Mapping Mountains – Trimble Surveys – Moel Hebog

10.12.22  Ynys Tywyn (SH 571 385) 

Ynys Tywyn (SH 571 385)

Ynys Tywyn is easily accessed from the centre of Porthmadog, it is one of those small hills that pays dividends, with little ascent being rewarded with extensive views.  I had visited once before in December 2014 when along with Aled we decided upon an easy hill as the forecast winter rain was bearing down on us.  On that occasion its summit was Trimbled.

That ascent was part of many that Aled had organised as we continued our investigation of Traeth Mawr; the flatlands to the immediate east of the Cob.  The Cob is the embankment built on the outskirts of Porthmadog to keep the sea from heading inland at high tide.  When it did so, the islands of Traeth Mawr must have been a wonderful sight, poking their wooded summits above the sea.  These now landlocked islands can still be accessed, although many are rough underfoot, but they are also rewarding to investigate. 

Plaque on wall at the start of the walk

Today we were in the company of a film crew from the Cynefin programme which is broadcast on S4C.  They were concentrating on the area surrounding Porthmadog and in particular the Cob.  They had approached Aled to be a part of this programme having found his article on Traeth Mawr published on Mapping Mountains, suggesting that a visit to one of these islands with the Trimble in tow would be good to film.

I drove to Aled’s and arrived at 7.10am having experienced slow progress on much of the route due to a dusting of snow on the road.  The journey was particularly beautiful as moonlight highlighted silhouetted hills that shone back under their covering of snow. 

Aled with the film crew from the Cynefin programme on S4C; Heledd Cynwal, Aled Davies-Jones, Lleucu Gruffydd and Rhys Thomas

We met Lleucu and Heledd; the producer and presenter in the centre of Porthmadog before having an early morning paned.  Afterwards we were joined by Aled and Rhys; the director/cameraman and cameraman respectively.  By now a mixture of winter rain and occasion hail was descending from above.

The walk to the top of Ynys Tywyn is only short, following a path through its wooded slopes to the impressive slanting rock that constitutes its summit.  The upper part of the hill had a sprinkling of frost on it adding winter colour to the scene.

It is not my intention to go in to any great detail of the filming in this article as a future On Location with S4C post will document this.  We stayed on top for almost two hours with Aled being filmed explaining the process behind using an Abney level and the Trimble. 

Porthmadog with winter showers pushing inland from the coast

During this I happily listened to the proceedings from the background enjoying being out on this small island, which nowadays is connected to the town of Porthmadog by the Cob.  I spent much of the time watching the play of light as winter showers pushed inland from the coast.

In the distance snow-capped peaks occasionally emerged from their winter shroud, with the upper part of Cnicht springing out of the grey misted scene with its pyramidal summit profile looking ever impressive.  However, many hills were obscured with deep grey cloud penetrating their depths. 

Snow-capped hills

For a relatively small hill Ynys Tywyn certainly has a dramatic and expansive view.  The workings of the film crew would occasionally be interrupted by the hoot emanating from the steam train as it chugged its way across the Cob, bellowing smoke across the harbour surrounds. 

At the summit of Ynys Tywyn with Aled explaining the fineries of the Trimble

The last shots were of Aled explaining the fineries of the Trimble and then it was time to head down.  For Aled the filming would go on for the rest of the day, but for me it was time to head home before the roads froze and darkness fell. 

 

Survey Result: 

 

Ynys Tywyn 

Summit Height:  21.8m (converted to OSGM15) (from previous Trimble GeoXH 6000 survey)

Summit Grid Reference:  SH 57192 38506 (from previous Trimble GeoXH 6000 survey)

Bwlch Height:  N/A (sea level)

Bwlch Grid Reference:  N/A (sea level)

Drop:  21.8m (from previous Trimble GeoXH 6000 survey) (30–99m Double Sub-Twmpau addition)

Dominance:  100.00% (from previous Trimble GeoXH 6000 survey)

 

 

For details on the survey of Ynys Tywyn

For further details please consult the Trimble Survey Spreadsheet