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00:02it all starts with a bold idea something that at first glance almost feels impossible this time
00:09it's something completely different not a rebuild not a tweak or a modification but a jet ski built
00:15entirely from scratch for months there's been a lot of work behind the scenes research sketching
00:21testing ideas and slowly figuring out all the small details needed to actually make it work
00:26and now after all that time and effort the plans are finally finished
00:39as far as anyone can tell this might be the first fully homemade jet ski ever built and shown and
00:45while the engineering alone was already a big challenge what really took the most time was the
00:49design side of it getting the shape right the proportions and the lines making it actually
00:55look and feel like a proper jet ski
01:09in this first part of the build series the focus is on the hull for the joints a polyurethane glue
01:15is used it expands slightly as it cures which helps fill any small gaps and creates a really strong
01:21bond getting these connections right is important since that's where most of the strength in the
01:27structure comes from
01:35the main design takes inspiration from a modern yamaha wave runner especially its flat bottom shape
01:42that kind of hull is known for being stable and getting up on plane quickly which makes it a solid
01:46choice for this project
01:59next up are ribbons the parts that define the fair curve of the hull they basically show how the final
02:05shape is going to flow from front to back giving a clear guide for the overall lines they're installed on
02:11both sides at the same time so the pressure stays balanced
02:24stringers run lengthwise along the hull and add a lot of stiffness and strength from front to back
02:30they mainly do three things first they provide longitudinal strength working a bit like the stringers
02:36in an aircraft wing helping stop the hull from flexing or twisting along its length second they
02:42support the outer skin giving it a solid structure to sit on so it holds its shape properly and third
02:47they improve impact resistance by spreading loads across multiple frames
02:57attaching the outer sheeting is up next all the nine millimeter sheets are already cut
03:02so it's time to start closing up the hull once the first piece is positioned it actually fits in pretty
03:08well next is the side and front sections and that's where things get a bit trickier
03:19this part has a much tighter curve so the sheet needs to bend quite sharply to match the shape
03:25after a bit of effort it finally goes on the front edge is pretty sharp but it's managed to sit
03:31properly against the frame the hull is already starting to take shape now it's on to the rest
03:49before closing everything up the outer sheeting is done using smaller pre-cut sections based on
03:55templates each piece is shaped in advance to match a specific part of the hull which makes it much
04:01easier to follow the curves accurately
04:14instead of forcing large sheets into place these smaller sections naturally sit where they're supposed
04:19to especially around tighter bends and more complex areas it takes a bit more time to prepare all the
04:26pieces but it helps keep the shape clean and consistent and avoids putting too much stress
04:31on the material while bending it into position
04:44for filling all the seams polyester fiber is used it not only fills the gaps but also adds a lot
04:50of
04:50strength to those joints at the same time it helps smooth out any small imperfections along the surface
04:57then it's time for sanding and quite a lot of it the surface comes out nice and smooth and the
05:03whole hull
05:04starts to feel much more solid
05:11the creator lays the fiberglass cloth over the surface of the hull he then rolls the polyester resin on
05:17soaking into the cloth and bonding it to the wood underneath as the resin spreads the fiberglass
05:23turns transparent and starts conforming to every curve after it cures it forms a solid outer layer
05:30adding a lot of strength and sealing the hull at the same time
05:37the stabilization strips are mounted along the bottom of the hull and they play a pretty important
05:42role at higher speeds they help keep the craft stable and they also control how the water flows
05:48underneath so instead of splashing out to the sides it stays more controlled when the hull is on plane
05:54they're then fiberglassed and the entire hull gets finished with a coat of marine grade paint
05:59sealing it up and giving it a clean look
06:06before moving on a proper hull stand is needed so the hull can sit securely while the rest of the
06:12build
06:12continues since a couple of parts were missing from the original full-scale templates a separate
06:17sheet with all the dimensions is used instead
06:24once everything is cut the stand comes together fairly quickly nothing fancy just a solid support
06:30structure that does its job when the hull is finally placed on it it makes a big difference
06:35everything sits stable at a comfortable working height
06:49now the first step is to make the outer ring again just like on the hull this time it's made
06:54slightly
06:54smaller than the previous one so it leaves a small ledge around the edge that little step helps everything
07:00sit properly and gives a clean defined edge for the next parts to line up against
07:14from there everything starts coming together almost like a puzzle each part finds its place and when
07:20it does it clicks in surprisingly well the front section goes on first and it lines up smoother than
07:26expected after that attention moves to the seat area and the rear framing where most of the structure
07:31really starts to take shape
07:42and then suddenly it's done the full frame is in one piece everything fits without much fighting
07:49which feels a bit too good at this stage in a build like this that's usually the moment where you
07:55start wondering what's going to show up later
08:09the last detail is adding two support strips for the seat to rest on
08:13underneath everything is left open on purpose so the engine jet drive fuel tank and all the important systems stay
08:20easy to reach
08:21it's practical but also a little exposed which means there's not much room for error once everything starts running
08:36the seat itself is generously sized enough for two people comfortably and even a third if needed
08:43on paper it all looks solid but the real test will only come once there's power water and speed involved
08:59the creator starts the flooring using a nine millimeter sheet material
09:03once it's placed on the hull it starts to make sense why the shape matters so much
09:08the floor sits slightly lower than the surrounding structure just enough to drop the center section down like a proper
09:14jet ski
09:15that lower profile helps give it a more natural ride stance later on
09:29next up are three thinner five millimeter sheets which are cut and fitted on top these follow the
09:35curves of the hull more closely bending into place and smoothing out the interior shape there are small
09:41gaps left in several sections but that's expected they are filled with polyester fiber filler to lock
09:47everything in and strengthen the joint sanding is essential before the next step
09:59after quite a bit of work it's finally ready for fiberglassing just going over everything again and
10:05again until the surface is properly covered next comes the sanding stage and that's where things really
10:11get real every little bump edge or uneven spot suddenly stands out so it all has to be worked down
10:19carefully
10:26before any paint goes on the structure first needs an epoxy primer this layer is all about sealing
10:33everything in properly locking the surface protecting it and giving the whole build a solid base to work from
10:39after that the whole surface gets covered in the final paint color everything looks solid on the surface
10:44now but underneath it's still a handmade structure and once water speed and load come into play that's
10:51when any weak spot would make itself known pretty quickly
11:07to manufacture the aluminum parts all the paper templates are first glued onto the aluminum sheet
11:12from there the next step is fairly straightforward cut everything out using a jigsaw fitted with a metal
11:18cutting blade
11:29since it's aluminum it cuts relatively easily and doesn't put up too much resistance
11:34still it needs to be done carefully following the template lines as accurately as possible
11:39to keep all the shapes clean and precise
11:51all the pieces are cut and cleaned up and now it's time to start forming them into shape
11:56a few of these parts need to turn into cones one section is for the intake and another is part
12:01of
12:02the first cap so there's quite a bit of bending involved
12:14normally this would be done with a slip roller or a proper sheet metal bender but since none of that
12:19is
12:20on hand a quick and simple bending setup is made directly on the welding table it's not fancy but it
12:26doesn't need to be once everything is clamped in place the bending is finally done
12:40the first thing to build is the intake the first piece to weld is this section right here the one
12:46that sits in this position and out of the whole jet drive this is actually one of the trickiest parts
12:51it has to line up perfectly because everything else in the system depends on it if this section
12:57is even slightly off the rest won't sit correctly later on
13:07the intake is designed to smoothly guide and accelerate the water as it flows through
13:13the goal is to make sure it reaches the impeller with as little turbulence helping reduce the risk of
13:18cavitation the circular collar lines up with and connects directly to the jet pump unit tying
13:24the whole system together into one continuous flow path
13:31the creator is assembling the steering system for the jet propulsion unit the reduction nozzle speeds
13:37up and directs the water flow coming out of the jet pump around it sits the steering nozzle
13:42which controls the direction of the craft on the water and the reverse gate which redirects
13:47the water jet forward allowing the jet ski to slow down or even move in reverse
14:02the jet pump impeller and drive shaft assembly is the main propulsion system of a jet ski
14:08the impeller pulls water in through the intake and forces it out the back at high speed creating the
14:14thrust thrust that moves the craft forward it sits inside the pump housing which acts like a pressure
14:19chamber the drive shaft connects all together this links the jet ski's engine directly to the impeller
14:25keeping the whole system running
14:34an opening is cut into the hull to fit the propulsion system since that area takes a lot of load
14:40all the
14:41cut edges are sealed and reinforced with fiberglass and resin making sure the structure stays strong
14:46and protected once that's done the whole assembly is set into place and mounted using a combination of
14:52adhesive and screws locking it firmly into the hull
15:04with that one of the most critical parts of the build is done it all looks solid but this is
15:10one
15:10of those steps where there's no easy way back once it's in it's in if anything is even slightly off
15:16it won't
15:17show up right away it'll show up later under load at speed out on the water for now everything sits
15:23tight and
15:24looks right
15:31now it's time to give this jet ski an engine the choice here is a superbike engine
15:37these things pack a serious amount of power rev all the way up to around 12 000 rpm and still
15:43stay
15:43relatively compact and lightweight it's a bit of an unusual choice for something like this but that's
15:48also what makes the whole project more interesting and compared to other options it's still fast and
15:54a lot more affordable
16:06this inline engine running on carburetors should make somewhere around 180 horsepower more than enough to
16:13make this thing seriously move it has a rubber in it which helps absorb vibrations but to actually mount
16:19everything securely a solid base is still needed so the plan is to build a steel frame that ties
16:24everything together and gives the engine a strong stable foundation to sit on
16:39the frame is fully welded and then mounted into the hull creating a solid foundation for the engine with
16:45that in place everything now has a strong base to fix on keeping the engine properly supported and
16:51aligned for what comes next
16:59and with those rubber engine mounts in between a lot of the vibration gets absorbed before it can
17:04transfer into the hull that's important because without it all that engine vibration would travel
17:10through the structure making everything louder and rougher and over time potentially stressing the hull itself
17:26another frame needs to be welded in as well this one specifically for mounting the bearing this part
17:32is all about alignment the bearing has to sit perfectly in line with the drive shaft and engine
17:37otherwise it can introduce vibrations or extra stress once everything starts spinning at speed so this
17:43frame acts as a solid fixed point keeping the whole drivetrain running smooth and true
17:59this setup is used to support and keep the shaft properly aligned
18:03at the center of it is a pillow block bearing it supports the rotating shaft while handling both
18:10radial and axial loads keeping everything running smoothly even under stress that bearing is mounted onto
18:16a steel support bracket its job is to provide a rigid stable base so the bearing stays exactly where it
18:23needs to be without flexing or shifting
18:33the creator is assembling the pillow block bearing unit to support the rotating shaft its main job is to
18:40hold the shaft in place while letting it spin freely with as little friction as possible at the same time
18:46it keeps everything stable and aligned which is especially important once the system is running under load and at
19:02higher speeds
19:04this setup uses a belt drive system instead of a traditional chain or gearbox
19:09the wide v-belt and pulleys handle the power transfer moving energy from the engine to the central
19:15shaft in a much smoother and quieter way the central shaft takes in the power from the belt and from
19:22there it gets distributed further through the system
19:32the exhaust is where things stop being simple the original setup from the bike just doesn't really fit
19:38this build so the whole system has to be rerouted to work inside the hull a custom manifold is made
19:44using
19:44a 40 millimeter tube and a series of bends
19:59the goal is to bring all four exhaust runners down and merge them into one larger pipe that part is
20:06fairly straightforward in theory but getting everything to line up cleanly is where it starts
20:10to get tricky
20:19for this setup the header is needed first the basic part is fairly simple but things get more
20:25complicated from here because it has to connect to all four exhaust pipes at the same time so
20:30everything should be lined up assembled and then welded together into one solid piece making sure all
20:36the joints meet cleanly and the flow stays even through the system
20:49the header is fabricated from a 60 millimeter tube it brings together four separate exhaust pipes
20:56through welded junctions forming a smooth transition into a single collector the idea is to keep the flow
21:02even and continuous so the gases and water move cleanly through the system without sharp interruptions or restrictions
21:21next up is the water lock system a water box or water lock acts as both a reservoir and a
21:27muffler
21:28it collects water inside the chamber which helps cool and quiet down the exhaust flow from there the exhaust
21:34this doesn't just exit directly
21:44it's routed upward first rising above the water line to make sure there's no chance of water flowing
21:50back into the system only then does it exit on the other side safely and in a controlled way
22:05the exhaust is finished by adding the water inlets four small tubes are connected directly to the exhaust pipe
22:11forming a simple but important cooling circuit this setup brings water into the system helping carry
22:18heat away and keeping everything from overheating while it runs
22:29a support bed is welded together from metal tubes to hold the cylinder head securely in place it's not just
22:36about holding weight it's about keeping everything aligned under vibration and load the cylinder head sits
22:42on this structure so it has to stay rigid and stable even when the engine is running hard
22:54at the same time the frame is designed to also carry the battery the creator has chosen a high
23:00performance agm battery it's a sealed lead acid type built specifically for power sports use
23:06things like motorcycles atvs and scooters the design makes it more resistant to vibration and movement
23:12which is important in a setup like this
23:25the ignition coils are connected the ignition switch is in place the battery is wired in and the fuel tank
23:31is hooked up just the basics needed to make it run the only question left is pretty simple will it
23:37actually start
23:51next up is plumbing in the cooling lines so the engine actually has some protection once it runs
23:57a basic cooling setup is put together for both the engine and the exhaust the lines are routed and
24:03connected keeping things simple but functional for a first test to supply water a garden hose is hooked up
24:09directly to the cooling system
24:19the idea here is to build up the seat frame it starts with the basic frame being assembled first
24:25then comes the curved section which is made using a simple but effective technique small cuts are made
24:31close to each other along the plywood this relieves the tension in the material softens it and allows
24:38it to bend smoothly into shape instead of fighting the curve
24:49once everything is shaped and fitted the whole structure is covered and brought together as one piece
24:56from there it's ready for fiberglassing locking the shape in and turning it into something strong and permanent
25:14the foam is then glued in place giving the seat its soft padded feel once it's secured all
25:21the exposed edges are trimmed using a hot knife cleanly shaping the material without tearing it after
25:27that everything is sanded down edges transitions and the surface itself until it all blends together
25:33into a smooth even form that's ready for the final covering
25:49the final layer is an artificial leather in a dark marine blue color
25:54it's stretched over the foam and carefully fitted so it sits tight and smooth wrapping the seat in one clean
25:59finish the material not only gives it a proper finished look but also makes it more durable and
26:06resistant to water and wear which is important in this kind of environment
26:19an important part comes next setting up the control system for acceleration and reverse the idea is to
26:26build a lever system inside the cockpit so everything can be controlled by hand a tube is used that fits
26:32over an existing shaft inside the hull allowing it to slide back and forth one end becomes the handle the
26:40rider controls while the other end is connected directly to the cable that operates the reverse cap
27:02the reverse cap sits on the jet drive nozzle and is designed to pivot downward when reverse is needed
27:08when it drops into place it redirects the water flow forward which slows the craft down or pushes it backward
27:15for this to work smoothly a ball joint is added to the mechanism allowing it to move freely without binding
27:29a control cable is then connected to it so the movement can be controlled remotely from the cockpit
27:35that way the rider can engage or release reverse with a simple motion while the mechanism responds cleanly at
27:42the nozzle as the lever moves it pulls on the cable and that movement is transferred straight to the nozzle
27:51the further it's pulled the more the cap drops into place redirecting the water flow and changing the direction of
27:57thrust
28:04a slight pull on the lever brings it into neutral pull a bit further and it engages reverse
28:10that movement is transferred through a cable which pushes the cap down over the jet outlet redirecting the
28:16water flow to make the system reliable in real operating conditions a few safety and control features should be added
28:34one of the key additions is a return to neutral mechanism if the control cable ever loses tension
28:40or fails the system doesn't stay stuck in reverse instead the reverse cap is automatically pulled back
28:46into its default forward position this ensures the system always falls back to a safe state even if something goes
28:53wrong
29:04a rear handle has been added at the back shaped a bit like a small spoiler it's mounted right into
29:10the structure
29:10so it's not just cosmetic it actually has to take a real load the main purpose is simple give a
29:16passenger
29:16something solid to hold on to especially when the craft starts accelerating turning or hitting chop on the water
29:24a cutout is then added for cooling opening up airflow to help keep temperatures under control
29:29to protect it the opening is covered with a mesh
29:44the next stage is manufacturing a passenger grab rail which will be added at the rear
29:49its main job is safety it gives a rear passenger a solid place to hold on during high-speed runs
29:55or when the craft hits waves and starts bouncing around
30:09instead of relying on the driver the passenger has their own secure grip point
30:14which makes everything feel more stable and controlled it also helps during re-boarding if someone
30:20falls off or needs to climb back on from the water this rail becomes an easy and reliable
30:33handhold
30:34the process starts with shaping the steel base the metal is cut to length then bent and formed to
30:40follow the contour of the rear section so it sits naturally on the hull without forcing the shape
30:45after everything lines up the full welds are completed locking the rail into a single rigid
30:50structure at this stage strength is the priority this part needs to handle real pulling forces not just light contact
31:09once the steel frame is finished the wooden grip sections are prepared
31:13these are shaped to fit the rail smoothed down and then bonded onto the steel using marine grade adhesive
31:20unlike many modern jet skis that use molded plastic or rubber coated integrated handles this version
31:26and stands out with its custom wooden design keeping the homemade style
31:39once everything is ready for painting the first layer goes on a special water resistant marine grade paint in a
31:46deep blue color
31:46it's chosen not just for looks but for durability since it needs to handle constant water exposure
31:53uv light and general wear from use on the water the same blue tone is also used on the seat
31:59tying the
31:59whole design together visually
32:09the body is painted in white which becomes the primary surface color
32:13on top of that additional design elements are added in blue and black creating contrast
32:18and breaking up the shape so it looks more dynamic and aggressive rather than flat
32:32the surface to prevent slipping on the surface rubber mats are added to the deck they provide grip for the
32:37feet especially when the surface gets wet helping keep a stable stance while riding to seal the connection
32:43of the lower and upper parts a marine rubber edge trim is used along the joint once the deck is
32:49finally
32:49brought down and secured this trim works like a gasket between the two halves
32:59the two halves and the two halves and the two halves and the two halves and the two halves and
33:04the two halves
33:04what started as just a pile of ideas templates and raw materials slowly turned into something real
33:10there were moments where things didn't fit where parts had to be reworked and where nothing really
33:16looked like it was going to line up the way it should but that's kind of what makes it what
33:20it is
33:20and now standing here at the end it doesn't really look like individual parts anymore it looks like a jet
33:26ski
33:26and now there's only one thing left the test drive
34:15everything up to this point has been theory fabrication fitting and careful assembly but
34:20none of it really matters until it actually hits the water once it's out there control is no longer in
34:26the
34:26workshop it's in the hands of the water itself it has its own rules its own resistance its own way
34:33of
34:34pushing back against everything that's been built and only a well-built machine will respond the way it
34:39should when that moment comes
34:54from raw materials to a finished creation this is just one story subscribe to macarium and be part of
35:01the next one your ideas might shape what we build next
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