Needz MOAR boat? U can haz 4/3 moar here: https://www.thingiverse.com/thing:5884064

Features:

• High stability / high speed hull – multiple revisions have arrived at a hull that gets on plane quickly and can execute full speed turns even when powered by a 750W 2216. Hull is a mashup of rigger (stability), ground effect (compensates for forward weight bias) and double concave (planing and laminar flow to pump) design concepts.
• Two stage impeller (mixed flow (higher pressure / lower velocity) transitioning into axial flow (lower pressure/higher velocity)). Excellent hole shot acceleration and zero priming issues
• High strength design with reinforcement rods, ball bearings and embedded nuts
• Modular motor mount with multiple motor options
  • Generic 2212 w/ 30 Amp ESC 1400KV to 2000KV (inexpensive out-runner, caturday trawling)
  • 2240 w/ Shark water cooled 40 Amp ESC (water cooled in-runner, slightly faster than 2212, lower torque relative to out-runners)
  • Generic 2217 2300KV w/ Shark water cooled 40 Amp ESC (inexpensive, quite fast out-runner with good torque)
  • Sunnysky 2216 2600KV w/ Shark water cooled 60 Amp ESC >^.^< (expensive, fastest out-runner so far, catnip kitteh fast)
• Ability to utilize water cooling and self-bilging
• Effective forced air cooling for out-runner type motors via associated cooling impellers
• Large hinged access hatch for battery and esc, strong magnetic latching
• Variable trim ride plate

Limitations:

• A long narrow hull design chosen for hydrodynamic efficiency limits internal volume
• Print settings should follow guidelines below in order to keep displacement low
• Electronics must be waterproofed before use (Josh at Flite Test did a good vid about various methods to waterproof RC electronics with Peter Sripol (Flite Test | Waterproofing Electronics))
• Must use extensive post processing for waterproofing. Due to the way FDM walls interface with fill there is capillary action between the individual lines of printed material at the base of the sponsons and especially at any exposed openings for embedded nuts. This causes water to slowly seep into the model. I've read that brushing in melted candle wax (Paraffin @ above 37 deg C / 99 deg F) can seal a 3d print. If you do use wax keep fire safety in mind as some FDM plastics are flammable and wax has now made it even more flammable. Another method that I've seen RC airplane makers use for waterproofing is to coat external surfaces in a very thin layer of gorilla glue applied by rubbing on with nitrile gloves. The layer must be very thin otherwise it will bubble up. On the more expensive / specialized handling side RC modellers will sometimes coat boats with polyester or epoxy resins - the fumes and resins require appropriate ventilation and ppe. I tried System Three epoxy resin clear coat recently and it gives ok results with multiple light coats. I've also read that it is possible to get a print to be water tight straight off the printer but that requires larger nozzle diameters than this design will allow for (too heavy).

BOM:

• Motor Options:
  • 2212 https://www.aliexpress.com/item/32672300112.html or https://www.aliexpress.com/item/1904754775.html, the gateway motor, something between a 1400 KV and 2000 KV might be good.
  • 2216 https://sunnyskyusa.com/collections/x-v3-motors/products/sunnysky-x2216 Sunnysky 2216 motor, going to test a 1400 or 2600 KV motor soon - these angreh little kittehs push over 750 W of power from a ~70g package >o.o< really impressive performance - no gps telemetry yet for speeds but this is by far the fastest option - paired mine with a 60 amp ZTW shark esc
  • 2217 https://www.aliexpress.com/item/2255800146800490.html I used a 2300 KV motor combined with a water cooled esc and the direct vent boat body + cooling impeller for the pond pictures featured
  • 2440 water cooling motor ZTW https://www.aliexpress.com/item/4000425168430.html, note you will need to use water cooling version of the stator / cover and verify it is supplying enough cooling water to the motor and ESC. KVs (4500) on suggested motor might be high for the size of the impellers. I am not sure if all 2440s and water cooling sleeves are built to similar dimensions but you might want to substitute with a lower KV motor if you have one
  • you can also design your own mount using the custom motor plate template step file (Dimensions center to center between the 3 mm mounting holes are 49 mm X 23.41 mm. The top surface of the mounting plate (measured from the large flat area not the post) is 18.738 mm below the center-line of the propeller axis). Keep weight and cooling considerations in mind if using an alternate
• Prop: https://www.aliexpress.com/item/32714017489.html
  • If 2212 Motor L10 Shaft 3.18 mm (motor) Cardan
  • if 2216 Motor L10 Shaft 5.00 mm (motor) Cardan - still testing
  • if 2217 Motor L10 Shaft 4.00 mm (motor) Cardan
  • If 2440 Motor L15 Shaft 2.3 mm (motor) Cardan
• ESC: Water proof ESC appropriately rated for your motor
• Servo: Waterproof 9g servo https://www.aliexpress.com/item/1005002219839349.html
• Reinforcement: 6 mm OD 4 mm ID Carbon Fiber Rods https://www.aliexpress.com/item/32310771446.html
• Power Source (btw if, like me, you are inexperienced with RC make sure to inform yourself about some of the precautions needed with lithium based batteries especially around charging and storage. Unlike your consumer electronics the LiPo cell is very much exposed in RC and special care must be taken. RC Review and FliteTest do some good youtube vids on the matter) :
  • Cat Grumpiness
  • 3S LiPo power pack (I was able to find a 1300 mAh one that fits well and can be removed via hatch 3S 1300 mAh 60C LiPo 75 X 34 X 24 mm) - The maximum extents of a battery able fit in the front of the boat are 82 X 36 X 26 mm; note this value has changed since 8/12/2021 update as motor mount moved so a bigger battery might fit
• 18650 batteries are no longer being supported, battery compartments are left in but I've come to the conclusion that its just not a good idea..I originally thought it would be cheaper owing to relatively inexpensive cells and BMS modules but once you add a constant current power supply for charging, nickle strip welder, and discharge rate / weight / C.G considerations LiPo starts to make a lot more sense...never mind the potential effects of water on Li Ion cells...
• Receiver and transmitter: Up to you (and your local regulations), I'm using a Flysky FS-i6X transmitter and FS-GR3E Waterproof receiver (note i6X will need to be in AFHDS mode to work with FS-GR3E)
• M3 X 6 X 5.3 Embedded Nuts (old link no longer works - possible substitution M3 X D5 X L6) https://www.aliexpress.com/item/4000232858343.html (also if using 2216 or 2217 some 3mm high nuts are needed)
• M3 Machine Screws (Button head and Flat head) https://www.aliexpress.com/item/32798146322.html or stainless https://www.aliexpress.com/item/32934186482.html
• XT60 connectors, 3.5 mm bullet connectors, grease (marine), filament material compatible glue. The connectors are sold by the same storefront as much of the material above.
• Sound system: Bongo Cats

Tentative Print Settings (Cura has a setting under Travel called combing mode which helps reduce stringing in the inaccessible interior). Personally I'm printing in PETG but ABS or ASA might be a good options too if you are setup for that with enclosure and ventilated space (due to easier gluing / reduced density - if using ABS or ASA I would advise against acetone smoothing as thin walls will likely deform). I excluded PLA as it is not as temperature / weather / UV resistant as the above materials and will swell / deteriorate in water unless waterproofed. I print at between 30 mm/s (TPU) and 50 mm/s (PETG) but it might still print well at higher default speeds. Thrust vector nozzle, stator bowl, and 2212 cooling impeller will be printed in TPU for its reliable layer adhesion as these components will be subject to cyclic loading and high shear stress - I've tested the 2212 cooling impeller in PETG as well. STL files are already saved in as print orientation.

*Note I've noticed that upon updating Cura that support generation varies between versions so you may need to tweak support overhang angles from posted values below - make sure to do a preview to check for proper support and alter as needed - values below updated for Cura 4.10.0

• PETG/ABS/ASA Parts

  • Boaty (PETG/ABS/ASA): 0.4mm nozzle, 0.16mm layer height, 1 walls, 5 bottom layers, 5 top layers, 16% grid infill, supports on overhangs over 70% touching buildplate (apx 116 grams)
  • McBoatface (PETG/ABS/ASA): 0.4mm nozzle, 0.16mm layer height, 1 walls, 5 bottom layers, 5 top layers, 16 % grid infill, supports on overhangs over 78% touching buildplate, brims are helpful for ensuring support adhesion (apx 218 grams)
  • Cover: (PETG/ABS/ASA) 0.4mm nozzle, 0.16mm layer height, 1 walls, 3 bottom layers, 3 top layers, 16% grid infill, supports on overhangs over 60% touching buildplate
  • Motor Mount (PETG/ABS/ASA): 0.4mm nozzle, 0.16mm layer height, 5 walls, 3 bottom layers, 3 top layers, 25% grid infill, supports on overhangs over 70% touching buildplate (note the advanced option "Enable Support Interface" in cura 4.10 creates a fairly dense support structure that can be a challenge to remove - you may wish to disable for this part), brims are helpful for preventing warping (apx 30 grams)
  • Ride Plate: (PETG/ABS/ASA) 0.4mm nozzle, 0.16mm layer height, 5 walls, 3 bottom layers, 3 top layers, 25% grid infill, supports on overhangs over 70% touching buildplate (apx 6 grams)
  • Servo Hatch: (PETG/ABS/ASA) 0.4mm nozzle, 0.16mm layer height, 4 walls, 100% infill, supports on overhangs over 70% touching buildplate, brim (apx 2 grams)
  • Stage 1 / 2 Impeller / Mid Stator / (Cooling Impeller): (PETG/(NYLON might be a good option too)) 0.4mm nozzle, 0.06mm layer height, 3 walls, 100% infill, supports on overhangs over 50% touching buildplate, brim. Note caution is warranted with the cooling impellers - the layer adhesion issues inherit to 3d prints makes it possible for the impellers to fracture under load. Wear eye protection and be mindful of risk when using

• TPU parts

  • Thrust Vector Nozzle (Open): (TPU) 0.4mm nozzle, 0.16mm layer height, 3 walls, 3 bottom layers, 3 top layers, 25% cubic subdivision infill, supports on overhangs over 70% touching buildplate (apx 15 grams)
  • Stator Bowl (Axial): (TPU *note the part can also be printed in PETG/ABS/ASA with the same settings - the part seals the gasket better in the harder plastics but the servo wire for the adjustable ride plate will need to be thinner 1.2 mm) 0.4mm nozzle, 0.16mm layer height, 3 walls, 3 bottom layers, 3 top layers, 25% cubic subdivision infill, supports on overhangs over 70% touching buildplate (apx 24 grams)
  • Stator Bowl Gasket: (TPU) Solid
  • Cooling Impeller: (TPU) 0.4mm nozzle, 0.16mm layer height, 2 walls, 4 bottom layers, 4 top layers, 100% concentric infill, (apx 2 grams).
• Motor (50 grams), LiPo (129 grams) (18650s are out), ESC (28 grams), servo (9 grams), and receiver (6.5 grams)

A note for early downloaders: I tend to iterate and reiterate a design multiple times before I'm happy with it. Designs subject to change...frequently...

N7 Cat Says: "Dis my bigges and shiniest objec yet, 2020 u cray cray, I jus gonna yeet away from u in mah boat wif mah other kitteh fiends"

Updated: 9/28/2020, Updated files Boaty and Cover, added provisions for gluing a 5mm X 2mm magnet on the cover and boat for magnetic latching

Updated: 9/29/2020, fixed a problem with McBoatnose missing modeled tube for carbon fiber reinforcement.

Updated: 10/2/2020, added a custom motor plate "McBoatface Custom Motor Plate.stl" for anyone wanting to use a motor other than the 2212. Intent is that you will be able to model your own motor housing (and share with others along with recommendations for ESC and battery :) for mounting onto the flat plate. 3 mm dia screws will secure the motor mount to the two sections of the boat, as the mount will be subject to vibration fastening hardware (embedded nuts or lock nuts) is recommended in your design. Like the original requires brims and supports.

Updated 10/4/2020, added battery holder compartments along the length of the hull for an integrated 3S 2P 18650 setup. I'm planing on spot welding the batteries together with pure nickle strips and wiring to BMS. Note there are two battery caps (non symmetric). Added a baffle near the motor cooling impeller to improve airflow and cooling. Additionally minor improvements to printability around the servo mount and filleting of vortex outlet. For custom motor users new battery holders and air baffle might interfere with especially big motors but you can model / clip them out if needed.

Updated 10/6/2020, added built in support for servo hatch opening, improved joints between the three boat hull sections by adding grooves and other features for the expanding polyurethane glue to latch onto. Fixed a printability issue with the fillet that supports the propeller shaft. Started first print of the boat section, may update if issues crop up after print finishes.

Updated 10/7/2020, added a channel in the battery compartment to allow for wire to be routed through.

Updated 10/8/2020, post printing improvements, increased diameter of battery compartment, prop shaft and carbon fiber shaft openings. Improved servo hatch support structure to make it easier to remove.

Update 10/9/2020, Estimated static resting position of the boat in water and calculated rough target mass for finished boat. After a print failure of the protective grid on the intake as well as impact durability test failures I have replaced with a filament heat stake method as shown below in post processing pics.

Insert 1.75 mm filaments into the slots and use a low temp soldering iron to melt the ends into the inlet - you could also use servo wire and glue in place...unless you like grinding baby fish into a pulp...u monster

Updated 10/11/2020, with 18650s looking like less and less of a good idea and mass being more of a concern I trimmed the battery compartments down to two 0.4 mm walls. This reduces mass and print time dramatically.

Update 10/11/2020, realized I derped and forgot to add an access port for servo wiring. I've created an access port on the battery compartment closest to the servo wire (port/left side). As there were some unbridgeable overhangs I made some built in supports that need to be pried or clipped out before use.

Update 10/12/2020, created an alternate path for servo wire on the top of the baffle in case I decide to house all electronics in the cover. After fighting with carbon fiber tube on second print increased the diameter of the carbon tube channel and started printing again :P Ever had a carbon fiber sliver? I haven't nor do I ever want to...make sure to wrap the end of the tube that you are handling in masking tape or something to protect your hands

Updated 10/14/2020, minor improvements to Boaty and McBoatnose to reduce support generation. Trying some new tricks to strengthen servo mount and embedded nut support by creating additional walls in those areas. Improved airflow on McBoatnose 2212. Updated the stator bowl to fix supports not properly generating

Updated 10/15/2020, McBoatface 2212 motor mount was a bit of a tight fit, adjusted motor mount. Adjusted joints between sections

Updated 10/16/2020, added receiver tray and antenna port to cover

Update 10/18/2020, added mounting points for turn fin in case they are needed - I couldn't find any info on whether one would be needed for a pump jet nor dimensions for standard mounting points. Converted the fixed ride plate to a variable trim ride plate using 1.5 mm servo wire as the adjustable retention mechanism. Backup retention provided by an embedded nut and M3 X 10 screw + spring. Joint held by filament joint

Updated 10/20/2020, some weird artifacts were cropping up in cooling impeller during slicing, increased to high resolution stl and fixed wall width. Encountered a problem with McBoatnose tips coming off due to single walls and how narrow it becomes. Blunted the tips. Also had to physically clip some of the joints between front and mid section in order to get it to fit, adjusted the model so this is not required. Carbon Fiber tubes now provide most of the support between the front and mid section. Created McBIGface for those of you with Z axis build volume above 280 mm so you can print mid and front sections as one piece #jealouscat (note that this will result in a weaker motor mount as you will still need to balance weight considerations with strength requirements - play around with slicer settings starting from McBoatnose as a baseline)

Updated 10/21/2020, increased prop clearance in stator bowl

Updated 10/22/2020, Major overhaul...N7 cat shredded all the toilet paper...McBoatface and McBoatnose now one part, motor mount now modular for both 2212 and custom motors, added a custom motor mount template, increased sponson size 25%, other minor improvements

Update 10/24/2020, tried to reduce weight of McBoatface by hollowing out the sponsons, turns out a solid object with grid infill doesn't contribute much to weight...who knew...saved 5 grams!

Update 10/26/2020, realized that the cover / McBoatface interface would allow water to seep in at the front seam, updated these two parts to improve water shedding in this area. Added a part called Compatibility Shim For Pre Oct 22 Update Boaty Prints.stl which will allow any prints of Boaty made prior to 10/22 update to be used with new McBoatface

Update 10/27/2020, major iteration work completed - only minor changes from this point on - latest files re-uploaded to sync with my local files. Post processing instructions will be completed once prints are completed

Update 10/28/2020, vortex was breaking during print, strengthened the part with additional walls

Update 11/4/2020, updated servo hatch (missing cutout for gear)

Update 11/5/2020, work in progress status lifted - no major issues encountered during assembly

Updated 11/6/2020, after dropping my completed boat noticed one of the sponsons cracked ;.; strengthened the sponsons with option to add 200 mm carbon fiber tube reinforcement (adds ~35 grams to total weight inc carbon tubes or ~ 15 grams without carbon reinforcement). Thanks to a helpful tip from the community I have added a 5 degree pitch up to the thrust vector nozzle - if your boat has a nose down attitude and the ride plate adjustment is not enough this should hopefully correct that. There is a moment force applied by the thrust which pushes the nose down, this minor tweak will hopefully apply a slight corrective force which allows the boat to get on stable plane. Added a ride plate servo wire retention slot to stator bowl. Increased McBoatface carbon tube clearance. Added a 10 deg pitch nozzle in case 5 deg is not enough, as I'm still waiting on batteries to arrive I haven't had a chance to perform test to determine which will be best. Performed submersion test and posted results near the top of this summary

Update 11/8/2020, moved the Boaty magnet catch to the top surface instead of underside to improve ease of assembly. Closed the opening in the baffle since servo wire was long enough to not need it. Moved the cover magnet closer to the Boat magnet to improve latching strength. Improved McBoatface by filleting the sponson to wing interface and creating water rejection channels near the vortex exits.

Update 11/15/2020, added a version of cover with provisions for 3mm LED navigation lights

Update 11/18/2020, first functional test of the waterjet, I found that even with TPU gasket air and water would spray out thus sealing the stator bowl to boat body with silicone or glue is necessary. I found an issue with air locking - I don't fully understand the cause but experimentally determined a way to resolve this via a pending modification to the thrust vector nozzle. Update uploaded (Thrust Vector Nozzle Variable Pitch) but untested - I'll hopefully get a chance to print and test by tmw. Testing confirms the air lock issue is resolved with this new nozzle - there is some loss of efficiency. I don't really know why this fixes the air lock but I suspect the stator bowl fins were not redirecting enough of the rotational energy generated by the prop resulting in an area of low pressure which would draw air in from behind the outlet...without high speed cameras or CFD I can't really say. N7 Cat says "wut he trying 2 say iz I putz mah paw ober da nozzle and dat fixes it"

11/21/2020 did some more study on propulsor units and updated the pitch and number of stator vanes - 5 vane stator uploaded - will test later and delete original if testing displays improvement. Test showed marked improvement in both trust and elimination of air lock using the 5 vane stator - original deleted. For anyone else designing or trouble shooting other pump jets on thingiverse the number of stator vanes needs to be a prime number and different than the number of prop blades otherwise a standing wave can develop. At some point in the future I might experiment with a properly designed axial flow prop and stator - salt sintering might be able to create a strong enough part for use as a prop.

11/25/2020 reverted thrust vector nozzle to neutral pitch

2/16/2021 Added a printable gasket

3/17/2021 modified the thrust vector nozzle to try and fix an intermittent airlock issue

3/19/2021 tweaked the thrust vector nozzle and modified the stator bowl by extending parallel fin surfaces in attempt to reduce rotational energy of water

3/21/2021 experimental two stage impeller / stator uploaded - my first try at a printed impeller - going to test TPU and PETG but am skeptical about the robustness of either. Note there are two versions of the second stage impeller

3/23/2021 fixed some clearance and mounting issues with the experimental impellers

3/25/2021 fixed some clearance issues with the mid stator causing it to bind to the second stage shaft

3/25/2021 had a chance to test the two stage impeller system and found flow was disrupted past 40% throttle - I suspect the pitch angle is too aggressive - removed files until I can remodel all the components

3/30/2021 tested stage 1 impeller and thrust feels like it has doubled :D moar powah! Will test the two stage setup soon. For now stage 1 works with existing parts and improves thrust

3/31/2021 tested two stage setup and it was overall a success, flow rate is higher with just the single stage but priming is much faster with the two stage setup. In fact device will prime even under full thrust, making for more reliable operation in choppy water. Two stage only functions with the new stator bowl axial, if you are only using the new stage one impeller it will still work with the old stator. Flow rates were getting so high that the nozzle started to impede flow, an open nozzle is now uploaded

6/22/2021 strengthened the servo mount and motor mount screw holes on part "Boaty"

6/25/2021 made the supports for the servo hatch on part "Boaty" easier to remove

6/30/2021 improved motor cooling impeller, larger fins, improved filleting, removed thin shroud, now secured by butting against cardan joint

7/29/2021 after testing on a small body of water discovered that the air intakes were positioned too low resulting in water ingress during rapid deceleration. Redesigned McBoatface repositioning air intake higher and adjusting wing profile.

7/31/2021 cleaned up stl files by removing some variants and the compatibility shim

8/1/2021 updated 2212 motor mount to allow wires to pass under

8/5/2021 improved motor cooling impeller profile

8/8/2021 uploaded an experimental rigger style front (McRigface :) - not sure if the profile is correct - will test it soon

8/10/2021 improved servo ease of installation

8/11/2021 still having issues with front of old hull dipping into water - old hull deleted and McRigface is the new McBoatface. Stage two impeller was shearing from the embedded nut - altered stage two impeller so that embedded nut enters from other end and added some more material to the embedded nut hole to hopefully prevent this

8/12/2021 wasn't happy with the thin walls on the 2nd stage update - moved the motor 10mm backwards and redesigned Boaty and McBoatface to accommodate. New 2nd stage impeller, Boaty and McBoatface loaded

8/14/2021 created internal baffle system in the sponsons

8/15/2021 unifying parts between boat project and pump jet. Updated water cooling stator bowl, uses embedded nut for more secure water nipple retention. Water cooling is useful for more powerful inrunner motors and associated water cooled ESCs. A new cover with holes for 3 X 5 water tubes is now uploaded

8/24/2021 added a direct vent version of boaty with a leaf blower inspired housing for the motor cooling impeller - increases cooling efficiency

9/22/2021 did a rudimentary mass flow rate estimation on the impellers and determined that they were not matched - adjusted the pitch of the second stage

10/5/2021 moved the stator vanes closer to the stage 2 impeller as dimensions changed in 9/22/2021 update, added some fins to the back of hull to assist lifting of back end

10/12/2021 filleted the embedded nut cutout for the M3 water nipple retention nut for improved strength

11/4/2021 2440 motor mount added - note shaft length and cardan joint changes

11/17/2021 improved clearances for water cooling cover, drive dog, and stator bowls

3/10/2022 2217 motor mount added - note cardan joint changes

8/11/2022 added a larger ride plate

8/19/2022 sunnysky 2216 motor mount added, altered covers to be hinged and increased opening size for motor and battery access, increased latching magnets from 5 mm dia X 2 mm to 5 mm dia X 5 mm. Alugalug

8/21/2022 modified cover for improved print quality and support removal

2/28/2023 working on upscale version to fit big big motors - N7 cat says "smol iz gud, illegally smol iz bettr, but sometimez u jus ned moar! Moar fire, moar powah, moar speedz, moar fire again!" for 4/3 Moar of everything check back in a couple weeks to https://www.thingiverse.com/thing:5884064

4/1/2023 paw smashed McBoatface into a surfboard inspired McSurfface, some loss of internal volume for hopefully better planing and smoother flow into the pump

4/21/2023 improved ride plate by following streamlines of boat, scalloping base profile and creating sharp trailing edge - should reduce drag

5/24/2023 made the concave on the hull a little less extreme - now a double concave. Stator bowl now has Venturi suction effect for either bilge pump or cooling - screw nipple directly into the intake next to the outlet. note: effectiveness of the bilge function is dependent on thrust, higher thrust levels = higher bilge pumping effectiveness

6/2/2023 added a bilge connection to the boat

7/21/2023 fixed 2216 cooling impeller