Boat Builder Central - Builder Forums

Matt Gent wrote: ↑Wed Mar 24, 2021 12:29 pm Aluminum boat building seems to be very regional. The petroleum industry in the gulf supports a bunch of Louisana builders, plus the PNW. I'd think it makes sense for low production / semi-custom boats elsewhere but tradition seems to reign.

• Do a lot of practice on off-cuts to get the welder settings and technique dialled-in. Once confident everything is correct, do more practice.

• Short welds then let cool to reduce heat build-up.

cracked_ribs wrote: ↑Wed Mar 24, 2021 11:08 am Very cool! I have often been curious to see one of these go together in aluminum. That's a very popular material where I live, but not often for home builders!

Jeff wrote: ↑Wed Mar 24, 2021 11:19 am Luca, Welcome to our Forum!!! We look forward to watching you build!!! Again, welcome!!! Jeff

Matt Gent wrote: ↑Wed Mar 24, 2021 12:29 pm Super cool project!

A friend and I want to learn to weld. We are tinkering with adapting a small S&G skiff (Lillistone's Fleet) to Aluminum as a "senior design project"' once we have the hang of it. CS25 is on a whole other scale!

Aluminum boat building seems to be very regional. The petroleum industry in the gulf supports a bunch of Louisana builders, plus the PNW. I'd think it makes sense for low production / semi-custom boats elsewhere but tradition seems to reign.

Dan_Smullen wrote: ↑Wed Mar 24, 2021 1:41 pm This will be a great project to watch!

Cowbro wrote: ↑Wed Mar 24, 2021 2:43 pm

Matt Gent wrote: ↑Wed Mar 24, 2021 12:29 pm Aluminum boat building seems to be very regional. The petroleum industry in the gulf supports a bunch of Louisana builders, plus the PNW. I'd think it makes sense for low production / semi-custom boats elsewhere but tradition seems to reign.

I have looked into it for a bit, there are plenty of options out there to order a CNC cut aluminum boat kit for anything from a 10' dinghy to a 40' trawler, the problem lies mostly in the construction technique. There isn't as much information out there like there is for S&G boats. If your welder settings aren't dialed or you weld something out of sequence you risk turning the whole thing into a giant curvy noodle. It also requires some much tighter tolerances for fit-up. You can't just pile in thickened epoxy to fill a 1/2" gap.

Luca, I am watching this with much interest, it seems like you are off to a great start and seem to be more than capable.

MikeyGnz wrote: ↑Wed Mar 24, 2021 4:15 pm Hi Luca

I've been building a GV10 in alloy as a practice project before I build a kit-set boat. See My Build for more details. Just looking at what you have done so far you seem to be a better alloy welder than me and are using heavier plate/sheet so you shouldn't have as many distortion problems as I had. Looking back on my experience the two main things I learned were:

• Do a lot of practice on off-cuts to get the welder settings and technique dialled-in. Once confident everything is correct, do more practice.

• Short welds then let cool to reduce heat build-up.

Looking at your welds and gear you probably know all this already though.

Good luck with the build, I'm looking forward to see how it all goes.

Mike

TomW1 wrote: ↑Wed Mar 24, 2021 11:58 pm Luca I look forward to following your build until you launch it. I know you will need to prime it with zinc chromate before painting for corrosion protection. What aluminum alloy are you using 5053. I worked for a major aluminum company.

Regards, Tom

lucastefanel wrote: ↑Thu Mar 25, 2021 3:05 am

TomW1 wrote: ↑Wed Mar 24, 2021 11:58 pm Luca I look forward to following your build until you launch it. I know you will need to prime it with zinc chromate before painting for corrosion protection. What aluminum alloy are you using 5053. I worked for a major aluminum company.

Regards, Tom

Hi Tom, correct, i'm using 5083.
Actually this grade alumium should be able to sail row without any paint without problems.
At work for maritime construction we used International paint with very good results so i think i will copy paste.
In details first coat of epoxy primer, second coat of aluminium specific paint and then at the end the final RAL paint, very long progress!

fallguy1000 wrote: ↑Sun Apr 04, 2021 8:17 pm Why 5083 instead of 6061?

lucastefanel wrote: ↑Tue May 11, 2021 5:11 am Finally i had the opportunity to step ahead on my project.
I started to install the bottom plates (totally 4 pcs), tack welding and bending giving the right shape on hull.
Not so easy, by biceps now are burning but result is amazing!
Initially i putted in position the plates, aft plates first and then going forward.
Once position was right i tack welded plates together from outside and then from inside on the structure, in this way i have been able to bend 6mm plates!
With pulsed aluminium welding machine i made around 300 points!!
Next step will be to install lateral steps and then turn her for frames installation and sides panels!
Still lot of things to do but i'm every day more excited on my personal results!!
Here you are some pics and the youtube link for this stage of job!

https://youtu.be/ZirfBII53N8

fallguy1000 wrote: ↑Tue May 11, 2021 9:04 pm This is what I am seeing that looks like a hook. I jist did a finger sketch, which is exaggerated the other way...hook will steal performance badly, the boat will be slower and cost more in fuel..sometimes results can be very bad, so please run a string test, some of the pictures have different color plate on the aft section, so it may be an ilusion, but it looks like 15mm of hook..

363CC20C-AEE2-4556-9A59-FD52E239C15E.jpeg

TomW1 wrote: ↑Tue Jul 20, 2021 3:32 pm Putting the L side on the stingers is not a good idea. but normally the bunks and rollers are put on the stringers and you do not want the L of the strakes over them. That is the worst place to put them. The welds on them will be subject to more stress over time than any other area.

So plan your trailer for the bunks or rollers to be on the stringers and your strakes to be out side that area.

Tom

lucastefanel wrote: ↑Thu Jul 22, 2021 7:04 am Thanks for feedbacks guys, also very interesting and technical page!
So, seems that best idea should be to test boat first, then lift she up again with crane and weld L profiles accordingly with how boat is running on water!
Of course, best way to work is now with hull upside down but also i can consider to install profiles later on after some tests.

I'm bit concerned on how to proceed..

TomW1 wrote: ↑Thu Jul 22, 2021 5:50 pm

lucastefanel wrote: ↑Thu Jul 22, 2021 7:04 am Thanks for feedbacks guys, also very interesting and technical page!
So, seems that best idea should be to test boat first, then lift she up again with crane and weld L profiles accordingly with how boat is running on water!
Of course, best way to work is now with hull upside down but also i can consider to install profiles later on after some tests.

I'm bit concerned on how to proceed..

I think you need to do them now if you know where your stringers are going to be placed. Less work and hassle later. Let me know the distance from the keel to the chine and I can come up with what size you should have. You should run them all the way to the transom. Also I will need the flat area of the hull, from bow to transom. Also the distance from the keel for each stringer.

Strakes are not the end be all. They help in planing and in turning with there straight edge. But over sized ones can cause problems also. Here is a strake on a Grady White !9
download/file.php?id=21853&mode=view[soundcloud][/soundcloud] Just to the right of the sounder. It only has one, while you will need two.

To be honest if your top speed is not going to be much above 45 or so you don't really need strakes as long as you have a good keel and spray rails. They are most effective above 50 mph.

It also looks like you have put spray rails on the chines. Good move.

Hope this helps.

Tom

cracked_ribs wrote: ↑Fri Jul 23, 2021 9:31 am Honestly...none of this needs to be very complicated.

If the stringers are going to be like a typical cs25, space the strakes out a bit on either side of the stringers. You don't want the headaches of welds on top of welds, and you do want the extra stiffness from the strakes to help you where the hull is floppiest.

If you're doing lots of smaller lengthwise stiffeners instead of a typical glass boat with two or four big stringers, just space them about thirds apart on the hull.