Rib Replacement

I have a ten foot jon boat I recently purchased to duck hunt out of, and while the hull is in pretty good shape the support ribs are not. The two in the center are either cracked or completely broken. I was wondering what would be the most effective replacement for these ribs. I've been looking at aluminum hat-section and aluminum angle iron but I'm not sure which would do a better job. Any other suggestions would be greatly appreciated.

Post a pic if posssible. I'd probably go with some aluminum channel with a decent wall thickness. Do you have the capabilities, or know someone that can weld it for you? How did the original ribs get broken?

The Aluminum on the boat is pretty thin stuff, I have a friend that welds for a living and he said it wouldn't be worth welding. I'd say the whole boat probably weighs in at 40 or 50 pounds. The ribs broke (I'm just judging from observation) from being crunched under foot and flexing with the bottom of the boat, they were that way when I bought the boat.

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Are the ribs rounded or square? Pictures would help...

If rounded, is the rib made out of thin Alum. with little indentions or cripples another words they are not smooth? If so, your probably better off fabricating new ones and rivet back into place.

If square, WW said the best method. If you can't weld it, Then you are going to need to fabricate flanges on both sides of the channel and rivet into place.

I had one with a couple of broke ribs that I simply put a plywood floor in and left the ribs alone. It lasted for years, but the boat stayed at the lake and I didn't trailer it.

Here are a few pictures of what I'm talking about. Sorry, I could have been more specific in my description.

You described it pretty good. I thought that you were describing rounded ribs. If you boat is as thin as mine was, make new ones and rivet in.

What is an alternative to having someone bend out new ribs or would that be my best bet? Looking around in the local hardware store gave me the idea for L-angle aluminum but it's pretty high when you buy it from a retail store.

You might have said, but I didn't see where you were from to help u out more. I picked some up reasonably at a local machine shop. It was left over scrap. Scrap yards are a good source. Any metal is sky high at this time.

The rib metal is called hat section.Most boat builders bend there own in a machine like the ones used to shape house gutters.



https://www.aircraftspruce.com/menus/me/aluminum_hatsection.html

Does it go up the sides, or just across the bottom?

If it goes up the sides, I would get some aluminum square, probably 6061 alloy, and cut and weld it in a U that fits perfectly in the boat. Cut it yourself with a hacksaw, and take it to a welder, and they should be able to do it without too much cost. Then, rivet it through the outside of the hull with 3/16 diameter pop rivets sealed with 3M 5200.

If it just goes along the bottom, and butts up against the hull at the side, I would probably use the same square tubing and rivets, but you have removed the cost of the welder, and making the correct angle.

I've been searching around and I've about decided to use L-angle aluminum with solid aluminum rivets(1/2" head, 1/4" shaft by 3/8" long) But I'm not sure if 1/16" L-angle aluminum would be sufficient to give me the support I need. Any other input?

Bassboy: I

bassboy1 said:

rivet it through the outside of the hull with 3/16 diameter pop rivets s

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I did a little test section witht the old rib and 3/16" pop rivets but they don't have the same diameter head as the original rivets and they don't seem to want to make the rib snug up to the hull very well. My concern is also that the diameter of the head isn't going to provide enough metal to really seal up the old holes or have sufficient area to "grab", and i'd hate for one to pull through. The holes are somewhat wallowed out from the old rivets moving around in them.

Drewski597 said:

I did a little test section witht the old rib and 3/16" pop rivets but they don't have the same diameter head as the original rivets and they don't seem to want to make the rib snug up to the hull very well. My concern is also that the diameter of the head isn't going to provide enough metal to really seal up the old holes or have sufficient area to "grab", and i'd hate for one to pull through. The holes are somewhat wallowed out from the old rivets moving around in them.

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I can see where your coming from, and definitely agree that conventional solid rivets will be ideal. A lot of people that I see online are adverse to using them, for whatever reason. Myself, I will use both about equally in various thru hull situations. Both have their advantages.

For future reference, if the back side of the rivet head is not big enough, they do sell aluminum backup washers that you put on the back before you tighten it down. Usually will make the backside as strong/spread out as the head.

Most people use 1inch x 1inch x 1/8inch thick or 1 1/4inch x 1 1/4inch x 1/8inch thick.1/16 is to thin.It will flex and either pop the rivet out or wallow the holes out.

im not condoning the theft of state property but old street signs are just a sheet of aluminum :wink: you could use one to make the floor thicker or even bend ribs into them with a hammer and a dowl rod

bobessary said:

im not condoning the theft of state property but old street signs are just a sheet of aluminum :wink: you could use one to make the floor thicker or even bend ribs into them with a hammer and a dowl rod

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Not to mention, they are of a good quality. When you build a house in what used to be woods way out on the end of an old country road, you are bound to find a few while clearing land. Plus, they show up at the scrapyard every now and then.

I sure appreciate all the input, I was thinking this would be a good bit easier than it's turning out to be, but I'd be headed for a big wake up call if not for the help.

You can use stainless panhead bolts with nylock nuts instead of rivets. You can get the size that will match your existing holes and they are stronger than pop rivets IMO. Just coat the hole and bolts with 5200m.

bobessary said:

not condoning the theft of state property but old street signs are just a sheet of aluminum :wink: you could use one to make the floor thicker or even bend ribs into them with a hammer and a dowl rod

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I never would have thought about a road sign. I'm in school, and our landlord's father aparently had an old sign the we found half buried in the woods. It's the perfect length for my ribs so when I figure out how to make some clean cuts and bends it'll be the new addition the my ten footer. Excellent idea. Bassboy was right... Woods and an old house seem to be the recipe for finding old road signs

Drewski597 said:

bobessary said:

not condoning the theft of state property but old street signs are just a sheet of aluminum :wink: you could use one to make the floor thicker or even bend ribs into them with a hammer and a dowl rod

Click to expand...

I never would have thought about a road sign. I'm in school, and our landlord's father aparently had an old sign the we found half buried in the woods. It's the perfect length for my ribs so when I figure out how to make some clean cuts and bends it'll be the new addition the my ten footer. Excellent idea. Bassboy was right... Woods and an old house seem to be the recipe for finding old road signs

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you can make cuts in those signs using a circular saw or table saw if you flip the blade backwards it makes pretty good cuts just another suggestion if you wanna try it