Sorry, long reply.
I got in touch with him (Mark Nye, www.gas-turbines.com
) last year when I was looking for a project.
To build an engine (no outdrive or other boaty bits) with a T58 turbine (Rolls Royce Gnome, 1200shp), using Mark Nye's conversion components and a UK sourced engine and reduction gearbox works out over 20K. If you had your own machine shop to built a lot of the items and could do the gearbox modifications yourself, then the cost comes down quite a lot.
To build a boat with a T63 engine (317shp) is much much lower, but last time I checked, there was only 1 in the country available, it was 7K, without documentation. The trouble, I believe, with a T63 is that it's quite a complex, and very lightweight design. It's a good engine, but won't stand up to abuse as well as some engines. (FOD, hot starting, etc)
There is 1 more engine I found, it's a russian copy of the T63 callled an Isotov GTD350 (400shp). Similar configuration, but in true russian style, very basic engineering. And since some of them were manufacturted in Poland for use in the Mil MiH2 helicopter, there are a reasonable number of them for sale for not much money, often with certification and very low hours too. There's one that pops up on ebay occasionally, the guy was wanting in the region of 2.5K for it I seem to remember. There's also at least a couple for sale in germany at the moment for similar money.
I've been told the trouble with diesel is that the sulphur in it can erode the turbine blades. But lots of people seem to do it so there must be a way around it, or maybe some engines use different materials and aren't susceptible. Not sure really.
Originally Posted by codprawn
And to get back on the subject - talking of gas turbines another advantage is they will happily run on red diesel.........
Have a look at this - the blokes gas turbine speedboat is really funny - there are some great vids to download - as long as you have broadband that is.