Images of a flaming boat pushed out to sea is what most people imagine when thinking about a Viking funeral and most people assume that the body of the deceased is fully cremated with an eventual burial at sea.
Modern laws and basic scientific principals make this generally impossible; extensive rules surround a full body burial (not scattering of ashes) and in most cases a flaming boat will not reach the temperatures required to cremate the body.
However, it is possible to have a Viking-style funeral with the already cremated remains of the deceased or with something of importance to the deceased. The decision to send-off cremated remains or another item is crucial.
Federal and state regulations abound regarding scattering of ashes and pollution of waterways. For example, in the United States, cremains may only be buried in ocean waters at least three miles from shore and cremains buried within inland waterways are subject to permit from the state.
So, it may be more practical to send-off in a flaming pyre something of importance to the deceased or even a photograph of the deceased rather than the cremains of the deceased.
Once it is decided exactly what will be contained in the funeral boat pyre the next decision to be made is the location.
As outlined above, practical considerations may be the deciding factor for location. Regardless, the body of water should be relatively calm and the size of the body of water should be relative to the size of the boat that is planned to be used.
A small pond will not accommodate a full size long boat but it may accommodate a small replica boat. Conversely, an ocean burial, even three miles from shore, might be too rough of water and the ocean waves may immediately sink a small model of a boat.
The second requirement is to obtain an appropriate boat or other floating item. The boat should be flammable and lightweight; avoid thick and dense wood as burning will be hindered and may ultimately fail. Something as simple as a cardboard box may be used or something more complicated as a custom built replica of a longboat.
Once all the preparations have been made, the Viking style funeral service can go forward. A send off at dusk will offer nice lighting and symbolically showcase the dusk of life.
Flowers or other offerings may be placed within the boat or scattered in the water around the boat. One traditional offering that can be included in a modern ceremony is to pour an offering of an alcoholic beverage in the water or on the ground.
Some words about the deceased can also be offered and a wish of good life in Asgard. The boat may then be lighted and launched in a Viking-style send off.