This is neat, but I wonder about applying thrust through the container?
I also was kind of expecting a kite TBH. I wonder if the extra work of a kite is a good trade off, I feel like the tying off the thrust issue is easier with a kite than a mast.
Edit: I see wingsail in the title and I think it’s slightly ambiguous. I want to say this is “mast” based? Not a tech issue but
From our first analysis, applying the thrust through the container seems doable; the containers are secured to each-other and the ship via mechanical "twistlocks", which are designed to handle not just ship loads, but also trucking loads (such as a 2g hard braking from a semi). The roll loads are actually the more difficult design challenge.
Regarding kites, we looked at those quite a bit. The challenge with those is that kites tend to be best for when the wind is coming from behind you or crosswind. For a container ship traveling at high speed, the kites would act more as a parachute and slow you down (even if you were extracting energy from them).
Master Mariner here with bridge experience from sail assisted vessels both conventional and through magnus effect equipment. Also a lifelong sailing competitor.
Have you considered the effect your design has on the drift and drift angle of a vessel yet? Looks like your aiming to benefit from conventional sail assisted lift but there is a thin line between lift and drift. The negative effect of drift induces increased consumption so some kind of trimming needs to be done quite fast to maintain lift effect. To maintain an optimal angle of attack to get the maximum lift requires quite fast adjustments which on sailboats can be done in two ways, either by trimming sails or adjusting course. Adjusting course on large cargo vessels takes quite a while so i don't see that as an option unless the sail is hooked up to a fast acting autopilot.
Do you have plans for how to get the effect of the sail into the loading computer? Would be surprised if any of the current software is capable of handling a dynamic input like that. Seems like an interesting problem, but tough.
Yeah, I'd say that kites would be far more practical considering that automatic piloting should be easily solved (trivial compared to e.g. driving cars or landing rockets) and structural changes to the ship would be so much smaller.
But https://skysails.com have completely given up on ships (full focus on stationary electricity generation), and they had already been at the point of operating an installation on a real life freighter. But at least it's not clear that their goodbye to ships was due to technological challenges: it might be because of unrelated business events, e.g. the shipping company they partnered with was already on the course to failure (chances are from their perspective the kite project has been a desperate hail mary from the start), and are some point the not-electricity part had mostly pivoted to shopping management software and that part was eventually completely separated from anything kite related.
SkySails which is the company knew tried kites seems to have given up ships and changed focus to land-based power:
> SkySails is the pioneer of wind-assisted ship propulsion systems based on kites. The technology was successfully proven on board of sea-going vessels between 2004 and 2012. However, in order to make the biggest possible impact on the ongoing energy transition, SkySails decided to focus on the dynamic energy sector with its SkySails airborne wind energy systems for power production for the time being.
> The SkySails propulsion system for vessels is therefore currently not marketed anymore.
I also was kind of expecting a kite TBH. I wonder if the extra work of a kite is a good trade off, I feel like the tying off the thrust issue is easier with a kite than a mast.
Edit: I see wingsail in the title and I think it’s slightly ambiguous. I want to say this is “mast” based? Not a tech issue but