Solution to problem of hull speed

I believe that a major, fundamental flaw in Mr Jansen's reasoning is that a vessel moving through the water is not a "closed system". It generates free surface waves which radiate from the vessel and energy is carried by the waves. Presumably Mr Jansen's claim is that his design does not generate waves because of the hull shape and location of the propulsors on the sides. I do not believe this will be true; the vessel is certain to generate waves. I'm confident that if he tests his prototype and it does not generate waves he will let us know.

 

Reading his last post I don't think I will take him seriously. Big words with no substance.

 

OK but first it's your turn to be the student. I am only making this response so that you might save thousands of dollars in lawyers and bogus engineering start- ups. (it's the outfitters making money on the miners)

(1) You have displayed misunderstanding of the fundamental concepts:
A boat propulsion system is not a closed system. Water flows into the system at some volume and velocity, then a forces are exerted on it for some period of time, the water leaves the system at a new velocity. If it were a closed system, it would be impossible to generate thrust.

(2) You propose to remove the displacement of water by the hull by removing the water from ahead of the hull and replacing it behind the hull. Has it occurred to you that if the hull does not displace water it will not provide bouyancy? What ever hollow your propulsion produces will just make the hull sink down into the new water surface and it will make waves from there. It's seems you don't even know what makes your boat float.

(3) Fitting the propulsion device at the point of maxiumum axial flow is a good way to maximize the amount of energy needed for a given thrust. The theroretical power required is thrust*velocity and you propose that the thruster be located at the least efficient place and maxium disk loading.

(4) You completely disregard the wave speed of the hollow that you expect to open ahead of your hull. Basically you are proposing the creation of a wave trough that routes water around your hull. It apparently hasn't occurred to you that there is a speed limit to how fast you can open this trough and that speed is 1.34 time the square root of the length i.e. the "hull speed" of the created hollow.

(5) it appears that you do not perceive the differences between transverse and linear waves here ...

(6) here you have left the arena for misapplication of principles and gone into to the realm of jibberish.

(7) Here you show you do not understand that the determinant of yaw stability is forces generated on the hull. In fact by the thrusters straightening the flow aft of the midpont will result in less restoring force applied to the aft of a yawed hull. This will decrease stability.

Thankyou, and please remember that I am just trying to get you to stop your patent council from fleecing you. There are apparently many people falling for this "patent your idea" scheme here in the US. It's gotten so bad that they can afford big advertising campaigns. One of them even features a retired heavyweight boxer that says "people ask me all the time George , how do I get my idea in front of companies?"

https://www.youtube.com/watch?v=_oxPovB51X0

http://www.uspto.gov/sites/default/files/web/offices/com/iip/documents/scamprevent.pdf

 

The OP certainly spins a story, but results speak louder, and that is what is entirely lacking at the moment. Fast Fred may offer odds about whether the OP will ever return with the test outcome !

 

I'm looking forward to seeing the results.

 

It sounds more like the OP visits boatdesign.net in an attempt to
fleece unsuspecting members and impress them with bs phrases like:

"my hull form completely integrates the propulsion system with control
of system flow, with an aim toward asymptotic closure of the system"

"In an infinite system, you're always in the middle, mathematically
speaking."

"Anyone not familiar with fractal mathematics will have to either
accept the math or learn the subject."

That kind of bs is probably effective and dazzling in the real estate
racket.

 

Hey...it's a living.

 

Unless you are familiar with fractal mathematics, you should accept the math he hasn't posted.

 

I'm not sure which will re-surface first, again, this or the submarine train.

 

I don't have anything new to say that hasn't already been said in this thread, but I'll chime in anyway.

Robert, hull speed isn't a speed limit. Pushing a displacement vessel past hull speed isn't new or difficult.

You mean you imagine it doesn't. Reality will show otherwise.

No "tendency to lift" means little arresting buoyancy when pitching, so pitching will be more severe.

"...the closed flow will couple dynamically with the vessel's displacement" is a sentence fragment without meaning in English.

The centre of buoyancy, while often corresponding to the length of the moment arm you're talking about, isn't technically related to yaw at all.

Less moment of inertia means it's going to be faster to pitch/roll/yaw, not slower.

 

After having read the patent application (http://www.google.com.tr/patents/US20140196655?hl=en&cl=en) and seen the enclosed pictures, my understanding is that you are hoping to use the side propellers as a kind of wave-eaters. It looks like you would like to suck the bow wave with the props and to level the water surface around the hull in that way.

If my understanding is correct, then I am afraid that it doesn't work that way and that you will be very disappointed by the end result. The bow wave shall still be there, because it is created by the volume of the hull moving through the water and displacing the same volume of water. And you will have propellers expelling water along the hull plating, thus creating a high friction resistance.

In order to hypothetically achieve what you are hoping to achieve, you would possibly need to move the props right at the bow, where the wave is produced, so that the low pressure area in front of the props can interact with the high-pressure area around the bow. And you would have to expel a huge amount of water backwards along the hull plating. But this, too, would mean a huge amount of friction on the hull plating, a highly-loaded (hence inefficiently working) propellers working with friction-created backpressure, and would require a rather heavy machinery (engine and gearing) to ensure a sufficient waterflow through prop discs. The added resistance due to the sum of these side-effects would IMO more than offset any possible (if any) gain from a partial cancellation of the bow wave with mechanical means.

My two cents worth.