We'll see how far I get with this one this winter... added structure in alignment slots by using 3mm square stainless bar and some carbon rod at strategic locations. the off axis 1" long segments of stainless bar that can only socket into place when the parts are aligned properly, worked really well in the stern
There is a lot of innovation here! The "V" pattern in the hull sections is a great idea to ensure alignment. All the reinforcement locations as you mention are great. And the partial filling of the windows to make printing easier and in some cases act like a blast shield is really cool!
Also for each rib the overhanging part that would require support is printed separately. . Produces stronger ribs that can't propagate cracks to the main hull. Potentially serviceable if glued in with e6000 or similar.
Also, the v shapes at the print bottom are only there as secondary alignment features, the primary job is warp prevention at the bed. There is a relationship between chamber temp, bed temp, abs nozzle extrusion temp, and geometry that is complicated, and can result in unusably warped parts. For the thicker regions I try to not have more than 1 sq inch of area and no linear dim larger than about 1 inch. I can cheat that if the part is a bit more flexible like at the ribs, but even then I will put a small no filled knotch to break up warp prone regions
propulsion subassembly print and fit done. the third part (rudder post) ended up with the most self aligning and secure interface between parts I have made yet.
Propulsion is in. Time to print a rudder Still trying with internal layout, I suspect 30ah at 7.4v is a skosh excessive ... But it will need the weight at some point.
I've run 2s for a long time successfully and have a lot of 2s stuff. If it turns out acceleration isn't acceptable or I can't get the pump flow rate I want then it's easy enough to swap out the batteries for 12 volts, That's why I put the attachment grid in the bottom. I can pull all the water channeling out with a pull of a few bolts to completely change it with little work other than some cad jockeying and print time.
some updates can be seen... Current weight rollup is sitting right about 23 pounds give or take a skosh. which means lots of ballast. the waterchanneling that has been hollowed out behind and in front of batteries (in front not shown, printing now) will be filled in with either lead shot or plastic shot and epoxy, to form the water channeling, all depending on how much weight I end up needing there. there is a location on either side of the ideal center of mass of the ship so I can adjust accordingly.
Holy Crap, Greg. That design is amazing. Are you using Fusion to do the CAD work? How are you doing the blast screens in the stern in CAD? just taking a big hull slice, carving out the holes, and doing a fit check? What's the stand-off from the outer hull sheeting? what's your average rib thickness running? how thick are the blast screens?
About half inch offset. There is a decent chance it will bounce rounds back and double hole, in that case I will cut them out. Ribs are 0.2 in wide. The shields are done by offsetting then triming and finally thickening the hull surface. They are 0.12in thk, solid. Easily cut out if I don't like how they work out. The stern used a pattern of circles then an extrude cut
So the current weight roll-up is 18 pounds not including cannons and super. Figure 2 lbs for 3d printed cannons in total, and a couple for superstructure, so around 23 to 25 pounds without ballast.
More work. Starboard side ribs are all in place. Modifications to the SJS pump turned out well. I will also continue to use lead shot mixed with epoxy for ballast. that worked far too well
