Finally a decent day for a photo (or 20.) I went down to the Waiwera estuary which is about 10 mins from my place and utilized the seldom used boat ramp and 'beach' for the pics. It was a bit windy to run the boat at the pond to try the new improvements, so this was the perfect alternative. Great spot for boating although very tidal. I've taken my 15ft yacht out from there but you have to watch the tides, (very fast outflow). Sorely tempted to launch the boat, but sea water and bearings don't mix😮 if I can find a lake somewhere with a beach access or ramp, I'm going to attempt a video of a proper back in, launch and retrieve, (ie drive the boat off and back onto the trailer)- hopefully😀

Truck (Jeep) is now completed and uses a 1200rpm/12v geared motor, proper diff (drifting diff, a bit wide but that's the nearest I could find) leaf springs all round, beam front axle, 'custom' 12x12mm ally angle frame (same as trailer) and the body donated from a push and go kids truck, which I bought on sale for $25 at our big Warehouse store. It was completely stripped, repainted and modified to fit on the frame. Bumpers are painted with a rubber sealing spray to look like the real thing. Inner headlights were 'chrome sprayed, along with the side steps (pads were rubber spray painted) The door handles and spotlights were also 'chromed'. Front nudge bar is polished and clear-coated ally rod and the rear bumper is 12mm flat ally, polished and clear-coated.

Frame is black acrylic painted along with mounting board. Steering servo is an El Cheapo Futaba copy linked to the drag link by dual ball rod ends. Made a few decals up and applied the MB sticker to the rear spare cover. Runs on a 3s LiPo and uses one of the crawler ESCs I took out of the Seaplane tender when I installed the Quickrun ESCs. Drags the trailer and boat around (7lbs) no problem, (bit gutless in reverse on grass), but forward is fine. I have ordered a 1000rpm/12v geared motor to try for even more pull, (don't need speed.) Not perfect by any means, but looks the part and works.

Due to the rather less than startling performance, I decide to have a look at the jet unit which seems to put out a ridiculous volume of aerated water, even though everything is fully immersed. I removed the intake grille, and found that water goes through it in an extremely disturbed fashion, due to the grille bars being flat rather than vertical.

I decided to make a new version from 1mm brass sheet and strip, with the bars vertical, and the difference was as expected,- much better undisturbed flow and more intake area. Hopefully this will make another improvement along with the previous better prop mod. I'll throw some paint at it, screw it back on and give it a go. Has to be better than the previous rubbish!

New grille now painted and installed. Grille was dipped in a can of etch, once dry dipped in a can of metal anti-rust black epoxy enamel, and baked at 50deg c for a couple of hours. Should stop the brass corroding for a few years.

I decided to make a new reversing bucket for the jet unit, as my first attempt was a 50% failure. It had very little reverse action but excellent directional control. Think I may have figured out why,- the jet stream was coming into the bucket near the middle, (rather than the top) so it was sort of cancelling most of the reverse flow. The new bucket is an old style version but is mounted a lot lower so the stream comes in near the top. Haven't tested yet, but should be better, (may not be as good directionally, but we'll see) May have to dremel some side relief holes in the bottoms to get better steering, I'll see how it works as is first.

The bucket was made from 2mm ply coated with polyester resin, with brass hinge plates and control arm epoxied on. I also had to change the control rod to a plastic pushrod as it has to bend on its' way down, (pushrod is a piece of 43yr old Graupner inner cable, - still using up my stash of cable stuff from back then,- hard to find anything like it these days) Waiting for the constant wind to drop for a calm(ish) time at the pond to test.

As the performance was still rubbish, even with the new grille, (but the reversing was way better with the new bucket) I have replaced the brass reducing nozzle I had originally made to concentrate the flow, with the original oversized plastic 'splatter' nozzle. I noticed a bit of backflow around the back of the brass one at half throttle, so thought it might be part of the aeration problem, (causing prop slip and cavitation ) If it still doesn't make a performance improvement, it will probably mean that the jet is at its' max at the 12,000rpm (approx) of the brushed motor on 12v (even though it is capable of taking 18v, not many brushed controllers can,) - the majority are maxed at 3s LiPos.

I have ordered a 3000kv 36mm inrunner to try, and will use one of the aircraft (one way) ESCs to see if it will make a difference at around 20,000 rpm, (small bearings are usually good for 50,000 on oil) I can limit the throttle on the TX if necessary. The main problem is that the prop is only 28mm and depending on revs will only push so much. The HSL has twin 28mm props the same and does around 12mph flat out, with 2 x 28mm 2000kv inrunners on 3s, so there's hope yet.

I have posted a few on the water pics from today, plus the 'new/old' nozzle with brass arm made to fit the existing steering rod.

Just a small addition to see if I can get the boat onto the trailer smoothly. First attempt was a bit rough and the boat seemed to stick half way. I thought it was the pads stopping it, but found out when I got home and checked, that I'd forgotten that the hull is slightly wider in the centre, and I'd set the guide posts up to the transom width. I spaced the guides out 5mm and now that should be fixed.

I also had a problem with the boat sailing right over the trailer and not centring as it came in, so I've made some guide posts for the front as well. Posts are just brass tube with brass mounting plates soldered on, and a brass rod inside fixed to the bottom half of the tube. The top half of the tube is a roller, which turns on the brass rod (to stop the boat grabbing as it comes in). I covered it with black heat-shrink, with one layer on the bottom and 2 on the roller. I'm trying for a more gentle retrieval than some you see on YT, where the boat (usually a small fast plastic job) comes in at light speed and almost spears the tow wagon.

Another small problem is, the jet doesn't pick up the water as quickly as it did with the smaller nozzle I made. The larger original one may not have as much back pressure and takes a few more revs to get it sucking. May need a small weight in the stern to compensate.

Thought I'd see if the trailer would fit in the test tank to try the guide post mod out (should have thought of this first time, DUH😮). Fitted perfectly with room to spare. The guide posts seem to work quite well, and the boat floats through nicely and lines up almost spot on, which is a bonus. Still looking for a better place than last time to test it properly.

I recently bought some thermal switches to try with the twin cooling fans in the dummy motor. Switches are 30deg C- N/O. I managed to find a handy position on the alloy heat sink to attach the switch (filed flats on a 3mm screw head and fed the screw from behind through a slot in the heat sink, where the wires exit) and was able to simply bolt it on. Interrupted the positive wires from the 2 fans and soldered them onto each terminal of the switch, (in and out).

I did a test with a 2s battery (fans are max 9v) with a voltage reg to reduce the power to 7v (fans sounded happy at that,- no increase in speed with any more volts). The fans came on straight away, as it was around 29 deg C inside at that time, so I got some ice from the fridge and cooled the heat sink, which turned them off in about 5 secs. Next, used my soldering iron to heat the alloy of the heat sink, and they came back on again,-works perfectly.

I have a spare power JST plug from the power board and will plug that into a small voltage reg for the reduced voltage (I'm using a 3s in the boat), then to the fans. Should be all automatic from now on. Could have just used copper tube,-but that's boring😁 lol. Could have used a higher temp switch, but I want it to start cooling sooner, rather than letting the motor get to say 60deg, then trying to cool it (copper windings take a while to cool)

Saw some very nice trailers on YT, which had nice small wheels for the wobble rollers at the back. I wondered where they might have got these, as I've never seen any for sale. Had a brain wave this arvo and went and had a look in the toy section of our big Warehouse store for suitable donors. After looking at all sorts of cars, I found the perfect size on a 'Hot Wheels' Batman car. Bought 2 cars for $4 , took them home, ripped the wheels out (bit of a job surprisingly,- probably because they were made in Malaysia😁) drilled them to 3mm and hey presto, better looking wheels. Pretty sure now, that's what the other guys used (or from similar models) Wheels are 13mm, - almost spot on for scale! (old bead set shown for comparison)

For those who may not have expreienced the joys of 'wobble rollering' and are even remotely interested, I've added a pic. They are a nylon roller with a large centre hole, and are a loose fit on the axle sets (which are sort of like a small truck bogie), so as to make the boat self aligning on the trailer (the rollers follow the shape of the hull) Usually come with black, red or blue tyres.

Received the new motor today for a power upgrade, and had to give it a try. It's a 3000kv 46mm Diam finned in-runner, as used in cars, rock climbers etc. It runs very smoothly and is very powerful and tourquey once the revs get up. A bit hesitant to start due to low torque at low revs but once it kicks in you can throttle it back a bit to a fast idle which is enough for 'cruise mode' to preserve the battery a bit.

Not as nice at low revs as the high powered brushed motor (for chugging around) but should improve the top speed by a good amount. I'm just using a cheap aircraft 60A ESC (fwd only) to test it and this got quite hot after a good full throttle 60 second run in the tank, so may need to go bigger (I have the same one in 80 A) or water or fan cool it. Motor is rated for 40A but I will try to limit the throttle on the TX. Possibly need a 2000KV by the looks of it, (this being a smidgen hot and the brushed being a bit tame. I have a cheap high voltage (18v) brushed ESC coming, to try to boost the brushed motor (capable of running to 24v) as another experiment, as it is presently only running on 3s as dictated by the present ESC.

Motor got to about 55/60 C after the run, but I clipped on the dummy motor/heatsink/twin fan unit, and it came on almost straight away with the 30C thermo switch I had previously fitted. Fans ran for about 3-4 mins and switched off at 28C (which was the room temp anyhow), so at least something works spot on. Should keep the temp down for general cruising around.

The motor has so much power it spat the reinforced silicone tube coupling off (worked well on the brushed motor) so I made a closer fitting one, but it tried spitting that off as well. It has run forward and rubs on the front of the motor now, but is still hanging in there this time. Biggest problem is the huge variety of sizes on supposedly 3.17mm motor shafts and couplings (and all other sizes).

Seems the Chinese haven't heard of reamers? (maybe their machines are just worn from making millions of fittings) Pretty much impossible to get a high speed shaft running smoothly as there is far too much play everywhere. Even the expensive one I just bought for the TFL jet units fits nothing exactly, and even though it's a 3pc rubber cross type, it's still no good if it's not balanced. Why they insist on making motors and couplings with these odd sized shafts and holes is beyond me, - but it's not just boats, it's everything with planes as well which can be extremely dangerous, if say, a prop comes off (most of their prop adapters are mostly rubbish,- the collet type being the best). If you make an accurate 4mm shaft for eg, and ream the adapter to 4mm, it can be made to fit exactly (maybe with a bit of polishing) perhaps they don't get this, or worse,-don't care.

You hear many boats on YT screaming their heads off due to unbalanced shafts, which will ruin the motor and drive bearings in no time. The aluminium coil connectors are only good for one direction (with the coil direction not against it,- they can be cut left or right hand) The correct direction will tighten the coil, whereas the wrong direction will unwind the coil, distorting it and unbalancing it, (the one I got with the jet unit was LH which was wrong for the prop fitted,- not to mention the rubbish fit.) If I wanted to use it, I would have to fit the opposite hand prop and run the motor backwards. The quest for the perfect coupling goes on😀