In the boats themselves, there was quick development. The early incarnations of today's modern vessels can be seen in some of the early propeller driven ships, mainly the 1906 pair, "Royal Iris" and "Royal Daffodil". The Wallasey twin screw vessels all had flying bridges with port and starboard docking cabs. As built, the two ferries still had the wheel at promenade deck level, however this was subsequently moved up onto the bridge so navigation was all on one level. They were all fitted with ahead and astern reciprocating engines and most vessels could achieve a speed of around 12 knots, which is about the same as today's trio of ferries. On early paddlers, the wheelhouse and side cabs were open largely due to the transition from sail to steam, and most ships at the time had open navigation bridges with the ferries being no different. Birkenhead did not use flying bridges, instead having a central wheelhouse and two outer navigation boxes which were raised up higher above deck level. Wallasey ferries employed a funnel livery of white and black and Birkenhead red and black. Birkenhead changed to orange and black after the second world war.