Hi Vosper21 Welcome to the forum. I put a single motor, shaft and rudder in my fireboat so I don't have any first hand experience of a twin drive system but I would think that the shafts should exit the hull at the same points as the single shaft but equidistant from the keel. Similarly the rudders should be directly behind each prop. There are members on this site that have done a twin drive system on the 46" model that can offer more informed guidance, hopefully they will chip in with some good advice.
Over to you chaps !
Please consider doing a build blog to document your progress. Good luck with the build. Robbob.
"Time flies like an arrow; fruit flies like a banana"
Thanks robbob for the info. Will await further input from other members. Will look at doing a Build blog later when the assembly looks a bit more presentable, this is my first attempt at building a boat so lots of info gathering. Vosper21
Welcome aboard Vosper21, again I have no experience of twin shafts but I am currently building the same boat and am just off the starting blocks in my blog as it does take time (the actual build is further on), but blogs are invaluable to other builders, so if you have any questions don't hesitate to ask. My blog is usually on the first page of entries as its an active one (The Vosper 46" RAF Crash Tender Kit By Vintage Model Works by M Turpin013) Michael PS have a look at robbob,s blog build its brilliant