As a lad I made literally flat plate boats from 1/8th balsa in a rectangle with a triangular front section. Real skimmer. Two little 1/16 th ply fins on top set at an angle and one underneath .A JETEX 50b on the back. Clear doped .Literally flew across the water with just the fin in it. I might do some again with Rocket motors. Link here if interested. https://www.modelrockets.co.uk/shop/https://www.modelrockets.co.uk/shop/ 👍

Thanks Dave. I'll let you know how I get on.
Steve

Hi Steve
Sorry, no I did not take photos of the build. if you have the Mobile Marine hull then I built a vertical wooden plate up through the top and strengthened with wood plates beneath the top moulding. if your rudder snake runs over the top make sure you allow for this when deciding how high to mount the motor/prop!!
This works but flexes when power is applied so if I did another I would mount the upright to the base and make a slot in the top to allow it to pass through. I would also provide support, below the top, to the upright behind and right up to the hull sides.
The force from the motor is truly awesome and plastic mouldings tend to (and do) flex.
I use two rudders as other members have found they work better than one.
I used 1/8" welding rods for the cage and did have some hard black netting at one time but have had no problems with just the frame. if I sailed in an area where the public had access then I would provide a cover. Just get the mount and prop sorted before you finalise as mine was too small!

Hi Dave
Following your advice on how to fix the ply board in the hull, I decided to try silicone. it worked well and allowed me to gap fill where necessary.
I am now ready to proceed further and reading your advice to Chris about motor mounts, getting them strong enough seems most important.
Have you got any detailed pictures of your mount you could post please?
Regards
Steve

Hi Dave,
Thanks for that. Not started it yet, am half way through another build at the moment but there's nothing like planning ahead! Where about's along the hull do you suggest the C of G ought to be, or thereabouts? Looping the air boat is not on my agenda! What overall weight does yours work out at?
Sorry for all the questions.
Chris

Hi Chris
Mine just has a large flat ply plate over the bottom of the hull with the rx rudder servo and battery fixed in place. I use velcro for the rx and made mounting blocks for the servo. An aircraft snake connects to the rudder. The battery is in a small wooden compartment. My ESC is just below the motor mount hanging loose.
You do need to strengthen the motor mount - I used lots of wood inside to make it all less pliable - the plastic is not strong enough on its own. You need to build a plinth to attach the motor high enough to attach your prop. This need to be well braced to take the thrust from the prop. Mine moves slightly and if I were to make another I would make it stronger.
Mine required two small sheets of lead up front to keep it on the water at speed.
Please post details of your build
Dave