Electrical thoughts

HAVING seen the myriad of silly aspects of the ‘all electric’ policies being mooted in the press and from Government officials. I must admit that it is all beyond my understanding, writes Orph Mable.

A common phrase amongst the intelligentsia, a few years ago, was ‘joined-up thinking’. I can’t see anywhere proposals for meeting electricity supply and demand being ‘joined-up’ in these various proposals being pushed upon us.

'Kill-off the diesel engine' brigade

If we consider the view of the ‘Kill-off the Diesel Engine’ brigade, then before it could be achieved there has to be both the determination and the development funds to achieve it. When you consider the financial clout of both the oil companies and motor manufacturers who have little wish to make the radical changes necessary to achieve it and will put many obstacles in the way.

History tells us that the only time that development focus and sustained funding come together is in times of major crisis (war or catastrophe). Other times it is driven by profit for individuals or companies. What profit is there for these two industries?

UK canal boating requirements

Coming at this from another angle and being a bit myopic when looking at the UK canal boating requirements in a non-diesel-engine era, I thought I’d discuss the idea of the ‘all-electric’ powered narrowboat. “Nothing new there” I hear you say. On the face of it you are correct, and there are several boats that have electric motors and diesel engine charging systems. In the motor industry this is known as a ‘hybrid’ system. British Waterways (CaRT predecessors) even had one around the Millennium period. To date, I haven’t met a purely all-electric boat operating as private or commercial on the canal system.

The freedom and flexibility offered by diesel engined boats has been one of the reasons that narrowboats have continued to flourish for decades. So much so that it has become the norm for boats with 1920-1930 designed diesel engines to be talked of as ‘traditional’ (not really true—in my mind). So if we are to banish the ‘hated’ internal combustion diesel engine what are we to replace it with that would give the same flexibility, power and ease of use?

Desirable benefit

Before considering a replacement, the desirable benefits to boaters that an internal diesel engine gives to the narrowboat must be understood.

1. Range between re-fueling—anything up to several weeks.
2. Good availability of fuel supply points
3. Relatively low cost of fuel—although increasing in today’s financial climate.
4. Domestic hot water—a by-product of engine cooling
5. Domestic electricity—usually from batteries charged when the engine is running.
6. Relatively compact propulsion system.

Any replacement system would ideally have to replicate all of these points or at least most.
Over the years of my involvement with canals and canal boats I have, from time to time, considered these requirements and have an outline concept of how I would go about meeting them. I must point out that at no point have I considered limiting the concept by cost.

Concept

Stern gear
Standard turbine style propeller dimensioned to suit the boat. This would be coupled to a 1.5ins stainless steel propeller shaft via a ‘standard’ stuffing box and greaser arrangement to a hydraulic motor that incorporates a substantial thrust bearing.

I have stipulated the hydraulic system to a. reduce vibration and any transference of shock to the propulsion equipment, and b. to give flexibility in the positioning of the propulsion engine.

Propulsion equipment
This would be an electric motor driving the hydraulic pump. A standard Morse type single lever control would be coupled to give speed control to the electric motor and direction control via the hydraulic pump. It would require either a 24v or 48v dc motor to give sufficient torque.

Electric power
This would come from suitable rechargeable battery banks (deep-cycle traction type) configured to supply the required motor voltage. I would stipulate that two banks of batteries be utilised to enable one bank to be in use and the other bank being charged/resting. The changeover between banks could be electronically controlled but must incorporate a manual changeover for safety reasons. The 12v domestic power requirements would be derived from the battery bank that is being charged/resting to ensure the motor load variations did not affect the 12v domestic equipment.

In road vehicles the weight of current batteries is a major problem and electric vehicle manufacturers are using very expensive mobile phone technology batteries to achieve acceptable weight and size. This is much less of a problem on water craft as the weight and size can be utilised to reduce the amount of additional ballast that is usually carried.

If sealed batteries are fitted on the baseplate of a narrowboat this would give the ballast required and help to maintain battery temperature at an acceptable level when charging/discharging.

Battery charging
Shore power. This would be used when moored for long periods and would supply a suitable battery charger that would be sized to charge both battery banks simultaneously. Plus 240v ac to an immersion heater in the hot water tank.

Solar panels
These would cover the majority of the roof area and be configured to supply charge to the charging/resting battery bank. Modern solar panels are becoming more powerful and reliable but would only supply DC power to augment other charging systems. They would not supply sufficient power on their own.

Charging engine
To avoid using an internal combustion engine and all the associated ‘bad press’ that goes with it I would opt for an external combustion Stirling engine. As there is no explosive residue the Stirling engine is a much cleaner option (and more efficient) but still has the advantage of being able to run on diesel fuel. These are not common engines and not cheap as mass production has not made them easy to source.
It is worth pointing out that the Swedish navy utilise the Stirling engine for a class of submarines, the Gotland Class, where other navies use nuclear power. The Gotland Class Submarine is an AIP (Air-independent propulsion) type—this means they use compressed oxygen to allow the diesel to burn whilst the submarine is submerged for long periods (weeks).

An alternative charging source could possibly be a hydrogen fuelled engine but whilst I am familiar with the fundamentals of the operation of such an engine, I have not studied the feasibility of its use.

I would estimate that 7-10KW charging power would be required. Additionally as the charging engine can be keel cooled, the hot water tank can be heated from the engine cooling system as with the normal propulsion engines of today.

Conclusion

I feel that the six benefits that currently allow narrowboats the popularity and freedom to travel the British canals has been met with this concept. Whilst realising that this is all a bit fanciful, I do feel that if someone were to be brave enough to consider some of the ideas that I’ve put forward, not only would it be a working electric craft but it could be used as a test-bed for electrical propulsion systems. That said I fully appreciate that it will never happen. As a parting thought, this system would give Her Majesty's Revenue & Customs a bit of a headache as none of the diesel fuel used would be used directly for propulsion, only being used for battery charging or domestic power.