Getting ready to re-start this airboat after 10 yrs of it sitting under the house. Will be fast electric and fully fiberglassed. I will be able to make use of the large estuary just down from my place and will build in camera mounts for off shore photography etc, and perhaps fit it with FPV.
Hull is 3mm marine ply.

It's now a tea tray with a cup holder😊 perhaps later a fast tea trolley?
JB

Just a few partitions cut for the radio box and front 2 sections, and a final bottom section for the bow. Cut a try-out cockpit profile as well, whole cockpit will eventually be the lift off battery and radio waterproof cover. Might fill the sections with poly foam to make it unsinkable as well, although all the sections will be sealed, so probably won't need it. Probably is going to weigh around 5.5-6lbs all up which should keep it on the water.

Motor mount and mount plate started. Mount will be glued to base plate and side braced with brass strip or similar. Mount plate will be screwed to rear beams through deck and will be removable.

Motor mount glued up (West system and filler) and airflow cutouts made for better cooling flow (these motors can get hot). Waiting for a day or so for glue to go hard enough to finish sand, then appropriate mount holes will be drilled and the whole thing resin coated. Was going to be in a pusher configuration (3 blade shown is a glow pusher prop) but in the interests of cooling and rudder mounting simplicity, it will be first set up as a tractor. Would do it otherwise, but can't get any bits at the moment. Was going to go for a scale caged pusher set-up with a wire frame mount, seat etc, but as this motor plate is just a screw on unit it could be done later.

This set-up is just a 'see how it goes first' job to find the best motor.
About 1966 I made a small balsa free running air-boat, with a DC Spitfire diesel which ran really well, and was heaps of fun. If it rained hard you could look for a 'lake' on a playing field and have hours of fun.

Motor mount (thrust angle adjustable) finished and wiring and radio gear hooked up. Have to make rudder and fit servo and rudder linkage. ESC is 80A and should be sufficient for the motor. Will have to buy a 3 blade tractor prop once the stores open again, or make do with a 2 blade. No BEC on this ESC so a UBEC was fitted with power taken off ESC battery wires, (do this with all my planes for safety as the first thing to go in a ESC is usually the BEC in a low battery situation (unless it has a safety power reduction feature ).

Will do a power test, and once that's all good and everything's in place, I should be able to glue the deck on. Motor lead extensions are high amp fine multi strand speaker cable, which is bigger than the ESC and motor wires to allow for current loss, (we shall see). Might have to fan cool the ESC yet (will know when run) as it will be enclosed in the waterproof compartment. Will have to figure out how to get air to it, -maybe a snorkel with a cone up behind the motor and an exhaust tube up high with a venturi as well (might need to cool the battery as well).

Made up an experimental rudder which is made from 3mm ply and covered with doped on Sig Koverall material. Leading edge has a carbon fibre tube to stiffen the ply and the base is 2 ply discs with plastic washers in between. Has a central bolt to adjust tension and play. Might not need to be so long but I can chop it down if necessary to suit. Would have made an aluminium frame with top support bracket, but can't access the hardware store to buy any. May make a dual rudder later but this should be enough to turn it easily for an initial test.

Tried the power out with a 4s 40c but 80A ESC got hot at 43A (half throttle,-motor's rated at 50A) and had too much power. Tried a 4000mah 3s with an 11" prop and that's a lot better (shoves the boat and small floor mat along at half throttle, - (about 10A) I can experiment with motors if needs be for economy, as I have a few 35 and 36 diam motors in the collection, which are quite powerful and lower kv (this is 1450kv.) The lower the revs the less noise it will make. This motor with an 8" prop on 4s would be over 100DB.

It's hard doing much when you can't get bits you need, and you're having to scrounge around through your junk boxes. Mind you it gets the pink mush working overtime😁
PS it's going to have a big fillet of epoxy at the base of the rudder for strength.

Rudder base filleted for a bit more strength and rudder servo mount and rod made. Might need to fit a 2:1 servo arm in the center somewhere to get more throw, but getting a rudder angle for around an 8' circle so might be enough. Tried rudder control on the 'speed limiter' (small floor mat😁) and it will steer at 1/2 throttle, so it might be enough as is for a first try. Servo mount will be screwed in with the rear top ply plate to be removable (slides out - will have access holes in the deck for the screws)

Motor mount blocks glued to center rear frames, - deck and mount drilled and screwed down (temporary). Remembered I had a spare canopy from my vacuum former tests and this can be a use for it (along with the 'volunteer' kamikaze pilot). More to do yet,- waterproof radio box and battery compartment, Everdure resin preservative inside of hull, glue deck on, sand, f/glass hull and make a cockpit recess for pilot.

I was thinking of perhaps making it amphibious (like the NZ 'Sealegs' boats) but it's fairly heavy at the moment due to the solid construction. I can always chop into it later if I change my mind, and the performance is sufficient to handle a bit more weight.

Figured out a way to fit twin rudders (had an epiphany/ eureka moment)😁 Top ply 'Y' plate yet to be screwed on to the blocks glued beneath the front of it. Red plastic tube pieces on front top of the rudders, are top grips of pins (made from thick walled spray-can inner tube, as are the bottom pins, - Martin will love that😂) which can be withdrawn to remove the rudders, (a semi gudgeon and pintle, setup). Rudders will be linked at the rear edge by the elevator horns (fitted) with a crossbar and clevises. Servo rod goes to the inner stbd rudder inner bottom front edge.

Once everything is secure I'll have another yard drifting session (maybe outside on the large berm) Hard to tell how it will go as plastic on grass is a lot more slippery than water. Should be a lot more controllable on water as there will be a bit more drag. Had to relocate the ESC as it got too hot in the bottom of the boat. I'll probably make a cover/scoop for it and waterproof it, but I'm hoping it won't get too wet up there.

Have to dremmel out a bit of a bulkhead/frame so the battery fits, and make a small battery cable extension to come forward through the rear bulkhead hole, to make plugging in easier, (will only be about 3" in length). There will be plenty of room up front for a camera now the ESC has moved out. Need to attach the RX and UBEC with Velcro and run 1 ESC servo plug extension. Soon as everything is tested I can glue the deck on and make a waterproof hatch (may need to get some sealing sponge from the hardware yet.) Deck will stiffen the whole thing up, as it's very flexible at the moment.