Brain Teaser: Renewable Powered ‘Flying’ Yacht

[clmanges]

I would be surprised if that were so. I would think the deep ballast would act as an anchor in the liquid medium underneath the surface waves. The hull would both heave and be shoved back and forth with each passing wave. The result would be roll as the hull pivoted around the more stable keel ball.

If it is to hard too gimbal the working space of the whole vessel. Perhaps individually gimballed elements of that space would be a good compromise.
halbkardanische Koje | kardanische Schiffskoje | gimbal bunk | gimbunk http://www.gimbunk.com/
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The concept is simple. And can be refined by adding a second axis.

Those look like huge consumers of valuable onboard space. AFAIK, hammocks still work; you just have to learn how to get in and out of them.

 

[portacruise]

I like the simple idea of hammock chairs and beds! But wouldn't occupied hammocks have a pulsing feel with at least some of the wave disturbances, or is there some kind of damper (springs?) effect that keeps them steady? Just thinking there might be a noticeable inertia effect depending on the amplitude and frequency of waves that causes a temporary and repeated change of boat speed and direction plus elevation? Maybe the inertia effect would be small and unnoticeable... And I guess the inertia Factor might also also be a consideration for the other approaches, like suspension or gimbals? Hammocks maybe not equal to the motion smoothness of a swath or hydrofoil, which are more or less decoupled from waves?

 

[zstine]

I agree with portacruise in that hammocks chairs and gimbal beds don't really satisfy the design brief. First, You can't cook, go to the bathroom, walk around, etc in a hammock or bed. And we've tried hammocks on a moving boat and at times it swings around dangerously and is even more uncomfortable. Even if the hab space was on gimbals, you haven't decoupled from heave. I think that up and down, weightless feeling, contributes a lot to sea sickness. So without decoupling from heave, you have only solved half to design brief.

 

[tlouth7]

It is a small waterplane area compared to a standard yacht, and coupled with high displacement that will give a much reduced motion.

I would be surprised if that were so. I would think the deep ballast would act as an anchor in the liquid medium underneath the surface waves. The hull would both heave and be shoved back and forth with each passing wave. The result would be roll as the hull pivoted around the more stable keel ball.

On the other hand the small waterplane means a reduced form stability and so less rolling and pitching moment generated by waves. Also the high moment of inertia from the large weight far from the roll axis reduced motion. Heave is a function of waterplane area and displacement so again that is reduced.

This is a well established approach to reducing motion in waves, the disadvantage being that such boats tend to be slow due to low SA/disp and L/disp. This could potentially be mitigated by using a kite rig (to get more sail area without increased heeling moment), by sailing at really extreme heel angles with a large rig, or by using a canting keel to keep the hull moderately upright.

 

[zstine]

plank on edge boats simply do not have a waterplane coefficient that is anywhere near a SWATH. They are certainly not decoupled from wave motion. And this boat type would certainly not meet the design brief of 'plateau' operations up to 6 ft waves. In essence, no perceptible wave induced accelerations in 6 ft seas, be it short chop or long period swell. Plank on edge boats are not even close to meeting the need.

 

[portacruise]

How long does the Decoupling have to last ie. is it only temporary while at rest, or also while underway? If continuous decoupling is required, it may dismiss active decoupling principles requiring continuous power, like hydrofoils because of the continuous energy required? That would only leave swath and huge Balloons with enough power to lift the whole craft, haha? With the speed and draft requirements, back to the blimp, which really isn't a boat at all, haha!

 

[zstine]

How long does the Decoupling have to last ie. is it only temporary while at rest, or also while underway? ...

Only while underway, 5knt to 10knt speeds. And even then, only in deep water. Anchorages and inland waterways, like the ICW, are generally calm enough to not cause seasickness in a boat this size and don't require decoupling. I would except any shallow water operation (where foils, etc. may need to be retracted) to not be decoupled from the sea..
I think at the sub-hump speeds we are talking, foils by themselves are out do to the massive surface area required, but perhaps combined with a buoyant demi-hull, they'd be ok. I'm curious if a submerged demi-hull of 100% displacement (~neutrally bouyant vessel) with as small as structurally possible struts is more efficient (maybe allow 10-13knt speeds?) than a 110% surface running demi-hull that pierces through waves. 110% bouyant hull with a ship displacement of 10ton results in max heave acceleration 1/10th that of a slow elevator. I don't even think you'd be able to feel the acceleration.

 

[Will Gilmore]

Anchorages and inland waterways, like the ICW, are generally calm enough to not cause seasickness in a boat this size and don't require decoupling.

I generally start to feel seasick as soon as the lines are cast off. It lasts for three days and then, it doesn't matter what weather we get, I'm good.

Have you looked at the gyro stabilizers available?

 

[member 76956]

I just saw this.

Didn't Infinity Motors (Honda) build autos with decoupled passenger compartments back in the '90s. I think they called it "The Active Suspension System." It was very expensive and I think it created cornering problems in high-speed turns. I don't know really, I never got to ride in one. Seemed like a good idea though.

BTW, I really like these kind of thought experiments. I'm just starting out; but, I hope you'll let me paticipate in some of your future chats. This is kind-of my cup-of-tea.

Cheers

 

[member 76956]

BTW, my idea of a decoupled living space is tying a couple of plimps together side-by-side and hanging a Bernd Kohler KD860 from it, like in the movie UP!

I also kind-of liked this guy's idea; but, I suspect it's a little too Steam-punk for you and a bit light on practicality. But, as an icon, I think it's pretty cool.

I also think the following is a good platform for a decoupled living space, in a central container, possibly with amphibious capability. Just add a pair of stayless balanced-lugs, on both sides, similar to the Harry Proas, or Quad Magnus-Effect sails, two on each side. Again, this is fanciful. It hope it meshes with your brain-storming style.