If Professor Pat can do it...so can I...lol.. The history of boating spans millennia, evolving from dugout canoes and rafts in prehistory to sophisticated vessels powered by steam and advanced engines. Early boats, appearing around 10,000 years ago, were used for fishing and coastal travel, with Egyptians developing reed and wooden boats for transport and trade by 4000 BCE. Over centuries, innovations like the Viking longboat, the Chinese junk with its rudder, and the Dutch yacht transformed seafaring, eventually leading to the Age of Exploration and the flourishing of yachting as a recreational pursuit in the 17th century. Modern boating integrates electronic systems, computer-aided design, and emerging eco-friendly propulsion, reflecting its continuous adaptation.
Just taken dads old boat out and it handles well. I might add some short chines to the aft section just to stop it skidding out so much on turns and it is a bit over powered. Only running on 4 S in the video, 6 S next 😂. Not sure if the YouTube link works.
Second test was slightly better, using the aluminium spiral cut universal which came with the jet unit. As you can probably hear, it was horribly out of balance (even with cable ties to reduce it). It was not even drilled centrally and the spiral is right hand when it should be left hand, (like a spring twisted against the wind, it wants to deform). Slight improvement in speed on the first test (no slip this time) but the noise was horrendous.
Have pulled the jet apart and found that the 3 blade prop is around 1 mm too small for the hole, causing cavitation (see loads of bubbles in the jet stream) which is causing loss of thrust. The prop is the wrong type as well, with rounded blades, so I have modified a larger prop with more pitch to fit snugly in the unit to hopefully increase thrust. The shaft is also wrong, with a flat cut almost half the diam and carrying on through the bearing, allowing the grease to fly out.
I actually saw a Chinese site on Al Expr stating that "some dimensions on the product may be different due to the number of machines and operators involved in its' manufacture," SERIOUSLY!!??? their quality control must be utter crap and the operators not skilled enough to eat their lunch😐 Why bother having a dimension at all?? Little wonder nothing fits properly.
Unfortunately, most model shops sell the very same stuff, unless you want to shell out muchos dolleros for European stuff. I have just ordered some 4mm silver steel to make a new shaft, so a coupling or silicone tube will fit better. Also ordered some solid connectors to try. Vibration is wasted energy so it needs to be eliminated. Hopefully the mods will improve things and allow the motor to run on 4s rater than 3s. Worked out that the motor is only 1200KV, so it's only doing around 13,000 rpm under load. Probably will need around
18,000 rpm for proper performance. Onwards and upwards (or forwards as the case may be.😁)
Sorry about the blurry vid again, but my camera lens is knackered.
Weather was perfect tonight for a test, so I did the 15km trip out to the Gulf harbour pond (most weed free pond) to throw the boat in. After a thorough under water hull inspection from the marine department, she was off. Everything worked ok except the silicone drive tube which had become enlarged due to soaking in the grease coming out the front of the jet shaft. It was slipping badly and probably losing about 60% of its' thrust. Manoeuvrability is excellent but reverse leaves a bit to be be desired. Steering in reverse is perfect but the thrust is not going forwards enough from the bucket. Might have to build in some nozzles to direct it better.
Smoke air and water are working as well as can be expected, (smoke is a bit wafty, but with too much air introduced it will disappear as it gets thinned out too much to see) I was not expecting miracles as this was a bit of an experiment (modified cheap jet unit with unknown abilities) but at least it shows promise😁. If I can find a coupling which is concentric it will solve the drive problem.
Trouble is, the Chinese insist on making a 4mm shaft, 4.95 (or whatever) which is useless for balance in a 4mm ID bearing for example. Fine for cars, but no good for boats or planes due to balance requirements (it's a mission trying to balance plane props due to this thinking,- they do it with everything) shafts for electric motors are a nightmare at times as the play they build in, can ruin an otherwise good motor. I might have to buy a flexible rubber/nylon universal or a collet style( preferable as these take up any undersize on shafts) to fix it. They included a spiral alloy one with the jet unit which is as loose as a rooster in a sock, and only good for slower things like 3D printers etc. One of these days they will learn how to machine things to fit.😐
Seemed to work a whole lot better in the tank for some reason Martin. Possibly due to the coupling slipping, (the squealing is it slipping) Just a bit of silicone fuel tube. I use it on all the boats as it's quiet, self aligning, and lets go if your prop gets jammed by weed. Problem is with the jet, it has a flat on the shaft for some reason which doesn't help the tube grip, and lets grease in causing slippage. I'll sort it eventually,- didn't expect miracles first time out (same with planes) - Almost always some small initial problems.
Motor should be spinning at 15,000 rpm with a 3 cell, but performance is not matching that, obviously,- just piddling along😁 Mind you, I used to cruise like that in the full sized boat, as the Zodiac motor used to suck gas like nothing at 20 knots plus, (gallons per mile, not miles per gallon!)
Think I've finally sorted the mixing smoke and water for exhausts problem. Graham has already done his using the same pen / e-cig unit but with some nice electronic controls for the on off system, but not having the electronic abilities I've just gone with a more basic method. Wired up the pen and installed a filler tube (2 tubes are better - one for a breather) these are capped after filling to prevent air getting back from the pump. This system has a water pump, an air pump and the smoke unit, (all adjustable with their own voltage buck) Thanks to Martin for his pen suggestion. I was previously using large capacity elements fitted in various containers for my experiments (truckloads of smoke available) but these pens are great for tight spaces and don't draw much current.
Air, and a small amount of the cooling water are mixed by venturis just short of the exits (the air pushing the smoke and blowing the water clear of the smoke tubes). I've fitted the same system into my ST but am still waiting for the air pump from China (postal system problem there, then Chinese new year holidays with new rules apparently) Get the odd bubble at rest but with the low exhaust you can't have everything.
Latest vid with boat in the tank.
Thanks Peter, took a while to get there, should see the pile of stuff I've collected while doing all this experimenting! Have a smoker for every occasion😁!
JB
Finally managed to get this to come out the right way up on You Tube (didn't like MP4,- came out upside down). Running the 2 boats from an HK 6ch 2.4 radio (slight crash and jostling by the Maiami at the start) . You'll get sick of it in a few minutes and fall asleep but I've put it up anyhow😁 If this doesn't make you seasick, nothing will!😊 Hit a Koi carp (Chinese sub) at 3.01!
"Koi carp (Chinese sub)"
Er ... that's the JDF, Japanese Defence Force sub JB.
Didn't get seasick, but it did 'make me eyes go funny' 🤓
This can never work for more than a minute or two cos you'd need to have absolutely identical performance of ESCs, motors and rudders (perhaps also hull forms) in both boats.
I tried it once with my destroyer and Sea Scout - no chance!
Had more luck 'escorting' a same scale (1/72) Flower Class corvette around the lake in the Olympia Park, Munich ca 3 decades ago 😉
😎
This vid is cut down from around 20 mins Doug. Each boat is totally independent of the other as one is on the left stick using one RX (elevator and rudder channels) and the other on the right stick using a second RX (throttle and aileron channels)
I think everyone has the idea that they are on the same stick? The eyes do go a bit wonky as the camera is only a small keychain camera (pre Go Pro days) which we used to mount on planes etc, and the boat movements are quick.
You can always change the playback speed (on the left of the You Tube logo)
JB PS I'm sure I saw a red star on that carp!
165footer job from Bangladesh navy. Armed with 1 37mm Chinese naval cannon (which I replaced with type 76F variant), 2 orlicons.
Actually used to patrol costal area here , also used in coast guard.
The class name is padma class patrol vessel, designed and made by BN.
Tried to make its rc version in 1:110th scale(I'm not great like you guys so please help me do better and suggest me where I can do better). Length 45cm, beam 7cm. Powered with dual 180.
The only thing I'm suffering is motor shaft connectoŕ. Those two universal joints I bought are not good enough for smooth rotation. They vibrates. So I used silicone tubes. Now I'm using latex rubber tubes .
Any suggestions or plan what I can use in peace!😆
This is my scratch built 36" RNZAF British Power Boat 64' HSL (arrived in NZ 1940). I actually went on board this vessel in 1968 when it was still in original form (the RNZAF having disposed of it in the 50s) This vessel is still around and has been recently re modelled (2nd time since early 70s) and I was lucky last year to have met the present owner and go on board (2nd time in 49yrs!)and take a few photos. The vessel was modified a number of times by the RNZAF over the years (air intakes, removal of the fore deck machine guns, wheelhouse turret etc so I sort of went in the middle. I found a few drawings of the type in an old mag which had side and top views plus the bulkheads and their positions, so I took them along to a copying shop and kept enlarging them until I had the desired proportions. This worked out quite well and using a few methods from other models I had built, managed to frame (ply) the hull and then fully strip plank it in balsa. it was then fiber glassed. The deck is ply, lined and varnish stained. The wheelhouse is varnished balsa with the top removable for access. The wheelhouse interior has detail such as controls, instrument panels, skipper, steps to wardroom etc but is not too detailed as it is not seen. The boat has full lighting by remote switch, lights are all LED.
The propulsion side has dual everything (motors, ESCs, sound units), would have had 3x but ran out of space! Motors are 28mm 2200Kv water jacketed in-runners (cooled by remotely switched pump) using 30A Chinese ESCs (have 5A BEC, Fwd and Rev). Twin sound units are 'GT Power' car units which have around 40 different sound selections, from Cosworths to diesels and are computer programmable (as well as manually on the unit ) for various functions. I am using one of the v8 sounds (8 cyls short in my application) which I think is as near as you are going to get to 3 Napier Sea Lions (for which there is obviously no sound available) They 'start' 'Idle' and are fully proportional in fwd and rev and can sound quite realistic (will attempt to put up a vid later).
Batteries are 2x 2200mah 2s 20c LiPos which will last around 2hrs at least of sailing (they also run the sound units) Still have a few small things left to do (have just made wheelhouse air intakes) but don't want to get too fiddly. Just want to keep it a practical model.
Thanks for the kind comments. Planking did take a couple of days but was not done all that neatly (just clamp and cyno) as I was glassing it later - it was all thin resin coated inside to seal it). Planking was just a hint at the original so you could just make out the planks through the glass. Have included a few more pics of the motors and interior which is not that flash but is unseen, (more for the fact that I had seen the original and was sort of putting down what I remembered from when I was 15) There is a small picture at the top left of the stairs which on the original, was a Photo from an HSL looking off the Stbd rear 1/4, to 2 64ft HSLs side by side climbing over its wake at speed
The stair set is the original from the wheelhouse to wardroom, which has been kept and used again by the present owner (down to utility room in front of engine room) and still has the original 'POWER BOAT' rubber treads (not bad nick for 79yrs old!)
I’ve never seen such a motley crew ... other than on my tugboat. Photo to follow. Ha! in addition the Junk is really a sight to behold and enjoyed by members and the public alike.
So glad to have this scrollsaw in the shop which has made cutting the bottom boards a very easy task. I cut the chines from Ash using this saw too with a fine blade. Look closely and there is a plexiglass cover on the table to give me a zero clearance around the blade hole, thus keeping small parts from falling under the table. A shop vac is attached to draw away the fine dust that this machine produces. My lungs are greatful too.🤓
This is my replica model of the Sirius Star designed by Max Coote of Ripmax, around 1954.
I found the drawings on the internet, and built the model from scratch. The boat is 41" and I have fitted an electric motor taken from a childs ride on car, 50 amp Chinese controller, 50mm prop, and 12 volt 7 amp lead acid battery.
It also has a Murco diesel fitted in the wheel house to give the boat a 50's appearance!
Sea trials soon!
My latest scratch build a junk cedar plank on frame /draft film mast cranked controlled,
crew ex footballers , wearing masking tape clothes , false keel fitted when sailed ,
cheers Larry..
