If you were standing here at the end of the nineteenth century, you'd see the entrance to a magnificent structure: the Merrion Promenade, Pier and Baths.
Built in 1883 and open from May to September, the iron and wood pier led out over a hundred metres to twin swimming pools, one for men and one for women, each larger than most pools in Dublin today. Sea bathing was tremendously popular at the time, and the baths, with water pumped in fresh every morning, provided reliable swimming even at low tide. The pools had changing rooms and other facilities right beside them.
You could take refreshments at the tea rooms half way along the pier, right by the bandstand where bands regularly played concerts. What's more, the Dublin Tramway Company would whisk you out from the city centre right along the seafront (you can see the pier and baths in the background of the picture below).
If that didn't suit, then you could get the train to Sydney Parade - both train and tram had tickets that included admission to the baths. A refreshing dip, a pot of tea and maybe an icecream - what more would you be looking for?
Sadly, the good times didn't last. The baths changed owner several times, and by 1920 had reached such a state of dilapidation that the iron superstructure was cut up for scrap and the pools were left to crumble. Only the concrete pool walls now remain and most people have no idea the Merrion Baths were ever here at all. No more bands or cups of tea or icecream.
The cache
This is a quick two-stage + final multi. One of the stages will be difficult or impossible to access at high tide, so check the tide conditions in advance. This site will help. It's probably not a good idea to do this in the dark either. Please be sensible. It's only a cache.
At the starting coordinates, you'll find a lamppost with floral decoration about 2 metres from the ground. The number of flowers is A. Proceed to the second waypoint.
Stand at the second waypoint facing the shore. The internal space in front of you is divided into two, a north section on your right and a south section on your left. These are the remains of the men's and women's pools respectively, and the wall straight away in front of you divided them.
In the wall on your left, you'll find several rusted bolts about a metre above the sand, spaced along the wall. They probably held ropes for novice swimmers to grab onto. Some of them are less damaged by time and sea water than others. Count them - that number is B. Don't count any on the right hand section of wall or on the dividing wall.
Subtract (A+B+B) from the decimals of the northing of the original coordinates. This gives you the final northing.
Add (A+B) to the decimals of the westing of the original coordinates. That's the final westing.
Thanks to Arinagour for originating the Lost Dublin cache theme.