Page 1 of 1
Tiny Speedboat Build
Posted: Mon Apr 25, 2022 4:36 pm
by Jetdriver69
Hey all, new to the forum and to boat building. I just finished modifying to a great extent a PowerWheels Dodge Viper for my small grandson and was looking for a new project.
I saw youtube videos of a father in Australia who designed a very small, weedeater motor powered speedboat for his 4 year old grandson and thought what the heck, that would work.
- Tiny-Motorboat.jpg (46.92 KiB) Viewed 4490 times
So as I was sitting in a hotel room on the beach in Santa Monica last November, I designed a 6.5 ft foam, wood and fiberglass mini cigarette boat powered by a Zenoah 320 4.5 hp RC boat motor coupled to a 3D printed 70mm jet drive.
The first picture is the pile of foam and wood I started with.
- IMG_1526.jpg (77.18 KiB) Viewed 4490 times
These next two photos are after cutting the sections of foam out with a hot wire and glueing them together.
- IMG_1693.jpg (86.12 KiB) Viewed 4490 times
- IMG_1679.jpg (71.68 KiB) Viewed 4490 times
Yes I know using this type of foam isnt the best for structural integrity and in hindsight, should have made the boat out of wood entirely. But after 3 layers of epoxy and fiberglass boat cloth and a whole bunch of epoxy thickened fillets in the joints, the boats looks pretty rigid for its use in a very calm pond or lake setting. Besides the kid is only so small for so long.
I'm just about done with the boat so I can post a few pictures a day until I catch up with the actual progress.
Re: Tiny Speedboat Build
Posted: Mon Apr 25, 2022 9:36 pm
by Fuzz
That is a great project! Grand dad..............lean, mean, spoiling machine
That is the best thing about grand kids, at least that is what I am told. Please post as you can and show the process to us.
Re: Tiny Speedboat Build
Posted: Tue Apr 26, 2022 9:38 am
by Jetdriver69
In order to move the CG a little toward center in the boat, I wanted to move the engine and jet drive a bit forward.
So I made a spacer for the water outlet out of pine which will be fully encapsulated with epoxy resin.
- IMG_1700.jpg (89.34 KiB) Viewed 4452 times
- IMG_1697.jpg (74.19 KiB) Viewed 4452 times
Attaching outside battens to the boat
- IMG_1695.jpg (101.84 KiB) Viewed 4452 times
- IMG_1694.jpg (100.12 KiB) Viewed 4452 times
Re: Tiny Speedboat Build
Posted: Wed Apr 27, 2022 1:53 am
by Fuzz
Enjoying seeing this
Re: Tiny Speedboat Build
Posted: Wed Apr 27, 2022 6:17 am
by cape man
Too cool!!
Re: Tiny Speedboat Build
Posted: Wed Apr 27, 2022 7:12 am
by jbo_c
I think these are great and look like fun. Most of the ones I’ve seen seem to be a tighter fit than I’d be comfortable with from a safety standpoint. Make sure you leave plenty of unobstructed space to slide out in the event of capsize.
Jbo
Re: Tiny Speedboat Build
Posted: Wed Apr 27, 2022 8:45 am
by Jetdriver69
Thanks for the comments. Yes leaving plenty of space to get out but the boat is pretty wide compared to the length so it should be fairly stable
I skinned the hull with foam sheets using clamps, screw blocks and marine adhesive.
- IMG_1714.jpg (84.62 KiB) Viewed 4399 times
Filled in the keel voids with expanding foam
- IMG_1715.jpg (82.91 KiB) Viewed 4399 times
Used epoxy body filler to fill in the seams and filled the bow section with contoured pieces of the foam
- IMG_1724.jpg (72.21 KiB) Viewed 4399 times
Re: Tiny Speedboat Build
Posted: Thu Apr 28, 2022 8:35 am
by Jetdriver69
To get the proper shape of the bow, I used thinner strips of foam glued vertically.
- IMG_1730.jpg (73.88 KiB) Viewed 4351 times
In places I couldn't clamp or use screw blocks, I used sharpened wooden sticks to keep the foam in place while the glue dried.
- IMG_1731.jpg (79.05 KiB) Viewed 4351 times
After all was dried, I used a knife to trim away the excess.
- IMG_1744.jpg (64.49 KiB) Viewed 4351 times
Re: Tiny Speedboat Build
Posted: Fri Apr 29, 2022 1:50 pm
by Jetdriver69
I glued thin plywood to the foam battens for a bit more protection
- IMG_1760.jpg (89.18 KiB) Viewed 4293 times
- IMG_1763.jpg (111.15 KiB) Viewed 4293 times
I made a trailer out of PVC pipe and wheels from Harbor Freight
- IMG_1770.jpg (102.45 KiB) Viewed 4293 times
Dry fitting the decking before cutting out the engine and cockpoit openings
- IMG_1758.jpg (94.26 KiB) Viewed 4293 times
Re: Tiny Speedboat Build
Posted: Fri Apr 29, 2022 2:43 pm
by narfi
Very nice!
You sure grandpa or dad aren't going to feel they need to try it first and swamp it before the little guy gets a chance in it?........
Can't wait to watch the rest of your progress!!!
Re: Tiny Speedboat Build
Posted: Fri Apr 29, 2022 4:35 pm
by Jetdriver69
Might stick my wife in it poolside to check everything.
She is 4'11 and about 95 lbs.
Re: Tiny Speedboat Build
Posted: Sat Apr 30, 2022 8:58 pm
by Jetdriver69
Dry fitting the engine mounting plate with the jet drive
- IMG_1796.jpg (105.63 KiB) Viewed 27042 times
Mocking up the space needed for the engine
- IMG_1797.jpg (84.68 KiB) Viewed 27042 times
Mocking up the seating and flooring
- IMG_1798.jpg (97.16 KiB) Viewed 27042 times
Glued in a wood header for screwing down the decking, windshield frame and the cleat
- IMG_1800.jpg (110.11 KiB) Viewed 27042 times
Re: Tiny Speedboat Build
Posted: Sun May 01, 2022 9:37 am
by Jetdriver69
Not sure if it will help getting the boat on plane, but adding lifting strakes to the hull.
- IMG_1803.jpg (101.1 KiB) Viewed 27024 times
After a bit of research and considering the simplicity, I just used half round wood moulding pieces.
I drilled through the foam hull and block glued them in place.
- IMG_1804.jpg (106.8 KiB) Viewed 27024 times
Will seal the holes with thickened epoxy resin and the outer hull will have 3 layers of boat cloth with epoxy resin.
- IMG_1805.jpg (98.81 KiB) Viewed 27024 times
Re: Tiny Speedboat Build
Posted: Sun May 01, 2022 3:09 pm
by Jetdriver69
Dry fitting the deck after cutting out the engine access and cockpit opening.
- IMG_1807.jpg (102.31 KiB) Viewed 27010 times
- IMG_1808.jpg (128.77 KiB) Viewed 27010 times
Re: Tiny Speedboat Build
Posted: Mon May 02, 2022 10:35 am
by Jetdriver69
Dry fitting the engine and jet drive
- IMG_1815.jpg (93.56 KiB) Viewed 26990 times
With the very long two stroke racing exhaust included.
I added a wooden frame so I would have a hardpoint for screws when I installed the decking
- IMG_1816.jpg (126.71 KiB) Viewed 26990 times
Checking clearance with the decking in place.
Surprising it all works
- IMG_1819.jpg (109.16 KiB) Viewed 26990 times
Re: Tiny Speedboat Build
Posted: Mon May 02, 2022 2:42 pm
by VT_Jeff
Legend!
Re: Tiny Speedboat Build
Posted: Mon May 02, 2022 5:41 pm
by Jetdriver69
Temporarily block scewed down the deck and dry fitted the windscreen and side rails.
- IMG_1820.jpg (109.97 KiB) Viewed 26969 times
I eventually made the windscreen a bit taller
- IMG_1821.jpg (127.49 KiB) Viewed 26969 times
I cut out retractable spring handles into the battens for easier lifting.
- IMG_1822.jpg (110.19 KiB) Viewed 26969 times
Re: Tiny Speedboat Build
Posted: Mon May 02, 2022 11:21 pm
by Jetdriver69
Mocking up the steering assembly.
I eventually used a 1/4 steel cable inside clear plastic tubing filled with lube and eyelets pressed into the ends.
- IMG_1825.jpg (110.59 KiB) Viewed 26956 times
Attached that to some RC boat push/pull hardware so when you move the handle bars left and right the cable moves the jet drive steering.
- IMG_1826.jpg (107.07 KiB) Viewed 26956 times
Eventually cut down the handle bars smaller and painted blue to match the boat color.
The wooden housing forward of the handle bars was supposed to be the location for a digital 2 stroke tach.
But the cable wasnt long enough and it was impossible to splice. So I removed the housing and mounted the tach in the engine bay.
- IMG_1845.jpg (94.87 KiB) Viewed 26956 times
Dry fitting the larger windscreeen which I eventually used.
- IMG_1847.jpg (93.39 KiB) Viewed 26956 times
Re: Tiny Speedboat Build
Posted: Tue May 03, 2022 9:09 am
by VT_Jeff
Any thoughts of popping a quick mold off of that hull/deck?
Re: Tiny Speedboat Build
Posted: Tue May 03, 2022 9:35 am
by Dougster
This is a fascinating build and I check it daily. Thanks for sharing.
Dougster
Re: Tiny Speedboat Build
Posted: Wed May 04, 2022 5:08 pm
by Jetdriver69
I was asked to use it as a mold previously but too much of a PITA.
Its definitely a one off.
I'm actually working so no posts for a couple of days but I have lots of pictures left.
I'm just about ready to hook up the engine controls and stick it in the pool so the post pictures are months behind.
Re: Tiny Speedboat Build
Posted: Thu May 05, 2022 8:50 am
by Browndog
Fun build thread to follow.
Well done!
Building a boat, especially one that will likely be outgrown, for a family member is really a gift of love and labor. Creating something unique and building lasting memories along the way for both you and them.
Documenting it for the forum is a gift to all of us. Thank you.
I can imagine already an RB 16 in the future for when the little guy gets a little bigger.
Re: Tiny Speedboat Build
Posted: Thu May 05, 2022 2:11 pm
by Jetdriver69
I actually like the Glen L Dynojet.
Stitch n glue construction mated to a recycled jet ski motor and drive.
But that’s way off.
Re: Tiny Speedboat Build
Posted: Thu May 05, 2022 5:50 pm
by Jetdriver69
Dry fitting jet drive steering
- IMG_1851.jpg (103.54 KiB) Viewed 38891 times
- IMG_1852.jpg (123.4 KiB) Viewed 38891 times
I finished the motor mount. Then will coat with epoxy resin and paint blue.
- IMG_1855.jpg (93.32 KiB) Viewed 38891 times
I replaced the 3D printed impeller with metal version.
Supposedly it is much more efficient.
- IMG_1868.jpg (75.02 KiB) Viewed 38891 times
Re: Tiny Speedboat Build
Posted: Sat May 07, 2022 9:02 am
by Jetdriver69
After adding thickened epoxy to all the interior joints and fiberglassing the interior foam with epoxy and 6 ounce boat cloth, I dry fitted the cockpit interior panels to hide it all.
Eventually I will fill the voids with expanding foam and fiberglass all the exposed wood.
- IMG_1869.jpg (116.69 KiB) Viewed 38858 times
- IMG_1870.jpg (96.61 KiB) Viewed 38858 times
Re: Tiny Speedboat Build
Posted: Sat May 07, 2022 6:53 pm
by Jetdriver69
Screwed down the decking and attached the instrument panel and windscreen frame.
- IMG_1894.jpg (120.24 KiB) Viewed 38845 times
Filled in all the screw holes with thickened epoxy and spread a layer of epoxy over the deck and sides.
- IMG_1908.jpg (114.59 KiB) Viewed 38845 times
Re: Tiny Speedboat Build
Posted: Sat May 07, 2022 7:00 pm
by Jetdriver69
Spreading the first layer of 6 oz boat cloth.
- IMG_1879.jpg (80.42 KiB) Viewed 38843 times
Didn't have enought left on the roll so I had to patch it.
- IMG_1880.jpg (66.66 KiB) Viewed 38843 times
Layer of 4 oz boat cloth.
- IMG_1882.jpg (63.87 KiB) Viewed 38843 times
After multiple coats of epoxy resin and trimming the excess cloth. That stuff is messy but at least it doesnt stink.
- IMG_1884.jpg (76.89 KiB) Viewed 38843 times
After letting the epoxy cure for 3 days, a good sanding with 60-80 grit.
- IMG_1893.jpg (93.24 KiB) Viewed 38843 times
Re: Tiny Speedboat Build
Posted: Tue May 10, 2022 8:42 am
by Jetdriver69
The finished motor mount plate. That just gets screwed and glued into the wood/fiberglass floor.
The blue boxy looking thing is a route for the the sterring cable
- IMG_1910.jpg (86.32 KiB) Viewed 38788 times
The 3D printed 70mm jetdrive and steering. Surprising good quality coming from China.
- IMG_1911.jpg (108.02 KiB) Viewed 38788 times
The steering system I came up with.
Eseentially a 1/4 inch steel cable inside a lubed clear tube.
- IMG_1923.jpg (134.87 KiB) Viewed 38788 times
The cable ends have eyes attached which connect to RC boat push/pull rods.
I made a 1/4 wood circle which routes the cable into the sidewalls and secures it in place with zip ties.
- IMG_1924.jpg (141.24 KiB) Viewed 38788 times
Surprising it works really well and infinetly cheaper than trying to source a correct length boat steering cable.
- IMG_1925.jpg (108.38 KiB) Viewed 38788 times
Re: Tiny Speedboat Build
Posted: Tue May 10, 2022 8:51 am
by Jetdriver69
Routing the steering cable, throttle cable and kill switch cable down through the sidewall and back through the rear bulkhead to the engine bay.
- IMG_1927.jpg (110.67 KiB) Viewed 38787 times
Eventually I will cover the voids with fiberglassed plywood to hide everything, glass some thin plywood onto the foam walls for better puncture protection and shoot expanding foam in the dead spaces.
- IMG_1928.jpg (99.32 KiB) Viewed 38787 times
That liitle box on top of the glare shield was supposed to be a housing for a 2 stroke tach, but the cable was just too short to make it back to the engine.
So I eventually moved it to the engine bay. Like a 3 year old is going to watch rpms anyway.
- IMG_1929.jpg (117.34 KiB) Viewed 38787 times
Re: Tiny Speedboat Build
Posted: Wed May 11, 2022 8:03 am
by Jetdriver69
Starting the deck fiberglassing.
- IMG_1932.jpg (104.39 KiB) Viewed 38756 times
I spread a layer of epoxy resin over the raw wood to encapsulate then put 4 oz boat cloth over that.
- IMG_1933.jpg (100.19 KiB) Viewed 38756 times
After letting it cure for a couple of hours, I trimmed the cloth at the tape lines and let it sit for 3 days.
- IMG_1935.jpg (107.98 KiB) Viewed 38756 times
- IMG_1936.jpg (108.69 KiB) Viewed 38756 times
Not a great picture, but fiberglassing the transom. I later trimmed at the tape lines which were the overlap from the hull fiberglassing.
Actually came out decent for my first time at fiberglassing until I discovered how much sanding, void repairs and filling was later to come.
- IMG_1931.jpg (94.98 KiB) Viewed 38756 times
Re: Tiny Speedboat Build
Posted: Wed May 11, 2022 9:30 pm
by Jetdriver69
Spread a coat of Total Boat Fairing compound over the sanded fiberglass top and bottom.
The first of many coats
- IMG_1964.jpg (80.58 KiB) Viewed 33103 times
- IMG_1966.jpg (78.27 KiB) Viewed 33103 times
- IMG_1970.jpg (98 KiB) Viewed 33103 times
After sanding down the fairing to eliminate high spots, I got to work identifying air voids in the glass.
Nothing to do but circle them with a marker, use a dremel to cut them out and bevel the hole and fill with epoxy resin thickened with microballons.
- IMG_1989.jpg (89.28 KiB) Viewed 33103 times
Yes I had to do this more than once. I think I will stick to wood from now on...
- IMG_1990.jpg (96.95 KiB) Viewed 33103 times
Re: Tiny Speedboat Build
Posted: Thu May 12, 2022 12:27 am
by narfi
Practice makes (closer to) perfect!!!
Re: Tiny Speedboat Build
Posted: Thu May 12, 2022 10:15 pm
by Jetdriver69
Now for something different. Making bezels for fake instruments out of thin ply.
- IMG_1991.jpg (131.99 KiB) Viewed 33072 times
Bezels cut out, epoxy coated and primed.
- IMG_2009.jpg (124.48 KiB) Viewed 33072 times
Sprayed silver and cleared
- IMG_2012.jpg (149.14 KiB) Viewed 33072 times
The instrument stickers I got off a kids electric car website.
- IMG_2065.jpg (77.08 KiB) Viewed 33072 times
The engine bay deck lid with air scoop glassed in.
The open slots will be for chrome marine air louvers.
- IMG_2008.jpg (108.84 KiB) Viewed 33072 times
Re: Tiny Speedboat Build
Posted: Sun May 15, 2022 1:26 pm
by Jetdriver69
After fixing all the air voids, spreading another coat of fairing compound and sanding down through 400 grit, I shot a couple of cpats of primer.
- IMG_2075.jpg (86.04 KiB) Viewed 33000 times
Let me primer cure, then I will shoot the hull bottom with gloss white.
- IMG_2077.jpg (95.08 KiB) Viewed 33000 times
- IMG_2099.jpg (69.73 KiB) Viewed 33000 times
Re: Tiny Speedboat Build
Posted: Sun May 15, 2022 2:49 pm
by cape man
Who's your Grandaddy?
Re: Tiny Speedboat Build
Posted: Sun May 15, 2022 3:04 pm
by Jetdriver69
I thought I was done and ready for paint, but i found more air voids and fixed those.
Then I thought the keel needed more protection so I glassed in some aluminum angle that I heated and bent to shape and cut into sections.
Epoxyed that to the keel and glassed over.
- IMG_2108.jpg (110.01 KiB) Viewed 32982 times
Then I decided since I had more aluminum angle to add that to the stern corners.
Epoxyed those down as it was only fiberglass and foam on the corners.
- IMG_2145.jpg (65.16 KiB) Viewed 32982 times
- IMG_2146.jpg (66.71 KiB) Viewed 32982 times
Re: Tiny Speedboat Build
Posted: Mon May 16, 2022 9:35 am
by Jetdriver69
I installed epoxy covered plywood inserts to hide the framing and filled the voids with expanding foam.
- IMG_2194.jpg (87.8 KiB) Viewed 32961 times
Will eventually fiberglass over the wood with 4 oz boat cloth and cover with a textured bed liner spray.
- IMG_2195.jpg (64.53 KiB) Viewed 32961 times
Finally fixed all the air voids, sanded down once again and re primed again.
Real painting is next.
- IMG_2230.jpg (76.04 KiB) Viewed 32961 times
Re: Tiny Speedboat Build
Posted: Mon May 16, 2022 9:42 am
by Dougster
Sure looks good. I like the angle iron touch. I have never tried to heat, bend and epoxy it though. Pretty sure I'd make a mess of it
Dougster
Re: Tiny Speedboat Build
Posted: Mon May 16, 2022 11:44 am
by Jetdriver69
Yes it wasnt easy.
I had to cut some scrap pine in the same curve line as the keel.
Then use a torch to heat the aluminum up and beat it to shape over the form.
Even then I couldnt get it bend as much as I needed, so I cut up the angle piece and fitted it to the keel one piece at a time.
Marine epoxied it in place, the fiberglass over that. If it comes off after all that then I quit.
Re: Tiny Speedboat Build
Posted: Mon May 16, 2022 2:02 pm
by Jetdriver69
Shot mulitple coats of gloss white. Then let it cure for 3 days and start laying down the tape for the blue stripes.
- IMG_2259.jpg (83.92 KiB) Viewed 32942 times
After the blue, I will spray it with an automotive high gloss clear with hardener.
- IMG_2260.jpg (70.54 KiB) Viewed 32942 times
Re: Tiny Speedboat Build
Posted: Tue May 17, 2022 11:06 am
by mhd
Looks great! Nice job!!!
Re: Tiny Speedboat Build
Posted: Tue May 17, 2022 11:36 am
by Jeff
Nice work!!! Jeff
Re: Tiny Speedboat Build
Posted: Fri May 20, 2022 10:20 am
by Jetdriver69
Taped off the areas to be painted Royal Blue
- IMG_2269.jpg (90.25 KiB) Viewed 25484 times
Taped in the masking
- IMG_2271.jpg (112.03 KiB) Viewed 25484 times
First of a couple of coats of blue.
- IMG_2273.jpg (94.92 KiB) Viewed 25484 times
After curing and masking removal. This is rattle can gloss paint and it flowed pretty good.
Adding the clear automotive clear with hardener really made it shine.
Then a wet sand, buff out with compound and wax.
- IMG_2276.jpg (84.02 KiB) Viewed 25484 times
Re: Tiny Speedboat Build
Posted: Fri May 20, 2022 11:56 am
by Dougster
So cool. I can't get over all the things you can do so well. Depending on my mood, it's either intimidation or inspiring
Dougster
Re: Tiny Speedboat Build
Posted: Fri May 20, 2022 12:38 pm
by Jetdriver69
I made a boat trailer of of PVC pipe and cheap Harbor Freight wheels and castors.
- IMG_2463.jpg (130.92 KiB) Viewed 25463 times
Used pipe isolation to cushion the keel and marine carpet on the rear supports
- IMG_2464.jpg (135.13 KiB) Viewed 25463 times
The engine deck lid painted with Royal Blue and racing stripes.
- IMG_2440.jpg (95.21 KiB) Viewed 25463 times
I bought one long marine louver vent off eBay and cut it up to fit both holes
- IMG_2441.jpg (99.83 KiB) Viewed 25463 times
The underside of the engine lid with decals. Will shoot automotive gloss clear over eventually.
- IMG_2442.jpg (86.56 KiB) Viewed 25463 times
Re: Tiny Speedboat Build
Posted: Fri May 20, 2022 6:52 pm
by OrangeQuest
Looking very sharp but the vents are not correct. One needs to be reversed so one draws in air and the other vents it. Otherwise, not a lot of air will go in.
Re: Tiny Speedboat Build
Posted: Fri May 20, 2022 9:11 pm
by Jetdriver69
The hood scoop draws the air in, the louvers lets the air out.
Re: Tiny Speedboat Build
Posted: Sat May 21, 2022 5:59 am
by OrangeQuest
Jetdriver69 wrote: ↑Fri May 20, 2022 9:11 pm
The hood scoop draws the air in, the louvers lets the air out.
Oh!! Opps! I had to look twice.
Re: Tiny Speedboat Build
Posted: Sat May 21, 2022 7:19 am
by Jetdriver69
No worries.
This entire project was a “I’m just making this up as I go”. Had to redesign things more than once and a few things I wish I would have done differently but that’s how prototypes go.
Re: Tiny Speedboat Build
Posted: Sat May 21, 2022 11:33 am
by Jetdriver69
I added some rub strips on the flat part of the hull.
Will use the same strips to wrap around the deck for some rub protection.
You can really see the glossyness of the automotive clear with hardener.
Pricey spray can but works good.
- IMG_2467.jpg (86 KiB) Viewed 25393 times
Sanded out and ready for primer
- IMG_2470.jpg (104.93 KiB) Viewed 25393 times
Masked out and primed
- IMG_2474.jpg (77.09 KiB) Viewed 25393 times
Top coat of Royal Blue.
The windscreen and sides will be gloss black and have two white racing stripes down the middle of the deck.
- IMG_2479.jpg (92.91 KiB) Viewed 25393 times
Re: Tiny Speedboat Build
Posted: Sat May 21, 2022 4:57 pm
by cape man
I'm intimidated...
Re: Tiny Speedboat Build
Posted: Sat May 21, 2022 7:19 pm
by Jetdriver69
I've been screwing around with this boat for a year and a half.
Starting from scratch with zero plans and no experience can make for a long project.
But throwing the boat in the pool tonight with kid installed to check for leaks and to see how low it sits.
I'm actaully way ahead of the picture progress.
Re: Tiny Speedboat Build
Posted: Sun May 22, 2022 4:53 am
by OrangeQuest
Been an interesting project to follow. And the results are amazing!
Re: Tiny Speedboat Build
Posted: Sun May 22, 2022 5:47 am
by Browndog
As I’ve commented before, this is a fun build to follow.
Looking forward to more posts and pictures of the finished project.
Re: Tiny Speedboat Build
Posted: Sun May 22, 2022 7:50 am
by Jetdriver69
Painted the racing stripes
- IMG_2487.jpg (105.14 KiB) Viewed 10338 times
The Zenoah decals are from the Japanese engine manufacturer.
A whole 32 cc and supposedly 4.5 hp at 14,000 rpms.
A top quality engine, much better than the Chinese knockoffs.
- IMG_2488.jpg (110.67 KiB) Viewed 10338 times
Masked off and shot the the gloss black for the windscreen and side rails
- IMG_2490.jpg (113.31 KiB) Viewed 10338 times
Now let it cure and shoot the clear.
- IMG_2492.jpg (92.13 KiB) Viewed 10338 times
Re: Tiny Speedboat Build
Posted: Sun May 22, 2022 1:09 pm
by Jetdriver69
Got to work for a couple of days starting Monday so I thought Id post another round of pictures.
Installed the boat name, vinyl lettering off eBay for cheap.
- IMG_2494.jpg (85.25 KiB) Viewed 10315 times
Made the boat into a mini cigarette theme.
- IMG_2497.jpg (104.77 KiB) Viewed 10315 times
Will shoot a layer of gloss clear over the decals.
- IMG_2498.jpg (112.84 KiB) Viewed 10315 times
Re: Tiny Speedboat Build
Posted: Sun May 22, 2022 1:17 pm
by Jetdriver69
A question for the builder experts, which I am not.
I put the boat in the pool last night with a 35 lb kid at the helm, but with no fuel tank or fuel weight.
The boat is super stable. I rocked it left and right pretty aggressively to the cockpit splash guard and it righted itself immediately with zero water getting in.
However the bow seems to be a little lower than the stern. But the jet drive outlet looks to be at the perfect level, just barely covered to the top of the outlet lip by the pool water.
Should I try adding ballast to the far aft of the engine bay to get the nose up or will the bow dig in under power application without it?
I did install lifting strakes assuming the boat can get fast enough to get on plane.
Thanks
Re: Tiny Speedboat Build
Posted: Sun May 22, 2022 3:00 pm
by cape man
Bring some water jugs or sand bags for the launch.
Re: Tiny Speedboat Build
Posted: Sun May 22, 2022 7:08 pm
by Jetdriver69
We got some ankle weights that would work great just to see what amount of ballast would work.
Re: Tiny Speedboat Build
Posted: Wed May 25, 2022 1:44 pm
by Jetdriver69
Painted the instrument face blue and attached the fake gauges and dry fitted the kill switch
- IMG_2499.jpg (96.9 KiB) Viewed 10238 times
Extra instrument decals that came with the set, so I made 2 clusters that be be screwed into the left and right cockpit sidewalls.
- IMG_2500.jpg (127.24 KiB) Viewed 10238 times
I added a rubber matting on top of the plywood flooring. Then shot textured bedliner over that and painted a gloss black deck paint with hardener.
- IMG_2517.jpg (121.37 KiB) Viewed 10238 times
- IMG_2518.jpg (106.25 KiB) Viewed 10238 times
Re: Tiny Speedboat Build
Posted: Fri May 27, 2022 10:30 am
by Jetdriver69
Installed the jet drive. I aligned the holes before fiberglassing and used cut down threaded stock with lock nuts on both ends
- IMG_2561.jpg (85.48 KiB) Viewed 4967 times
Installed the steering. The hole throught the hull will have rubber boots on both ends through a grease filled fitting I made.
Hopefully no leaks
- IMG_2563.jpg (76 KiB) Viewed 4967 times
Installed the pump and motor mount plate
- IMG_2564.jpg (86.87 KiB) Viewed 4967 times
Bolted down the engine and attached to the jet pump
Red wire is for the kill switch, clear tube is the steering and black wire is the throttle cable.
Still have to route the water cooling lines
- IMG_2566.jpg (118.93 KiB) Viewed 4967 times
Re: Tiny Speedboat Build
Posted: Fri May 27, 2022 12:03 pm
by cape man
I am so enjoying this one! Can't wait to see it running and floating!
Re: Tiny Speedboat Build
Posted: Fri May 27, 2022 11:13 pm
by Jetdriver69
Installed the sidewall instrument clusters and painted trim piece
- IMG_2567.jpg (106.45 KiB) Viewed 4943 times
The trim piece hides the opening cut to access the bolts that secure recessed handles on the battens
- IMG_2568.jpg (72.63 KiB) Viewed 4943 times
Installed an automotive door trim rub strip to help protect the finish
- IMG_2569.jpg (85.22 KiB) Viewed 4943 times
The trim had 3M tape attached but added small wood screws dipped in epoxy.
- IMG_2570.jpg (102.6 KiB) Viewed 4943 times
Covered the screw heads with clear and added the US flag on the stern
- IMG_2571.jpg (99.59 KiB) Viewed 4943 times
Re: Tiny Speedboat Build
Posted: Sat May 28, 2022 6:29 am
by cape man
You have to be really close!
Re: Tiny Speedboat Build
Posted: Sat May 28, 2022 9:01 am
by Dougster
Terrific looking build!
Dougster
Re: Tiny Speedboat Build
Posted: Sat May 28, 2022 9:46 am
by Jetdriver69
Still have to hook up the steering, throttle cable, kill switch and water cooling lines.
I’ve had it in the water to test for leaks but no run up yet.
Re: Tiny Speedboat Build
Posted: Sat May 28, 2022 7:10 pm
by Jetdriver69
Mounted the engine deck lid with chrome marine hinges and added two 10 lb hydraulic lifts.
- IMG_2592.jpg (97.85 KiB) Viewed 4894 times
Added the two stroke battery powered tachometer and hour meter.
Pretty simple and cheap, just wrap the lead around the spark plug cable.
- IMG_2593.jpg (59.73 KiB) Viewed 4894 times
I originally was going to use a go cart drifting seat with lawnmower sliding mounts.
But i didnt like the way it looked and the seat got in the way of opening the deck lid.
So I designed a simple seat out of plywood, foam and marine vinyl.
- IMG_2605.jpg (112.41 KiB) Viewed 4894 times
Re: Tiny Speedboat Build
Posted: Sun May 29, 2022 7:38 am
by cape man
If the kid has half the fun using it as you are building it...
Re: Tiny Speedboat Build
Posted: Sun May 29, 2022 9:06 am
by Jetdriver69
If I didnt have to constantly redesign things or replace cheap Chinese parts I bought off Alibaba months ago.
I recently installed the twist grip throttle and it snapped in half the first time I used it.
I'm going for a large lawnmower type hand throttle on the side wall now.
That will be easier to ensure reduced power settings are used with a stop engineered in the housing somewhere.
Of course I will have to design that when it shows up in the mail.
Re: Tiny Speedboat Build
Posted: Sun May 29, 2022 9:26 am
by Jetdriver69
Installed and cut to length the exhaust.
Will have to tune it when the engine is running.
- IMG_2631.jpg (85.59 KiB) Viewed 4863 times
Used header heat wrap to protect the transom and used a RC boat exhaust support to keep it from vibrating too much.
- IMG_2632.jpg (81.01 KiB) Viewed 4863 times
Re: Tiny Speedboat Build
Posted: Mon May 30, 2022 6:37 pm
by Jetdriver69
My grandson very excited to get in the water
- IMG_0165.jpg (121.29 KiB) Viewed 3262 times
Seems very stable. I rocked it pretty aggressively it righted itself immediately.
- IMG_0198.jpg (91.66 KiB) Viewed 3262 times
I think the bow is a little lower than the stern but the jet pump outlet is at the perfect level.
No leaks, so that is good.
- IMG_0193.jpg (92.6 KiB) Viewed 3262 times
Not sure if I will have to add some aft ballast when the boat is under power. Thats the next test.
- IMG_0191.jpg (83.31 KiB) Viewed 3262 times
Re: Tiny Speedboat Build
Posted: Mon May 30, 2022 9:25 pm
by OrangeQuest
If you don't add ballast to the aft area, it will plow when he lets off the throttle and steer left or right. It will act like the stern is lifted by a wave and turn sharply and uncontrollable.
Re: Tiny Speedboat Build
Posted: Tue May 31, 2022 8:39 am
by Jetdriver69
Thanks for the input.
I’m going to test with two 5 lbs hand weights as far aft as possible and go from there.
Re: Tiny Speedboat Build
Posted: Wed Jun 01, 2022 2:22 pm
by Jetdriver69
Attached the steering cable to the RC boat push/pull rod.
- IMG_2662.jpg (91.08 KiB) Viewed 3203 times
The Steering bar gives full travel left and right, but I need to add some static stops to keep the kid from moving the bar too far.
- IMG_2660.jpg (121.92 KiB) Viewed 3203 times
Probably going to cut the steering bar down by about 1.5 inches each side to shorten the throw.
- IMG_2659.jpg (125.73 KiB) Viewed 3203 times
Re: Tiny Speedboat Build
Posted: Wed Jun 01, 2022 3:38 pm
by cape man
What's left? Fire that baby up!
Re: Tiny Speedboat Build
Posted: Wed Jun 01, 2022 4:39 pm
by Jetdriver69
Today I hooked up all the water cooling plumbing and drilled the holes for the inlets and exhaust.
Still need to install the gas tank and lines and kill switch.
Had to completley redesign the throttle. The cheap Chinese knock off twist grip snapped in half the first time I used it.
So bought a large steel lawnmower type hand throttle and made a housing for it for the right side of the cockpit. The epoxy is drying on the wood as I type.
Then paint royal blue and route the throttle line through the bulkhead.
Cut the handlebar control down by 1.5 inches on each side to reduce the throw necessary for full nozzle deflection.
Gots to work til the 7th, then off until the 30th. Flying to Cabo, yeah its rough.
It will be done before 30 June!
Re: Tiny Speedboat Build
Posted: Thu Jun 02, 2022 7:43 pm
by Matt Gent
This is awesome!
Re: Tiny Speedboat Build
Posted: Thu Jun 02, 2022 8:47 pm
by Jetdriver69
You guys are too kind.
Just a grandpa spoiling his only grandson.
Re: Tiny Speedboat Build
Posted: Tue Jun 07, 2022 5:06 pm
by Jetdriver69
Back from a trip for a couple of days then back out again for a while.
Drilled the hole in the transom for the water cooling inlet
- IMG_2668.jpg (57.2 KiB) Viewed 3094 times
And attached the supply line
- IMG_2669.jpg (61.87 KiB) Viewed 3094 times
Hooked up all the cooling supply and exhaust lines
- IMG_2673.jpg (97.08 KiB) Viewed 3094 times
Re: Tiny Speedboat Build
Posted: Wed Jun 08, 2022 2:15 pm
by Jetdriver69
Put the boat back in the pool with the kid onboard and 16 lbs of aft ballast.
Yes that makes a lot of difference in how the boat sits in the water.
I think im going to use exercise ankle weights that would be easily removed once the kid gets heavier.
When you add the 6 lbs for fuel and tank, it should be about right
Re: Tiny Speedboat Build
Posted: Tue Jun 14, 2022 3:36 pm
by Jetdriver69
Redesigned the throttle assembly as the cheap Chinese twist grip throttle broke the first time I used it.
So I bought a heavy duty lawn tractor hand throttle and made a wood housing covered with epoxy resin.
- IMG_2703.jpg (49.19 KiB) Viewed 2379 times
Dug out enough wood so the throttle can sit flush with a dremel
- IMG_2704.jpg (65.66 KiB) Viewed 2379 times
Screwed in place and workks very well and secure.
I havce a tiny Cigarette Racing Team decal coming that will fit between the screw heads.
- IMG_2706.jpg (113.84 KiB) Viewed 2379 times
I didnt like the look or the throw length of the bicycle handlebar steering so I made a yoke set up using thick walled PVC pipe.
- IMG_2707.jpg (107.44 KiB) Viewed 2379 times
Re: Tiny Speedboat Build
Posted: Fri Jun 17, 2022 3:23 pm
by Jetdriver69
Ran the throttle cable through the bulkhead and connected to the engine. Works great with full range of throttle movement.
Hooked up the dash mounted kill switch to the engine. The line was hidden through the dash and under the floor months ago.
- IMG_2711.jpg (112.38 KiB) Viewed 2347 times
The fuel tank finally arrived and dry fitted. The RC boat fuel lines should arrive this week sometime.
- IMG_2709.jpg (97.1 KiB) Viewed 2347 times
Showing the throttle connection, kill switch wiring to the coil and battery powered tachometer lead wrapped around the plug wire.
- IMG_2710.jpg (88.77 KiB) Viewed 2347 times
Hopefully run the fuel lines and fire this thing up when I get back from a trip.
Re: Tiny Speedboat Build
Posted: Fri Jun 17, 2022 3:48 pm
by Jetdriver69
Forgot this pix.
Installed the dash cover, easlily removed for steering maintenance if required.
- IMG_2712.jpg (109.7 KiB) Viewed 2342 times
Re: Tiny Speedboat Build
Posted: Fri Jul 01, 2022 10:56 pm
by Jetdriver69
Hooked up the 2.5L fuel tank to a shutoff valve and fuel filter
- IMG_2728.jpg (116.07 KiB) Viewed 2277 times
Then hooked the whole mess up to the carburetor.
The other yellow fuel line is for the primer bulb overflow. Just an old 35mm film case with an inlet nipple added on top.
If it doesnt storm tomorrow, we will try to fire this thing up.
- IMG_2729.jpg (85.83 KiB) Viewed 2277 times
Re: Tiny Speedboat Build
Posted: Sat Jul 02, 2022 9:17 am
by cape man
Drum roll.....
Re: Tiny Speedboat Build
Posted: Wed Jul 06, 2022 2:07 pm
by Jetdriver69
I had a devil of a time getting the RC boat engine to start.
Apparently these finicky little engine require a precise starting sequence or forget it.
No choke, very little prime, cover the velocity stack with your hand and slowly pull though once.
Then 1/4 throttle and a tiny shot of starting fliud and off it goes.
The little engine is way more powerful than I thought. I dont doubt it could put out 4.3 hp at hight rpm's
Even at idle around 3800 rpm and directly connected to the jet drive it is putting a bit of thrust.
At 1/4 throttle it about pushed me over in the pool and at 1/2 throttle it tried to climb out of the pool.
Me thinks this thing will be much faster than I thought too. Wouldnt be surprised if it gets to 15 mph and should easily get on plane.
Going to have to mount an idle stop for when the kid gets on board...
Re: Tiny Speedboat Build
Posted: Thu Jul 07, 2022 6:35 am
by cape man
Awesome!
Re: Tiny Speedboat Build
Posted: Sun Jul 10, 2022 1:27 am
by BarraMan
Re: Tiny Speedboat Build
Posted: Sun Jul 10, 2022 1:19 pm
by TomW1
What a great picture. You did a great job.
Tom
w
Re: Tiny Speedboat Build
Posted: Mon Jul 11, 2022 4:06 pm
by Jetdriver69
Thanks for the comments
The kid is pretty smart and it will be tethered to me via the cleats with a long rope contraption I made.
Pretty much leaving it at idle and let him putt putt around until he gets a hang of it.
I still need to modify the exhaust a bit, fix a leak where the jet drive seals to the hull, adjust the idle and hook up the kill switch.
Maybe tomorrow and get it in the lake by this weekend unless I have to work.
Re: Tiny Speedboat Build
Posted: Mon Jul 11, 2022 4:41 pm
by cape man
Youtube!