Resistance and powering

[William D. O'Neil]

H&W did not have its own towing tank. (Aside from the Admiralty tank at Haslar, Deny's had the only one in the UK at the time.) Does anyone know whether model tests were conducted to estimate residuary resistance for the Olympic class? If not, how was resistance determined?

 

[Doug Criner]

I don't know if model tests were run. But there have been ways to calculate resistance, as early as the 1870s with the work by W. Fraude. In the case of the Olympic class, the actual resistance of similar, earlier, ships could be scaled up. Google "Historical Ship Resistance Calculation", etc.

 

[William D. O'Neil]

Yes, but Froude's contribution was to develop a reliable method for determining resistance on the basis of model tests. A serviceable approximation to power required for maximum speed could be obtained by using Froude's procedure to scale from trials data for another ship of comparable prismatic coefficient, but model testing almost always quickly paid for itself in fuel savings.