# new to forums / building a cat frame



## riverjunkie (Aug 5, 2013)

hi everyone, been browsing the forums for a long time getting info.and finally decided to sign up.so i just started rowing rivers about 2 months ago in my cheap fishing pontoon. iver done some 12hr floats in the main wilamette and lower mckenzie, but dont trust my setup to hold up to actual white water and i want something i can carry someone on. i wanna be able to do the mfnf willamette and upper mckenzie when my rowing skills get better, for fly fishing. and like everyone im short on cash but have the ability to bend / build my own cat frame with 1"X.065 seamless steel tubing and have my dad or a friend weld it for reasonably cheap ( wholesale tubing prices ). i think i want a 14' cat maybe the rmr tubes. but have never been in a cat and have nothing to design it off of. or i could build it like on the games with frames post.do anyone have any preferences on welded vs modular. and do i have to have the tubes to design the frame? and would 1"x.065 seamless tubing be too weak.
thanks for any input, and sorry for the long post


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## MT4Runner (Apr 6, 2012)

You'd probably enjoy 14' tubes if you want to do multidays. You can do multidays or overnights on 12' tubes if you pack light.

If it's mostly for day trips, a 12' cat would be more fun.

I'm new to cat boating, too. Been kayaking 15 seasons, rafting 11, just took my first cat run yesterday.  It's a blast. Waaay more maneuverable than a raft, not quite as maneuverable as a kayak, but doesn't take nearly as much skill.


I'd go with 1 1/4" tubing for a bit more stiffness/strength for your crossbars, or double up your 1" for more strength (make a tunnel hull/truss between the tubes).

0.065" would be a very appropriate wall thickness for steel.
I built mine from 1 1/4" EMT conduit, which is about 1.5" and ~0.065" wall. Standard precautions apply about welding galvanized. 

Here's some info on painting:
http://www.mountainbuzz.com/forums/f15/1-3-8-emt-pipe-for-frame-build-42884-2.html#post330040

These are sick:
Vortex Pictures









So are these.
MADCATR Creations - Custom Fabricated Stainless Steel and Aluminum Rafting Equipment


Best ideas are:
Tunnel Frames
Spread out foot bars (as opposed to both feet together in the middle)
Adjustable oar towers
Folding Oar towers
Scout bars/footrests

You do not need the tubes to design the frame.

My preference is modular for a cargo boat. Fullsize and fully welded is just too huge for storage or transport.
Could go breakdown or welded for a play frame...your call. If you want a lot of fine details, it's probably easier to go welded instead of breakdown/modular.


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## cataraftgirl (Jun 5, 2009)

The one thing you might need to have the tubes up front for is depth of your drop rails. If you know your tube diameter and where the D-rings are placed that helps a lot. Too deep on the drop with higher placed D-rings on smaller diameter tubes can cause problems....not enough room for proper strap placement.
Example - I had 14 X 22 tubes. I was using a welded steel frame with only a 9 inch drop, and that was fine. Switched to an NRS frame with 11 inch drop, and the drop rail was very close to the D-rings, which made getting the strap tight enough a problem. If it were me, I'd get the tubes first. It would suck to spend a lot of time building a frame and then find out that it doesn't quite fit the tubes you really want. Especially if you're on a budget, and your tube choices might be limited.


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## MT4Runner (Apr 6, 2012)

cataraftgirl said:


> The one thing you might need to have the tubes up front for is depth of your drop rails. If you know your tube diameter and where the D-rings are placed that helps a lot. Too deep on the drop with higher placed D-rings on smaller diameter tubes can cause problems....not enough room for proper strap placement.
> Example - I had 14 X 22 tubes. I was using a welded steel frame with only a 9 inch drop, and that was fine. Switched to an NRS frame with 11 inch drop, and the drop rail was very close to the D-rings, which made getting the strap tight enough a problem. If it were me, I'd get the tubes first. It would suck to spend a lot of time building a frame and then find out that it doesn't quite fit the tubes you really want. Especially if you're on a budget, and your tube choices might be limited.


Fair comment.

Mine are 14' x 25" Maxxon tubes, and my 12" drop rails barely clear the D-rings.

Worst case, ask around about D-ring placement on here for the type of tubes you prefer and people could measure theirs...do it before winter hits and folks store their tubes! :lol: ...or ask the vendor.


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## riverjunkie (Aug 5, 2013)

Thanks for the replys,I like the idea of the modular frames because I live in a duplex with a small garage.and it seems like it would be nice to be able to add bays / change the configuration especially since I don't know how I'd like mine setup.it'll mostly be used for flyfishin, but I want the option to be able to carry a passenger for day trips. And the tubing I'm talking about would be hyd steel tubing with an actual 1" od.does tubing get stiffer in larger diameters even tho it has the same wall thickness? nd I've read so much stuff on the internet about tubes that it hard to decide which tubes will be good for summer time fly fishing,and taking someone on the water.like I said I'm new to this so I'm sure I won't be doing and crazy whitewater for awhile.thanks again


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## MT4Runner (Apr 6, 2012)

riverjunkie said:


> hyd steel tubing with an actual 1" od.does tubing get stiffer in larger diameters even tho it has the same wall thickness?


Very much so!!!

1.5" is over twice as stiff as 1". 
2" is 4x as stiff.

A pop can is stiffer than 1", but you need a minimal wall thickness...for ding resistance. Ding that pop can and your 1" x 0.065 is now a lot stiffer!! :lol:



> I've read so much stuff on the internet about tubes that it hard to decide which tubes will be good for summer time fly fishing,and taking someone on the water.like I said I'm new to this so I'm sure I won't be doing and crazy whitewater for awhile.thanks again


If you don't do a tunnel frame, 1" would be fine.
Build it and learn from it. Go fishing!


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## riverjunkie (Aug 5, 2013)

Lol,thanks again mtr4runner. Now you got me thinking bout using 11/4. Lol which I could still probably build the welded frame for under$400. I was just trying to be a cheap a$$ and build it for under 200. Btw how do you like you're maxxon tubes? The only reason I was thinking bout going 14ft was cause the Rockymountains only came in 14' & 16'. Nonetheless whichever route will be a good experience and test of craftsmanship. Does anybody have some frame dimensions for a 12 or 14ft cat.


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## MT4Runner (Apr 6, 2012)

Just a fishing frame? Go cheap ass. You need to start somewhere. If you know you might build again in the future, don't worry so much about this one. Do your best and learn from it. Maybe it will be great. Unless it's really poor, it will at least be good.

Rockymountains are welded PVC and 5yr warranty.

Maxxons are glued PVC and no warranty, but they're dirt cheap. They come in 12', 14' and 16' flavors. My 14' tubes were only $800. It was an inexpensive way to get a taste for cat boating. With an NRS floor, I'm into my entire rig for ~$1,100 (I had oars/oarlocks).

I set my inside tube spacing based on the NRS floor--40.5" from outside loop to outside loop. Tubes went out from there. With 25" tubes, I'm:
40.5" + 25" = 65.5" center to center
65.5" + 25" = 80.5" outside to outside.

Tube diameter is more important for frame dimensions than tube length.

Frame length really depends on how much (or how little) storage space you want on your cat.


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## riverjunkie (Aug 5, 2013)

Did you go with the extra diameter maxxons? And does anyone know how far I would want the drop rails / floors for my cat to be if it had say 22"diameter tubes? was thinking 11" should be half way and then minus ~3 -4" for the straps to cinch down. Also does it matter if the frame goes over the outside of the tubes. Srry for the bombardment of questions I'm just trying to prepare myself,so I can do this right. And does anyone have any good sites for getting the rest of the accessories like seats,oars,oarlocks and everything else I'll need. Thanks again


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## MT4Runner (Apr 6, 2012)

Yes, I have the 25" dia Maxxons.


Your cat floor will get shallow quickly. Losing 3-4" will be too much if as little as 2" will do.
Pencil in 9-10" drop and check if your intended tubes/drings will accommodate that.


You get what you pay for with accessories. NRS has everything, but not necessarily the best of everything. Other vendors have more limited selection of higher quality goods. Several vendors for custom soft goods (bags and straps) and dryboxes.


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## cataraftgirl (Jun 5, 2009)

riverjunkie said:


> Did you go with the extra diameter maxxons? And does anyone know how far I would want the drop rails / floors for my cat to be if it had say 22"diameter tubes? was thinking 11" should be half way and then minus ~3 -4" for the straps to cinch down. Also does it matter if the frame goes over the outside of the tubes. Srry for the bombardment of questions I'm just trying to prepare myself,so I can do this right. And does anyone have any good sites for getting the rest of the accessories like seats,oars,oarlocks and everything else I'll need. Thanks again


The frame needs to have an adequate length of drop bar inside the tubes for structural support. The top rails should rest on or just barely past (outside) the center line of the tubes. If you are building a double top rail frame, then the outer rail can be a little wider. Just make sure that between the inner & outer rails that they rest firmly on the tubes. I ran into trouble on 22 inch tubes when I switched from a 9 inch drop to an 11 inch drop frame. The drop rails were too close to the D-rings and it made strapping difficult. It worked, but wasn't optimal. Plus it didn't leave much clearance between my rower floor/cooler/dry box and the water. One other thing to think about. You say you want to use this cat for fishing, which means you will probably want floors to stand on. With larger diameter tubes, and deeper drop rails, it's easier to stand up. Smaller tubes + shallower drop = slightly harder to stand up. For those of us who have crappy knees, this is important. 

I'll try to attach photos of my two cat tube sizes to show the difference. You can really see the difference in pictures #2 & #3. Teal boat is 24 inch tubes, red boat is 22 inch tubes. Picture #4 shows my original 9 inch drop modular frame on the 22 inch tube boat. You can see how shallow the drop rails are.

Hope this info helps. My advice would be to get the specs on a couple different brands of tubes you like & can afford, then map out your frame. Just know that when you get the tubes & frame together you'll have some tweaking to do. Hard to get it perfect the first time. I'd look at either NRS or Cascade Outfitters to shop for your basic gear. Also check out backcountry.com once you know what you want, as they often have really good sales on stuff, especially oars at the moment. If you ever want custom sized soft goods, like drop bags, look at Stitches-N-Stuff, Jan is awesome to work with. Most important have fun & be safe on the river.


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## richp (Feb 27, 2005)

Hi,

Do something like this and you can adjust infinitely the amount of drop, even if you change tube sizes.

FWIW.

Rich Phillips


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## cataraftgirl (Jun 5, 2009)

richp said:


> Hi,
> 
> Do something like this and you can adjust infinitely the amount of drop, even if you change tube sizes.
> 
> ...


Nice use of the NRS parts. You've solved my biggest pet peeve with the NRS cat frame....... too much flex on the lower rail. I like that center cross brace with the speed rail fitting. Any trouble with the LoPro rubbing on the tube? I assume that you lengthen or shorten the LoPro piece that extends down from the cross bar to determine your drop depth. Cool idea.


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## Avatard (Apr 29, 2011)

richp said:


> Hi,
> 
> Do something like this and you can adjust infinitely the amount of drop, even if you change tube sizes.
> 
> ...


Except for three problems

1) crossbar is cutting into your clearance, especially if this is done on the ends of the frame where the tube profile provides less buoyancy

2) that homemade yoke weighs about 4lbs more than it should

3) it looks like the low pros will gouge into the tubes


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## riverjunkie (Aug 5, 2013)

Thanks everyone again for your input,greatly appreciated.
Catarafgirl-yea you can see a big difference,it looks like the frame is skimming the surface. 
Richp-I like the design of the frame,going with a modular frame seems like the way to go.
And is it gonna make a big difference structurally if I don't go with the bent rails that go from top rails to bottom, that conform to tubes.( not sure what there called ). And instead just make a straight 90 design from top to bottom rail.sorry for the crappy explanation, don't know how to describe better.


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## MT4Runner (Apr 6, 2012)

riverjunkie said:


> And is it gonna make a big difference structurally if I don't go with the bent rails that go from top rails to bottom, that conform to tubes.( not sure what there called ). And instead just make a straight 90 design from top to bottom rail.sorry for the crappy explanation, don't know how to describe better.


Yokes.

Not an enormous structural penalty, but triangles are stronger than rectangles. You can add gussets for strength.

Remember, every adjustable/modular joint adds weight.


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## catflipper (Jun 22, 2011)

Bunch of good ideas. An additional thought is that a lot of people go with a smaller core frame and add cargo modules for additional capacity. In your situation that might allow for 2 smaller fully rigid frame pieces that are still portable. Not sure how that would work for fishing - where do you envision your passenger sitting?


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## riverjunkie (Aug 5, 2013)

I've seen those cargo modules in pics and always wondered how they attached to the frame lol.and I was thinking I would want to sit near the middle and have my passenger up front,but having never rowed a cat idk what's best for handling. My main purpose will be fishing but I want to be able to do some local whitewater with my gf, and son when he's older and I'm more experienced.which brings up another question,would having a couple solid standing platforms limit my whitewater abilities? I was thinking about welding some kind of channel along the length of the bottom rail, into which I could slide a standing platform in and out and secure with some bolts when being used for fishing.I know one boat can't do it all,but the reason I've decided to go with a cat is they seem like the safest / most versatile way to be able to run whitewater / be able to fish.in my reading experience it seems like ppl are always talking bout spots where drift boats sink or can't go that rafts and cats easily slide through. Thanks again


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## orto11 (Mar 8, 2013)

Canyon is doing modular frames now that have a lo-pro style welded on them so they don't fill with water and freeze. They are a stronger and lighter tubing than the NRS frames, the fittings are also almost half the weight .They can custom build you any accessory or bar configuration.I guess they had enough requests for frame kits they are going to start sending out kits for people. 

You just order the width or accessories and they come all welded up so no bolts or pipes filling with water, then you can assemble at home or move as desired

I ordered this bar from them so my cooler bay was adjustable on my old frame to sell it. They also make aluminum floors that attach to the NRS style frame


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## Osseous (Jan 13, 2012)

riverjunkie said:


> I've seen those cargo modules in pics and always wondered how they attached to the frame lol.and I was thinking I would want to sit near the middle and have my passenger up front,but having never rowed a cat idk what's best for handling. My main purpose will be fishing but I want to be able to do some local whitewater with my gf, and son when he's older and I'm more experienced.which brings up another question,would having a couple solid standing platforms limit my whitewater abilities? I was thinking about welding some kind of channel along the length of the bottom rail, into which I could slide a standing platform in and out and secure with some bolts when being used for fishing.I know one boat can't do it all,but the reason I've decided to go with a cat is they seem like the safest / most versatile way to be able to run whitewater / be able to fish.in my reading experience it seems like ppl are always talking bout spots where drift boats sink or can't go that rafts and cats easily slide through. Thanks again



You're on the right track.... but remember, everything in boating is a compromise. Figure out what your priorities are- and where you're most willing to accept those compromises. Go a little bigger than your first inclination, because cats begin to lose their advantages QUICKLY as weight/draft increase. I've had 3 boats in 3 years as a result- and my current rig is essentially just what you're looking at doing. 14'x23" Sotar ST cat.... DRE custom frame that I designed. I have a rowing section with a rear bay for gear and a place to mount my anchor drop. Front section is modular- attached with two split speedrail fittings. It "drops on" when I need it. This front section is a cooler for a seat (Engel 80) and a standing section/leaning post. For floors, I bought 1 1/2" polyester seat belt webbing and weaved them. These floors are rigid to stand on, drain instantly, light weight- and cheap to make. They're also forgiving when you hit a rock.

For me, this design allows a pretty hard core solo whitewater boat- that I can lift and handle alone. It's incredibly agile rigged for just myself on a whitewater day. When I have a partner, it transforms into a custom fishing craft- perfect for a rower and single angler. I wouldn't want to row it with two anglers- it would be a complete pig.


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## riverjunkie (Aug 5, 2013)

Osseous said:


> You're on the right track.... but remember, everything in boating is a compromise. Figure out what your priorities are- and where you're most willing to accept those compromises. Go a little bigger than your first inclination, because cats begin to lose their advantages QUICKLY as weight/draft increase. I've had 3 boats in 3 years as a result- and my current rig is essentially just what you're looking at doing. 14'x23" Sotar ST cat.... DRE custom frame that I designed. I have a rowing section with a rear bay for gear and a place to mount my anchor drop. Front section is modular- attached with two split speedrail fittings. It "drops on" when I need it. This front section is a cooler for a seat (Engel 80) and a standing section/leaning post. For floors, I bought 1 1/2" polyester seat belt webbing and weaved them. These floors are rigid to stand on, drain instantly, light weight- and cheap to make. They're also forgiving when you hit a rock.
> 
> For me, this design allows a pretty hard core solo whitewater boat- that I can lift and handle alone. It's incredibly agile rigged for just myself on a whitewater day. When I have a partner, it transforms into a custom fishing craft- perfect for a rower and single angler. I wouldn't want to row it with two anglers- it would be a complete pig.






I really like the idea of Two separate frames,and seen a design like that on the jpw site.I think that's the route I'm going to end up going.cause welding a frame up with 1" 
Tubing is gonna be a hellve lot cheaper right now than buying speed rail fittings and emt. I think 100' of tubing will be enough and I can buy that for under $200 and my time spent is well worth the savings in my mind.
Anyone have any ideas on frame width I was thinking 60" or so maybe even 50" for fishing smaller water but don't know if that's gonna cut into stability.


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## Avatard (Apr 29, 2011)

14' boat? 66" frame will probably still allow a 120qt cooler, and will fit a 38" drybox. Use 9' or 9.5' oars


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## MT4Runner (Apr 6, 2012)

riverjunkie said:


> Anyone have any ideas on frame width I was thinking 60" or so maybe even 50" for fishing smaller water but don't know if that's gonna cut into stability.


You need to search some old frame discussions and do some more reading.

Your stream-of-consciousness questions are only going to get you limited answers from a few people. I could tell you everything I know, and you're still only going to get one person's perspective. There have been some great multi-page discussions in this forum about frame width, bay sizing, etc. Read a bunch of them.


Search suggestions:

oar length
frame width
oarlock height
tube size
bay size
rower's bay


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## riverjunkie (Aug 5, 2013)

avatard- your post brought up a good point to me, i didnt even think about cooler spacing.

mtr4runner-im just trying to get more opinions to my questions,i probably should search somemore for old threads. just a hellve lot easier to ask.but i guess like all good things in life nothing is easy.thanks again for all your input.

i am going to sit down and start to draw out a frame design, and print / study more designs of frames i like.thanks again everyone for the input i really appreciate it, and sorry for the endless questions i know the frames not gonna come out perfect the first time i just like to over-prepare


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## laterwagged (Sep 29, 2011)

riverjunkie said:


> avatard- your post brought up a good point to me, i didnt even think about cooler spacing.
> 
> mtr4runner-im just trying to get more opinions to my questions,i probably should search somemore for old threads. just a hellve lot easier to ask.but i guess like all good things in life nothing is easy.thanks again for all your input.
> 
> i am going to sit down and start to draw out a frame design, and print / study more designs of frames i like.thanks again everyone for the input i really appreciate it, and sorry for the endless questions i know the frames not gonna come out perfect the first time i just like to over-prepare


If you are close to Portland, take a trip down to Andy & Bax with a tape measure. They have several fully rigged Cats/rafts in the basement. You can get a pretty solid idea of what you want.


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## cataraftgirl (Jun 5, 2009)

laterwagged said:


> If you are close to Portland, take a trip down to Andy & Bax with a tape measure. They have several fully rigged Cats/rafts in the basement. You can get a pretty solid idea of what you want.


Excellent idea. Nothing beats looking at something in person.


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## riverjunkie (Aug 5, 2013)

I live in Eugene / Springfield area so it's about a 2hr drive. But My girl is always wanting to go to the malls up there,could be a good excuse to stop by lol.


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