Breakwater Design


Maybe I need to clarify my position:

I’m a firm believer in “thermoeconomics”, the belief that the value of all things is deeply connected to the amount of energy required to create them.

I think that the success of an independent seastead resides in the interface between it and the sea: the breakwater. A small size swell produces 10kw/linear wave crest meter. You’ll need 10x0.2(conversion efficiency)x0.2(Capacity factor)= 250m2 solar panel to equal this on a 24/7 basis.
My point was that a sailboat/Oasis of the Seas/Floating retirement community is not a “seastead” because it is not an independent economy, because it doesn’t produce more than it consumes.
Of course it’ll need customers, those customers are gonna be on the mainland and they’ll have access to the ease in transportation and energy economy of scale it provides.

Without a way to put the energy of the seas in our pockets, there wont be no seastead…


We might have a word definition problem here. Most people don’t think of a breakwater making power. But they can think of a wave-energy machine as a breakwater. Most people don’t think of a energy-maker making anything but electricity, when it could be making hydraulic pressure to make that electricity. Or it could be lifting weights, lifting water, compressing air, churning dirt or sewage, slowly turning the seastead to face the sun, but those processes don’t usually enter my mind when i hear the word “breakwater”.


You forgot 4 x 50 kw wind generators…

[quote=“thebastidge, post:120, topic:821”]
You made a factually incorrect statement,
[/quote]Not so. What was incorrect was to compare a cruise ship operation with a seastead. (I’m not saying you, but whoever brought cruise ships into conversation)

A seastead will most likely “sit” at anchor for 9-10 month out of a year. The solar and wind generators can produce plenty of hydrogen (during all that time) which can be stored and later used for propulsion.


200kw is 266hp coming off the blades, not counting losses in the generators. Lets call it 300hp. Is your seastead and it’s anchors adequate to deal with 300hp worth of wind blowing on it’s windmill towers (and for that matter, everything else too)? Imagine a boat with 300hp and a tow rope to the tops of those towers, jerking on them as hard as it can, how stable is your seastead? Living on a windmill has got to be as annoying as living on a regular boat, i can’t see one ever holding still.


Very stable.

[quote=“KatOnTri, post:124, topic:821”]
i can’t see one ever holding still
[/quote]Nothing will “hold still” on the ocean.


So you are saying the four 50kw windmills will be swinging to and fro like the tops of any sailing mast? How much weight are we talking about up on the masts, per installed generator?


If the weight is to much as a “conventional” wind turbine we could go to lower power and more turbines, or better off, use vertical axis wind turbines.



Those may be your beliefs, and you’re totally entitled to them. However, they’re not proven facts, so please tread more carefully in what you pronounce as absolute truth.

Most of us are using the words seastead and seasteading as if we have a common understanding of them. In fact, we have fairly divergent ideas about what seasteads are physically and economically possible, letting alone the aspects of power/authority/government.

Below the following line, please return discussion to ENGINEERING aspects of BREAKWATER DESIGN.

Thank you!


As I was saying… REDIRECT the forces, rather than building a battering ram…

(Jonas Smith) #130

There is no information on those on Hexicon’s website. They do have wind turbine floating platforms, but they are regular moored truss structures not anything like the pictures from the links you posted.


Supposed to be going in, off the coast of Malta within the next few years. Study was done, design developed, does it really matter, if it’s on their website, or not?

(Jonas Smith) #132

Yes, it does matter…

The floating wind turbine concept put forward by Hexicon AB for Sweden, Cyprus and Malta was excluded after failing the European Investment Bank’s technical and financial due diligence conducted nine months ago.

I looked everywhere but I wasn’t able to find any “studies” on the viability of this breakwater system. It looks to me like just another pie-in-the-sky design with no real engineering data behind it…which is probably why it was rejected and cancelled.


OK, so the bank of Europe sucks. Is that MY fault? Doesn’t invalidate the design. Their design study didn’t pass first muster at the bank. So, they have to have another study done, to re-validate the design, to meet some new spec…

Me? I’d ditch the wind-turbines and put in hydro-electric, between the breakwater and the down-pipe, and use the platform for my own purposes.

(Jonas Smith) #134

Yes, I’m sure the European Investment Bank’s technical due diligence team suck at what they do and the design is fine. I’d love to see some engineering studies on the breakwater design though…


I am unclear on where the downpipe goes and what it does.


They’re just jet-nozzles, to direct the energy and mass of the top of the wave downward. Think of them as exhaust manifolds, to redirect the flow. Odds are, they don’t need to be pipes at all, but slots, like on leading-edge flaps of aircraft.


Well, i give them creds for use of water to maintain position.

But there’s a problem with the water entering the machine in the first place, and it’s the same problem with all such floating systems in deep water (that is, not sitting on the beach), and that is: the water doesn’t travel horizontally on the surface. As the wave seems to approach their breakwater, the water itself is moving up and will just lift the breakwater. If i assume it’s too massive or smartly designed to not be lifted, the water will rise up in front of the breakwater, but i am guesstimating only half of the top of the wave will flow into the back sluice vs being reflected off the front and away from the breakwater.

In the meantime, i imagine a lot of money went into holding the breakwater down against the lifting force of the wave, unlike the Pelamis Wave Power designs (Pelamis went into bankrupcy in November 2014, maybe their designs had problems too?).


Anchoring like a tension-leg platform would solve that.


Would solve which? It won’t affect how the water moves.


Anchoring the nose would allow it to pivot onto the current and using enough anchorage to hold the nose down, allows a portion to break over the bow, but forcing itself down to pull against the downward thrust of the added mass, or at least that’s how I would suppose it should work.Think I’d make a few changes to the design, just based off what little I know, but, in theory, it should work.