Gentlemen, gentlemen, please accept my sincere apologies if I've unintentionally opened a rift between the two schools of engineering.
My experience of steam is limited to a couple of builds, one of which was incredibly underpowered due to limited airflow, although Mr Bishop was kind enough to put a pic in Model Boats. The other was a large model of a WW1 Saint class rescue tug which looked superb and sailed wonderfully using an old York oscillator and a huge Cheddar boiler. I wish I still had that one because it was bl***y lovely!
The new one is a variation on an open launch. It's about 1m long with a relatively narrow beam and comes in at about 4.5kg. The engine is an 11mmx11mm twin, in-line oscillator driving a 75mm prop. The original vessel in 1886 used a forced air system which I could reproduce should the need arise.
The reason for the original question was that I've always believed that the steam pipe should be as short as possible to minimise, or so I thought, power loss. Since, in this vessel, the steam pipe was extended, I wanted to know what, if any, the actual losses would be and, if necessary, incorporate changes.
My knowledge of the physics is based on information from Mr Nelkon and his textbooks of the 1960's plus some formulae, sorry algorithms, from my son and a home lesson on computational fluid dynamics
so each and every snippet of information that stops me from making a complete 'horlicks' of the build is much appreciated.
