In message , Nick G
writes
Deep water waves that have the greatest wavelengths and longest periods,
travel the fastest and are the first to arrive in regions distant from the
storm which generated them

Methinks it might be something like this if the wave was generated by a
storm in deep waters (assuming the wave length to be double the depth
available):

The square root of (9.8 m/sec (acceleration due to gravity) X 4,000 m (an
estimate of the average depth of the Atlantic Ocean)) which works out at
roughly 198 meters per second,

Therefore the wave would take about 5.6 hours to travel 4000 km.
________________
Nick G
Exe Valley, Devon
50 m amsl

Actual wavelengths are a lot shorter than you have assumed. The
longer-period swell waves from a storm typically have periods up to
20-25 seconds. This gives deepwater wavelengths of something like
600-1000 metres. Individual waves in this period range have velocities
of 60-75 knots while the group velocity is half that i.e. 30-37 knots
approximately. The waves would therefore take approximately 60-72 hours
to travel 4000 km.

The majority of storm waves have periods rather shorter than discussed
above and therefore take longer to travel the same distance.

Another point that has to be considered when looking at swell travelling
over large distances is that swell travels on a great circle track. From
conventional synoptic weather charts, or from navigation charts, it is
not possible to determine how swell will propagate. What is needed is
charts with a gnomonic projection. On such a projection great circles
are straight lines. As an example of this great circle travel, a SW'ly
storm off the NE coast of USA will produce a swell that would reach the
west of the British Isles from a direction slightly north of due west
i.e. not from the SW.

Norman.
(delete "thisbit" twice to e-mail)
--
Norman Lynagh Weather Consultancy
Chalfont St Giles 85m a.s.l.
England