At the time of Ragnarök, the largest ship Naglfar (ship of nails – ship of the dead) will be loosed from its moorings as the sea rises and will set sail with the Jotunn Hrymir (according to Gylgaginning) and/or Loki (who has broken free of his bonds - according to Voluspa – though Hrymir is also mentioned). The ship, Naglfar, will carry the Sons of Muspell and some from Hel (one Edda source says the "people" the other the Champions of Hel) to the Battle with the Gods and the Einherjar.
In the Norse heathen world, the nails of the dead were always trimmed at death, because Naglfar is constructed from the uncut nails of the dead. By trimming the nails of the dead, Ragnarök is delayed, since the construction of Naglfar is slowed. The tradition of cutting the nails of the dead, according to Dr. Rudolf Simek (author of "The Dictionary of Norse Mythology" and other works), continued in Eastern Europe where the belief was the Christian Devil would build a ship from uncut nails to take people to the Christian Hell.
There is also a practical and courteous side to this custom and that is the respect of the remains of the departed. Modern funeral homes in the US, like the rest of modern culture often focus on the superficial. They will cut fingernails, but probably not toenails unless you ask. They might not put shoes on the dead unless you ask. I know this from arranging several funerals of friends and for my parents. We know though that our ancestors who died of natural causes and or old age and/or illness believed they would need to make the walk to Hel. To do so, they need shoes. Again, in your time of grief these may not be things you focus on, unless you ask. My experience though is funeral homes will accommodate your wishes though so let them know.
Our heathen ancestors believed that they could take possessions into the next world if they were cremated or buried with them. We call these grave finds. That is something to consider and again based on experience, funeral homes will give you time to put pretty much whatever you want in the casket before it is closed. So, my parents have made their walk well dressed and well stocked.
For most people addressing their own mortality is a difficult thing. That leaves it to relatives to try and guess or figure it out. If you are a heathen that may not be what you want if a relative/next of kin of another faith is left to plan your funeral and decide…Best advice is to leave written signed instructions and/or put in your will. This is especially important to those going in harm’s way. In the Ranger Regiment and JSOC we wrote out all of this in detail down to who would carry our casket, what music would be played, what would be read – all that detail.
“From the east comes Hrym with shield held high;
In giant-wrath does the serpent writhe;
O'er the waves he twists, and the tawny eagle
Gnaws corpses screaming; Naglfar is loose.”
“O'er the sea from the north there sails a ship
With the people of Hel, at the helm stands Loki;
After the wolf do wild men follow,
And with them the brother of Byleist goes.”
Voluspa – The Poetic Edda
“Then shall Fenris-Wolf get loose; then the sea shall gush forth upon the land, because the Midgard Serpent stirs in giant wrath and advances up onto the land. Then that too shall happen, that Naglfar shall be loosened, the ship which is so named. It is made of dead men's nails; wherefore a warning is desirable, that if a man die with unshorn nails, that man adds much material to the ship Naglfar, which gods and men were fain to have finished late. Yet in this sea-flood Naglfar shall float. Hrymr is the name of the giant who steers Naglfar. Fenris-Wolf shall advance with gaping mouth, and his lower jaw shall be against the earth, but the upper against heaven, --he would gape yet more if there were room for it; fires blaze from his eyes and nostrils. The Midgard Serpent shall blow venom so that he shall sprinkle all the air and water; and he is very terrible and shall be on one side of the Wolf. In this din shall the heaven be cloven, and the Sons of Múspell ride thence: Surtr shall ride first, and both before him and after him burning fire; his sword is exceeding good: from it radiance shines brighter than from the sun; when they ride over Bifröst, then the bridge shall break, as has been told before. The Sons of Múspell shall go forth to that field, which is called Vígrídr, thither shall come Fenris-Wolf also and the Midgard Serpent; then Loki and Hrymr shall come there also, and with him all the Rime-Giants. All the champions of Hel follow Loki; and the Sons of Múspell shall have a company by themselves, and it shall be very bright. The field Vígrídr is a hundred leagues wide each way.”
Gylfaginning – The Prose Edda
Tullstorp Runestone in Scania, Sweden showing Naglfar and Fenrir – Photo by Sven Rosborn