Saturday, 27 June 2015

Mapping Mountains – Trimble Surveys – Moel Hebog


15.06.15  Castell Cricieth (SH 500 377)  

Castell Cricieth (SH 500 377)

Having surveyed Carreg yr Eryr (SH 526 378) and Moel y Gadair (SH 521 391) earlier in the day I wanted to investigate the recently elevated P30 status of Castell Cricieth.  Its P30 status was first spotted by Alex Cameron who rightly judged that with a 48m spot height appearing on the Ordnance Survey enlarged Geograph map and with bwlch contouring between c 15m – c 20m with interpolation indicating a bwlch height of c 18m, the hill that the castle sits on top of has an estimated c 30m of drop.

Having previously surveyed the heights of Castell Dinbych and Castell Caernarfon I contacted Cadw beforehand and their representative kindly permitted me to visit and survey the hill.

I parked close to the centre of Cricieth in one of the housing estates adjacent to the main street; my first objective was the bwlch which map inspection indicated to be on the town’s recreational grounds.  As I locked my car I found the area of the bwlch to have a pitch and put on it as well as a bowling green.  Thankfully the bowling green was visually lower, otherwise play for the day would have to be suspended whilst Trimbling took place.

Once on the pitch and put I assessed the lay of the land close to the 6th fairway, rather disconcertedly there was a pitcher and putter making his way around the course and by the time I kneeled on the ground and put my chin on the grass to assess the contouring of the land, my actions had come to the attention of the bowling green assistant who I suspected would also be the person in charge of the pitch and put.  I thought this would happen and I came prepared with one of my best and friendliest smiles and explanations, he was understanding to the needs of surveying and thankfully said that it was all right for me to continue ‘as long as you don’t get hit by a golf ball’, as the pitcher and putter seemed inclined to hook many of his shots this latter piece of advice was taken on board and seemed appropriate.

The fairway on each hole consisted of closely cropped grass with the ‘rough’ between being surveyable.  This was proving great fun as I had never surveyed a pitch and put course before! 

I collected data from two initial points, one on the fairway of the 6th and one in the rough between the 2nd and the 5th holes.  As the Trimble was doing its stuff I helped the pitch and putter find his wayward shot as the ball was immersed a centimetre deep in the thick rough.  I also looked up at the castle which looked rather grand perched on its hill top.

Gathering data on the 6th fairway
Gathering data in the rough between the 2nd and 5th fairways

As I packed the Trimble away I left the recreational grounds and walked through the housing estate, noting on the way that ground beside a bench next to the road looked as if it could be a teense higher, therefore if time permitted I would survey a third potential position for this hill’s critical bwlch once the castle had been surveyed.

Castell Cricieth was first constructed in the 1230’s by Llywelyn the Great and later heavily modified by the forces of Edward 1 in the late 1200’s.  It has a turbulent history with it being besieged by the Welsh in 1294 / 1295 and later re-taken by the Welsh during the years of uprising led by Owain Glyndŵr.  During the recapture of the castle it had many of its walls torn down and was set alight.  The vestiges of what survives are on show today.

Approaching the castle two proud Red Dragon’s fly above the remaining towers and the path onward leads the members of the public into the lower modern castle entrance, this is where the admittance fee is paid, I had been granted free admittance and signed their VIP book after I introduced myself to Sylvia Jones, who was expecting me.  My thanks are given to Cadw for letting me survey the castle and for giving me free admittance, this is greatly appreciated, diolch yn fawr iawn.

Approaching Castell Cricieth
As I walked up the path toward the top of the hill and the remains of the castle I looked back toward the area of the bwlch, which if not for the recreational grounds would no doubt have houses built on it, so pitch and putts can be a very helpful tool when surveying.

Thankfully the recreational grounds where the pitch and putt is situated exist, otherwise this area would no doubt have houses built on it and therefore surveying would be compromised

The castle is dramatically positioned overlooking Tremadog Bay and the sea with all but its landlocked entrance being hard to reach.  I investigated its outer southern grounds before venturing into its remains.  The highest point inside the castle was not hard to find as it was on grass under one of the walls.  I considered putting the Trimble on this point, but decided to investigate the other parts of the castle before doing so.

I exited the main entrance and walked around the eastern side which overlooks the sea, on this side of the wall were small rocky outcrops, I followed these upto their highest point, which proved to be directly on the opposite side of the exterior wall to the high point within the walls.

As the Trimble gathered data from the high point outside the walls I stood and chatted to a number of people as they passed, including a romancing couple who I apologised to as they swept each other up in their arms and I sheepishly approached trying to explain what I was about to do, thankfully they seemed interested and asked a number of questions, others were out with their dogs and guide books examining the various towers and reading about the history of the castle as they did so.

The highest rock outcrop outside the walls is diagonally opposite the high point inside the walls
Gathering data at the high point outside the walls

Once five minutes of data were gathered I headed back inside the walls and set the Trimble up on the high point inside the castle.  As it slowly ebbed down to its 0.1m accuracy level before data can be logged, I had a brief look at the exterior walls to see if they hid any natural rock outcrop in them, I could not find any so happy with my placement of the Trimble I continued to wait.

The Trimble was sitting in a bowl of walls and took a long time to reach its prescribed accuracy level, during this I chatted to Rachel who was out with her niece, they had been to Dylan’s on the seafront of the town for lunch, this is where I had a 7.15pm appointment to meet my brother and Al, Frances, Laura and Sam to celebrate Alun’s 60th birthday.  Rachel highly recommended Dylan’s and it looked inviting from outside as I passed it earlier in the day.  We chatted for quite some time, when they left I looked at the Trimble’s screen and it was still on 0.11m, I left it another couple of minutes and the 0.1m accuracy was attained, I pressed ‘Log’ and scampered off to wait for five minutes as it collected its data.

Gathering data at the high point inside the walls

Leaving the castle I thanked Sylvia and walked back down the road toward my car and the area of this hill’s bwlch.  I looked at the continuing downhill on the valley to valley traverse which went through a locked and closed off gate, I then chose my spot and placed the Trimble down on a patch of grass beside a bench and waited and waited and waited.  I was in no rush and spoke to a few people as they passed, one explained that the gate had once given access down a public footpath but had been closed off as someone had died there after having lying at the back of houses overnight, I also encountered three lost French tourists who were looking for their car, this was parked next to the sea and they were walking toward me which was heading inland, I tried my stumbling French (non-existent) and pointed them back toward the sea.

The last data set of the day at the critical bwlch of Castell Cricieth

Aha, bril, 0.1m, press ‘Log’ and quickly scamper off, five minutes later I switched the Trimble off, packed it away and sauntered back to my car to get my boots off.  A few minutes later I was parked above the town in a lay-by and changed from my walking gear into my smart let’s get a lot of nosh in my tummy gear.  I even had time to relax in the early evening sun and have a read for 45 minutes.  Next stop Dylan’s and Alun’s 60th.


Alun, Laura, Sam and Frances outside Dylan's

Survey Result:


Castell Cricieth

Summit Height:  49.6m (converted to OSGM15)

Summit Grid Reference:  SH 50003 37733

Bwlch Height:  19.3m (converted to OSGM15)

Bwlch Grid Reference:  SH 49943 38015

Drop:  30.3m (30m-99m Twmpau status confirmed)

Dominance:  61.02% (Dominant status confirmed)



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





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