28.02.15 Ynys
Hir (SH 566 398, bwlch only)
Thirteen months ago Aled took
me to a magical land of small wooded islands, all situated around Porthmadog,
with most having been tidal islands with their land area dictated by the inward
wash of the sea. The first of these
islands we had visited was Ynys Hir, in affect this name is given to two hills, both of which are next to the A487.
I’d passed these hills on many occasions travelling between mid and
north Wales, but I had never thought to investigate their inner realms. On that first island adventure the Trimble
had surveyed the respective summits but not the connecting bwlch. The data produced on that day complimented
that from the Ordnance Survey Historical 1:25,000 map and not that from current
maps, which do not include an uppermost 30m ring contour as the two Ynys Hir
summits were surveyed as 37.3m (SH 566 396) and 36.9m (SH 566 398) respectively.
Having visited Ynys Galch (SH
567 393) and Ynys Pen Syflog (SH 561 395) earlier in the day we parked in a
large lay-bi beside the wooden gate that gives access into the island
realm. As soon as one enters this land
the atmosphere changes from that of busy road and overhead sky to a
labyrinthine land of trees and undergrowth, all overshadowed by rising wooded
slopes and impressive small crags.
A path leads from the gate upto
the bwlch between the two Ynys Hir hills, bisecting the bwlch is a solid stone
wall, on the other side of which is a manicured green lawn adjoined to
buildings named Bodawen. The contrast
between one side of this wall and the other is immediate as within the island
territory the land consists of overgrown brambles, fallen trees and a snaking
growth of ivy, whilst above are the islands and a thick canopy of mature trees.
The critical bwlch was judged
to be a couple of metres from the wall and the remnants of a rolled up wire
fence proved ideal to lay the Trimble on so it was at least partly elevated
above the undergrowth. Soon we had also
found the remains of a broken glass cabinet which when positioned on top of the
rolled up wire fence elevated the Trimble 1.09m above the bwlch.
Gathering data at the critical bwlch |
Measuring the offset between the ground at the bwlch and the internal antenna |
As the equipment rhythmically
beeped each of its gathered data points we stood under a tree and chatted, 14
minutes later the Trimble was switched off and we delicately made our way over
a fallen tree and back onto the path.
A few minutes later and I was
driving toward Nantlle with the first spots of rain falling, and once at my
brother’s house the wind howled across the land and the rest of the afternoon
the rain fell.
Survey Result:
Ynys Hir
Bwlch Height: 11.1m (converted to OSGM15)
Bwlch Grid Reference: SH 56713 39759
To read the
blog post on the survey of this hill’s summit please click {here}
For further details please
consult the Trimble survey spreadsheet click {here}
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