Hi ya there, Flag D
Can you tell us what type of M.T.B. this is? Because of the size you say and the number of propshafts .
The only vessels that spring to mind are the Camper and Nicholsons M.T.B. (I am sure these were only 3 shafts)
The other one is the Fairmile D which was a 4 engine - 4 shaft M.T.B. However, the size you give 1/24th, 53" LOA, about 15lb displacement, this is a little bit small for the Fairmile D,
The reason I ask is - do you want the model to come onto the plain? because if its a round bilged hull it doesnt matter how much power or what size motors you are going to put in, you are going to reach a point where the hull willgo no faster and you are just literally wasting power.
Aye
John E
BLUEBIRD