# Need Help Fabricating Cataraft Frame



## Felton45 (Jan 19, 2016)

Hey everyone, I am in need of some serious help and information from everyone. I am trying to get my first cat and Ive been looking at used ones and just cant seem to really find anything that suites what I wanna do. I am a Welding fabricator, I do mostly tig welding at work everyday 5 days a week and I have all the equipment to make a cataraft frame. With that being said I dont really have very much knowledge about cataraft frames, and I know most everyone is going to recommend going with a NRS frame or buying my first frame. But i dont see the point in doing that when I can cut the cost of the frame down by a lot if I do all the work myself. Plus it would be a fun little side project. I plan on using either 1 1/4 sch40 6061 t6 aluminum or 1 1/2 sch40 6061 t6 aluminum and I plan on having a full floor to have something stable to stand on while fishing. I am planning on getting 14' tubes. Since I have never really looked at a cataraft up close I need help with all the dimensions. I researched around quite a bit but didnt quite find everything I need. So I was wondering if I could get some of you to post your cataraft frame dimensions on here so that I can get started on mine in about 2 weeks. I was planning on running like 9.5ft oars so I am guessing around 66 wide frame would be good? How far between the tubes should I do? And whats a good length on 14' tubes? Anyone have any recommendations on fabrication design? I was thinking of putting in diamond plate floors and having one cooler and on dry box for storage, any other ideas? I only wanna have to build one frame, so Id like to do it right the first time. Has anyone ever gotten their frames rhino lined? At my shop right now we have an aluminum structure and a big base that all got sent out and got rhino lined and came back super nice. It is crazy tuff stuff and I was wondering why I have never seen it on catarafts? Any ideas would be greatly appreciated! 14' cataraft owners, i need dimensions and pictures if your willing to help me out. Thanks again everyone!


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## mattman (Jan 30, 2015)

I don't have a 14' cat, but 66" is pretty standard width for a 14' raft frame. 9.5' oars is about right for a boat that size. Tube diameter will play a big roll in your ideal frame, once you buy your tubes, setting up your frame will be a lot easier. 

Probably the best way to determine distance between tubes is to build your frame to fit the cooler and dry box you want to use provided they are a reasonable size for the tubes you have, 120Qt cooler is pretty normal for 14' boats, for instance.
Basically you want the rails of your frame to line up on the center line of your tubes, wider is ok, but not narrower.

If you are able to add a bay for some rocket boxes, or water jugs, it would make your rigging easier, a row of rockets can be a nice place to strap a table. Also, having slots to strap down a rocket box on each side of you is handy for the floor.

Check out the" let's see them rigs" thread on this site using a search, lot's of pictures to give you ideas there.
And you can also get ideas for dimensions from the web sites of oar frame and cat manufacturers.

Good luck on your frame, hope this helps some.


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## festivus (Apr 22, 2006)

*frame*

My 2 cents

I think 6061 is a mistake as it is limited in its ability to bend. Having rounded corners is more important on a cat frame than a raft. Consider 6063 instead. Having welding skills is a big plus but you need a good bender as well like a jd2. 

Size your frame based on your tubes. The rocker may limit the practical length of a frame on one boat vs another. You really need to think hard and long on a 14ft cat as to where your going to put your passenger... as in behind you or at the front. It is critical to know what you will be carrying, because a unbalanced cat is a real drag to row.

If you will not have passengers, a shorter frame is nice because you can shift the frame on the tubes. A trailer with a short day frame is a nice way to have versatility here.

Welding can be a liability for your first frame if you do to much of it because you will be wanting to change the dimensions or move the towers frequently. Consider some tees on side bars for adjustability, and do not fix your towers.

Also, to much floor is a mistake on a cat. Weight is a critical factor, as a heavy cat quickly becomes a pig to row.


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## k2andcannoli (Feb 28, 2012)

I'd stay away from rhinos lining, the frame rubs the top of your tubes. Just some sand and small rocks in there and you can do damage to your tubes, I imagine rhino would be hard on your rubber. If you want her to be pretty, just get it powder coated.

If this is primarily a fishing frame, you'll want a much different set up than if you just ran rivers. In addition to the floor, you'll want to think about thigh hooks to get you stable when standing, an anchor, a place to dress fish, rod holders, and a place to keep the fish you catch.


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## Rockgizmo (May 21, 2009)

I went with 1-1/4" pipe. The support pipe is 1" 6061. All the straight pipe is 6061. The bent pipe is all 6063. I had the frame built to fit a 14' cat 22" diameter tubes. The frame is 66" wide with 38" btwn the tubes.





















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## Felton45 (Jan 19, 2016)

Thank you everyone on your input so far! Every bit of information helps a ton! Mattman- I plan on running 25" diameter tubes and thank you for the suggestion and tips, I like your idea of building the frame to fit exactly what you want on there. Festivus- Thank you very much for your input and advice. I was thinking in the beginning of just using 6061 and instead of doing rounded corners I was gonna do two 45 degree angles to make a 90. I saw one guys frame like that and I thought it looked pretty good that way. Does that not work very well? Do I need to do rounded corners? K2andconnoli- Thanks for the info, that makes total sense! rhino lining is very ruff and your probably right, it would wear on the tubes a ton. I will look into powder coating! Rockgizmo- Great pictures and very nice frame! Thank you very much, I love the idea of the 6063 for the bent pieces and 6061 for the straight pieces, I also love the 1" tube for the bracing. Is that 1" tube plenty strong enough? Thank you very much everyone, great full help11


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## Felton45 (Jan 19, 2016)

This is the frame that had the 2 45 degree joints to make a 90 degree. I am either going to do that, or I might go with the 6063 just for the bent pieces like Rockgizmo did. Is there any pros or cons between the rounded corner and the 2 45's?


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## Felton45 (Jan 19, 2016)

Rockgizmo said:


> I went with 1-1/4" pipe. The support pipe is 1" 6061. All the straight pipe is 6061. The bent pipe is all 6063. I had the frame built to fit a 14' cat 22" diameter tubes. The frame is 66" wide with 38" btwn the tubes.
> View attachment 10962
> View attachment 10963
> View attachment 10964
> ...


Rockgizmo, I noticed you put some gussets under some of your joints, was that to help add strength to that joint? Or is it for the tube to kind of sit on those gussets?


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## caverdan (Aug 27, 2004)

IMHO, the 45's work the same way as rounding it with a bender. I have frames built both ways. The thing you don't want is a sharp corner you can hurt yourself on when pushing or loading. 

I have a 14' NRS cat. IMHO, The big thing with cat's are balancing your load proper. You can't just throw everything in and go, like with a raft. The other biggie is not getting it too heavy that the floor ends up really close to or under water. As soon as the floor hits the water......it turns into a slug. The higher you make the floor......the more wieght you can haul and still maneuver

Good luck. That blue frame is pretty sweet looking.


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## Rockgizmo (May 21, 2009)

Felton,

Marshall welding used to make frames like the pic you posted. I know a few boaters who row them and love it. As for the rounder corners I like them for strapping the frame down. Not sure if it makes a difference just more welds. 

I had DRE weld the frame up to my design. I added the 1" and gusset to added for strength. 


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## mattman (Jan 30, 2015)

The point about needing to load cats properly is so true, I thought I new how to load my boat until I got an 11' cat! Being off on weight in any direction is really noticeable with a cataraft.

Like the 25" tubes, that extra floatation will help keep maneuverability as you add weight.
There will be more wind drag, but the right choice, especially for a 14' boat, IMO.

Nice frame Rockgizmo!!


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## Felton45 (Jan 19, 2016)

Thanks guys. I think Im going to go with the two 45 degree corners just because my shop doesnt have a tube roller. We got everything but a tube roller lol, we even have a plate and angle roller just not a tube roller. We have a press break that Im going to use to make a dry box. Does anyone know what grade aluminum people usually use for dry boxes? I know you have to get a certain grade so that it doesnt crack when you press break it. I also read going perpendicular with the grain helps it to not crack on the corner. Can anyone post any pics of their dry boxes so I can get some ideas for mine please? Another main dimension I need is how low to put the floor? Id assume the higher the better. But it also has to be low enough to hold the tubes on there good right? Im gonna run 25" diameter tubes, how low should my floor be?


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## k2andcannoli (Feb 28, 2012)

Length of your down rails is pretty important, in addition to the things you mentioned, you also need to make sure your d rings on the tubes you are buying will be correctly positioned. Otherwise you might throw your frame on your tubes and then have one hell of a hard time strapping it down because your rails will be to close/ on top of your d rings. Since you're going with 25" diameter you'll probably be fine because they are just so big, but on my 11.5'x19" it was an issue.


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## Rich (Sep 14, 2006)

Lots of good advice so far. My 2 cents:

-I am a big believer in welded frames, HOWEVER, the advantage of the fence rail/fitting frames is you can experiment with the fit and geometry.
Make your seat and oar towers adjustable IF, you have more than one size person using the frame OR, unless you are 100% positive on the size/geometry. My frame is adjustable because I am 5-10 and my daughter is 5-3. Looks like Rockgizmo has adjustable seat and oar towers.

-A welded in diamond plate floor might be a good idea for a fishing boat but a bad idea for a Class IV+ whitewater boat. One idea is a removable plywood floor. Makes frame more versatile and much lighter for moving and storage. 

-Just to avoid confusion: 1 1/4" Sch 40 is 1.66" O.D. and 1 1/2" Sch 40 is 1.9" O.D. Might be appropriate sizes for loaded fishing rig, but I am using 3/4" Sch 40 (O.D.= 1.05") for a whitewater boat and 3/4" 6063 is very bendable with a $80 tube bender (6" radius). The double 45s on the top frame create 2x4 more spots where a weld rubs a boat tube. You probably need to use bends for the bottom rails anyway so you will have to find somehow to bend tube. Several fabricators in Denver quoted $10/bend.

Good luck with your project!


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## Osseous (Jan 13, 2012)

Who's building your trailer? 
You set out to build a cat you could handle by yourself- without a ramp. If that's what you really want, ditch the diamond plate and the dry box. Weave your floor out of seat belt webbing. It's stiff and stable, drains instantly in whitewater and won't ruin flylines when you or your angler steps on them. You can wear studded wading boots without falling on your ass or tearing up the floor. A dry box on a fishing cat is just a place to put too much shit and weigh you down. Use a small dry bag instead- or buy an 80-100 qt cooler and use it as a forward seat. There will be plenty of room inside for beer and a small dry bag of necessities. Keep it SIMPLE. Keep it LIGHT. 

Forward station can have a cooler seat and a woven floor with a leaning post for your angler. If that's detachable, your boat can be rigged for solo use, or add the station when you have a partner along. I take the leaning post along and attach it to the front of my rowing station when I'm solo. Light is Right.

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## J (Nov 6, 2003)

Check out rowframe.com. he's got diagrams, like e drawings, etc of cat frames with measurements.


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## jamesthomas (Sep 12, 2010)

Since your a fabricator without a bender check out whitewater machine works stuff. I think his rowing module with plug and pin extensions are pretty awesome. The ultimate in flexibility. Really lightweight too. Never touched one but the concept seems sound.


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## Felton45 (Jan 19, 2016)

Great information everyone! Thank you so much! K2andconnoli- Thanks for the input. Now that you mentioned that I think it would be a wise idea to order my tubes and get them here to make sure any part of my frame doesnt get in the way of those d rings. Rich- Very valuable information! So your cat has 3/4" sch 40? Does it seem sturdy? Do you know what most manufacturers use for their frames? I do know that I will be the only one rowing and but like you said Im not 100% on the size/geometry so it is a great idea to keep somethings movable. Do you know if they make anything to set in between cataraft frames and the tube so that welds wont rub on the tubes? Osseous- Great advise! I already own 2 trailers and I will be setting one of them up to haul/store the cat. But i have read that its easy to overload a cat and they suck to row overloaded so I do need to keep in mind to keep things light! J- Thanks for the link, Ill check it out. Hopefully i can find a dimension for floor depth. Keep the ideas coming guys, feel free to post what you have and things you like or dislike about certain set ups. Once I start building my cat Ill keep everyone updated on progress and will upload pictures so you guys can see how it turns out. Thanks for all the help so far!


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## Osseous (Jan 13, 2012)

In all things human powered- light is right

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## Rich (Sep 14, 2006)

3/4" Sch 40 works for my use which is very lightweight, Class IV+ with tough access and occasional portage. Generally solo day trips but also works for 3-5 nights (Middle Fork/Selway). There is a trade off of strength and weight. 3/4" is .39 lbs/lf and 1.5" is .92 lbs/lf.

Most pipe fitting frames are 1.25 to 1.5" Sch 40.
Most welded frames are 3/4" to 1" Sch 40
I am not an engineer, but I believe most 1.25/1.5 frames are over built.
And a welded frame will be stronger than a frame with fitting with the same diameter aluminum tube.

My most important point is to assess what uses you will be doing.
If always fishing with trailer and boat ramp, a heavy boat is ok.
But whitewater with tougher access requires a lighter boat.


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## mttodd (Jan 29, 2009)

With regards to drybox material. I believe most are using .080 thick 5052 sheet. I've built some out of .100 material, but you really don't need it that thick. I would recommend 1.25 pipe as it is plenty strong and gives you the ability to use bolt on trinkets and oar locks that nrs sells.


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## SpeyCatr (Aug 14, 2013)

You could always build your base welded frame out of 1 1/4" aluminum (1.66" OD) so you can use the clamp on NRS oar towers to start and after using them for a while you can fine tune the sweet spot front to back and height wise with them to find that good rowing geometry then you can add welded on oar towers later (if you decide to ditch the NRS oar towers). If you buy the taller NRS towers - 8" is probably good to start unless you're planning on rowing form something taller than a seat - you can push them out to lower them if they are too tall. Just a thought anyways...


You wouldn't be out much money as if you decide to use them to start you can sell them later.


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## mattman (Jan 30, 2015)

I'm a big fan of going with a removable plywood floor, saves ya weight, some cost maybe,
and adds versatility, lot's of people love there diamond plate floor, but I have also heard the complaint that it was hard on the eyes.


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## tallboy (Apr 20, 2006)

I built mine out of 1.5" EMT and had it powdercoated. Super easy to bend all the corners with a conduit bender and it has held up great. It is on an 18' cat, the main rowing frame is 8.5' and the trailer frame is 3' It weighs just over 100 lbs, (the equivalent aluminum frame with all the crossbar fittings weighs almost as much but is more $$$)

The dimensions for mine were based on the AIRE Leopard D ring placement and the Yeti 120 cooler I had. I would look at what you want to haul and if you plan on taking it on any longer trips and go from there. My cooler is 40" wide so I ended up making the frame 44" between tubes. This has been really nice to have the extra space in width (storing rocket boxes and water jugs sideways). It is 10" deep and I made the top outside dimension a little wider than it needed to be for a 27" tube just in case. Your cat will handle like a pig if you make it too deep and overload it...frame dragging in water is muy malo.

Spend the time geeking out now, use a program like sketchup and dimension all of your boxes so you can see how they will fit. Its well worth the effort so you know what works and what doesn't. Believe me, ending up 1/2" too narrow will make you kick yourself.


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## CURTO (May 27, 2010)

A little help here, I'm in the process of welding up a Cat frame, I have 24" tubes, what is a good distance for the drop down rails, 8" seems too small?
Thanks CurtO


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## DRL River Gypsies (May 19, 2010)

Hey Curt!


I typically go 9" center to center on the drop but that's typically 21-23" diameter tubes. With 24", I typically go 10" or 11" but I wouldn't want to go anymore than that. A major consideration is the inside D-ring height on your tubes. Some of the Aire and RMR tubes have a pretty high inside D-ring location limiting your floor drop. 


Good luck and let me know if you need any help. THANX, Dusty


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