The hotel checked in a few days before I did. While I arrived on the tiny island of Klädesholmen in classic Swedish style - driving a Volvo over a bridge - the new Salt & Sill was being towed into the harbour on Sweden's west coast behind a tug boat.
The country's first floating hotel sounds gimmicky and an excuse for bad jokes about the earth moving. But ineffably cool Sweden is, of course, far too classy for tasteless novelties. The floatiness is purely functional: it sits on the water because there was no more room in the fishing village and diners at Salt & Sill's restaurant were craving a place to sleep after feasting on herring and schnapps.
Its stark modern lines a sharp contrast to the traditional red fishing huts and houses, Salt & Sill's hotel might have sailed down from outer space. It was actually built on the neighbouring island of Tjörn before being floated into place. Given that its 23 rooms opened only this month - the day I turned up - you might expect a degree of chaos, but there was something instantly calming about it.
Unlike the flat waters of Sweden's Baltic coastline, the west coast is wild and rocky; its barren humps of granite look as if the ice age has only just retreated. There are islands off islands off islands, and the hotel, too, is another little island. Its threshold is water and you cross a wobbly bridge to reach your room. Despite arriving too late for any schnapps, I felt drunk when I visited the bathroom in the night. Then I realised I was swaying only because the whole hotel was being nudged by the ocean current which sweeps into the harbour (and powers a turbine beneath the hotel to provide all its heat).
An hour's drive from Gothenburg's City airport, Klädesholmen is a proper working harbour. Its large fishing sheds make it the herring capital of Sweden - most of the country's catch is landed here. When Susanna Hermansson came to the island looking for a summer house for her husband's parents nine years ago, she bought a small restaurant instead. The family called their slightly accidental venture Salt & Sill ("sill" is herring in Swedish), and served seafood straight from the fishing boats every summer. "There are not many restaurants that have herring on their specials boards," says Hermansson. "The Swedish love herring but we eat it only at Christmas, Easter or midsummer - every time we celebrate something. We thought we must teach people to eat herring all year round."
In the morning I was woken by the lonely "peww" of gulls and the sun rising over the water. I padded around my floating room, its wooden floors soft as velvet beneath my feet. The rooms mix local granite, old wood from derelict fishing huts and new wood stained with environmentally friendly treatments. Their chic minimalism is, once again, functional as well as aesthetic: the hotel had to watch its weight to make sure it would float.
Refreshed by a breakfast of pickled herring gently flavoured with blackcurrants (there are yoghurts and hot English options, too), I took a small orange-coloured car ferry to the island of Flatön for a "lobster safari". Surrounded by yellowing leaves of aspen and silver birch was Handelsman Flink, a hotel and restaurant that takes its name from a local shopkeeper. The famous Swedish folk singer Evert Taube lodged in a room behind Gustaf Johansson's counter for a few years in the 1940s and named Johansson "Flink" ("quick" in Swedish) because everything took so long in his sleepy shop.
The small fishing boat piloted by Niklas Krafft was genuinely quick but Handelsman Flink's head chef had to cut its speed when we hit a monster swell. This was a working trip to catch our own lobster supper in the cold coastal waters which slow the lobsters' growth and make them particularly tasty. Krafft's pots lay on the sea bed 20m below us, and as the boat lurched in horizontal rain, we - a group of six - had to lean over the edge and haul them up.
It was heavy work and the first pot held nothing. Krafft's face darkened - it was raided not by the seals which pop up everywhere but by another fisherman. Lobster currently fetches a tantalising Skr1,000 (£80) a kilo and lobster piracy is a growing problem - strangely reassuring when everything in western Sweden appears preternaturally perfect. I hauled in the second pot. Inside was my shiny black pal Lobby, who waved one claw reproachfully at me. A Swedish passenger whipped out a hip flask to "celebrate the catch". Burning scotch and a heaving sea was not an ideal recipe for hunger but my appetite recovered back at Handelsman Flink.
Then Krafft handed Lobby to me and motioned to his cauldron of boiling herb-filled water. Lobby eyeballed me. Sorry, old friend. I cast him into the scalding abyss where he died instantly, and turned a brilliant red. Krafft showed us how to remove flesh from lobster claws before disappearing to prepare it while we enjoyed a sauna and Jacuzzi. The fresh lobster was slightly sweet and aromatic to taste and was followed by a delicious main course of monkfish crowned with a claw of lobster flesh.
The sign of a good fish supper is when a fish lunch the following day does not repulse you. Back at Salt & Sill, I idly watched a white jellyfish tentacling its way through the blue-black water like a plastic bag with purpose, before tucking into matjessill (herring) and other pickled herrings served cold and variously flavoured with mustard and smoked whiskey or apple, chillies and vanilla. These were served on a traditional wooden tray, alongside warm new potatoes and a sour cream called gräddfil, washed down with the restaurant's own lemon and dill flavoured schnapps or beer from Grebbestad - famous for its oysters - further north.
My final afternoon was spent visiting the lonely iron-age stone circles of Pilane and the excellent Nordic Watercolour Museum (0046 304 600080, akvarellmuseet.org) in the well-heeled village of Skärhamn on Tjörn island. The even more well-heeled town of Marstrand was a good stopping point when I turned, reluctantly, back towards the airport. Its steep little streets are usually exceedingly well-trodden but it was pleasantly deserted off season and offered fine views from the formidable fort constructed by the Swedish king Carl X Gustaf in the 17th century to repel the Danes. It is not surprising that this magical coastline was so fiercely fought over.
• Ryanair (ryanair.com) flies to Gothenburg from Stansted, Glasgow and Dublin. Salt & Sill Floating Hotel and Restaurant (+304 673480, saltosill.se) has an introductory rate until Feb 28 from Skr1,490 for doubles (about £115). Handelsman Flink Hotel (+304 55051, handelsmanflink.se) offers lobster-catching boat trips from Skr995pp, lobster lunches from Skr185pp and lobster dinners from Skr485.
