Avoiding engineering calculation paralysis

Two recent examples have in equal measures frustrated and amused me.

In their plans for Ruby Rose 2 Nick and Terysa have oodles of calculations but they appear to be aimed at justifying fitting large diesel engines because an all electric boat isn’t possible. They seem to have totally missed what was shown to be possible in their interview with Dan and Kika from Sailing Uma.

Then there is the subscription website “Attainable Adventure Cruising, The Offshore Voyaging Reference Site” with an article in the last week “Induction Cooking For Boats—Part 1, Is It Practical?” where I joined a discussion coming from our very different approach.

Both these present a numbers based “engineering” approach to decision making about the “practicalities” of moving away from fossil fuels. Sadly due to the initial assumptions the approach almost always leads to the conclusion that renewable energy sources cannot provide enough power for either propulsion or cooking.

The approach rejects working examples because they don’t present numbers in an “acceptable” way.

Our problem with this approach is that it is simply too easy to make assumptions about what is needed and the conclusion depends far more on the assumptions than on the calculations. In both these cases the assumptions are based on the expectations and lifestyle of a couple.

Ruby Rose have assumptions about never compromising on a luxury lifestyle with every modern convenience.

John and Phyllis have decades of experience cruising in high latitudes and strong views on what is safe and seaworthy. They have a stated goal of not considering anything that has not got a 10 year history of reliability.

Both these approaches are flawed if the goal is sustainability (or if budget constraints are tight). So if your assumptions are that you need to motor for an hour at full speed, and 500 miles at cruising speed, cook for a couple of hours every day, run a water maker, washing machine, multiple fridges and freezers, electric auto pilot, video editing laptops every day then you are going to conclude that renewable energy sources can’t cope.

Cynically if you control the list of things that you want to run all the time or anytime regardless of the conditions then you can guarantee that you will never be able to manage with renewable resources (at least until the last oil well has run dry and the Netherlands has disappeared under the sea).

Yet there is another way. One that we find most often from people with limited resources.

Embrace the limitations

Or start at the other end. Start with the resources that are possible.

  • What battery bank capacity can I afford?
  • What size battery bank can I fit (size and weight)
  • How many solar panels can I fit (and afford)?
  • Is wind generation going to fit my boat, my budget, my geography?
  • Is water power generation either from regen on an electric motor or something like Watt and Sea going to work (how much time sailing at suitable speeds)

These provide the constraints. Then sustainability becomes how you live within the constraints. There are plenty of options.

  • A vegetarian or vegan diet (as recommended as a key way of reducing our carbon footprint) can reduce the cooking energy significantly (no a roast chicken cooked for several hours is not required every week, if you want it then save your energy up first, or use a solar oven)
  • Set your passage plans according to the energy you have, probably slower (but then the whole point of sailing is surely to sail)
  • Set your cruising ground according to the season and energy available and required (so you probably can’t sail sustainably into an Arctic winter which is just a constraint, like the ones the majority of people live with all the time)
  • Have food available that doesn’t need to be cooked if you are short of energy (Huel and the like)
  • Plan to use appliances when you have the energy, keep the ones that have to be on to a minimum (eg freezers, fridges, autopilots).
  • Embrace the constraints. Do you really have to be able to do the washing, make water and cook for 2 hours on the same cloudy day – if yes then why?
  • To be honest the list is endless, we have gone in just a few years from it being normal to only use an engine in harbours to expecting to motor constantly for days at a time. From no refrigeration and basic hobs to dishwashers and ovens and drinks coolers in the cockpit.

The argument that it isn’t possible to live within the constraints of renewable energy is disproved by history. It is disproved by the examples already documenting their experiences eg Sailing Uma; and Beau and Brandy.

The challenge is to our assumptions, our privilege, our expectations of luxury. The opportunity is to open ourselves to the impact our lives have on others and to stop seeing ourselves as deserving something that our actions deny for others both now and in the future.

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