The Earl of Zetland began a twice weekly Lerwick to Unst service with weekly visits to Out Skerries and the ports of Yell Sound .
The Earl of Zetland is an iron screw steamer of 253 tons .
The Earl of Zetland , an iron screw steamer of 253 tons , began a twice weekly Lerwick to Unst service with weekly visits to Out Skerries and the ports of Yell Sound .