To; Seaweed, Goldie and ShaunJ,
Thank you all very much for your input and advice. It's pretty much covered all I needed to know. As for the "Nereide" I've managed to find quite a bit in newspapers and surfing the Net. Captain Mainland was hired by the Govt/Benevolent Society to carry cargo for a Mission Station to the Sierra Leone port. The ship caught fire, was sunk and "brought back to life again". Alas not for Capt. Mainland who caught yellow fever and died while waiting for the ship to be repaired.
Thanks again everyone ! MAPS
PS. Just so you know Skoosh, Capt .Thomas Mainland was the son of the Orkney born George Mainland snr. who went down with his ship the Knapton in 1820/21