Aluminum Trailer - Need help

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Jimmyt
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Re: Aluminum Trailer - Need help

Post by Jimmyt » Sun Jun 09, 2019 10:33 pm

Garage resulted from buying the cheapest lot in the neighborhood. None of the builders wanted it because of the dramatic slope issues. Basically, I had to build a 12 ft deep foundation, which became my garage. Drive out on one end, partial walkout in back, and 12 feet underground in front and on one end.

Still trying to get it cleaned up after the house fire and reconstruction, but I made room to get the boat in as quickly as I could. If you don't keep things conditioned, the mold, mildew, and critters will take over pretty quick around here. Got room cleared for a small furniture project for my youngest daughter, and her middle sister just put in an order for a project. Good to get back in the shop some.

Glad to get measurements for you, As we get close to complete, I'll depend on you to tell me what you need. I know you need the bend angles for the I beams. I'm working on it as I get time. I thought retirement was gonna be all drinking and sailing... :P

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Neo
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Re: Aluminum Trailer - Need help

Post by Neo » Sun Jun 09, 2019 11:04 pm

Jimmy you sound like man after my own heart :D
"12 feet underground"... sounds cool in more ways than one :D
"Fire" ... Sorry to had you had a fire.
"Critters" ... I have frogs living in my anchor locker! .... It's funny how they tend to jump ship when out on salt water :o

If I manage to get to an Ali trailer before you (which is unlikely) I was going to use my tiling laser/square to measure angles. Technically I should have enough information to calculated them now but need to be triple sure before I spend a fortune to have those I-Beams bent.

Just one thing on your diagram I don't fully understand... It looks like 21"+57" should add up to 61"??
Image

Also are the I-Beams "W" or "S" Section?
Image


I'm technically retired too so if you ever find yourself near Sydney lets sail! :)

All the best.
Neo

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Jimmyt
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Re: Aluminum Trailer - Need help

Post by Jimmyt » Mon Jun 10, 2019 7:04 am

Beams are W-section.

The tongue is drawn beside the I beam and referenced to it. The tongue square tube is set back into the I beams 21 inches. The square tube is 62 inches long. My brake assembly is welded on at 57 inches from the opposite end of the square tube. This last dimension is dependent on which brake system you buy, so in the last sketches, I gave you the CL of the hitch ball to the end of the I Beam - in case you bought a different brake. I'll try to get you a CL wheel to hitch ball, and a v-block to CL hitch ball so you can try to mimic the factory weight distribution if you want.

You may want to consider an adjustable v-block mount (Sumner did one I think). Based on the ramp that I use, I would need to retrieve the boat with the V-block 3 inches forward of my desired position. Then, after the boat settles on the trailer, I'll need to move the v-block back three inches to make contact with the bow. Tomfoolery did a nice diagram of this phenomenon. This movable V-block is only necessary if you don't want to do the Mac bump. If you're a "bumper", disregard.

I was thinking a variation of Sumner's idea moved with an over-center lever arrangement, with pin-lock handle.

At any rate, let me know what else you need.

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Re: Aluminum Trailer - Need help

Post by Neo » Mon Jun 10, 2019 7:21 am

Hi Jimmy,
I'm a Mac "bumper"... I find that part fun :D .... Have bumped up to 20 inches in the past (long story :D ) ... That was fun too :?
Our hitches are very different here so best to get measurements just to the end of tongue.
It's late at night here but more question are on way for sure :wink:

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Re: Aluminum Trailer - Need help

Post by Jimmyt » Mon Jun 10, 2019 7:40 am

Image

Had a lightning strike on the chimney cap. Set the framing on fire and burned from the top down. No one hurt, just burned about 1/3 out of the upper floor. Whole roof structure had to come off, and house had to be stripped to studs.

Good opportunity to get the honey-do list done at one time. Had good insurance and a good contractor. Did military design/construction in my former life, so this was a tiny project. Lost both of my welders (water and soot), so wound up with a tig/stick combo that I'm really happy with.

My wife, the electrical engineer, separately contracted lightning protection and surge arrestance as the rebuild completed. Guess she didn't want to go through it again...

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Re: Aluminum Trailer - Need help

Post by Tomfoolery » Mon Jun 10, 2019 8:12 am

Neo wrote:
Sun Jun 09, 2019 4:40 pm
Yes I can weld and need to investigate the potential consequences of cutting and welding the bends, even if it means bracing the bends I don't mind that but need to be sure I (or a pro welder) is not going to affect the integrity of the Ali.... An Ali Trailer no stronger than Ali Foil is not so good :D
This is what concerns me. If it were steel and you cut and mitered those 'bends', you'd use full penetration welds since it's dynamically loaded. In crane boom and other fracture-critical work, we X-ray the welds. Fatigue is the killer on dynamic structures. A full-pen weld is as strong as the base metal when done by the numbers.

BUT, aluminium is a different animal. It has no fatigue strength (or endurance limit), which is the cyclic stress level below which it will never fatigue (steel does have this theoretical fatigue strength, though), so it's easy to get stress levels at stress raisers (like imperfections in welds) that result in microscopic cracks that eventually lead to large cracks. And most welds create stress concentrations or raisers.

That's not to say it can't be done successfully, but you need some expert welding, and it would help to keep the design stresses as far below yield and ultimate tensile as possible in the area of the joints.

I would go out of my way to bend those beams before cutting them. They're bent in the weak axis, so there's that at least. :|

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Re: Aluminum Trailer - Need help

Post by Jimmyt » Mon Jun 10, 2019 8:42 am

Image

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Re: Aluminum Trailer - Need help

Post by Jimmyt » Mon Jun 10, 2019 8:44 am

Image

Measures 14.5 deg; calculates 14.839 deg.

Agree with Tom - bend it. Use large radius bends. Aluminum is a fickle beast.

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Re: Aluminum Trailer - Need help

Post by Tomfoolery » Mon Jun 10, 2019 9:14 am

Jimmyt wrote:
Sun Jun 09, 2019 3:06 pm
Tom: first, you walk on my lawn. Then, you get in my grille about not getting Neo's dimensions fast enough. I can't buy a break from you :) .
:D :D :D :D :D :D

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Re: Aluminum Trailer - Need help

Post by kurz » Mon Jun 10, 2019 9:59 am

really interesting topic.

If you can bend - go for it. Take care you get the rigth material that is bendable. Alu has different styles of alu. There is one that even you cannot bend, others will be easyer. Guess which one is the cheaper...

Check for one that knows the rules. Why not weld the connections and dubble it with screws. We do have screws when the frame goes to the coupler tongue. So at the beams you have just half of the load.

So a professional alu welder in vehicle contruction in your country should give you the ansers in 5 minutes. Tell us...

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Re: Aluminum Trailer - Need help

Post by Neo » Mon Jun 10, 2019 2:55 pm

Shocking photo Jimmy. You guys must be proud of what you've bounced back from. :)
And you're hero no doubt with 14.5 deg ... well done 8) ... 14.5 deg doesn't seem so bad... might try bending it on my knee :D
Would the total linear length of the I-Beams be 90"+123"+27". Which just so happens to add up to 240"!

I've found out that other I-Beam trailers over here use 6061-T6 Aluminium Alloy but I'm guessing there's even more to it than that. I

Thanks for your thoughts on this Tom and Kurz. It's clear that I need to get in front of someone that really knows about Industrial practises for Aluminium I-Beams. It doesn't look like anyone around me does anything like this level of structural engineering... But will persist :)
Tomfoolery wrote:
Mon Jun 10, 2019 8:12 am
I would go out of my way to bend those beams before cutting them.
So would you go this far? :D .... https://www.youtube.com/watch?v=uaUx2ouKntc&t=495s
Not a 5" I-Beam I know but I was kinda surprised just how easily it bent.... Without heat too.

All the best.
Neo

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Re: Aluminum Trailer - Need help

Post by Jimmyt » Mon Jun 10, 2019 5:12 pm

Yes, the I beams are 20 feet long. I took a whack at the bend radius and it looks like 33-36 inches.

The 14.5 deg offset doesn't seem too bad, until you start trying to control it and make a uniform radius without kinking it. I think it's doable though.

If you can bend it over your knee, I'm going to start calling you Mr. Neo! :D

As Tom pointed out, you're bending the easy axis, so the 5" web might not be much worse than the 4" if the flanges are about the same.

Hydraulic press is probably how I'd try it, since I have one. Looks like it works fine based on the video. I might try to spread the bend out more, but what he got looked pretty good.

I would encourage you to secure the rig better than the video shows. I've had 20 tons on something and had it come out of the press. Needless to say, I give it a lot of respect ever since. When you're bending (I wasn't), you create forces that tend to push the outer support blocks away from the center. Either use a buck that's solid all the way through the press, or bolt the support blocks to the lower support piece. Don't want to spit a steel shape out on anyone. :? Even if the steel doesn't hit anyone, having all of the other pieces and a 20 ft I beam crashing around could be dangerous. I think with a little care and planning, it can be done fairly easily - if you have access to a press.

My inclination would be to bend it cold, but I'd have to research it. Maybe Tom can weigh in on heating 6061 Aluminum to bend it. He's way better at Material science (and most other stuff too).

Almost envy you - seems like a fun project!

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Re: Aluminum Trailer - Need help

Post by Neo » Mon Jun 10, 2019 5:48 pm

Thanks again Jimmy ... and the estimated bend radius is very handy too. :)
This project wouldn't be so hard if I lived in the US but in Country NSW, Australia suppliers are saying they can't supply or bend a 5" Alu I-Beams (of any type) :(

What do you guys make of this https://www.thefabricator.com/article/b ... 1-aluminum

And however big your project is someone is doing it bigger! ... This gives me hope :D https://www.thehulltruth.com/trucks-tra ... build.html

All the best.
Neo

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Re: Aluminum Trailer - Need help

Post by Jimmyt » Mon Jun 10, 2019 6:01 pm

Gonna be tough to build an aluminum trailer if you can't get aluminum. :(

But, you still need a trailer, so what can you get?

There are some pretty good coatings available. I'd build a steel trailer if that's all I could get. You'll have steel parts on an aluminum trailer too, so either way, you have to clean and maintain it.

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Re: Aluminum Trailer - Need help

Post by Jimmyt » Mon Jun 10, 2019 7:11 pm

Neo wrote:
Sun Jun 09, 2019 11:04 pm
Just one thing on your diagram I don't fully understand... It looks like 21"+57" should add up to 61"??
It's that new math :D

Sorry, it's just the way I think when I'm planning a project of my own. I did detailed engineering drawings for a number of years, and finished my career doing 3D building modeling. Use a shorthand version now that I am retired. Usually I'm the only one looking, so I don't even think about what it looks like from a different perspective. Basically, how big, and what are the pieces; how do they fit together; what are the critical relationships.

If you can't understand it, it just means you need to add more beer! 8). If you still can understand my sketches and doodles, after several beers, you may find that 21+57 equals 61 anyway. :P

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