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Position Control

Home Forums Archive TSI Engineering Position Control

This topic contains 38 replies, has 17 voices, and was last updated by Profile photo of ellmer - http://yook3.com ellmer – http://yook3.com 5 years, 4 months ago.

Viewing 9 posts - 31 through 39 (of 39 total)
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    Profile photo of i_is_j_smith

    I disagree regarding seamounts…there are TONS of locations where a E-TLP could moor. I was just reading about MODEC TLPs and how they could possibly moor in up to 6000ft depths. A quick scan of Google Earth shows a plethora of seamounts, ridges, rises, guyots, and shoals that would be a perfect location for a vertically-moored TLP. And most of those are WAY outside any EEZ and far from the continental shelf.

    For an example just scan the Madagascar Plateau, around 34S 44E.

    Profile photo of wohl1917

    Michael, you found that article on-line! I Googled it every which way but came up with nothing. There is more detail in the hard copy located in picture captions and foot notes. You’re also right about the general rule of thumb with the 1/7 ratio in anchoring. Carl Palsson and I crunched the numbers on that assuming a 13,000ft depth and came up with 28.284mi scope but due to the verticle separation of the lines they could over lap by as much as half of that distence. Also, anchor weight has a lot to do the the scope requirements but I’ve not located much info on that or at least no hard fast rules like the 1/7 ratio. Typical moorings I’ve seen have no where near 1/7 scope, more like 7/1. Deep ocean currents and winds are pretty much constant so there wouldn’t be too much ‘swing’.

    i_is_j_smith, Smitty, I conceed the point on seamounts but would point out that the reason we know about most of them is because fishermen discovered them because they discovered that the fishing was good there. Google them and you will find that over many of them the ‘fishing rights’ are being disputed. Putting a Seastead there would be asking for trouble I think…

    Excuse any misspellings, my spell check isn’t working for some reason, all is well, John.

    Profile photo of SailorTrash

    Took a bit of creative Booleanisms to find it.

    One could expect vessels/seasteads anchored in the same general area to swing more or less in tandem as currents and winds change, so one might risk some overlap. Me, I wouldn’t, but I’m chicken when it comes to crashing m’boat. Heh.

    Profile photo of i_is_j_smith

    Putting a Seastead there would be asking for trouble I think…

    I agree. I was just reading about the discovery of a new, unique lobster species discovered in 2006 in the Walters Shoals…one of the areas I have been looking at for a TLP-based seastead in the same area as I described above. While this area is definately in international waters I could envision some group trying to get a seastead blocked because of environmental concerns.

    Truth is, no matter where we put a seastead there will be some existing nation that will try to get us stopped. We could be anchored in 3000m of water in the middle of nowhere and some nearby nation will claim “fishing rights” or “mineral exploitation rights” or some other such nonsense. We are going to be a thorn in somebody’s side no matter where we go, so we need to be prepared to defend ourselves both politically and physically.

    And this issue is just as valid for a drifting seastead. You decide to do some fishing and Tonga comes along and says you are in their fishing zone. What are you gonna do, just take their word for it and drift somewhere else where it happens all over again?

    Nah, as long as we find a spot off the shelf and well outside the EEZ (300nm should be fine) we should be willing to defend it as ours.

    Profile photo of glenra

    “I conceed the point on seamounts…fishermen discovered them because they discovered that the fishing was good there…. Putting a Seastead there would be asking for trouble I think…”

    There’s actually a lot to be said for deliberately positioning a seastead near a seamount that supports fishing or other commercial uses of the sea. Deep-sea fishing tends to be dangerous, uncomfortable and expensive because of the isolation. It would be a natural fit for seasteads to sell boating support services. With seasteads around, a fishing ship wouldn’t need to go all the way back to dry land for more fuel, food, first aid supplies, hot showers, or engine repair. Seasteads are range extenders; commercial boaters would come to think of them as favorite truck stops along an empty highway.

    Profile photo of Thorizan

    Excellent thoughts. I know how slow moving flotsam or other nautical debris attracts thousands of fish, the fisherman may even be quite happy that structures like yours exist out there.

    There is no fate but what we make for ourselves. Each to his fate.

    Profile photo of wohl1917

    Glenra. So long as we were close but not too close…

    Profile photo of Farmer
    Ocean Area (square miles) Average Depth (ft) Deepest depth (ft)
    Pacific Ocean 64,186,000 15,215 Mariana Trench, 36,200 ft deep
    Atlantic Ocean 33,420,000 12,881 Puerto Rico Trench, 28,231 ft deep
    Indian Ocean 28,350,000 13,002 Java Trench, 25,344 ft deep
    Southern Ocean 7,848,300 sq. miles (20.327 million sq km ) 13,100 – 16,400 ft deep (4,000 to 5,000 meters) the southern end of the South Sandwich Trench, 23,736 ft (7,235 m) deep
    Arctic Ocean 5,106,000 3,953 Eurasia Basin, 17,881 ft deep


    I see that there seems to be some kind of agreement that anchoring at average ocean depth is NOT possible – i beg your pardon – I object – costeau anchored calypso in mid ocean with a thin polypropylen line.

    What is not possible is anchoring with chain, or wire cable, due to the weight of the anchor rig – you need a neutral buoyant anchor line –

    I made a suggestion on another thread – here is the link.




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