Saturday, 3 January 2015

Mapping Mountains – Trimble Surveys – Moel Hebog



31.12.14  Ynys Tywyn (SH 571 385)   

Ynys Tywyn (SH 571 385)
After a week at my brother’s in Nantlle it was time to head home, but not until I met Aled in Porthmadog to catch up with all things hilly, place-namey and hill-listy.  We sat in my car nattering away until he persuaded me to visit Ynys Tywyn which would take no more than half an hour up and down including surveying its highest point.

As I’m easily persuaded I quickly got my wellies on, grabbed my camera, Trimble and rucksack and drove to the end of the Cob and found a parking place overlooking the harbour.

Ynys Tywyn is as its name implies; an island, it is now joined to Porthmadog by the Cob which extends in a north-westerly to south-easterly direction across the mud and sand of the Afon Glaslyn estuary.  When travelling into Porthmadog this small island is easily missed as a large cream coloured house obstructs all but the highest trees growing on the island.

Plaque on wall at the start of the path
As we made our way from the car to the path that climbs up to the high point the weather closed in and the first few wind-blown rain drops fell.  The weather forecast was not good, but we hoped that the downpour would relent until we had visited the summit and arrived safely and dry back at the car.

Leaving the road and arriving on the earthen path was like being transported to another world where the busy bustle of the town was instantly left and an overgrown pleasant island land found.

Heading toward the summit of Ynys Tywyn
The path led to a rocky summit with two positions vying for the accolade of the highest point, one was on a large rock with a big vertical drop on one side, whilst the other was in the middle of a strangly looking gorse bush.

We decided to survey the rock summit first and attached the Trimble to my rucksack and placed the latter on the safe side of the summit.  By doing so the Trimble could be aligned with this high point but would not be blown over the vertical drop as it was attached to a weighty rucksack.  However, when this contraption was first set in place the wind blew the rucksack down the rock, so once positioned again in place, Aled lay on the rock with his head cushioned on the rucksack to keep it firmly in place.  I wonder if OS field surveyors ever have to do things like this.

Gathering data from the first of two high points on Ynys Tywyn
As the last of the 300 datum points were collected I grabbed the Trimble and rucksack and moved over toward the gorse bush, Aled found a stable position for the Trimble and I placed my rucksack down slope from it just in case it decided to take a roll, again safeguarding it from an early death over a cliff.

Gathering data from the second of two high points on Ynys Tywyn
Thankfully the rain that had started had now stopped and once the Trimble was packed away we headed down to gain a view of the cliff from below it on its eastern side.
 
Aled then showed me the sluice gate which the Afon Glaslyn is fed through, from this vantage point the island overlooked the river with its lower section protected by gorse and sapling trees.

The Afon Glaslyn passing Ynys Tywyn
Across the other side of the sluice gate was the continuation of the footpath and another small island; Ynys Cerrigduon, which looked like another small compact island, this time with a trig pillar at its summit.  This little beastie could wait for another day. 

Happy that summit data had been collected from Ynys Tywyn we headed back to the car for an hour or so of hill chat before Aled headed out with his friends to Beddgelert to bring in the New Year.

  
Survey Result:


Ynys Tywyn
 
Summit Height:  21.8m (converted to OSGM15)

Summit Grid Reference:  SH 57192 38506

Drop:  21.8m (converted to OSGM15) (Double Sub-Twmpau addition confirmed) 

Dominance:  100.00%


For further details please consult the Trimble survey spreadsheet click {here}




1 comment:

Alex Cameron said...

I agree, a it's lovely little walk up to this peaceful corner of Porthmadog, with some of the best views around. I was in town on the 17th December to buy some xmas presents from the Purple Moose Brewery and to climb nearby Ynys Hir, but also somehow managed to find my way onto Ynys Tywyn after spotting the NT board off the main road.

I had my video camera with me and felt inspired enough to capture the view, though it would be so much better on a bright sunny day https://www.dropbox.com/s/9hy8yd94p1sqlp8/SANY0068%20Ynys%20Tywyn%20view.wmv?dl=0