheel would seem
ideal as a marine engine. As we write there's a 50ft (15.24m) wooden
Herreshoff-type being fitted with a derivative of the space buggy's
propulsion system in a traditional South Coast boat yard. A yacht that once
had a 45hp diesel will make do with a 10kW Wheel, her existing Fischer Panda
15kW generator topping up a hefty bank of 10, 220amp/hour carbon fibre
batteries. There'll be solar panels and a wind generator too.
Dave Tether of Solomon Technologies, which is developing the system, fitted
the prototype to his 33ft (10m) heavy displacement cruising yacht to replace
a 22hp diesel. From a bank of ten deep-cycle marine batteries weighing 500lb
(226.7kg), the 50lb (22.7kg) Electric Wheel, rated at just 4.5kW, the
equivalent to 6hp, could move the 9-ton Seaward at 6 knots for six hours.
Uncoupled from its shaft he also uses it to haul his boat up the slip at
So how come a 6hp electric motor can do the job of a 22hp diesel? Simply
speaking, diesels only develop maximum torque near the top of their revs;
electric motors do so from start-up. To put it in perspective, a 20kW Wheel
puts out as much torque (150ft/lb) as a Ford Mondeo's 2-litre petrol engine.
Eighteen months later Tether reports that, although he has a small 1.5kW
Kawasaki petrol generator on board Seaward and charging facilities at the
dock, he has never had to recharge the batteries. Why? Because, when she's
under sail, the Wheel works in 'reverse' as a dynamo, turned by the trailing
propeller, topping up the juice extracted by the device in propulsive mode.
Clever, huh (as the Americans would say). "It's an 80 per cent efficient
generator," says Tether. Apparently it will, in nanoseconds, switch from
power to charge mode while the yacht is motoring, ie. slide down a wave, and
it will start charging. And given that the ratio of sailing to motoring time
of the average sailing yacht is, perhaps, 4:1 that gives plenty of time for
charging. "But for Pete's sake don't use the word perpetual motion," says
Tether. There's no magic involved.
The Wheel (incidentally, it's waterproof, so will live quite happily in a
dank, wet bilge) is still in pre-production stage; the price for a 4kW model
(equivalent to an 18hp diesel) is currently $7,500. But next year Tether is
predicting a price of $5,500 and $4,500 the year after. A typical,
high-revving Japanese 18hp diesel currently costs around $6,500. And that's
without the tank, fuel system, exhaust and sterngear.
Clearly the costs will need to drop considerably before the Wheel - whether
you fully believe its claims or not - stacks up directly against a
conventional diesel installation, especially in small yachts. But what about
more conventional electric motors, such as Brimbelow's E-Drive and the
various Lynch motors that currently power a host of river craft, such as
Creative Marine's Firefly and Frolic, Swancraft's Mayflower, John Williams
Bros' Dearest and even the National River Authority launches? Could a 5kW
electric motor power a 25ft (7.6m) long-keeled, heavy displacement cruising
yacht, bearing in mind that it would primarily be used to get her into and
out of harbour? How many batteries would she need, and how many hours of
motoring at what speed could we expect?
Jim Keating, past chairman of the Electric Boat Association and managing
director of DesignEta, believes it is just feasible. He suggests marrying a
5kW Lynch motor, with a bank of six, 12V Chloride leisure batteries, providing 36V
x 160a/hrs and calculates that, in flat water, just 1kW (1.5hp) of the
available 5kW would be sufficient to propel her at about 4 knots. "There
would be 4kW of additional power available for use in heavy weather,
maneuvering, towing or high speed dash to 6 knots, maximum," he says.
The drive would be by toothed belt to the shaft, geared down to turn at an
efficient 960rpm at full power (600rpm/1kW would give 4 knots). The
batteries would be mounted as low as possible, and positioned to trim the
boat correctly. "Then maybe the ballast weight could be reduced," says
At 6 knots, Keating expects 1.5 hours of silent running (not much,
admittedly but enough to get a cruising yacht out of trouble, perhaps), 2.5
hours at 5 knots or 5 hours at a more realistic 4 knots. At this speed a
small 30lb (13.5kg), 1kW 230V AC petrol generator running in the fo'c'sle or
cockpit locker and linked to a high output 'smart' battery charger (not a
household trickle charger) could, in theory, 'keep pace' with the motor. Its
2.3 litres of fuel would last up to eight hours. Flat out, generator
running, would eke out your endurance to, perhaps, 3 hours, but all these
scenarios presuppose some sort of small (and possibly pricey) box between
alternator and battery terminals to sense battery state.
The efficiency of such a 'hybrid' system might only be around 35 per cent,
but diesels are no better than 30 per cent. "And a generator running at a
constant speed is more efficient than the conventional engine," says
Keating. Apart from the whir of the motor and the hum of the generator,
concealed in its soundproof box up forward, such a system would be
mercifully quiet and vibration-free. "If you anticipate low use of battery
power, then consideration could be given to using a wind generator or solar
cells," says Keating. To fully recharge our batteries would take the little
AC generator 8-12 hours, or a tank full of fuel.
A viable alternative might be a DC generator, as fitted to Whitbread yachts.
A 1.8 kW diesel generator, charging a bank of three 190a/hr deep cycle
carbon fibre batteries at 50 amps, would replenish them in about 12 hours
from dead flat.
"The key to it all," says naval architect John Perryman, "is to dispense
with the generator and exploit the self-generating properties of a DC motor
such as the Wheel being 'driven' by a variable pitch propeller when the
yacht is sailing." At its simplest this could be of the Swedish type,
whereby a rod is manually moved to alter the pitch until the optimum charge
rate is reached, then feathered when the batteries are full.
"Fit a Kort-type nozzle around the prop," John adds, "and you could improve
thrust by as much as 40 per cent, which also means 40 per cent improvement
in battery duration."
It all sounds tantalizingly close. Jeremy Freeland of Bossoms Boatyard,
which builds a 4.2 ton displacement, long-keeled cruising yacht currently
fitted with a 9hp diesel, is more cautious. "The positive factors," he says,
"are quiet and pollution-free running, better weight distribution and less
space than a diesel, especially if batteries are used as ballast. The best
place for them would be under the floor, to augment about 1.3 tonnes of
encapsulated lead shot ballast, as opposed to 2 tonnes. And they'd need to
be well vented."
But no small electric motor, he reckons, would punch a 4-knot tide; running
time from the battery bank, unless it was huge, would be short and the cost
would be about 1,300 pounds more than a 9hp diesel. "In a nutshell, the
standard diesel can not be replaced by an electric motor on a sailing craft
where a similar performance is required," he concludes. "Electric power is
suited to inland use where better hull shapes and still water is more the
New technologies could change all this, the most exciting being the
so-called 'fuel cell'. Zemar's electrochemical engine (ECE) combines
hydrogen (carried in a fuel tank) and oxygen (from the air) to produce
electricity and water, storing the energy in batteries for use by the
electric motor. The only bi-product is pure water. Noiseless and cheaper to
run than a conventional engine, the ECE is claimed to be "the marine power
of the millennium". No moving parts, running on a fuel that is safer than
petrol or LPG (forget the Hindenberg; hydrogen can be safely stored these
days) the ECE's only drawback is a current cost of 7,500 pounds for 5kW.
Victron Energie's new Sterling engine, patented by a Scot in 1816 and best
described as an 'external combustion engine', is another idea waiting its
time. Used to drive a generator, it is said to be 90 per cent efficient.
Noise levels are that of a fridge.
Again, it's too expensive for the owner of our little cruising yacht.
Perhaps an ECE/Wheel combination will one day provide the solution. But even
with the technology available now, the argument of diesel vs electric is not
as one-sided as it once looked. If the sound of your diesel is getting on
your nerves, the answer may lie in a hybrid system and, more pertinently, a
commitment to doing it wherever possible under sail - the ultimate
energy-saving device, invented over 5,000 years ago.