the small dimensions and shallow draught of the "bramble" class were designed to facilitate navigation on the complex coastlines and great rivers of africa, south asia and the far east. the drawback this imposed was a limited fuel supply. the type entered service with a standard bunkerage of just 50 tons of coal. for "thistle", considered one of the better-performing ships of the class, this would only provide two and a half days' movement at her sustained cruising speed of 11.5 knots, and full-speed runs used nearly twice the quantity of coal over any given length of time. in practice, storage was found for 145 tons of coal, but this was still sufficient for only one week of cruising.