Thanks guys for the details that you have sent.
Two issues for me (1) I wish to get about 300 degrees rotation on one monitor.and (2) It is as is typical situated on a high mast mounted platform naybe 300mm above the deck (model is Billings Tug Zeeland)
I have a geared linkage somewhere on the graupner kort nozzle drive that I think achieves about that sort of rotation, so probably would be helpful if I could find that to copy. A swiveling upstand pipe all the way deck to platform is do able but I have to have some sort of a rotating gland at the base for the hose to allow that sort of rotation.
Maybe I should just put two fixed hydrants on the platfor facing outwards!
anyway thank you all for info to now.
Raynor J