Hello tony the sauria was built for Gasilee and sons Ltd London for use at Felixtowe when the were expanding the port and needed a bigger tug than the Rana and Fossa.
She was built using the same hull as the Northsider but with a few modifications, the wheelhouse arrangement and the funnel were different and she did not have the very heavy belting around her like the tyne tugs had, the Watercock and Burma built for London tugs Ltd also used the same hull as the Northsider, but with slightly less power although they were originally built with an open wheelbox and 'blinking!' great funnel, they had a fibre glass wheelbox built by Motivators at Gravesend and added later. but they never had the Flair of the Sauria or Northsider and unfortunately went to an early grave being broken up at sheerness. the Sauria went to Greece and worked there for years before being sunk by a bomb placed in her bilges, a sad end for what I think was a lovely lookin tug, Geo.
have a look at the two Gasilee tugs thread