Retrofitting

The balance between radiant heat and excessive humidity with winter boating strikes a happy medium in an old, solid fuel burner.

Companies such as Torqeedo in the Netherlands sell a range of both inboard and outboard electric motors up to 80hp – and they’re good examples of the technology being retrofitted successfully.

Jamie Looner runs the vintage sailing yacht Barbary (1926) on Lake Taupo. He converted her original Perkins 55hp diesel to an all-electric power train five years ago. He claims to be the only commercially-operated electric yacht in New Zealand. He switched to help preserve the lake’s pristine waters which serve as the town’s drinking water supply, as well as offering a Taupo sailing experience second to none.

While he sails when possible, the 48ft ketch often needs more breeze than is on offer. To help maintain the schedule when touring the lake, Jamie would ‘donkey on’ and motor-sail. But as he points out, the wind is ‘free, and clean’ though not always a good business partner and ‘no wind means no sailing’.

Barbary’s electric motor was supplied by ELCO in the US, her batteries by Hawker and charger by Enatel, here in New Zealand. Jamie says the actual time to make the conversion was very short – it took only two hours to fit the ELCO motor onto the existing straight shaft running gear. The hardest part was cleaning up after the old Perkins. Both motor and batteries have performed flawlessly and have been ‘worked hard.’

The 54 Hawker two-volt batteries are lead acid, and though they weigh more than a lithium pack they are much cheaper. Still, the whole installation added only a tonne to Barbary’s 13 tonnes, and pushes her along at four knots for over a 100-mile range, or at 5.8 knots for a 45-mile range.

Based on the 1,500 recharge cycles, there are another two years of life left in the batteries. Recharging is done overnight, plugged into mains power at the dock. The fuel savings from the conversion has paid for the batteries twice over in five years – a second vessel is now being converted.

ADVANTAGES

Still, electric propulsion does have advantages over diesel engines. A major one is high torque and a near flat torque curve characteristic. In short, the power is available instantaneously and smoothly.

This suggests much bigger diameter props with a higher blade area and potentially coarser pitches can be fitted to a direct-drive shaft, giving much higher mechanical and propulsive efficiencies. In turn, more of the power makes it to the water, meaning less drain on the batteries…… meaning less battery capacity…less weight. You get the idea.

DRAG-REDUCING HULLS

For anyone considering installing electric propulsion the best place to start is with a new build, and ideally with composite construction. Composite construction reduces structural weight compared to aluminium, albeit with a higher initial cost. Reduced weight allows for a more slender hull form, reducing drag, so fewer batteries.

Studies by Swiss composite specialist Gurit have shown that the higher cost of a 20m commercial catamaran’s composite construction was more than offset by the reduced fuel and maintenance costs relative to a diesel-powered craft over a 20-year service life.

Depending on the level of technology – e-glass/foam or carbon/foam – the 10 to 20 percent increase in construction cost over alloy can be offset by a similar reduction in fuel costs. This becomes particularly significant when you consider that fuel/ maintenance cost over the 20 years was more than four-and-half times the construction cost of the alloy vessel.

Effectively, the savings from a carbon vessel brings the operator most of the cost for a new vessel after 20 years. This is not to mention the benefits of lower CO2 emissions. A composite, electric-powered ferry would pay its way – and with zero CO2 emissions from the vessel itself.

In summary – a viable, electric-powered vessel requires careful analysis: of the vessel, its total weight and operating speed – which will influence the hull form – and the battery life required. B

New Zealanders tend to live in denial about living in a cold country. We build houses like tents and sleep with the windows open all winter. We like fresh air and will endure any amount of cold that comes with it. The rest of the world looks at us with horror from the closed window comfort of central heating or the humid insulation of tropical climates.

Our boats are no different. We keep the hatch open; we have no insulation and no heating. We are perpetually on a summer cruise, with rum sundowners and flow-through transoms and seem not to take note of the three other seasons.

I spent my youth surfing all winter and sailing in shorts. It was fun – and miserable cold was considered something that built character. That was until I got older and I married a Canadian. Both cultural exchange and age taught me one important thing: there is no dignity in hypothermia.

While other aspects of my life became well-insulated and warm, our yacht Siward did not. I yearned for a nice on-board heater to beat the Canterbury winter. I even noted the installations on other boats in our bay and measured up potential locations for a heater in the interior.

The complexities of installation and the fact that when summer rolled around I would forget about the cold, meant that a heater was never added to her inventory. The best I could do was offer a hot water bottle to anyone foolish enough to spend a winter evening aboard.

The idea of winter heating remained a distant wish until we purchased our new yacht Whitney Rose. Her clean lines and glowing timber interior drew many admiring looks, but it was her handsome solid fuel heater that occupied the space next to the mast on the forward bulkhead that drew the most attention.

oxygen and for this reason keeping a hatch cracked open is always advisable. This allows fresh air in and vents moisture out.

Once the humidity starts to drop to around 50 percent the heat kicks in. After an hour we will be sitting in 24oc and 34 percent humidity. By then we are swanning around in T-shirts. Any trip on deck will be followed by a string of curses that roughly convey the fact that it is quite cold out there.

The downside to a solid fuel heater is that you have to carry the firewood. On Whitney Rose we have a special sack that stores beneath one of the bunks full of pine cones and untreated builders’ off-cuts.

The ship’s arsenal also includes a bow saw which comes in handy for trips ashore to scavenge the odd dead pine tree. With control of the vent and flue damper we can have everything from a roaring fire to a slow, smoldering all night burn.

The other disadvantage of the solid fuel heater is that every season we have to sweep the chimney. Gritty experience has taught me never to buy a two-dollar shop brush for the job. Exactly halfway down the flue the head will snap off and you will spend the next hour trying to entice it back up, only to ram it all the way to the bottom in frustration and spend the next hour trying to tickle it out of the bottom of the flue into a very sooty firebox.

On a cold night memories of this stuff will wash away like a sooty stain on your hands, as you warm your feet to the sound of expanding cast iron. The initial lighting of the fire will send a tell-tale puff of smoke out of the chimney.

This is a sign to any boaties anchored within eyeshot to head over to say hello. The fact that you appear on deck in a T-shirt in winter will further lure them in, to the point that they will be gathered around the saloon drinking your rum with an unwavering eye on the heater saying “Oh, I have always wanted one of these on board.” B