Next message: Robert Gainer: "Re: on finding Pitcairn Island"
Peter Fogg wrote:
> What is found between New Zealand and Australia are a number of underwater sea mounts, mountains
> that rise from the sea floor about 4000 metres below to within a comparitively short distance, some of
> them, from the surface. When the sea is agitated the area above the mounts has a different characterisitic
> compared to the open ocean, and could lead to speculation; such as land being near.
Could Peter elaborate on his sources for the contention that the sea
surface gets a detectably different "characteristic" above a seamount?
I have a very little experience fishing over seamounts in the general
area in question, though rather further south (around 49 degrees
latitude). We certainly had times down there when the sea was agitated,
as would be expected, but nothing that suggested to me that land was
anywhere near. [In my case, the summits of the seamounts were around 700
metres depth. They stand on the South Tasman Rise at around 1400, while
the surrounding area is 4000 metres or so in depth. Clearly, a seamount
which comes very much closer to the surface would be more likely to have
effects visible to a surface observer.]
Of course, we had SatNav and charts to tell us that land wasn't close,
plus a powerful sounder to tell us just how deep the water was, and thus
were not looking for subtle signs. Add in an enclosed wheelhouse and
work to do that kept me from watching the sea all day long: Maybe there
were features in the wave patterns that a sailing-ship master, running
his easting down across the same area, would have observed.
Trevor Kenchington
--
Trevor J. Kenchington PhD
Gadus Associates, Office(902) 889-9250
R.R.#1, Musquodoboit Harbour, Fax (902) 889-9251
Nova Scotia B0J 2L0, CANADA Home (902) 889-3555
Science Serving the Fisheries
http://home.istar.ca/~gadus
