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Jet Boat design
- Thread starter BazzaOz
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comfisherman
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Mini jet boats have gotten so popular on the west coast of the USA the used jet ski market had gone up. There was one place in british columbia that was selling new takeout sea do spark engines but that hasn't been around in a while. Mercury discontinued the sport jet in 21' so thats out as well. Seems like the sea doo and yamaha skis are popular for donors. The friends of mine usually buy full jet skis when the go on sale after the season in the lower 48 and rob the power train. Several places make replacment intake grate and bucket dumps and trim nozzles. Several in the USA, Canada and a few in New Zealand. If it were me the donor ski would be whatever has the best aftermarket parts source. For me thats sparc and the yamana line as we have a local guys making alloy intake and stomp grates.
Ive tried to pick my buddies dad's brain as hes built double digits of them ovet the last 10 years. Hes adamant that I ovethink it, hes had hulls from several companies the current looks like a cope but they all look similar. His big components are: as big and reliable engine as possible, a proper higher flow intake grate, available stainless impeller, a uhmw clad bottom and dont skimp on the fuel cell size. His current rig is a 300 hp 11 or 12 foot setup with home machined intake and stomp grate. I asked about the flat jet pad and deadrise and he just laughed and said " your not going through water, your beating it into submission with the throttle. Dead rise is dependent on how hard we hit the rocks.... my first pre jet flat was caused by a beaver damn at 35mph and we just copied it on the next ones". Not a refined sor but his machines have opened up much of the backcountry that was prior only plane accessible.
Ive tried to pick my buddies dad's brain as hes built double digits of them ovet the last 10 years. Hes adamant that I ovethink it, hes had hulls from several companies the current looks like a cope but they all look similar. His big components are: as big and reliable engine as possible, a proper higher flow intake grate, available stainless impeller, a uhmw clad bottom and dont skimp on the fuel cell size. His current rig is a 300 hp 11 or 12 foot setup with home machined intake and stomp grate. I asked about the flat jet pad and deadrise and he just laughed and said " your not going through water, your beating it into submission with the throttle. Dead rise is dependent on how hard we hit the rocks.... my first pre jet flat was caused by a beaver damn at 35mph and we just copied it on the next ones". Not a refined sor but his machines have opened up much of the backcountry that was prior only plane accessible.
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300hp and 12' sounds good , home machined intake and stomp grate you mean hand welded ?
Jet pad ?
Transom angle is insignificant in this case . I'm not big fan of very short hulls . Slightly lengthening the hull will make it easier to glide without compromising agility.
How they fasten the uhmw ?
Jet pad ?
Transom angle is insignificant in this case . I'm not big fan of very short hulls . Slightly lengthening the hull will make it easier to glide without compromising agility.
How they fasten the uhmw ?
comfisherman
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Jet pad is the term they use for the flat spot directly in front of and encompassing the intake grate. Think its more officially called a delta pad.
The 300 hp version was to move weight on a small platform. Most are closer to 150 hp. His goal was to move two guys and a quartered moose on a small as a boat as possible.
The southern Oregon and Idaho boys are rocking sleeker mini jets, but their water is more traditional white whater. The guys here are rocking tundra drainage, deep cut bank tiny creeks that wind many miles up the berry and tundra flats. There are runs that they take the smaller 9 foot boats on that the wider more powerful "bigger boat" can't make. Admittedly my courage to ride along usually rapidly diminishes when we need the smaller boat. Missing a turn at speed can be a bumpy ride and long slog pushing the boat back to the water.
Early intakes were hand made to adapt the glass intakes, then fully hand welded. Then someone 3 d printed a shape they liked and an outfit down south does a casting. Buddies dad's has a mill that he cuts the machining on it to clean up the castings. Almost everyone here works in some kind of trade or used to, so the garages have abnormal tool collections of 5 and 6 figure tool toys.
Current method is stainless cap screws, and prodigious 5200. Have seen others rivet and some rivnut and bolt... this particular fellow often ers on the side of rugged and done vs. More refined methodology.
The 300 hp version was to move weight on a small platform. Most are closer to 150 hp. His goal was to move two guys and a quartered moose on a small as a boat as possible.
The southern Oregon and Idaho boys are rocking sleeker mini jets, but their water is more traditional white whater. The guys here are rocking tundra drainage, deep cut bank tiny creeks that wind many miles up the berry and tundra flats. There are runs that they take the smaller 9 foot boats on that the wider more powerful "bigger boat" can't make. Admittedly my courage to ride along usually rapidly diminishes when we need the smaller boat. Missing a turn at speed can be a bumpy ride and long slog pushing the boat back to the water.
Early intakes were hand made to adapt the glass intakes, then fully hand welded. Then someone 3 d printed a shape they liked and an outfit down south does a casting. Buddies dad's has a mill that he cuts the machining on it to clean up the castings. Almost everyone here works in some kind of trade or used to, so the garages have abnormal tool collections of 5 and 6 figure tool toys.
Current method is stainless cap screws, and prodigious 5200. Have seen others rivet and some rivnut and bolt... this particular fellow often ers on the side of rugged and done vs. More refined methodology.
Dino Marko
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Look for YT jet boat build . There's lot of info.
Dino Marko
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You mean youtube? Yes already looking, hence I asked for a sample design already, perhaps I can start build.
Where are you intended to use this jetboat . Inland waters ?
Laurence Bellamy
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Hi Lancing Marine in the UK can support with Castoldi waterjet parts particurly the older units 05, 06, 238 as well as current models. Hi we at Lancing Marine distribute Castoldi. We have a lot of older parts. Castoldi https://www.lancingmarine.com/blog/castoldi.aspx
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