Super cavitating very high speed stealth surface vessel

[Bob Abell 2Participant @bobabell2]

Wow!……..Gerra load o` this fellas!

**LINK**

Not you, Paul!

Bob

[Bob Abell 2Participant @bobabell2]

Don`t let Paul see this!

[Paul TParticipant @pault84577]

Ok Bob I'll let you design this on.

[Andy StonemanParticipant @andystoneman15177]

It doesn't do anything for me Bob, Its not steam propelled.

Andy

[Paul TParticipant @pault84577]

Andy

It could be flash steam powered.

Paul

[Bob Abell 2Participant @bobabell2]

This is worth looking at, Paul……. I think this could be a worthy contender!

What thinkus thou?

Bob

[Paul TParticipant @pault84577]

Bob

This would be a truly spectacular model and would look amazing at speed.

How big?

Paul

Edited By Paul T on 01/01/2015 20:06:39

[Bob Abell 2Participant @bobabell2]

How about……..4`-0"

Using the existing motors, if possible…………..MFA 850………One in each pod?

Don`t know how the ship is powered at the moment……….Is it jet powered in the pods/

I like the expanding wing things!

Hey!…….I can see a lights on, in the Drawing Office!

Bob

[Paul TParticipant @pault84577]

Bob

It would be designed to be built in five sections: hull, wings and sponsons, transport and storage wouldn't be a problem so 4ft would be achievable.

Looking at the drawing the propulsion is by counter rotating propellers in the nose of each sponson but there would be a lot of research to do as the science is really cutting edge.

Paul

[Bob Abell 2Participant @bobabell2]

So the next project won't be an anticlimax afterall!

We could have four brushless motors in the pods, but how do we keep the water out?

They are a bit like submarines

Sounds like a great project though

Bob

[ashley needhamParticipant @ashleyneedham69188]

Personally I would take those drawings with a pinch of salt. They will not be giving much away here. rather like looking at a cross section of Dan Dare`s Anastasia;

Brushless yes, ordinary waterjets/tunnelled props or simply ordinary props at the rear of the prods is as close as you will get. just consider that a model boat will be massivly overpowered compared to the original.

Getting a model to rise at it goes faster (using the outriggers) will be very difficult. Not that I KNOW, but you develop a feel for things when you dabble with the unusual.

This is no reason not try mind you….

Ashley

[Paul TParticipant @pault84577]

Hi Ashley

I've been delving into the internet all morning looking for information on this boat and apart from a couple of videos and photos (all showing the boat in the water) there isn't much to go on so it looks as though it will have to be drawn virtually from scratch.

From what I have seen so far the main problem wont be getting the boat to rise, conversely it will be stopping the sponsons from surfacing.

There is a lot of research to be done to understand the cavitation principal and even more work to translate the science into a format suitable for a working model.

It will be a challenge to design, build and sail.(lots of fun for me but not for the ducks when Bob sails the thing)

Paul

[Bob Abell 2Participant @bobabell2]

The method of operation is clouded in mystery…….As it's top secret!

The sponsons are heavy and don't float????…….Why?

The boat sets off with the sponsons wide open, which allows the hull to float on the water surface

As the speed builds up the sponsons pivot down and surf the water?

The props are fore and aft in the sponsons

Have I got this right, Mr Designer, sir?

Sounds like a cracking project!

Bob

[Paul TParticipant @pault84577]

Bob

This might help explain,

The designers of the full size boat claim a combination of a stealth jet fighter and an attack helicopter in a boat.

Privately developed by JMS for possible use by the U.S. Navy, the boat would reportedly be invisible to enemy ships' radar, while also being faster and more economical than existing military vessels.

The company's big claim, however, is that GHOST is the world's first super-cavitating watercraft.

Supercavitation, in a nutshell, involves surrounding an object with a bubble of gas, so it can pass through the water with very little friction. In the case of GHOST, the objects in question are its two submerged buoyant tubular foils. Although the company isn't clear on how the process works, presumably the foils would have to be designed in such a way that when GHOST's gas turbines thrust it forward, water is deflected outward at the front of each foil, creating an envelope that closes behind it.

[Bob Abell 2Participant @bobabell2]

Paul

That sounds splendid, but won`t the bubble of gas get washed away, as it speeds along?

Dare we send an Email to the designers?

Don`t see why not?

How will the latest legislation affect the plan marketing?

After all, we don`t receive any money in the process?

Bob

[Bob Abell 2Participant @bobabell2]

Just found this……

**LINK**

Bob

[Paul TParticipant @pault84577]

Bob

Supposedly the gas jacket is constantly maintained but I haven't been able to find any information about the system so its difficult to make informed judgement.

I will keep looking.

At the moment I don't know what the new VAT rules will mean for the charity downloads but I will be contacting HMRC next week for definitive advice.

Paul

[Paul TParticipant @pault84577]

And it does look a bit like this from the film Battleship

Edited By Paul T on 02/01/2015 19:37:19

[Bob Abell 2Participant @bobabell2]

Paul

Look at the spray on the 2nd last picture

What is causing it?

Bob

[Colin BishopModerator @colinbishop34627]

I think it is water Bob…

It's the fireworks on the last image that worry me!

Colin

[Diede van AbsParticipant @diedevanabs87670]

Bob,

The spray is simple: It is a fast moving craft and the foils have a positive incline towards the hull, so water will climb up over the edge.

You can see on that same second picture they found out it were an issue and they (retro?)fitted a set of extra foils perpendicular to the foils, as spray guards…

This craft is extremely tempting and interesting to build, but don't underestimate the balance issues of it: because the surface area at sea level is extremely small, even the tiniest unbalance will result in a severely listing craft. Real life SWATH ships (which I count this one as) do have dynamic balancing systems to counter crew movement…

But PLEASE, design and build a model. It will be a great craft if you get it going!

[Bob Abell 2Participant @bobabell2]

Hello Diede…..A Happy New Year to your good self

I knew you would emerge from the woodwork at the mention of a new exciting hair brained project

Your comment about computer control to trim the craft, is a bit disturbing!

It must be similar to those two scooter things that you stand on?

This will test the Drawing Office skills to the Nth degree!

I have already suggested the motors and gear to be housed in the main hull and have a Timing belt drive, through the legs to the prop shafts

The sponsons would then be buoyancy aids……….Alas, the idea was pooh poohed by him upstairs!

He's now having a few days in an obscure secret cave, stark naked, somewhere in Snowdonia, to sit and contemplate the design

All the best……Bob

[Diede van AbsParticipant @diedevanabs87670]

Hi Bob,

Best wishes for you all too!

Better keep the motors in the sponsons, to keep the center of gravity as low as possible.

The sponsons are the main buoyant bodies, they will be responsible for about 98% of the flotation when in rest. The remaining 2% will come from the foils.

The balance issue is because the sponsons will be completely submerged and the foils are the only bodies protruding from the water… and as their volume is very small, placement of batteries, receiver etc. will be very sensitive. The slightest unbalance will push one sponson way further into the water which causes the listing I mentioned.

It is not impossible to get it right, but it will be a tough challenge.

Now, I know you are not afraid of a challenge every now and then…

Edited By Diede van Abs on 03/01/2015 12:13:14

[Paul TParticipant @pault84577]

Dear All

In his infinite wisdom Capt Bob has had a blue sky moment and decided that it will help everyone to better understand what is going on if all aspects of this project are discussed on the open forum and not by private email.

So lets start this ball rolling:

I am currently in a secret cave in Snowdonia researching the real Ghost ship like fun I am…..I am actually in my nice warm lounge eating chocolate and drinking coffee but the research part is true.

The first stage of research is simply searching the internet for information about the real boat, I am looking for history, pictures and if possible drawings or blueprints.

Before I can start the drawing process I need either a set of designs for the real boat or some photographs showing side, top, front and rear elevations. It also helps to have details of the overall length, breadth etc. so that I can dimension and scale the drawings correctly.

All that I can say at this point is 'the better the information the better the drawings'

Paul……..back to the cave

[Bob Abell 2Participant @bobabell2]

I seem to remember, I saw a program on the telly about a craft similar to Ghost?……Only a few weeks ago

Or have I been dreaming it?

We actually tried to visit Betws y Coed today in Snowdonia!

But had to turn back at Chester, the rain was simply incessant and there was no chance of finding Paul's secret cave

How long has Ghost been subject to the public gaze?

Bob

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