This was originally posted on my political blog at https://politicalmusingsofkayleen.blogspot.com/2022/01/way-way-way-off-topic-thoughts-on.html.
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In recent years there has been a strong interest in a return to using sail-driven vessels for cargo - largely in the interests of reduced environmental impact. Probably one of the most spectacular of those currently under construction is the "Ceiba" - website here (they have quite interesting videos) - and there are a few in operation elsewhere (see here - I'll refer back to one of these shortly).
This is intended to be a for-profit commercial venture, which such projects have to be if they are going to be a viable option for reducing the impact of commercial mechanically-driven cargo vessels, many of which have appalling fuel characteristics when they are at sea (they change fuel grade when close to land), quite apart from the inherent impact of using fuel rather than wind.
That
is a noble and actually widely desired goal - even mechanically-driven
vessels have been looking at using parasails and vertical turbines to
gain some advantage from the wind. Traditional rigging clutters decks
and makes modern containerised cargo handling impossible.
They've also been looking at air injection to break down boundary layers, which, based on my experience racing small sail dinghies (which used venturi bailers to remove water - which also sicked air if left open when the bilge was dry) as a kid, I KNOW works. I'll come back to this again shortly.
To simplify considerably, some of the main reasons sail-driven vessels lost out to mechanically-driven vessels was a combination of:
- greater surety of travel times - mechanically-driven enable schedules to be made and more-or-less kept to;
- faster travel - cargo ships now travel at up to 30 knots and don't have to worry about the doldrums when crossing the equator; and
- the
lack of rigging enabled the use of shipping containers, which cuts down
time in ports and thus shipping charges, as well as also reducing the
need for, and thus cost of, skilled and unskilled labour to load and
unload.
Now, the sail cargo projects that are getting most attention are those using traditional approaches, but at least one (refer to the second link above) is using modern materials (aluminium, which has an extremely energy-intensive manufacture) and containerisation. These do have advantages over timber in terms of strength, but their mining and manufacture causes damage and GHG emissions that are contributing to the climate crisis and environmental damage.
There are, however, some lessons that can be learned from modern shipping practices, and I would suggest they are the following.
Firstly, build ships to use containers - perhaps to "10' container", or cube. I've put a cross section below showing how this could be done, but it may need stronger construction techniques than traditional timber - e.g., epoxy reinforced timber, perhaps, or a modest amount of metal work, as is being done with "traditional" construction.
A
double skinned construction could be achieved in a number of ways. As
the inner liner would only need to deal with the pressure of a leak, and
not the impacts of going over waves (although that would convey a pressure surge),
perhaps a plywood material would suffice - but having a cavity that a
tank could be put into to use water ballast would add modern sailing
knowledge into the mix, just as does using containers, and things like
air injection under the hull to break down the boundary layer.
Is it traditional? No.
Does it allow better use of the advantages of traditional techniques? yes.
The second suggestion that would enable better use of sail power is cleaner rigging - something which allows space for handling containers, and possibly increased safety by not needing people to aloft as often, something which may incorporate the means to handle 10 t containers, like . . .
We could also put solar panels on the yard arms to, amongst other things, drive electric bow thrusters or short term electric propulsion for entering / leaving ports etc.
Just a few thoughts aimed at trying to combine the best of traditional with the best of modern . . .
(And
in terms of usage, I'd suggest a vessel like this may be good for
archipelagos, much as small planes can be used flexibly. Also, I used to
use my blog here for such ideas, but haven't used it for so long I se little point in trying to resurrect it for this.)
