Sileas is a 52 ft ex-admiralty pinnace or harbour launch built in 1940 by James A. Silver Ltd. of Rosneath, Scotland. This boatyard was well known for its high quality vessels built under the direction of master designer and craftsman, John Bain. Sileas was one of three boats commissioned in 1940 by the navy and is built in double diagonal construction of teak on oak frames.

These boats were used to run cargo and crew from the harbours to and from the larger warships which would sit off-shore. Some were fitted with guns for harbour defence.

It is thought that the Sileas was in Admiralty service until the mid 60’s ending up at the naval base at Invergordon.

It was bought by a Glaswegian company which was involved in pier construction at Invergordon, and in turn sold to MacLean and MacRae, partners who ran a boatyard at Kyle of Lochalsh.

MacLean and MacRae operated the boat (named Vital Spark at this time) under contract to David MacBrayne, plying mainly between Kyle of Lochalsh and Toscaig. This was a daily service carrying mail and passengers and ran for close on twenty years until being sold in 1987 to MacNab MacKenzie who operated it as one of several pleasure-boats from Ullapool to the Summer Isles.

Three years later the boat was sold to Iain Morrison of the Isle of Mull who operated the boat between Ulva Ferry and Iona, Staffa and the Treshnish Isles from 1990 until October 1994.

Vital Spark was then taken off service and lay in a sheltered bay at Croig near Dervaig in Mull until December 1996 when the boat was bought by Jim Michie (the present owner).

Almost all of 1997 was taken up with restoring the vessel, the main work being carried out in Samalaman Bay, Glenuig, Moidart.

The boat was floated onto a trailer at Allisary, Lochailort and in late July 1997 it was taken by road to Glenfinnan and then down the forestry commission gravel track from Callop to Giusachan on the side of Loch Shiel. The boat was then physically pushed off the trailer using a large digger while being pulled by the Glenaladale Estate boat.

After the launch the "Spark" was moored at Dalilea where it underwent its stability tests and Marine Safety surveys, gaining a Class V Passenger Certificate.

Vital Spark was re-named Sileas after the wife of the first Laird of Glenaladale, Iain MacDonald. Sileas translates from Gaelic as Julia or Juliet.

Passenger pleasure cruises started running on the Sileas from Glenfinnan on Loch Shiel in April 1998. The boat can carry 50 passengers and has both covered and open seating on deck and a bar/saloon and toilet below.