Electric drive conversion - main ideas

This picture shows our boat the summer (2006) before conversion - but it looks just the same now!

It's a 38' ex-hire boat, all steel, cruiser stern, Colecraft design, originally built 1982. My wife, Jane-Gordon-Cumming, and I bought it in 1997 in working but not exactly wonderful condition! Since then many things have been altered to get and keep it in good condition and and make the domestic arrangements more convenient.... to suit us, anyway!

By the time this photo was taken, we had already been wondering about conversion to electric drive and so had recently had several major things done to keep the boat up to scratch...

1. A "deep" repaint - most of the metal angle-ground back to "bare" - and the boat re-blacked. Roof and gunwales painted with "grippy" paint - i.e., sand included (this also has the advantage that the roof isn't glossy and so doesn't reflect bright sunlight too badly!) New name (yellow) patches and lettering.

2. New stern tube - i.e., prop shaft tube/bearing. New "shoes" - plates welded to the bottom and along bottom edges.

At this point the boat still had an old 1.8l BMC standard direct-drive diesel which despite all efforts was getting noisier and noisier... and in fact this photo was taken shortly after we'd just decided to seriously consider conversion to electric drive again - our otherwise lovely few days on the Thames (in the second heat wave of 2006) was nearly spoilt by the sheer noise of the engine...

Domestically, the boat has an old Paloma (gas) water heater that we find works superbly. During our ownership, central heating was fitted using an Alde (gas) boiler - again, works superbly. We don't "winterise" our boat against cold weather, simply turn the boiler on at lowest setting! Oh, and put out a box of chemical drying agent - the cabin is thereby completely free of nasty damp over winter months.

I changed the bow doors to open inward or outward - like a cat flap - the doors bolt to the frame, but the frame itself hinges the other way and bolts to the cabin. Absolutely crucial adaptation - if the doors are opened outwards, people sitting on the tiny bow deck have to lean past the doors to talk to each other and they are in the way for crossing the deck when locking, etc.. On the other hand, if they open inwards, you can't put up the dining table... and they get in the way of watching TV.

The gas cooker and gas fridge were updated during our ownership - the cooker is actually faster than our home gas cooker! - and the fridge... well...

Compared to an electric one, brilliantly silent, of course. However, tended to fail in hot weather... for 2005 I added computer-type fans (turned on optionally) to help circulate the cooling air it needs to have a chance to work. But, of course, these only circulate the cabin air.. which can be terribly hot. As it was in the first 2006 heat-wave when we boated to Banbury and made some nice cheese from the milk.....

So I thought a bit and realised there was a source of (water) cooled air in the cabin bilge. Snag, when lighting the fridge it definitely leaks a bit of gas before it lights. Wouldn't want that building up in the bilge! So I drilled holes in the side of the fridge cabinet above gas level and holes through to the cabin bilge under the dinette seat to its right and connected these with tumble-dryer hose. So for the second 2006 heat wave - the trip when this photo was taken - if you turned on the fans it drew up genuinely cool air.

The milk didn't go off and the fridge stayed cold. Fascinating to feel the air coming out from the fans when you turned them on - started desperately hot and then cooled... and cooled. And the fridge worked. There's an idea that gas fridges don't "really" work which is actually rubbish. In fact you can get electric fridges use the same principle - I had one at one time! The advantage is that they are completely silent. But they DO need (as does a compressor electric fridge - but slightly less crucially) what us scientists call a cold "sink". In our case, cold air from the cabin bilge.

Anyway, so, with our engine noisy and vibrating a lot, we started to think seriously about trying my idea of electric drive....

I'd idly thought about this frequently by the time this photo was taken and even phoned people up or emailed them to see what sort of things were available. And I'd chased other conversion attempts and read about them eagerly only to deduce they... didn't really work very well!

Yes, there was a solar boat heralded in the press but one of our friends had met it... apparently it couldn't accelerate or decelerate normally or that used too much power. I'd received encouraging data about "hybrid" boats. Encouraging until I phoned to visit one.... the BW receptionist said nobody was around to talk-to. I said, but you must have heard what people are saying about it, are they pleased? She said "Lordy, they are forever out of power and wondering how to get it working... it's never ready to run electric first thing..."

Out of the mouths of babes and sucklings and receptionists.

So I set myself a list of what I wanted and decided to see if it could be achieved:

1. The boat must be able to run exactly like a conventional narrowboat... meaning..
2. No need to arrange ahead charging points or whatever. It must be able to recharge itself so you could carry on indefinitely if one was stalled for bad weather or simply changing your mind... not to be able to decide things at whim would ruin the feeling of freedom narrowboating has!
3. The boat must have at least as much power as conventional drive.
4. We'd spent such ages adjusting domestic arrangements to make us happy, the conversion must go in the existing engine space.

Point 4 was a major stumbling block - I'd gone as far as asking an "expert" to see our boat and suggest a system. Lordy, he completely ignored all we'd discussed by email. We "MUST" have a ton of batteries under the bed. And, be clear, they might explode, so lots of safety considerations. I decided not to expostulate and listened in disbelief. Engineer Alan glanced at me bristling the man was a fool and curiously realised I was just keeping very quiet and mildy asking questions meant the man dug himself even deeper into the absurd....

My brother-in-law had come along said over lunch "the man's appalling!" I said dryly "Yes, Alan doesn't like him, either... I can see why."

Des (brother-in-law) went back to his idea we'd do better to get a new boat altogether designed for the job. I love him dearly but this was financially utterly out the question and besides the point was to find out how to convert OUR dearly-loved boat with all the little domestic alterations I'd sweated over for hours to this electric drive.

Oh, I didn't mention that I'd made under-bed drawers which.. don't work terribly well, but are sealed from whiffs from the holding tank. But that's a problem still to be answered, Jane still finds the loo smelly and off-putting. I'm trying to find a unit to answer her complaints... there seems to be a choice of two... macerator unit or vacuum unit.

Before making other posts to reveal how I resolved the drive problem - with masses of useful advice when I found it! - let's be clear all those problems were resolved. The converted boat now works exactly as my requirements demanded. Truly wonderful.