Some of these models have been vastly overpowered. The extreme heel in that turn gives the game away.
'Nellie' was designed as a stealth boat and its mission was to hide just below the horizon while tailing suspect vessels with her very sophisticated surveillance gear. She was capable of about 30 knots at full chat, but generally just on transit between missions or if the boozers on shore were nearing closing time. It was NOT a planing hull; Vospers called it one of their 'short fat warships'. That one looks like it's trying to do at least 60!
I was given a demo of an example which I think was being built for a review in MMI by a guy called Chris. He had fitted twin Speed 600BBs "according to to the instructions" (no...) and asked me if I thought it was a bit too fast. I don't think I needed to pass comment - my face must have shown my thoughts on the matter. The model C3PO shows is indeed my plank-on-frame prototype and was fitted with two Mabuchi 545 5-pole motors on 7.2v through Graupner 2:1 gearboxes onto 5-blade PropShop props. The commander of the real vessel, Chris Pratt, had a go with the sticks and said its speed and presence on the water were absolutely spot-on.
I would suggest either a MFA 540LN or a Mabuchi 555 from Component-Shop, either running on 3S LiPo packs.
Dave M