 Later that year an Act of Parliament was passed enabling construction of a lighthouse , yet despite pleas for a light arriving almost weekly at the NLB , events proceeded only slowly . It was not until 1834 that Robert Stevenson returned in the company of his son Alan . A painstaking survey made it clear that there was little choice for a location . The single largest area was a rock that measured only 280 sq ft ( 26 m2 ) at low tide . Readings for wave pressure indicated that any tower would have to withstand forces of 6 @,@ 000 pounds per square foot ( 29 @,@ 000 kg / m2 ) . There were suggestions that a tower of cast iron or bronze might be sufficient , but Stevenson senior wrote that " no pecuniary consideration could in my opinion have justified the adoption of an iron lighthouse for Skerryvore . " On more than one occasion the surveyors had to warn passing vessels of the danger . A ship from Newcastle , whose charts showed only the main rock some miles away , was boarded near Bo Ruadh . The Master , oblivious to the dangers , was found lying at ease smoking a pipe with his wife beside him knitting stockings . 
