[Seavox] [Ont] additional terms for platform ontology
Roy Lowry
rkl at bodc.ac.uk
Thu Oct 2 08:26:30 BST 2008
Hi John,
Not sure I fully understood your answer to Nan's 5000lb anchor point - this was on my list of queries as our host lab uses something called a POL Mooring Platform with a range of possible anchor weights and was unsure where to draw the line between resting and bolted.
Some questions about things deployed from ships:
We use a piece of kit called a Moving Vessel Profiler (http://www.brooke-ocean.com/mvp_main.html) - a specialised winch that repeatedly drops and recovers a free-fall CTD fish from a moving ship. Is this 'DroppedLine' or something different?
We also use other free-fall instruments (XBT, XCTD and FLY turbulence probe). How would these fit into your scheme of things?
Am I right in assuming that towed undualators such as SeaSoar and UOR would still constitute a secondary platform?
Cheers, Roy.
>>> graybeal at mbari.org 10/1/2008 4:29 pm >>>
> The terms 'mounted on a surface buoy' and 'attached to a mooring
> line' may not convey as much information as you'd like.
Agreed. On the other hand, I'm pretty confident there are NO words
that will convey as much information as I'd like! Sometimes words are
not enough.
So those words (roughly) were provided to me as the specification, but
no reason we can't respond with better words.
I would argue that a 'surface buoy' has a connotation that is
operationally consistent across all applications. It's tethered, yet
floats on the ocean. This means it wobbles back and forth to varying
degrees, and may go under water in extreme current conditions in some
installations. But mostly, the instrument that's mounted 3 meters up,
or 1 meter down, on the fixed structure will stay approximately there.
If we try to get any more precise then that, we have a long haul's
worth of work to do, don't we? That seems beyond the point of this
vocabulary.
The mooring line is an interesting case. We could explicitly create
one term for those things above the catenary, and another for below --
though this starts to get into subtleties. Maybe a better way to say
it is that we have these categories:
- generically attached to the line between mooring and anchor (details
unknown)
- attached to a part of the line that tends to follow sea surface
height
- attached to a part of the line that tends to be stationary with
respect to sea floor
Obviously the 'tends to' is a critical part of the definition, since
exact height below sea surface/above sea floor will change as the
mooring is driven about by currents.
> There are also instruments that are towed - would that require a
> separate term than 'lowered from a ship'?
I'd say yes, hence my TowRope example. It suggests the first 3 in
that list (e.g., ShipTether) are not ideal because they could include
either dropped or towed. 'DroppedLine' and 'TowedLine' would be more
precise, how do those sound?
+1 on the 5000-lb anchor question....
john
On Oct 1, 2008, at 7:52 AM, Nan Galbraith wrote:
> Hi All -
>
> The terms 'mounted on a surface buoy' and 'attached to a
> mooring line' may not convey as much information as you'd
> like.
>
> The buoy may be a wave rider or may be more constrained,
> with a changing relationship between the sea surface
> and any particular point on the buoy. Also, we have some
> mounts on our surface buoys (which are not wave riders)
> that allow a sea temperature sensor to float on the sea
> surface (at least until fouling stops the motion).
>
> Our moorings are designed with a catenary in the line to
> absorb some of the wave energy; anything below this point
> would have a vertical coordinate that's mostly relative
> to the sea floor, while most of the instruments are above
> this point and their depths are relative to the sea surface ...
> more or less.
>
> There are also instruments that are towed - would that require
> a separate term than 'lowered from a ship'?
>
> Last, I'm not sure about the term "bolted to the sea floor" -
> does a 5000 lb anchor constitute a bolt?
>
> Cheers -
> Nan
>
>> In response to a request, I have been trying to come up with some
>> names for various mount-points for instruments. I would like your
>> feedback on the following list of situations -- what is the mounting
>> point in each case?
>>
>> I have tried to vet this against a few captains and marine
>> technicians, but I suspect there will be a lot of variation in terms
>> here.
>>
>>> 1 - mounted on a surface buoy
>>> 2 - attached to a mooring line
>>> 3 - resting on (but not bolted to) the seafloor
>>> 4 - rigidly attached to any fixed structure, incl. bolted to
>>> seafloor
>>> 5 - on a moored profiler, i.e. a device that actively moves up and
>>> down
>>> 6 - lowered from ship
>>> 7 - rigidly attached to ship
>>
>>
>> My proposals (items with asterisk(=*) are not already a term in the
>> Platforms ontology):
>>
>> 1. SurfaceBuoy
>> 2. SurfaceBuoyTether* (typically near the top) or MooringLine* (the
>> line the connects the entire assembly) or MooringRiser* (typically
>> near the bottom); definitely one of the last ones if it is attached
>> to
>> a line that does not come to the surface buoy)
>> 3. BenthicNode (if powered) or BenthicStage* (if not powered) [other
>> options: BenthicDeck*, BenthicStructure, BenthicRester*,
>> BenthicSitter*]
>> { if the implication is that it can move but not under its own
>> power, BenthicSlider or BenthicRoller; other option: BenthicDrifter}
>> 4. BenthicMountpoint* or BenthicMount* or BenthicFoundation*
>> 5. VerticalProfiler
>> 6. depends on what it's lowered on; possibilities include
>> ShipTether*=ShipLine*=ShipCable*, or ShipAnchor*, or TowRope* (last
>> is
>> more 'trailed'), as appropriate
>> 7. Ship
>>
>> Comments please,
>>
>> John
>
>
>
>
>
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John
--------------
John Graybeal <mailto:graybeal at mbari.org> -- 831-775-1956
Monterey Bay Aquarium Research Institute
Marine Metadata Interoperability Project: http://marinemetadata.org
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