Considering I just finished doing the ribs out of plywood on my Bismarck, the thought comes to mind, "Could I have just printed these out and saved myself tons of effort?" What do you guys think? Anyone tried just printing out your ribs?
I see no reason why not. As long as it fits on the print bed, it's good to go. I've also thought about doing that. I probably will, next time I build something new. 3d print the ribs, keel, subdecks, decks, etc. My printer has a small bed, so I'd have to go in tiny sections, but that's fine by me.
As soon as I get my ABL working I’m going to start reprinting the structure for my Bis in PETG. Why? Why not. I enjoy the creative process. Seeing what works or doesnt. Learning for myself.
My next build will probably be DKM Prinz Eugen. I think I will try out the 3d printed ribs on that build. I think they will actually be stronger than 1/4" ply. I'm thinking PETG with carbon fiber.
https://photos.app.goo.gl/Vwf2jwY3KwqNKFYS7 Don't 3d print ribs. 3d print the whole hull. Why glue ribs to a keel to a subdeck and then glue in water channeling/bottom filling blocks when you can just design it all in, right off the bat? Pictured are FN Mogador and two revisions of my 3d printed FN Suffren Rookie Cruiser kit. Mogador is currently with @Nate G being built for battle in 2021, the larger cruiser Version 1.0 battled in 2020, Version 2.0 is in final stages of fitting out for testing during 2021 with a production run of kits hopefully being made once the design is verified through multiple battle events this year.
No reason to use the CF infused stuff. Twice as expensive as regular PETG for not much proven benefit. printing the whole thing as one piece wastes a LOT in terms of support. Plus you are looking at less than ideal layers on either the keel or ribs or the sub decking. Something will have the weak link. Printing individually will allow a better printing orientation for strength. But what do I know... 4 years ago I 3D printed my Iowa ribs, deck, and keels as one piece and the layer lines across the keel made it too weak.
You are right, but in practice the difference in strength has proven negligible. Printed in tower-orientation, aka bow pointing up in the air, is the strongest orientation for the ribs but arguably the weaker for the subdeck. We have destructively tested 4~ test articles and the actual Version 1.0 prototype hull. We've smashed them, crushed them in a vice, tried to pull them apart, shot them with BB and pellet guns, and then at Nate's battle last fall had a Vittorio Veneto unload it's sidemount into the subdeck rim at point blank range, tweaked hard, full magazine. Subdeck didn't have a scratch. Ultimately, you would want to reinforce your 3d printed hull with a layer of glass cloth + epoxy. The glass + epoxy will settle into the layer lines and bond extremely well. Almost like the laminate backing to safety glass. And by building your hull this way, you basically eliminate a traditional "keel". Almost like cars, body on frame vs unibody. The whole impenetrable bottom area of the boat becomes the keel, make the whole structure quite strong yet lightweight.
Thanks guys, lots of good points made. I wanted to print just the ribs because a keel is actually really easy for me to make from wood. I have all the woodworking tools, it's just those pesky ribs are such time consumers
An excellent suggestion on glassing, sounds like a win-win. What material did you use for the printed boats?
The grey cruiser pictured is regular old PETG. The white hull is ABS not because of any real increase in strength, but because (like most engineering choices ;-) )it's cheaper with minimal difference in strength and quality. PETG generally is stronger because it's a bit more flexible, ABS is more impact resistant and less dense (lighter) but can be difficult to print.
That's my experience as well with those materials. ABS always likes to curl on the edges if you don't raft the print well.
I would add that if you are thinking of building a 3d printed big boat, something long that could cause longitudinal stress and/or something very heavy, you would want to add reinforcing rods to the hull/subdeck to help add strength. @BigGunJeff did a wonderful job on his 3d printed Alabama which is designed similarly to my two hulls pictured above. He embedded rods to add strength to the hull longways. https://rcwarshipcombat.com/threads/3-d-printed-alabama-big-gun.445862/#post-530286 Yes ABS can be a pain, but I print in an insulated + heated cabinet. The whole cabinet stays at 120F for the duration, which greatly reduces ABS's negative tendencies.
Perhaps as bsgkig117 says, adding in support rods and glassing the lower hull could yield a viable big boat. I have carbon fiber rods that I use in my other hobby that should be ideal. They are much lighter, yet stiffer than steel. Oh, so many ideas and so little time!
