Victor III

[JHapprich]

Great model! Especially the propeller!!!

Jörg

[bwi 971]

The project had been on hold for a while—I needed to focus on helping one of my kids spread her wings and move out of the house.

A few months ago, while digging through the workshop for tools, I noticed the lower hull was badly warped—bent downward and twisted. I immediately knew it was the resin. Even though I had reinforced the hull with frames, they weren’t strong enough to counter the forces from the resin absorbing ambient moisture (same as the gears of the pump).

I noticed the lower hull seemed to live a life of its own—sometimes it behaved and returned to its intended shape, but not for long. One thing was clear: the resin didn’t like moisture at all. At that point, I considered the sub a CTL (Constructive Total Loss) and decided to start over.

I redesigned everything, this time integrating both longitudinal stiffeners and bulkheads more effectively. I also switched to a Z-split hull configuration.

The internal frames are shaped to securely hold the WTC. Their thickness and width are a compromise between structural strength and keeping the center of gravity as low as possible once the WTC is installed.

Despite using plenty of supports, the new printed parts were still warped—concave in the middle where the longitudinal joints were, and flared at the base near the build plate. I assume it’s from shrinkage in the thicker areas of rising resin. You can clearly see this in the two pictures below.

I tried using heat to reshape the parts, applying pressure where needed—and it worked great. Will they warp back under sunlight? No, since the temperature needed to soften the resin again is much higher than what they’d experience in the sun.

Each part was reshaped individually, then matched to its counterpart using both short and long rulers. After alignment, I glued the pieces together and used putty to fill the seams where necessary.

Grtz,
bart

[He Who Shall Not Be Named]

Bart, I am so glad to see you rejoin this fight. And... yes... family first.

I so love seeing old tools being put to good use. Tool-porn!

Keep slugging away -- the VICTOR's were such good looking boats!

David

[Subculture]

Would it not be better to use the printed parts as a master, cast a tool and make it from GRP?

[He Who Shall Not Be Named]

Would it not be better to use the printed parts as a master, cast a tool and make it from GRP?

I'm with Andy: after all that research and work, don't flog this horse any more.

Do as he suggests. Loft some tools off the resin pieces and produce proper GRP hulls. That's what I do.

David

[bwi 971]

When I made the latest adaptations to the model, I added spacing protrusions to reduce play between the hull and the yokes—helps keep everything aligned and tight.






As usual, I’m using 2 mm stainless steel dowel pins for strength and proper positioning when gluing the stern sections. Gaps are filled with putty—just standard finishing work to smooth things out.





For sanding, I use an abrasive cleaning stick to keep the paper from clogging. Simple trick, but it helps a lot.








On the topic of GRP: I definitely understand where you’re coming from. GRP would be the better long-term option, no doubt—and if this were a production hull, I’d probably go that route too.

But since this is a one-off, I’m choosing to stick with resin. I’ve come this far and found a resin that holds up—especially in terms of moisture resistance—so I’m confident it’ll do the job. I just need to get on top of the distortion.

That said, I hear the advice loud and clear—and it’s appreciated. I was trained as a ship’s engineer, so yes… I can be a bit hardheaded and set in my ways. But I’m always learning from what you guys share.

Gtrz,
Bart

[bwi 971]

My resin printer broke down recently—a good reminder why the whole “right to repair” discussion still has a long way to go.
It started with a punctured nFEP film, which led to a resin leak. Unfortunately, the LCD frame tape let go, and resin seeped onto the LCD itself. That was it—only about 50% of the screen remained functional.

Since it’s an 8K printer, I looked for a direct replacement screen, but all sources were out of stock. Even the most optimistic lead times were a month or more. I can’t help but wonder if that shortage is intentional—pushing people toward upgrades?

Luckily, 12K upgrade kits were still available, and with a discount, the price difference was only about €50. The swap required a new LED driver and motherboard, but the installation went smoothly. I did have to re-slice all my parts due to the different pixel pitch between 8K and 12K—but the printer’s back in action now.

In the meantime, I also installed the sintered bushings for the propeller shaft (stern tube bearings) in the stern.
The outer bearing had to be turned down to 9 mm to fit the tapered section of the stern tube.The inner one dropped straight into the 12 mm recess—no adjustments needed.



Since it’s been raining since yesterday, I took the opportunity to snap some photos of the lower hull from a previously assembled hull (wrong resin choise). You can clearly see how much the resin hull has deformed just from ambient moisture.
Crazy stuff...











Grtz,
bart

[Subculture]

Warp factor eleven there. Nasty. I really prefer radial hull splits, as it forms a natural structure, but if a longitudinal split is the only option you will consider then you have to accept a much weaker hull.

Something I’ve not seen others do is incorporate vented box sections in the print along the length of the boat. So say a box section along the lower half as a backbone, then perhaps some additional box or triangulated sections along the lips either side and a radial box section at each end of the hatch would then form a full structure. This is tricky to incorporate into a hull if using more conventional methods of construction, but with printing it’s easy if you’re working from your own files.

That would stiffen the hull hugely whilst making very little difference to the weight.

If the inside was then lined with some resin and light glass cloth, that should really make things bomb proof and the boat should be close to the toughness of a glassfibre hull and likely stiffer without the rigmarole of having to make tooling,

[He Who Shall Not Be Named]

Warp factor eleven there. Nasty. I really prefer radial hull splits, as it forms a natural structure, but if a longitudinal split is the only option you will consider then you have to accept a much weaker hull.

Something I’ve not seen others do is incorporate vented box sections in the print along the length of the boat. So say a box section along the lower half as a backbone, then perhaps some additional box or triangulated sections along the lips either side and a radial box section at each end of the hatch would then form a full structure. This is tricky to incorporate into a hull if using more conventional methods of construction, but with printing it’s easy if you’re working from your own files.

That would stiffen the hull hugely whilst making very little difference to the weight.

If the inside was then lined with some resin and light glass cloth, that should really make things bomb proof and the boat should be close to the toughness of a glassfibre hull and likely stiffer without the rigmarole of having to make tooling,

Rigmarole. Schools used to have Rigmarole shop classes, but all that Rigmarole stopped decades ago. Now they teach robot language and how to direct and service robots.

So goes a Craft.

[Subculture]

The crafts are still there Dave, they’ve just moved overseas.

[He Who Shall Not Be Named]

The crafts are still there Dave, they’ve just moved overseas.

Ouch! But, I take some solace in that the Dark Art's have found a secure repository elsewhere -- for that day when God or some towel-head hits us with a massive EMP.