Figured out a way of getting the rudders, tubes and shafts in in one lot. I drilled holes on an angle in the rudder shaft tube position in the rudder box, which allows the tube to go through and then be rotated vertically. A piece of ply with appropriate matching holes, will be fitted over the tubes (complete with rudders and shafts) and glued in place. The tubes will then be positioned and cyano'd in place. When fitting the rudders/ shafts, they will have to be turned facing the center to avoid being caught on the box.

The jet tube hole has been bored in the box and the box shortened as well. This should be how it will go together, - diverter box screwed in first, then rudder box glued in, (siliconed onto diverter box jet tube tube) then rudder shafts and tubes.

Managed to get the rudders in using the angled hole method, worked perfectly. Pics show insertion sequence. Nothing permanently fixed in yet.

Sorted out a slightly better way of inserting the rudder box, by making a small block for the rudder shaft tubes, and fitting the tubes to that first, with enough protruding to fit into the top of the box. The rudders are pushed through as before on an angle, the block and tubes then fitted inside over the shafts, and slid down to the box.

This keeps the shafts lined up and vertical. The box will be glued into the transom with sealer round the jet tube at the same time, and when set, the rudders will be installed, the tubes slid down and glued in place.

Had a play with servo positions, and will late glue ply side plates to the foam with cutouts for the servos. Battery will sit in a tray above them. I have to buy some pushrods and clevises for the 4 servos which means another 100km round trip to the hobby shop. Also have to make a silicone coupling. My reamers turned up from Ali Exp, so I'll be able to make the 1/8 end of the coupling, a nice fit on the motor shaft.

Once everything is glued in and sealed, it should be time for a tank test.

Rudder box is now glued in, Rudders fitted, (too late now if they are wrong) rudder tillers made as well as a couple of servo savers. The servo savers work one direction,- FWD, so the servo throw can start with the servo right back, and operate FWD with no chance of stalling the servo, (tension can be adjusted with various rubber bands or small springs. Works like a normal pushrod when pulling.

I'm using 3 of these for the valves in the diverter box, so they don't overstress the valves. Hopefully there was enough sealer between the rudder box and rear jet tube on the diverter box, or there will be a lot of bailing going on😁. With all the exits in the hull,(4) not to mention the diverter box (7) leaks may be a problem.

Made some new couplings for the motor to jet unit yesterday, and fitted the jet unit. Messy job, as there needs to be a lot of silicone plastered around. better too much than too little, as when it's in, it's in, and a big job to get it out. One area of concern is between the jet and diverter box, as there is not much of the jet tail inside the box, plus the silicone made it slippery and wanting to pop out, instead of sticking in the taper as it did without. This made the jet mounting/grille holes hard to line up, so it got a bit messy.

The couplings are made from aluminium, and turned down to 1mm over the internal diam of the silicone tube. The tube is kept from slipping by rough splines carved with a sharp tool, indexing the chuck manually, (rough, but it works) and once together the ends of the tube are held tight with small cable ties.

It would be better if there was more room to use a longer bit of tube for it to be more flexible, but there is only 25mm to play with. Runs quite smoothly, but not that quietly, due to the rubbish bearings which come with the jets. They tend to scream a bit at high revs (12,000 +) due to the excessive clearance, (forgot I was going to change them for NMB bearings.)

Just the reverse duct outer nozzles to fit better and to be siliconed (into the ducts) and epoxied to the hull, then it can have the basic tank test. Motor and jet were tested in the sink in a bowl, and it pumps well.

Also updated the servo savers with springs.

Finished installing the reverse nozzles and epoxied them into the hull. Also working on the pushrods. They require ball ends, as the throws on the pushrods are not linear with the servos being at 90deg to the diverter box arms. Servos are on 2 trays screwed to plates glued to the sides of the bay. The can be removed by undoing 1 screw per side.

Hopefully having a basic test today without the servos hooked up, weather permitting, ( will have the bailer ready😁)

It works, (sort of) concept proven,- has a few leaks at the front of the box where the jet fits in (I was 90% sure it would have, as it's in a place underneath you can't get to. 😐) Nothing a bilge pump can't handle. I've made a dam by the jet flange which contains any water, so any leakage can be removed from behind that. It's 100% waterproof inside so not a worry. May pull it all out in future and try a different sealer, but it'll be fine for now.

The max throttle used in the test was only 50% so it may have to be reduced on the end point. Lots of water in reverse which is more than I hoped for, so it should fly in reverse. Rudders work reasonably well, but could do with the bent over tops like the original (see pics at start of blog) to stop loss off the tops of the blades when turning, but they will be more than adequate as they are..

I was going to bend the tops and bottoms, but I wouldn't have been able to get the rudders in as I did. A bit tricky trying to work the flaps in the vid without the servos to hold them open, needed 3 hands😁

Spent the day doing the 100km round trip to the model shop to pick up some ball ends and making the pushrods and servo savers for the diverter box. Everything is set up for another test with the radio this time. Also added a bilge pump to handle the leaks from the system. It sits in a bracket on the inside of the coaming, (last pic) and the pipe runs to a low point and is fitted with a strainer.

A better dam was also made to keep any water in the stern, away from the motor. Looks messy, but there's no clean way to put silicone in an area like that to create a 'sump'. The bilge pump outlet will go straight out through the transom.

Vid of the valves and steering working.

Another test today with the servos fitted which worked out very well. The bilge pump was tried and also did the job spot on. It removes all but a teaspoon of water and more than keeps up with the leaks. I might have to either fit it with a switch, or see if I can make it automatic.

More than enough flow in all directions with a quick response in all directions. Next test will be at the pond, (with rescue airboat on standby) to get a better idea of manoeuvrability. Jet picks up water with no hesitation which is a bonus,- no more weight required in the stern. May need adjusting when the cabin is built.

A slightly better vid showing the valve /diverter box working in FWD and reverse. Also the bilge pump outlet installed and pump working. The leaks are impossible to seal effectively, even with O-rings on the valve shafts and all joints glued and siliconed. Bilge pump takes care of it in seconds.