You have no idea what type of sailing or boating
I have, and I won't go through my résumé here. But I have been directly involved in a number of record
setting attempts, and worked with a number of major racing
programs, and distance attempts.
You are right that the first step is to dream, the next step is to identify what people before you have tried, and what worked and what didn't. The next step is to see what technology is out there, and what would have to be created to make an attempt technically possible.
Right now the state of the technology is such that an outboard cannot cross the Atlantic at planning speed. This isn't an opinion, it is simple fact. Uscg like saying I want to take a balloon to the moon might be a dream, but that doesn't make it remotely technically possible.
The fact that the OP suggested a record
attempt that is currently technically impossible doesn't bother me, it is that he has spent so little time even trying to figure out where the state of the art technology is, and what he could reasonably expect to need to create to do so.
From the bottom up outboards are designed in such a way as to ignore fuel
efficiency. They have other advantages, but for this concept
the OP has intentionally selected the worst tool for the job, and then made the attempt all about trying to force it into compliance.
So lets look at the problems an outboard presents to this type of attempt
1) prop efficiency is directly related to prop size. The larger the prop is the more efficient it can be. But an outboard is inherently limited in size because of the leingth of the drive leg, and the cavitation plate.
2) the gearing hub and drive leg create massive drag at high speeds. Again this can't be removed, because of the inherent design of the thing
3) planing is incredibly fuel inefficient. Because they require the motor
to produce enough power to not just drive the boat, but also to lift
4) outboards are severely limited in the size of the vessel they can power at planning speeds.
So what can we do to fix these problems... Well 1) can be amelorated by adding a deeper drive leg, but at the cost of huge parasitic drag from the extra wetted surface. 2) can be improved by shortening the drive leg, and removing it from the water
, but this negatively effects 1). 3) can be eliminated by slowing down, but this is outside the attempts challenge. 4) restricts the size of the boat which also restricts the available fuel capacity, it is this relatively huge fuel capacity that is required because of the inherent limitations of 1-3 above. Fix the fuel efficiency problem and there may be some hope.
But there is no way forward within the design limitations placed on the challenge. Because the OP has specifically selected equipment
that is inherently a poor choice to try this.
If instead he had asked what it would take to beat a powered distance record, we could be talking about different designes, and realistic technology to implement to achieve that. Realistically the cheapest way is to design a larger version of what currently holds the record, or try and find a design that is more efficient that the current