Here is a little heads up or maybe a big heads up after a paddle around South Stack and into the bay yesterday.
Five of us set out, well equipped, from Dafarch and explored the coast to Penrhyn Mawr, moved into Abrahams bosom and paddled in the lee of the cliffs due to the Easterly (F4) up to South stack. Winds were a problem but swell was not. All this was done on the ebb but with a fairly small tidal range and lack of swell, the sea was very flat, except for wind derived chop and some minor wind/tidal effects.
The rear of South stack was stunning with oily water and climbers in abundance on the crags. The rock folds there, never cease to convey the power on this planet to me.
Looked at going through the channel inside of South stack, however, there was quite a flow through there, so decided to paddle the outside of the South Stack and forge into the bay from there. Quite hard to paddle around this due mainly to the rotoring wind down off the cliffs and obviously the tidal flow.
Gavin and I were alongside each other as we both noticed the HSS ferry inbound to Holyhead (approx. due North) and we both commented on the possibility of the wake potential from this vessel, based on some talk in previous posts here on the forum.
At this stage were we now firmly into the bay and really just battling the wind rotor. I suggested that we head for a cave ahead of us which can be seen on the GPS track below (Most Northerly point of the trip). All this time I was still mentally flagging up to watch seaward in respect of the possibility of a wake from the ferry.
As Gavin and most of the others reached the cave (and luckily didnt go into it), I glanced seawards to see a three set train of waves inbound with the leading wave face at least 6-8 feet high. These waves had a wavelength of about 2 boats length and were closely followed by a second set of the same height and frequency. I yelled at everyone "SWELL" and "Paddle straight out through them until I say different", which they duly did. You can clearly see this on the GPS track (NW track in a very straight line!). The waves were not breaking, however the suckback and resultant explosion onto the cliffs and into the cave completely engulfed the cave in foam and sent spray into the air about 30-40 feet. I then asked everyone to paddle South back around South Stack and regroup behind the island. Which everyone did without event. During this time the bay became complete chaos as wave refraction and clapotis was the order of the day and continued well after we had left the "impact" area.
Interestingly, from first "noticing" the HSS which was probably due North of the S.Stack lighthouse to the "impact" of the first wave in the bay was 9 minutes. Food for thought.
The regroup mustered everyone and we discussed the incident. we then headed out into the race South and paddled back to Penrhyn Mawr and into Dafarch after stopping for lunch in Porth Ruffyd.
A valuable lesson for everyone on the trip and I believe for anyone considering a trip around the stacks. You WILL have to factor in the effects of an inbound HSS if you are paddling in this area or anywhere where these vessels operate. There is no doubt that these were not weather generated swell and it was so obvious that they were linked to the ferry.
I propose to send a letter to the coastguard informing them of this. I also spoke to some guys from Plas Y Brenin, who recommended complaining to the ferry company as they have previously been warned about slowing down on the approach to the stacks, with reports of climbers there been nearly washed away from their belays.
If anyone can think of anyone else I should inform, then let me know.
MikeM
