Motorized yachts seem to be quite a bit larger with much more Sq footage built above the water level than their masted brethren, why is this?
I’m assuming the masts have something to do with it. Is it because they would torque the boat too hard if they were higher up? They already seem pretty high up as is and older vessels like Galleons in pirate movies seem just peachy with a ton of room above the water level. Why is it that most luxury yachts now are so low?
Edit: to clarify I mean shorter as a function of verticality not the length of the boat.
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I guess I’ll have to settle for a small crew and a tiny boat, instead of my dream of recreating Pirates of the Caribbean.
I think you might be looking at the difference between sailing yachts which are designed to sit in and cut through the water at low speed and most motor yachts which are designed to plane over the water at higher speeds to achieve fuel efficiency.
The most obvious factor is the power requirement of a boat/ship, which is partly a function of its size (must overcome mass and the amount of resistance to movement which increases with surface area of the vessel). Winds can only provide a fairly limited amount of power per unit area of sail, but motors can provide huge power outputs per unit volume.
A big problem as well is that sails are weight ABOVE the waterline. Tend to offset that by adding a deep keel to prevent turtling (rollover). However, a well-designed motorized vessel can have the bulk of the power system below the water line, so a lot more mass (weight) can be placed ABOVE the water line.
Also, the lever rule comes into play a bit with sails. The distance of the push from center of mass accentuates the sideward movement that results. High sails will accentuate lateral rotation. TO avoid that and still get good power from having large area of sails would require extending the sails outward while close to the waterline, and that adds its own problems. This is also partly why keels run so deep, the lever rule at work in the other direction.
Top underline the point, imagine the amount of sail that would be needed for a ship like the Titanic to get the same power that its massive engines provided.
There’s a few reasons, I think. I believe that there’s nothing inherent about sail power that make huge yachts less common. There was a whole fleet of non-motorized steel cargo ships in the early 1900s. [Sail powered freighters](https://en.wikipedia.org/wiki/Flying_P-Liner?wprov=sfti1) The Flying P line ships were in the neighborhood of 400 feet and 15000 tons, with motorized rigging to reduce crew requirements. So the tech was there 100 years ago for massive sailing yachts.
I think that the mega yachts are mostly flex; flamboyant consumption. Having a boat that requires hundred of thousands of dollars to keep fueled is a pretty simple way to show you’ve got more money than you know how to spend. They are not interested in saving on fuel. And I suspect the owners are the kind of people that want their floating mansion to be in exactly where they want it when they want it. With no dependence on the weather.
People wanting the ability to sail upwind its the main reason. If you think about historical sailing ships from before the steamship age, they actually have a lot of freeboard—which is the name for the height of habitable structure above the water line. These ships were designed for sailing downwind (the same direction as the wind is blowing) or across the wind (at a right angle to the wind). Having a lot of freeboard like a modern motor yacht just meant that the wind pushing against the superstructure and hull would act with the sails to push the boat in the right direction—no problem, or at least just cause the boat to heel (lean away from the wind) a bit more when sailing across the wind. Back then, trade routes were established so that ships were always sailing downwind or across the wind.
Modern yachts need to be able to travel in any direction efficiently, so that they can go on day sails, out and back, all while the wind is blowing the same direction; they need to be able to race on loop shaped courses, and cruise routes built around modern schedules rather than the prevailing weather patterns. So the ability to sail upwind is much more important. Rather than acting like a parachute like old time sails, using primarily drag to move the boat, modern sails act like a wing, where lift is the primary force. This allows for sailing as close as 30 degrees off a dead upwind course, making it possible to track (turn back and forth) on headings close to the wind to make a course dead upwind. This is where freeboard becomes a huge problem. The superstructure and hull don’t generate lift at the correct angles to help the sails out. They just act against the sails.
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