Buit a lot of Fairey boats, most of the originals from the 60's had teak decks. The 31 inch model,s deck strips would be about 5mm wide but 6mm looks good too.
Try to get hold of a copy of Model Boats July 2013 my article ,Away with the Faireys, shows you a way of doing it.
Real teak is hard to get and poses problems of getting varnish to stick because it is an oily wood. The suggestions already posted have merit and a good fine grain brown coloured wood will do nicely.
Happy boating