http://www.warsailors.com/shetlandbus/boatss.html

This might be - However that is not confirmed

M/S Svalen (SF 106 A)

Departed Alden, Askvoll on May 25-1940 with 6 people, arriving Baltasund on the 27th.
These were on board:
Skipper Jens Værøyvik, Anton Tviberg (policeman, organizer of the voyage) and his brothers August Tviberg (owner of the boat) and Sigvald Tviberg, nephews Alf Tviberg and Thorolf Kviberg.

Jens Værøyvik, together with Hermann Midtbø, had transported 2 Norwegian officers and 8 British soldiers across to Shetland on board Vega a few days before - follow link for more details. Anton Tviberg had previously (unsuccessfully) attempted to escape with a group from Askvoll and Bergen.