# Pros and cons of aluminum decking vs plywood decking



## Jeffrey (Jan 27, 2013)

I wanted to expand the topic to say for riveted boat but couldn't.

I know that the aluminum would last forever and the plywood has a lifespan, but other than that...

I bought a riveted boat. This is my first aluminum boat so this is my first time.

I am trying to contain the cost of my mods so that my inexpensive boat doesn't wind up being an expensive boat. That being said, it looks like the plywood deck would be less expensive. But, by the time you apply the various coatings for rot and skid prevention, how close to the cost of aluminum plating will you get? I am still trying to figure out how best to treat the plywood. I don't think I want carpet, so it would be plywood with a nonskid surface applied.

Then there is the feel. When done right, would the plywood deck have as good of a feel as the aluminum? I really like the look of those aluminum decks, but maybe a well done wood deck would be as nice.

If I went the aluminum route, welding would be out of the question. I have never welded and dont have a tig welding machine. The tig welder would cost as much as several boats. I was looking at several aluminum brazing products online. They look interesting, but the demos show people working on small pieces. I don't know how well this would work when attaching aluminum angles to the hull or attaching aluminum decking to the ribs. Screwing or riveting might be a viable option. The riveting tools are inexpensive. Since the hull is riveted, I don't know if there is any reason why the decking and supports shouldn't also be riveted. 

There is also a middle ground. Could rivet an aluminum frame and the screw a wood deck to it. Plywood would be easier to cut.

I would like some advice from the more experienced boat builders on this site. I don't want a sentimental family keepsake as much as an affordable functional fishing boat. I will use this in shallow inshore saltwater flats and marshes, and will put a mudmotor on it.

Thank you!


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## tsaints1115 (Jan 27, 2013)

Another option, one I'm going with as I switch to aluminum, is a threaded nutsert or compression rivet. Drill the hole, insert the rivet and compression tool, after it's compressed you have a fitting that a screw can thread into to hold the aluminum down. Plus for maintenance you can unscrew the deck and reattach as needed.

As far as aluminum sheet and angle material check around for a metal suppliethatht carries used metal. Many times you can finreturneded material from someone that ordered extra. It's still new but sells at a used price. That's where I got all of mine at $2.50 a pound.


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## MrSimon (Jan 28, 2013)

I'm a big aluminum fan!

As you said, once you treat, seal, and paint plywood .... it costs about the same as a sheet of aluminum.

Old aluminum ladders make excellent bracing material. I've gotten a few 20 foot ladders off Craigslist for less than $20. Its a great option.

Riveting is the way to go ... with some nuts and bolts thrown in where you need them. A good rivet gun shouldn't be more than $50 and rivets are fairly cheap. 

Spend a lot of time sitting in your boat thinking and visualizing what you want .... then draw some pictures .... refine them .... and just get started.


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## MRichardson (Jan 28, 2013)

tsaints1115 said:


> Another option, one I'm going with as I switch to aluminum, is a threaded nutsert or compression rivet. Drill the hole, insert the rivet and compression tool, after it's compressed you have a fitting that a screw can thread into to hold the aluminum down. Plus for maintenance you can unscrew the deck and reattach as needed.



Now that sounds intriguing. Can you point me to a link/site for these? Or advise where I can find them?


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## Country Dave (Jan 28, 2013)

_
The pros and cons of aluminum vs plywood for decking are as numerous as the boats themselves. Ok that’s a bit of a stretch but there are many. Depending on the wood the usable lifespan for decking is going to vary greatly. The grade/quality of wood, the products that are used to treat it for bug infestation and rot and the environment they are going to be exposed to are the major factors. 

The funny thing about wood is it doesn’t rot underwater. Its only when the wood is exposed to moister and air does it start to delaminate. Wood is a great materiel to work with, it’s relatively easy to cut and shape, it’s strong, the cost is nominal and it will last a long time if properly cared for. However for the harsh marine environment its days are numbered. It has an expiration date and unfortunately there are too many variables to get an accurate estimate on its usable lifespan. For small or smaller boats wood is also heavy, especially after being sealed up in varnish or resin. Remember Thompson’s water seal and alike doesn’t play well with aluminum. If you don’t have some type of insulation between the treated wood decking and the aluminum the aluminum is going to degradate 

Aluminum has a much longer usable lifespan for decking but just like everything else it will not last forever. Remember the second law of thermodynamics. :LOL2: But as far as practical application, yes it’s probably going to last as long as you’re going to want it to. The down sides are ironically a mirror image of the upside of using wood, unlike wood it can be difficult to work with and it can be costly. What’s you’re application? Are you talking about covering an existing deck or just the floor? _


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## Jeffrey (Jan 28, 2013)

I am starting to like the idea of aluminum sheet metal for decking instead of those fancy tread plates. If sheet metal is good enough for the hull then why not for a false floor? Most people are already standing on the sheet metal hull anyway. I think I am going to use sheet metal and spray bed liner on it!


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## harleydoc (Jan 28, 2013)

One way to look at it is like this. Most of these old tins boat we are working on and replacing wood is over 25 years old with the wood for the factor that was not sealed the way we are sealing wood now. 25 years is a long time I don't see where it would be the same price metal vs wood. The metal would last forever but
Do you really need that Much time. I think wood would be just fine and a lot easyer to work with and if you mess up a cut a lot less money to buy new wood vs metal. And for carpet. Carpet is for the house leave it at that. I hate carpet in a boat it holds water.


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## tsaints1115 (Jan 29, 2013)

https://www.rivetsonline.com/

This is an online place but I got mine at Menards.


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## Jeffrey (Feb 2, 2013)

If I chose to go with a plywood floor, could I rivet it to the aluminum ribs, or would the rivets tear through the wood?


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## harleydoc (Feb 3, 2013)

Most people just use stainless screws to attach it. I don't see why you could not use rivets if you can find some that will be long enough to work.


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## RiverBottomOutdoors (Feb 4, 2013)

Go aluminum if you can. More expensive that's its only con.


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## Ictalurus (Feb 4, 2013)

Jeffrey said:


> If I chose to go with a plywood floor, could I rivet it to the aluminum ribs, or would the rivets tear through the wood?




I rivited my wood deck to the ribs, no issues and easy to remove if needed. I used 1/4" ply (over blue board) for the floor decks.


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## Jeffrey (Feb 16, 2013)

Ictalurus said:


> Jeffrey said:
> 
> 
> > If I chose to go with a plywood floor, could I rivet it to the aluminum ribs, or would the rivets tear through the wood?
> ...



Could you post a link to the blue board you used?

Was the blue board between the plywood and ribs or just between the ribs?

What did you coat the plywood with?


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## JMichael (Feb 16, 2013)

Jeffrey said:


> Could you post a link to the blue board you used?
> 
> Was the blue board between the plywood and ribs or just between the ribs?


The blueboard goes between the ribs. You get the thickness that makes the foam the same height as the ribs so your floor gets support from the ribs and the foam. Here's one example of the blueboard but it comes in different sizes and thickness. 
https://www.lowes.com/pd_14546-46086-202631_0__?productId=3050997&Ntt=blue+insulation+foam+board&pl=1&currentURL=%3FNtt%3Dblue%2Binsulation%2Bfoam%2Bboard&facetInfo=


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## Jeffrey (Feb 16, 2013)

The floor of my boat is 51" for most of its length. But, the ribs are 1.5" high. If my floor sits at the level of the ribs, it starts out at around 52.5" wide and narrows over the length of the boat.

If I go with standard size sheets of either plywood or sheet metal, then if I want each piece to span the entire width I will have to cut each piece longways and the have quite a bit of waste.

Do most of you will floors wider than 48" try to make each piece span the width or do you put bracing on the hull midways and have multiple pieces span the width of the boat?


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## JMichael (Feb 16, 2013)

I can't speak from experience since I don't have a boat that wide but one thing I noticed on a build that seemed like a great way to handle that situation. Move the floor material all the way to one side so that it's touching the side. On the other side where the floor is short, you install a rod locker or similar to hide that missing flooring or make it unnecessary.


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## Jeffrey (Feb 16, 2013)

That's using the ole noggin'.


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## Country Dave (Feb 16, 2013)

Jeffrey said:


> The floor of my boat is 51" for most of its length. But, the ribs are 1.5" high. If my floor sits at the level of the ribs, it starts out at around 52.5" wide and narrows over the length of the boat.
> 
> If I go with standard size sheets of either plywood or sheet metal, then if I want each piece to span the entire width I will have to cut each piece longways and the have quite a bit of waste.
> 
> Do most of you will floors wider than 48" try to make each piece span the width or do you put bracing on the hull midways and have multiple pieces span the width of the boat?




_Ok so if I understand this correctly your issue/concern is that standard cut plywood or aluminum sheet 4x8 or 48x96 inches will be ok length wise but will fall short by 3 inches because your floor is 51inches wide. What’s the spacing of your ribs? And what’s the length of the floor. 

If there is a rib that falls close to, or on the 4ft mark then make your cut on the center of it and butt your second peace up to it. I think it’s more wasteful to install a rod locker or storage box the length of the whole floor. I think that would be a heck of a lot more expensive just in material than a second piece of plywood or sheet of aluminum. Just saying. 

I mean if you can benefit from a rod locker or storage like that then it’s all good, but remember you just lost a whole bunch of floor space. I haven’t seen many rod lockers 3 inches wide. _


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## Jeffrey (Feb 16, 2013)

The width at the floor is 51". The width at the height of the ribs is 52.5" at the back of the boat and narrows as I go forward. I could have a welder tack channels where indeed them, so I could get extra supports. If I used a 48"x144" sheet of aluminum, I could get two pieces that are 52.5" to span the floor, and then have the waste. Maybe that is the way to go, but I could get a lot more efficient use of the sheet metal if I had a channel tacked in the middle and had two pieces of aluminum to span the width of the floor. I would have a seem in the middle, though.


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## Country Dave (Feb 16, 2013)

_Ok the width of the floor is 52.5 inches at the top of the ribs, got it. How about the spacing of the ribs? How many inches apart are they? If you measure from the front, or the rear does any one of the ribs fall on or near the 4ft mark? What is the length of the floor? _


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## Jeffrey (Feb 16, 2013)

Notice that as the ribs go up the sides that some are thicker than others. I can cut around this. I want the floor to extend 2" below the rear bench seat so that when I stand face the back of the boat, my toes will still be on the floor. With that in mind, here are the dimensions. Let me know if more pictures or measurements would be useful. And as always, thank you for the input.


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## Jeffrey (Feb 16, 2013)

I didn't mean for the pics to be sideways.

The spacing of the ribs is not uniform.


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## Country Dave (Feb 16, 2013)

Notice that as the ribs go up the sides that some are thicker than others. I can cut around this. I want the floor to extend 2" below the rear bench seat so that when I stand face the back of the boat, my toes will still be on the floor. With that in mind, here are the dimensions. Let me know if more pictures or measurements would be useful. And as always, thank you for the input.


_Ok Jeffery the pics are a huge help. I see it’s a modified V. A little tapered in the front and then it flattens out as it goes back. I’m not sure exactly what you mean by you want the floor 2” below the rear bench. Do you mean you want to raise the floor all the way up so it’s just 2 inches below the top of the bench like a Bass boat? 
Or you want the floor to be 2 inches up from the bottom of the bench? _


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## JMichael (Feb 16, 2013)

Country Dave said:


> Notice that as the ribs go up the sides that some are thicker than others. I can cut around this. I want the floor to extend 2" below the rear bench seat so that when I stand face the back of the boat, my toes will still be on the floor. With that in mind, here are the dimensions. Let me know if more pictures or measurements would be useful. And as always, thank you for the input.
> 
> 
> _Ok Jeffery the pics are a huge help. I see it’s a modified V. A little tapered in the front and then it flattens out as it goes back. *I’m not sure exactly what you mean by you want the floor 2” below the rear bench.* Do you mean you want to raise the floor all the way up so it’s just 2 inches below the top of the bench like a Bass boat?
> Or you want the floor to be 2 inches up from the bottom of the bench? _



As you move from front to back, once you arrive at the front edge of the rear bench, the floor continues and goes underneath the bench for 2 more inches.

Although once you put the floor in, I wonder if there will still be room for your toes between the floor and the bottom of the bench. It looks like it's going to be a tight squeeze once that floor is in.


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## Jeffrey (Feb 16, 2013)

Ok, I measured it. The bottom of the bench is 3.25" above the hull. The ribs are 1.5" high. If I used 1/16" sheet metal, then there would still be about 1.75" gap between the bottom of the bench and the floor. You wouldn't want to stick your entire foot in a gap that small, but you would still want the floor to go under the bench a bit so your toes would still be on something solid. If you dropped a hook or lure you lure you would want a bit of floor before it fell off the edge.


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## Country Dave (Feb 16, 2013)

Jeffrey said:


> Ok, I measured it. The bottom of the bench is 3.25" above the hull. The ribs are 1.5" high. If I used 1/16" sheet metal, then there would still be about 1.75" gap between the bottom of the bench and the floor. You wouldn't want to stick your entire foot in a gap that small, but you would still want the floor to go under the bench a bit so your toes would still be on something solid. If you dropped a hook or lure you lure you would want a bit of floor before it fell off the edge.



_
I would advise not having any gap. You would want the floor to come up all the way flush with the bottom of the bench. If there is a gab you could get your foot or anything else for that matter stuck in it. Not good, especially if you were running/underway. 

You have two choices, raise the floor up high enough to meet the front of the deck so there is no gap, or extend the front face of the bench down to meet the floor so there is no gap. You’re going to have to find a way to support your floor anyway. The ribs taper in at the center and you won’t have any floor support there. 

If you look at my build you can see that I laid horizontal supports to level the floor. What are you plans for making the floor level? _


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## Jeffrey (Feb 17, 2013)

Tell me if this is important or if I am worried about nothing. The aluminum hats that the ribs are made of have a height of 1.5" from the flange to the top of the hat, and the flange is 1/16". So, the total height of each rib is 1 9/16". If I used 1.5" square tubes or 1.5" channels against the bulkheads or between the ribs for additional bracing, it will be short by 1/16". If that 1/16" was far enough away it wouldn't matter, but since it will be right next to the ribs there will be a small gap when I lay the sheet metal floor on top. Do I need to fill this gap with something or will the sheet metal flex enough so that it doesn't matter?

Next question, should I have the welder tack square tubing or channels for the additional bracing? If I use square tubing, there will be a small but imperceptible gap below the channels where a film of water will collect, and if I use channel then the edges of the channel will be pressed into the hull.


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## Country Dave (Feb 17, 2013)

Jeffrey said:


> Tell me if this is important or if I am worried about nothing. The aluminum hats that the ribs are made of have a height of 1.5" from the flange to the top of the hat, and the flange is 1/16". So, the total height of each rib is 1 9/16". If I used 1.5" square tubes or 1.5" channels against the bulkheads or between the ribs for additional bracing, it will be short by 1/16". If that 1/16" was far enough away it wouldn't matter, but since it will be right next to the ribs there will be a small gap when I lay the sheet metal floor on top. Do I need to fill this gap with something or will the sheet metal flex enough so that it doesn't matter?
> 
> Next question, should I have the welder tack square tubing or channels for the additional bracing? If I use square tubing, there will be a small but imperceptible gap below the channels where a film of water will collect, and if I use channel then the edges of the channel will be pressed into the hull.




_Brother it’s so hard to try and figure things out from someone else’s description. If I was in front of your boat that would be a little different. I can tell you what I did to level my floor. The height of the ribs on my floor are 1.5 inches tall. The square tube I used is 1.5X1.5 The factory ribs don’t come in to play. I just used Stainless steel threaded rod and drilled through the ribs so I could attach my square tube. 
They are only the same height at the very end of the tube. I used garden house as an insulator so the bottom edge of the square tube would not rub into the floor. Hope that helps. Do a search on this site about installing or leveling a floor. I’ve seen some guys build nice wood supports but I’m not a big wood fan. _


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## Jeffrey (Feb 17, 2013)

Country Dave said:


> Jeffrey said:
> 
> 
> > Tell me if this is important or if I am worried about nothing. The aluminum hats that the ribs are made of have a height of 1.5" from the flange to the top of the hat, and the flange is 1/16". So, the total height of each rib is 1 9/16". If I used 1.5" square tubes or 1.5" channels against the bulkheads or between the ribs for additional bracing, it will be short by 1/16". If that 1/16" was far enough away it wouldn't matter, but since it will be right next to the ribs there will be a small gap when I lay the sheet metal floor on top. Do I need to fill this gap with something or will the sheet metal flex enough so that it doesn't matter?
> ...



If I am looking at this correctly. You have spanned the bottom of your boat with square tubing. I think you have a shallow v, similar to mine. What is the white I see? Did you paint or coat the bottom with something? Since you spanned the bottom with square tubing, then your floor will be flat instead of take the shape of the shallow v. I can't tell, but I guess the bolts holding the tube run horizontally?

Edit: I looked at your build out post. You put primer down. Looks good. I am still a bit confused about the whole corrosion issue with aluminum. I am not sure what sets up corrosion and what doesn't. One of the big selling points of aluminum is its corrosion resistance, but some conditions set up corrosion while others don't.


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## Country Dave (Feb 18, 2013)

_Good morning,

Yes my boat is a modified V hull like yours. The bow has a V and as it goes from bow to stern the hull flattens out. There is about 9°of deadrise or another way to put it is, the floor and transom has a slight tilt up from the center. Again about 9° 

I put down primer and paint on the floor before I put on the floor supports. I use my boats mostly in saltwater. If salt form a high salinity environment gets trapped against unprotected aluminum it will start to pit the aluminum. If you’re going to use your boat in only fresh water you should never have a problem. 

Once my floor is in I won’t be able access the boats original floor so that’s why I put primer and paint on it now. 
Another reason is, it helps keep the boat quiet. Between the steelflex on the bottom of the hull and the primer and paint on top of the floor it really helps with hull slap. 

As far as the floor goes, yes I want it flat. If anyone is going to go through the trouble of putting a floor in why would you not make it flat? Putting a floor down and having it taper in seems like a big waste of time, what’s the point?
I would rather just step over the ribs, just saying. Hope this helps. Good luck with your build. _


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## Jeffrey (Feb 18, 2013)

It seems then that you would need to put primer on the channels that support the new floor and the bottom of the new floor, also.

I am going to use my boat in salt water. Maybe I should put primer on the inside and steel flex on the outside.


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## Country Dave (Feb 18, 2013)

Jeffrey said:


> It seems then that you would need to put primer on the channels that support the new floor and the bottom of the new floor, also.
> 
> I am going to use my boat in salt water. Maybe I should put primer on the inside and steel flex on the outside.



_The bottom of the aluminum sheet of 0.90 that I will be using for my floor will get some self etching primer which is probably overkill. Water and moister will have a tendency to settle on the floor because of gravity it’s got no place to go from there. It’s really not going to be an issue with the floor supports however it certainly not going to hurt anything to put a little coat of something on them. _


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## Jeffrey (Feb 18, 2013)

Country Dave said:


> _
> Another reason is, it helps keep the boat quiet. Between the steelflex on the bottom of the hull and the primer and paint on top of the floor it really helps with hull slap.
> _



You have certainly given me a lot to think about! I didn't know before what all people did to set up their boats. Sounds like you really do it right.

What is the reason the steel flex on the outside and primer and paint on the inside make it more quiet?


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## Country Dave (Feb 18, 2013)

Jeffrey said:


> Country Dave said:
> 
> 
> > _
> ...


_


Yes, in addition to the steelflex being very hard, it insulates the hull and makes it quieter. Think of it like the coating on an M&M but obviously much harder. Sorry that was the only example I could think of right now, I’m tired. :LOL2: The steelflex is a two part epoxy that cures really hard, it really protects the bottom of the hull from debris in the water or if you run up on sand or an oyster bar or whatever. 

The primer and paint on the floor is to, as I mentioned before help protect the aluminum from corrosion and it also insulates noise. The hull is protected from both sides. Instead of having just a thin coat of paint from the factory it now has thick layers of primer and paint on the inside and a couple of thick coats of steelflex on the outside. 

Good luck with your build._


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## Jeffrey (Feb 19, 2013)

Country Dave,

My original plan was to put 1/16" aluminum sheet metal directly on the ribs, and put either 1.5" square tubing or channel against the sides to support it out there. I was going to have a welder tack the tubing or channel. You can see that every other rib on my boat is wide, so by the time I notch out for them I would need the extra support against the sides. So, I was going to have a floor that followed the shallow v. I can see that it would be pretty easy to have a totally flat floor. Just span the width of the boat with square tubing like you have done. It would cost more since I would be buying a lot more square tubing.

If it is still exposed, could you take a few close up pictures at different angles of how you bolted your tubing to the ribs? I would like to see a bit more detail of how you did it. It looks like you didn't bolt the tubes directly up to the ribs, but offset them a bit. Did you offset them to keep the tubing off of the rivets that hold the ribs down? I would like to see how you did that and how you have the garden hose. Also what kind of hardware you used and how (or if) you insulated the stainless steel from the aluminum.

Is there a limit that you try to maintain as to how far you are willing to span the sheet metal?

Thank you,

Jeff


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## Country Dave (Feb 21, 2013)

Jeffrey said:


> Country Dave,
> 
> My original plan was to put 1/16" aluminum sheet metal directly on the ribs, and put either 1.5" square tubing or channel against the sides to support it out there. I was going to have a welder tack the tubing or channel. You can see that every other rib on my boat is wide, so by the time I notch out for them I would need the extra support against the sides. So, I was going to have a floor that followed the shallow v. I can see that it would be pretty easy to have a totally flat floor. Just span the width of the boat with square tubing like you have done. It would cost more since I would be buying a lot more square tubing.
> 
> ...





_16th thick seams a little thin to me, unless you back it with something. If you have to span it any distance at all its going to flex. 
Q. Did you offset them to keep the tubing off of the rivets that hold the ribs down? 
A. No. This boat is all welded no rivets. I offset them because; the ribs have a taper to them. They are fatter at the bottom and narrow as the go up, not unlike most of my redneck bodies. :LOL2: If I butted the channel up flush with the ribs they would pull in and tilt when I tightened them down. 

Q. Also what kind of hardware you used and how (or if) you insulated the stainless steel from the aluminum.
A. I used stainless threaded rod stainless washers and nuts. You don’t have to insulate between them. The only thing that is less reactive with aluminum is plastic and that doesn’t make for very good fasteners. :LOL2: I hope you get my humor. I set the square tube in place and marked were I needed to drill so it would go through the rib. 
It was a major pain in the ass because; the angle is too tight to drill all of the way through. The drill didn’t have the clearance from the sides of the hull. I would take the tube out, drill through it lay it back in place and by hand with a small drill bit, go through the tube to mark the spot in the rib were I needed to drill, remove the tube and repeat and repeat and repeat. Like I said pain in the ass._


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