Information for this period is pretty scarce. The main change at this time appears to have been the change of administrative body. The teaching of Marine Engineering, Navigation and all evening class provision for the local secondary schools was administered by the Greenock Burgh School Board, but in 1919 with the termination of the School Boards under the Education (Scotland) Act of 1918, it was administered by the Renfrewshire Education Authority.
To meet the demand for accommodation, use had to be made of a number of local facilities, e.g. old junior secondary schools, unused church halls and even an old, private commercial college (The George College). Overcrowding and lack of space was however very much the issue at this time. An entry in the log book of 1930 stated that “it has become urgent that all departments should be incorporated in one building. Still excellent work is done in spite of very adverse conditions.” What was to be done? Services continued to expand - in 1931 a Junior Instruction Centre opened in an annexe at Shaw St and at the Sailors Rest at the Dock Breast with 272 boys and 95 girls. Boys were carefully arranged according to educational attainment and religious belief and graded into 12 sections. The centre was open from 8am to 5pm
The girls were divided into 5 sections. Subjects on the syllabus included: Cultural Subjects, Physical Instruction, Manual Instruction, Technical Drawing, Domestic Subjects, Dressmaking & Needlework.
As the years progressed, it was obvious that the demand placed on the school to cater for local technical and commercial education outweighed its capacity and in 1936 an extension to the building was opened, after the demolition of adjoining tenement property in William St. This extension, opened by Sir Godfrey P. Collins, K.C.B., M.P., the then Secretary of State for Scotland, cost £15,000 and consisted of an engineering laboratory, electrical engineering laboratory, wireless installation rooms and lecture rooms.
It is believed that, it was at this time, the name of the institution was changed to The James Watt Memorial College. The confusion about the name of the college exists because as late as 1944 the Joint Committee of the Organisation of Science classes still referred to the institution as The Greenock Technical School.