# MAKING A NEW JON BOAT SUPPORT RIB HELP?



## Swampthing(True) (Nov 14, 2012)

hey I need to pick some brains here I Just got one of my ribs in my 14ft Jon welded up it was cracked i nliek 3 places yikes. And to be safe I am thinking of adding another rib about 6 inches infront of that one to take allot of the stress off of it so I dont have to spend another 100 freaking bucks to get it re welded. My questions are what would you guys use to make a new rib out of and is it ok to bolt it instead of rivets I would be using stainless bolts and over sized washers along with some good sealant? Another thing I am considering is if I put a floor in the boat would that stiffen it up and keep the new welds from ever cracking again ? I did have the welder add a thick piece of aluminum to the side of that rib for extra support when in some rough water Ill attach a picture to show you the rib.Any knowledge would be great thanks and Just for a piece of mind I am running on a super tight budget so I dont care if its a redneck fix or not as long as it works and is solid. pics would be apreciated.


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## bassboy1 (Nov 14, 2012)

Take that rib out, and install a new one using the same holes. I don't think you're done having problems with that one. 

A _decent_ aluminum fabrication shop with a brake should be able to bend you a new hat section that matches the profile of the old one. If you do the removal and installation of the new one (which is where a good portion of time is), and give them the old rib to copy, it shouldn't be much to make a new one. 

Then, hold it in place, and drill up from the outside of the hull (so you use the existing holes in the boat), then bolt or rivet the new one into place. 

Granted, this _isn't_ the redneck fix, so it's not going to be a dirt cheap fix, but it will fix it for good.


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## Rich27028 (Nov 14, 2012)

i see no problems with what the welder did - should be plenty strong - 

my feelings are you are trying to out think this - welding is as strong or stronger than the org metal and he also added a extra piece - i would not worry about it -

and yes a floor would stiffen the boat a lot -


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## PSG-1 (Nov 14, 2012)

Rich27028 said:


> i see no problems with what the welder did -




Sorry, but as an AWS-certified welder, I'm gonna have to disagree. And I can't believe they charged 100 dollars for that. The welds look OK, but the overall job is mediocre. I'm sorry if that pisses anyone off, but, I've been doing this for a long time, and I've seen a lot of welders come and go in my area, they 'go' because they do work like this.

As bassboy already mentioned, any decent welding and fabrication shop would have made a piece of U-shaped channel to place over that rib, after welding the existing cracks in the rib itself. The channel should be made to cover the full length of the rib, and if it's a slight v-hull that also requires a notch, bend, and weld to make it follow that angle.

Then, the new channel would be stitch welded every 12 inches or so, with at least a 6-8 inch long stitch welds, on a staggered pattern, that is, on the opposite side of the channel, you put a weld where there isn't one on the other side. You have to remember that in addition to being 1/3 the weight of steel, aluminum also has 1/3 the strength, and this must be taken into consideration for all joint design, fit-up, and welding.



> should be plenty strong -
> 
> my feelings are you are trying to out think this - welding is as strong or stronger than the org metal and he also added a extra piece - i would not worry about it -


It is true that the weld itself is stronger than the base metal, this is also something that has to be taken into consideration. I've seen welds that looked pretty, peel right off aluminum like it was a bead of caulk, and that was from improper joint design, improper penetration, and/or overall lack of consideration of forces being applied to the joint. Again, aluminum is 1/3 the strength of steel, so this means that whatever you would do with steel, you have to do it 3 times better, thicker, and stronger with aluminum.




> and yes a floor would stiffen the boat a lot -



Now THAT, I do agree with! A floor, as long as it is attached to the ribs, will act as an additional structural member, which ties everything together and stiffens it up. Also, putting foam under the floor panels will dampen vibration and noise, as well as giving it some added strength, as well as added buoyancy in the event of getting swamped.


Now, as far as putting a rib in front of that existing rib, you could do it with a piece of aluminum channel, rectangular or square tube, or angle. 

Use at least 1/8" thickness, by at least 1 & 1/2". 16 ga is going to be too flimsy. Preferably do it with the tubing, as it gives more strength, being a closed-shape design. The good news is that aluminum is very easy to work with, you can cut it with a regular circular saw, just as easy as cutting lumber. So, make a good, close fit on that rib, then use some SS carriage bolts, from the underside of the boat, with 5200 sealant.


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## PSG-1 (Nov 14, 2012)

bassboy1 said:


> A _decent_ aluminum fabrication shop with a brake should be able to bend you a new hat section that matches the profile of the old one. If you do the removal and installation of the new one (which is where a good portion of time is), and give them the old rib to copy, it shouldn't be much to make a new one.



You don't even have to take the rib out. Use a contour gauge (available at HD, Lowe's, etc) Some have plastic needles, and others have metal needles, but both are used to precisely match the profile of something, such as doing tile work, etc. 

The contour gauge will give an accurate profile, and you simply transfer the marks from the positive side reading of the gauge, they will be exactly the same as the marks from the negative side.


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## Rich27028 (Nov 14, 2012)

well i dont feel so bad -- 1 1/2 out of 3-- at least im running 50 percent -- 

i do agree with PSG-1 but this is a boat not a 747 - i still think its plenty strong to take fishing --- bring it to me -ill put a 30 horse on it and run it at the coast for a year - hard - then we will know --


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## shawnfish (Nov 14, 2012)

bassboy1 said:


> Take that rib out, and install a new one using the same holes. I don't think you're done having problems with that one.
> A _decent_ aluminum fabrication shop with a brake should be able to bend you a new hat section that matches the profile of the old one. If you do the removal and installation of the new one (which is where a good portion of time is), and give them the old rib to copy, it shouldn't be much to make a new one.
> 
> Then, hold it in place, and drill up from the outside of the hull (so you use the existing holes in the boat), then bolt or rivet the new one into place.
> ...



agreed. was the guy you paid to weld it up your buddy? if so id hang with your enemies it would save you some money.
i cant beleive the guy had the stones to ask you to pay for that. any welder i know and myself included would be ashamed to say that was my work. like bassboy said remove that rib and replace it using rivets and you should be good to go. good luck


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## richg99 (Nov 14, 2012)

Only issue I can see ( and I bow to the greater experience of our welder poster) is putting stainless bolts in, instead of using aluminum rivets or bolts. 

Dis-similar metals ( Stainless and aluminum) might not mix too well over the years. Rich


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## PSG-1 (Nov 14, 2012)

richg99 said:


> Only issue I can see ( and I bow to the greater experience of our welder poster) is putting stainless bolts in, instead of using aluminum rivets or bolts.
> 
> Dis-similar metals ( Stainless and aluminum) might not mix too well over the years. Rich



Correct. It could indeed pose a problem, if the boat is not maintained properly. It's more of an issue in saltwater, and this is why I always recommend my customers have me install a zinc anode on the hull of their boat, at the transom. The zinc should also be connected to a bonding wire, attached to the bonding wire of the engine, or directly to the negative terminal of the battery. 

Also, when using an aluminum boat in saltwater, it's a good idea to have a coat of suitable primer and bottom paint, such as Interlux Trilux 33. A coat of interprotect primer should be used before applying the antifouling paint, as it is rated for use below the waterline on all metals, it is a 2 part epoxy. 

WARNING! DO NOT USE CUPROUS OXIDE-BASED ANTIFOULING PAINT, IT WILL DESTROY THE HULL WITH ELECTROLYSIS. Use Cuprous Thiocyanate-based antifouling paint anytime it is in contact with aluminum.

Keep the bottom paint in good shape, maintain the zincs, and you can keep an aluminum boat in saltwater throughout the year, with no ill effects from electrolysis.


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## richg99 (Nov 14, 2012)

I'm afraid that ANY bottom paint, around here ....wouldn't last a single season. ( Texas saltwater flats, hundreds of miles of them). 

Oyster shell reefs abound, and they shift with the tides and currents. Running and drifting over five inch deep flats is a daily "opportunity".... We love it.....

Tons of aluminum jons here. Never seen one with bottom paint, but I have seen many with the original paint pretty well knocked off after a few years.

regards, Rich


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## jigngrub (Nov 14, 2012)

richg99 said:


> Dis-similar metals ( Stainless and aluminum) might not mix too well over the years. Rich



Is that why aluminum boat manufacturers use SS hardware to mount motor and accessories on their boats? So they'll corrode to pieces and you'll have to come back and buy another one... in 100 yrs?

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Fabricating another rib with 2 angles and a channel will be easy like others above have mentioned. I wouldn't worry about using .125 thickness angle, done properly .063 will be fine. Use closed end blind rivets for your fabrication.


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## richg99 (Nov 14, 2012)

I suspect that they use Stainless because of its strength. I wouldn't hang a big engine from an aluminum bolt of the same size either. rich


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## PSG-1 (Nov 14, 2012)

richg99 said:


> I'm afraid that ANY bottom paint, around here ....wouldn't last a single season. ( Texas saltwater flats, hundreds of miles of them).
> 
> Oyster shell reefs abound, and they shift with the tides and currents. Running and drifting over five inch deep flats is a daily "opportunity".... We love it.....
> 
> ...




Yes, my boat is also subjected to the same abuse, through commercial oyster harvesting, and anything else I can throw at it. And this is why I re-paint the bottom once a year. It's about 80 dollars a quart for Trilux 33, and it takes about 1.5 qts to do one of my 16 foot boats. So, I'm looking at about 250 dollars a year in paint, and then probably another 100 a year in zinc anodes. 

But, it's a lot cheaper than a new hull. Again, if the bottom paint and galvanic protection systems are properly maintained, an aluminum hull will last a long time in saltwater. But neglect either one, and the results ain't pretty.


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## Swampthing(True) (Nov 15, 2012)

Thanks guys for the advice!


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