This is a cheap and easy to run rescue boat to help recover lost RC offshore/boat that are lost in the middle of the lake ;).
Use carbon fiber plate or other material to link and rock solid the structure.
Motor 35 mm 790 Kv
1 low profil servo 9Kg
1 Lipo 3s. The cell is capable to hold 2 x 3s batteries for long days running.
Look pictures for azssembly and use right sized nuts and bolts depending of the material thickness you choose.
I also used PVC Hoses Diam.100 mm x 1Meter length including front legs.
See video for demonstration:
EDIT: Thanks to Roaoro, I added the rear motor mount support that missed.