The issue of the 'sunk cost' (energy wise) of a boat built in 1982 (for example) is a moot point...
The real issue - from an environmental perspective - is the "embodied energy" used to produce the boat, and then the "lifetime energy usage equivalent".
To explain that: the difference in embodied energy in a wooden boat as opposed to a fibreglass boat is that more trees can be grown to replace the timber used in the wooden boat, so potentially a 'zero sum'. No impact.
Whereas the oil and electricity and/or coal used to produce the fibreglass, the resin etc etc etc, that has an embodied energy cost, which has to be amortised over the life of the vessel.
It's like the argument for and against
buying a new car. Will the tiny improvement in fuel efficiency offset the massive amount of embodied energy involved in making all the components that go into a new car?
The basic science says not.
So in fact, we're better off using older cars for longer, but at some point, that comparison reaches a zero sum.
For example, if comparing a 7-litre V8 Caddy from the Seventies to say a 1-litre turbo-charged city runabout today.
Even if the "design life" of the runabout is only 10 years, it *might* be producing less CO2 and energy cost than the Caddy, even over its relatively shorter life span, than the Caddy has over its much longer lifespan.
In other words, the Caddy is still consuming 13mpg while the runabout gets 70mpg.... but because the runabout will fall apart in 10 years (maybe) and require replacement (with all the embodied energy in that) while the Caddy can go on for another 30 years (probably) continuing to amortise it's *original* embodied energy cost, at what point does the overall energy
consumption balance out??? If it does???
If that makes sense to anyone....
I'm not sure yet if we've reached that point, but it would need a LOT of genuine, scientific measuring to come up with the answer.
So for now, I continue to drive my 25-yr-old Toyota that gets 33mpg, rather than "upgrading" to a more modern car (a Prius??) that gets 78mpg, as the embodied energy in the Prius is probably a lot greater than the (diminishing towards zero) embodied energy factor in my old Corolla. And as the Corolla has only 150,00km on the clock, and I do around 10,000km p.a., the lifespan of the Corolla is probably another 20 years, at my rate of usage, but if I switched to a smaller car with much lower fuel
consumption, would that overall usage equation balance out somewhere over that 20 years...???
Personally, I doubt it, but it probably would for someone doing higher miles and consuming more fuel and oil.
So, basically, YMMV.....as will mine....
And perhaps it is / will be the same with
boats, if anyone ever gets around to calculating such energy consumption / embodied energy factors...??
Also need to factor in is that a wooden boat might also use natural fibres for its lines and
sails (as used to be the case) so fully sustainable, 100% replaceable. No environmental impact. (But for now lets not count the water and electricity used to make ropes and
canvas.....but it is a factor...so noted...)
So whereas the fibreglass or
steel boat has a much higher embodied energy quotient, thanks to the mining of the oil, iron ore, coal etc used to produce it, plus the electricity-from-coal used to actually make the actual boat.
BUT.....if the fibreglass boat lasts 60 years (many have done so and are still afloat) while the wooden boat rots away in less than that (as used to happen) then does the cutting down of *another* forest to make the second boat (required to make up the time to 60 years and so make up for the rotted one) not negate the embodied energy in the 'glass or
steel boat???
I know, I know, there are 100+-yr-old wooden
boats still sailing, and lots of wooden boats from the Sixties still sailing....but most 'old wooden boats' have gone to Davy Jones. Especially
work boats. Yachts there are plenty, but again, not all, because other than sinking or actual run-over-it-with-a-dozer destruction, most fibreglass boats built are probably still around today. (Exaggeration for the purpose of making a point, not a scientifically measured fact...).
I don't know, and I don't believe anyone really does know, but it *would* be interesting to see an academically researched paper that went into such questions in much, much, more detail.
As a further point, to illustrate the 'unknowns' - someone mentioned man-made ropes earlier, and the fraying of said ropes into 'microfibres' that are having an 'unknown' effect on the
environment and the
food chain, but which is beginning to be of concern to scientists studying microplankton and other small organisms, who are now seeing increasing quantities of microplastics embedded in the tissues of such organisms, not just in their gut (like seabirds or turtles, dying from plastic bag ingestion). This "environmental impact" is currently 'unquantifiable' but clearly is becoming an issue. Time will tell how much of an issue, but, in the meantime, do we go on recklessly, regardlessly, discarding such 'waste' into the environment? Can we even, practically, prevent it???
So, to be "pure" and "fully sustainable" should be be going to back to wooden boats (perhaps epoxy-sheathed for longevity..??) and natural fibres like flax and cotton for lines and
sails...??
I don't see anyone arguing for
that level of "sustainability" on this (or any other) forum. But, strictly speaking, to reduce our "impact" to zero or better, those are the sorts of steps we perhaps should be contemplating.
Certainly, that's what the Prius-driving hippie-crites would have us believe. And forget MUSTO, we'd be back to animal skins for warmth, and air-filled intestines for floatation. NOT!
So, like others have said, I think, on balance of probabilities, a sailboat, even a relatively new, fibreglass sailboat, probably has less impact over its lifestyle than even a wooden boat of the same size, especially if that wooden boat is not sheathed to keep out teredo worm and
rot.
But the 'balance' is going to be, necessarily, subjective, and each sailor (and boat owner) will have a slightly different take on what is, to *them* the more important factors in this equation.
Wood, or fibreglass? Sheathed or not sheathed? Natural ropes or synthetic? Maybe it might even be possible to sheathe
Dyneema in natural fibre outer sheathing, as that wears first and fastest??? Wood-fired
stove for
heating (burning driftwood) or diesel-powered furnace??
And again, as I said previously, how relative is that - probably very small - impact of the microfibres from synthetic sails and lines, compared to the impact of trash
washing unhindered into the oceans from both developed (but especially) developing countries?
For example, one 'monsoon's worth' of rubbish-choked run-off into the oceans might dump more microplastics in one hit than the entire whole-of-life degradation and production of microfibres of the entire world's yacht fleet for the next 50 years....
So, should we give a toss...???? Or not?? Or by how much of a toss??
Again, it will come down to 'personal choice' and we must respect each other's individual choices. No right or wrong answers here.
On the subject of nuclear power, on the other hand, if we say it's a "better" solution than coal-burning power stations, we are being, at best, disingenuous. It's not just the lack of acceptable long-term
storage of the intractable waste that's the issue for the wider population (and by that I don't mean just the greenies - I mean *all* the general population) it is the lack of 100% guaranteed safeguards against nuclear explosion, meltdown and widespread contamination that is the issue.
Remember Chernobyl and Pripyat?? Unable to be safely inhabited for 100,000 years or so. How much more of the planet can we risk that happening to??? Not an acceptable risk, IMHO, and it appears the general public agrees with that view.
So, sorry, no, "fission" is most definitely NOT the answer to our present problem. "Fusion" or "thorium" *might* be a solution, down track, if we can figure it out. But we're not even close to that point yet. Emphasis, yet.
Add to that the cost of building a nuke plant these days, and renewables are already in front, financially. It's actually cheaper to build renewables now than coal-fired plants, megawatt for megawatt.
OK, accepted, that's "production per watt cost only" - not "balanced deliverable power cost" which requires the addition of mega-batteries like the one Tesla recently built here in South
Australia, but, even that cost is dropping almost while we watch.
And please do remember that the *real* cost of coal, oil and gas-fired generation does NOT include a 'correcting factor' for the *actual* cost to the environment, to
health sytems, etc etc. If it did, renewables would probably be WAY cheaper, even with the additional cost of the 'balancing batteries'.
That much at least the economists HAVE calculated. Without the "cost of carbon" being factored into the cost of coal/oil/gas-fired power, renewable generation is ALREADY cheaper than fossil fuel generation.
I read recently that a
solar PV plant capable of generating power for the whole planet would be about 350 square kilometres in size. Do any of you realise how big
Australia is and how much sunlight falls on it?
At that rate, in central Australia's Great Victoria Desert
alone we could put enough
solar panels to power 10 planets (at our
current rate of usage).
Of course, we might need a
lithium battery the size of
Ireland to balance that power into the grid, but hey.....we're talking 'stardust' for the moment. Pure "hypotheticals".
But molten
salt batteries, and other cheaper battery tech, is coming on stream to do just that, so, it really is just a matter of time.
So those of us on sailboats, with a few solar
panels and a cuppla batteries providing all the power we need on a day to day basis, right now, today - well, we're just ahead of the curve!!!