If this is going to be a speed boat, perhaps a brushless is the way to go. Much faster, smaller and lighter. There are members who would be able to advise as to the size but at the same time, consideration with regards to the battery would also be useful. With LiPo batteries, the brushless will often work with several cell arrangements with 2s at 7.4 volts up to around 4s at 14.8 volts. Each variation will increase the RPM of the motor. I hope this is right but I am sure a kind member will correct me if not.
Peter.

Hi Terry,
I note from the SLEC website that they recommend a Brushless Motor : 3536/8 1000Kv.

"Parts Needed to Complete the Model
10in x 4mm Prop Shaft PR830B
4mm to 5mm Coupling PR840C
Small Rudder PR833A
2 Bladed Prop 40 with 4mm thread PR 834A
Brushless Motor : 3536/8 1000Kv
50amp Brushless ESC with Reverse
3s Li-Po Battery Pack
White Metal Fittings Pack Available Part No PR804A"

Considering the size of the boat (25.75") and the motor diameter (36mm) I would be more inclined to fit a 35mm prop. I'd use a 3-blader but that's a matter of taste / aesthetics 😉

For reference, my 24.5" Sea Scout gets on the plane and runs very nicely with a 2830 1000kv brushless, 30mm 3 blade brass prop, running on a 3S (11.1V NOM) battery.
See my trials results here
https://model-boats.com/gallery?q=Sea%20Scout
Hope this helps,
Cheers, Doug 😎