They are pretty good boats. Classic 70's. Based on the same hull as the non fly bridge version you'll see on the Thames. I'm pretty sure that they are semi-displacement and they have a round bilge with a shallow keel.
Think there was one going at Littlehampton for about £40K. Late model and well looked after.
They were lightly built under the auspices of the late Colin Chapman of Lotus fame so not a great heavy weather boat. Also, unless it has been modded, a Moonraker is a pig to handle in a following sea.
V much a "leisure" boat IMHO.
Check for stress cracks at base of frint cabin window, the bows tend to flex, CC designed them light as per F1, Also the engines are pigs to work on, the better engines are the 175's gives you 17knts cruise with clean bum also get one with the spray rail at bow.
If a tardis is required and not to many sea trips in F3 or above then they represent a good buy.
Some are home completed as well.
A couple of the later ones had big engines 220's and I think up to 300's fords.
Unless its a minter don't bother, some real cheapy bits and build in places, stress cracks all over the gaff and as mentioned a pig down the weather, if its a doer upper it'll break the bank. Buy late as possible and the biggest engine option. Oh and the wiring is a nightmare, cobbled together out of shoe string, forever blowing up or melting.
As with all older craft buy on condition rather than anything else.Went to look at a couple of these when searching for a boat and the condition went from very scruffy to one of the best looked after older boats I had ever seen,it was lying down at the Hamble.It was owned by the founder of a company building boats which were legendary for their sea handling capabilies.The prices asked for these boats is remarkably high and has collected a devoted following over the years.
I view some of the previous comments with some scepticism.
I owned a 1972, non flybridge, Moonraker 290 (2 x 145hp Perkins) around 1994, so already 20+ years old and view it as an excellent boat.
Ignore the comments about semi-displacement. It was known as the Softrider because it had a medium V plus small keel, with very fine entry forward. The ride was excellent and if you drive sensibly it was no problem at all in a following sea, least ways not in anything any of us are ever likely to go out in.
I don't think speed varied much with the different engines, but be aware that the Perkins 145hp and 175hp are becoming more difficult for spares. Having said that the sheer numbers of these engines ought to mean a fair spares position for some years yet. The Perkins also had a reputation for consuming oil. Not a problem but be aware.
Interior fit out is fine so long as you keep out the water! Quite a lot of veneered chip board was used.
These things are all "horses for courses". If you can afford £100k then there are better boats but if your budget is nearer £30k I can think of many worse boats.
Personally I would still go for an earlier non-flybridge boat but with 175hp engines. The flybridge is piddly anyway. Probably better quality.