Update.the boat took a ton of water up the original flexshaft tube,i kinda thought it would.maybe as much as 1.1/2 pints!!on an eight min.run.Amazingly the Turnigy ESC and servo still work..they were completely submerged.
basically the motor is sat too low and just drips in fast.
Ripped the motor and mount out,a bit of heat from a small gas blow torch melted the epoxy easily.
i plan on mounting the motor towards the front on top of the cross member stringers and then the 2 lipo packs on the side of the hull.
i need a longer flex shaft which will take a few days.
Also i now have a spare 2000kv 80mm medusa motor from another boat(long story) which i will fit instead of the 2300kv 70mm medusa,which ran ok but a lower KV will be more torque and longer run times on the same 4S 10000mah packs.
I will post some more pics when i get the flex shaft in.

Birddognit,these hulls make good electric boats,definately worth doing.10 minute run times on a sensible setup is easily possible.
Brod..