Friday, 20 May 2011

Electric Engines

Super Seals came with the choice of an inboard or outboard engines. Over the years, many owners have converted their outboard powered boats to diesel inboards, this being a relatively easy thing to do.Stargazy however still has an outboard in a well, and I feel their are certainly some advantages to this setup:

  • The engine can be removed from the boat for servicing, and can be taken home over the winter.
  • No Stern gland or seacocks for water to creep in through.
  • Replacing the engine is easy, carrying a spare is feasible (even a lower powered one for emergencies).
  • Clearing the prop is easy, and can be done from the cockpit.
  • No smells down below, many yachts smell of diesel downstairs, especially when under power. This is a sure fire way of feeling sea sick!
However their are obviously many disadvantages to this setup:
  • It's nosier in the cockpit, the engine is under the tiller.
  • Its easier to steal, although it is locked in place!
  • Manual starting (although newer engines are available with electric start).
  • Petrol is volatile, and storing large quantities of petrol has to be done carefully.
  • Fuel consumption is higher than with a diesel, an inboard would probably consume around 1 to 1.5 litres and hour. Our outboard probably consumes around 4.5 litres an hour.
  • Now that 2 stroke outboards are no longer available new, and equivalent 4 stroke models are bigger and heavier, there may not be a model that will fit in the well.
For the type of cruising we will do, I can live with most of these, she sails faster than she motors, so the engine is not my first choice, however sods law dictates that the wind always comes from where you want to go to!

We currently have an 8hp Mariner Sailpower outboard, about a 1998 vintage. While I can't see that in the near future we will need to change, its always good to have a plan in mind to cover any eventualities!

A 4 stroke outboard engine is certainly an attractive proposition, as noise and consumption are lower than 2 stroke. However due to the bigger size and weight of 4 stroke outboards, I doubt that I could find one to fit in the existing well, without serious modifications. I intend to take some measurements with me when we vist the Southampton boat show later in the year, and to trawl round the various manufacturers stands to see if there is a possible fit.

We could look to fit an inboard, however I feel it could be a whole pile of hassle, and is not reversible if we change our minds!

I'm also keeping my eye on the electric engine market. There has been some innovation in recent years, however I'm not sure this will this mean it may become a serious contender...

Torqueedo is a German company, they produce a range of electric outboards, ranging from trolling motors to some reasonably big beasts, such as this one:

(Cost approx. £2699.00 which is comparable with a new 4 Stroke Yamaha - £2015.00)
Now on the surface, it looks like a great idea, it has some clever power management technology that allows you to see what range you have left, using a built in GPS.

The Cruise 4.0 needs a 48volt supply. Torqueedo have been working on a this power pack:
Its a Lithium power pack, which weighs about 20kgs, and approx. 104A/hr, and you'd need at least 2 of these (at around £2k each). I'd recon a budget of £7-8k would give a setup that could be used, however that's a big outlay. And at 4.5knots, you would still only have a range of 13miles! Recharge time is quoted at 11hours per battery.

I love the idea of electric propulsion, however the equivalent 40kgs of combustible fuel (approx. 40litres of petrol) would give me a range of 30/40 miles and with £4000 I could motor for approximately 2800 miles!

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