A replica Viking ship has set sail for Dublin from the Danish port of Roskilde, in an attempt to recreate the voyages undertaken by early Norsemen.
The crew of the 30m-long (100ft) Sea Stallion from Glendalough is recording the experience of the journey.
After reluctantly accepting a tow across the North Sea, the vessel has been moving around Scotland and has just left the Isle of Skye, where a change of crew was made.
FRIDAY 27 JULY: A NEW CREW
Glenn MacLeod, new crew member
I have hardly any sailing experience.
I joined the navy in 1977 and they gave us a small induction to sailing in fibre-glass boats, but I just had no interest in these types of boats, and I just treated it as an ordeal and never really took onboard much of what we were taught.
Apart from that, my sailing experience has been zilch.
But I don't think you could get a better introduction to sailing than being part of a crew on a Viking longship - it's the best introduction I could have dreamt of.
I love woodwork, and it is a marvellous experience to see all the traditional methods that our ancestors used to make these vessels.
Their boats are so beautiful; they are just pure form and function for the job they are designed to do.
It is just amazing to be able to be part of this project and to see every aspect of it, from the original boats at the museum to this Irish longship.
This boat has an incredible history; it was constructed around 1040, 1042, before the Battle of Hastings. It had a long life in the Irish Sea area and no doubt the west of Scotland was involved in its journeys.
And then eventually, after the Battle of Hastings and of Stamford Bridge, for some reason it made the long trip to Denmark.
No-one can be sure what that reason was; but my own belief is that it could have been involved in the battle of Stamford Bridge and have been one of the few survivors that escaped.
The Sea Stallion is making its away around Scotland
It is just a wonderful thing now to be living the experience.
Modern day life had become very effete and this has been a chance to experience life as it was spent by your forebears.
Instead of being cocooned in a car on a road with your CD player, you are out there experiencing life in the raw. It's as it should be.
FRIDAY 20 JULY: THE HIGHS AND LOWS OF THE OPEN SEA
David Short, crew member
We had been in Norway for a week already and time was pushing on. We had been forecast several small windows in the weather where we could have made a break for it, but these things did not really materialise.
Feeling the strain: David and the crew reluctantly accepted a tow
Then, there was a forecast of some wind in the right direction, so we had something to go for. We left at midnight on Monday (16 July). We rowed out to sea and waited for the wind to appear, but we just sat there, bobbing about, for eight hours.
When we left port we had been very excited because we thought we could finally take on the project. So, we rowed out in what was a quite nice evening. We sat there waiting for the wind to change direction; the sails were just flapping in the breeze, it was just blustery and nothing to speak of.
I slept for half of the eight hours while we just sat there.
Not long after I woke up, the decision had to be made to tow because the wind was not likely to change in our favour for some time.
We had a schedule to keep, so the choices were either go back to Norway, possibly wait another week and fall behind schedule, or accept a tow.
A lack of blankets made it a long, cold night for the Stallion's crew
We thought, hopefully, after accepting a tow, further across the North Sea the wind would be in our favour.
We were towed for roughly 20 hours, which was very disappointing for the crew because no-one wanted to be towed.
The whole point of the project was to try to sail the boat with no engine and to use nature to make our way to Dublin.
But that's how it is, we have a schedule to keep, which the Vikings would not, and we had no choice really.
It is quite boring really, because there are no duties in terms of sailing a boat - everyone is off-watch and trying to relax.
To begin with, the mood was quite high because everyone just wanted to keep their spirits up. People were singing and playing music, but then the time began to drag a little while we were being towed.
Shrouded by sea mist, the Sea Stallion looked like a ghost ship
The night was quite cold because there were not enough blankets. This is because there are only enough blankets and mats for those people who are not on watch.
But when everyone was off-watch and trying to sleep at the same time, we basically had to do shifts of sleeping uncomfortably or in mild comfort with the blankets and mats.
So it was not a nice night. People, by this point, were resigned to the fact that we were getting towed over to Kirkwall (Orkney Islands) and just wanted to get there because there was not much to do.
Luckily on the second day, some wind did blow in our favour. So we dropped the tow rope and sailed for about 14 hours, I believe.
Sailing for the final part of the North Sea leg of the journey was really good. The wind was initially quite light and we were going along quite slowly, but after about six hours we got some decent wind and we got some quality sailing in.
It was nice to see the lights from the coast come over the horizon while we were under our own sail.
The boat also feels more natural when under sail because when it is being towed, it does not cut the path it wants to and it is almost dragged through, which makes it less comfortable.
WEDNESDAY 11 JULY: THE LONG WAIT
Hans Jacob Andersen, crew member
People have been very nice to us, but we have had a week of doing absolutely nothing. Now everyone wants to get on with the journey. There are just a couple of thousand inhabitants in this area of Norway, so there is nothing going on.
We have been making some repairs to the ship, and washing some clothes and otherwise just relaxing.
Hans says he is ready; despite some concerns
We have been told that the wind is finally shifting, so we're going to try to leave tomorrow morning. We're going to start out on a south-western heading, and, hopefully, the wind is going to turn - caused by a low pressure front moving in over Ireland.
We can then turn upwards towards Orkney, which we should reach in about four days. This leg of the journey is more than twice the length of the last, and will be a lot harder.
Hopefully, it won't rain as much, but there will be bigger swells, so there will be more water coming in over the sides.
The next leg of the trip will be twice as long as the first
It's four days at sea, so you have to manage to sleep somewhere during the trip. I personally got a bit cold at the end of the last leg, so I was happy to get ashore.
But we'll see, maybe it's going to be calm and sunny - then we'll have no problem.
It would be nice to get some sun there, my mother crammed my bag with sun lotion. Of course, water might become a problem. We have very limited supplies of fresh water aboard.
Four days is not a problem, but if we run into calm weather without any wind, then we might be there for six or seven days, and then it starts becoming a problem.
All the water has to be rationed. There will be no washing, no chucking water over the side. Some of the crew got very seasick on the way over. Some of them were sick for 24 hours. I don't know how long you can last being sick like that.
The crossing will be a gruelling effort
This is my own personal opinion, but the front of the ship had a tendency to dig its way down into the swells. When you surf on the swells and go faster than them, you tend to dig yourself into them instead of rising above them.
That could be a problem if the swells are any bigger, or if we have more weight in the front of the ship. We may have to move crew members from the front of the ship to the rear in order to avoid that.
If we do dig ourselves into a bad wave, that's going to be lots of cubic metres of water rushing into the ship within seconds.
Supplies of fresh water on the ship are limited
We will be lying in the water much lower, and the next wave is going to do the same, so that is one of my biggest fears in all this. Otherwise, I think we'll make it.
I hope we don't end up with a storm on the way, because there are two low pressure fronts moving in, one way north of us and one a bit south. If those move closer together, that might produce something that might be unhealthy for our expedition.
I think we're ready - we just have to remember to diminish the sails before something potentially dangerous occurs.
TUESDAY 3 JULY: TOUGH REALITY
Susanne Malmstrom, ship's nurse
Launch day (Sunday, 1 July) was great; there were a lot of people in the harbour. All the family and friends came to say goodbye and to have a good trip. They brought small presents; and some of the patients where I work - they came with flags. It was fantastic.
When we left Roskilde, I have to say I cried a little bit when I said goodbye to my kids and to my husband. In the inlet, it was very beautiful with all the boats that followed the ship out to sea.
The crew is learning fast
Then, the first night came and I have to tell you so much happened. The weather changed; it began to rain. It was very wet and cold. People were seasick, of course. You can always see a person who is about to be sick. They go and sit by themselves and look out over the ocean. And I had the same feeling.
We were getting more and more cold; not because of the wind but because of the rain. And there were a few people whose equipment was not good enough and they found out too late because by then, they couldn't just go out and buy new socks.
In the early stages of the voyage, some of the young women especially were getting very cold.
They said, "I'm OK, I'm fine; I can handle it", but you could see in their faces something was wrong.
We put more clothes on them; and I could see one girl was really not good. So we decided to move her to our "safe" place and to work on her to keep her warm. The signs of developing hypothermia were quite different to what I expected.
Susanne checks her medical kit
One girl didn't answer me correctly when I asked her to do something, so we decided she had to leave to the safety of the support ship. We took four across in all.
The waves were big at the time and it was quite difficult to get across but they did it. They're now back with us and doing fine.
On reflection what has happened was probably the best way to start because we are now better prepared for what is ahead. Yes, everything is wet - our underwear is wet - but as I speak, the weather is perfect.
The Sea Stallion hopes to reach Dublin on 14 August.
The ship's crew will be writing a weekly diary for the BBC News website. More regular updates and a satellite map of the ship's latest position can be found at BBC History's Viking Voyage website.
The ship's voyage is also being filmed for a BBC Two Timewatch programme in the autumn.
THE SEA STALLION FROM GLENDALOUGH
1. The crew of 65 men and women will sleep on the open deck, as the Vikings did, and take turn keeping watch
2. Satellite navigation equipment will make sure the ship stays on course. Vikings had to rely on the position of the sun and stars, the colour and movement of the sea and wind direction
3. Oak planks were cut radially for maximum strength, overlapped and nailed together. Axes and other tools used to make the planks were replicas of those used by the Vikings
4. The sail, mast, rigging and rudder on the original were missing so these have been copied from other finds
5. Shields, vital in battle, were tied over the oarports when the ship was in port
Sources: Viking Ship Museum, Denmark; National Maritime Museum, UK. Photos: Werner Karrasch and Erwan Crouan