Cat Frame



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  • Cat Frame

    What is the narrowest you can go with a cat frame? Has anybody made one narrow and how did it perform? I have a Aire Leopard and was thinking about narrowing the frame for some of the smaller rivers and was wondering what was the narrowest you could go with one. Thanks

  • #2
    Narrow Cats

    Originally posted by 450HUNTER View Post
    What is the narrowest you can go with a cat frame? Has anybody made one narrow and how did it perform? I have a Aire Leopard and was thinking about narrowing the frame for some of the smaller rivers and was wondering what was the narrowest you could go with one. Thanks
    Years ago Jay Massey did this with his Panther catarafts he used on the Moose John River. That particular river is fairly narrow and choked with brush, sweepers and shoreline vegetation, so he wanted something more narrow than the standard configuration. I think his boats were about 18 inches narrower than the standard frame setups, and it served him well.

    On the extreme end, you can bring it together until the tubes touch if you like. With a Leopard this means you will be sitting on top of the tubes, rather than between them, but that's the way it is with the Cougar and the old Panthers anyway. This also eliminates one of your drop rails; you only need one, and you can secure the inner D-rings of each tube to it. If you go this way you will probably want a short vertical riser and a small crossbar for a foot brace, which can also be secured to the center rail.

    Now for the downside. When you narrow your cataraft, you compromise stability and safety. On rivers with swift current and midchannel obstacles, you increase your chances of overturning if you were to broach against something. This is because the boat has a very narrow footprint, instead of the normal stance. A Leopard with the tubes brought completely together will be 18' long and roughly 4'6" wide, which is, in my opinion, way too narrow.

    Another option that allows you to keep all your options is a removable section on each of your crossbars. I have a leopard with 18" removable segments on each of the crossbars, which allows me to narrow the boat quite a bit. But honestly I have never used that feature and never saw a need to. I had it built that way after I saw Jay's boats, and thought it would be a good idea. I guess I never floated a river that was narrow enough for it to matter much. That said, I have floated many places where each oar blade was on the bank in places, so....

    Lots to think about on this one. Alaska Raft and Kayak can do it for you.

    Michael Strahan
    Site Owner
    Alaska Hunt Consultant
    1 (406) 662-1791


    • #3
      Thanks Mike

      I have alot to think about on this and I plan on giving Tracey a call.


      • #4
        Another issue is that shorter oars will be needed for a narrower frame. If you go with the standard oar length split of 1/3 inside - 2/3 outside of the oarlocks, a 1' narrower frame will require oars about 3' shorter than normal. Although there are ways to reduce that difference.

        JoeG, who may chime in on this yet, has a Jacks Plastic Welding cat with a narrow frame and oarlocks mounted at the end of long extensions to enable normal length oars. JPW makes several of the narrow, personal cats that are often paddled like kayaks, but Joe's was a bit too large for this, so was fitted with an oar frame. After flipping a few times he built a wider frame, and seems to be happier with it that way.

        Years ago I split a four tube Aire Cougar into two cats, and made a new frame about 18" narrower than standard one. This was specifically to be able to use shorter oars in Sixmile Creek which is quite narrow in spots. I went from 10' to 8' oars with that frame. Then for unremembered reasons, I refitted the existing frame with 6" missing from it's width, and used 9' oars for that one. I ended up much preferring the wider frame, even for Sixmile. I found the added stability to be more important than the convenience of a narrower boat.


        • #5
          Frame Adjustment

          BMR did some work last year for a gent who needed to narrow his frame for the rivers he was running in New Zealand however that boat was far from the size and capaicty you are utilizing for your adventures. If memory serves me I think the length of his cat was 15ft of all things and was not a brand I reconginized.

          Any Who

          After we completed the project which was making the bars 25 inch inside to inlcude the knuckles we did a trip on the Lower Gulkana from Sourdough Down to see what issues needed to be resolved. As Jim stated first noticable issue was oar length however for normal Claass I water it handled fine. Mind you I would not have used it to carry a load nor oar class IV type water but for basic rafting / fishing normal Class I it was fine IMO.
          OBWT we also shorten the upper frame to match the hatch so to say.

          After you work out your details feel free to give BMR a shout if you require assistance. I have no problem assisting in something fun during the winter that is after hockey this weekend.



          • #6
            I talked to Tracey today and he said it wouldn't be a problem at all. He said I could narrow it up to only 12-16 inches in between the tubes and be fine/safe. We also talked about the oars and think that can be taken care of with out a issue.

            Tracey has helped me out alot with my raft and went out of his way to help me so I trust his word. I will probably be giving this a go and test it out some during the summer before hunting season.


            • #7
              Oar length correction

              I said, "...a 1' narrower frame will require oars about 3' shorter than normal." But since narrowing the frame by 1' only moves each side in by 6", the oar should be about 1.5' shorter than normal.

              BTW, one way to change this a little is to raise or lower the oarlock a bit and use the oar in either a steeper or shallower angle. You can only do so much of that though, and if you move far away from the 1/3 - 2/3 split you either gain or loose leverage. I find that very light boats can use close to a 1/4 -3/4 split, and very heavy boats might be better served with a split nearer to 1/2 - 1/2.


              • #8
                width between oar locks and oar length

                From the cataraft man himself Madcatr Dave Nissen on some advice to me on building cataraft frames,

                The oar lock should be at 17- 20deg. of of vertical and about 67" - 69"center to center for 9' oars and over 70" for 10' oars.

                Do the math on the proportions (width : oar length) and follow accordingly when reducing the width to determin oar length.

                This has served me well with a cat that is 31 inches inside width. However, I am guessing that the closer one approaches to zero width betwen the tubes (especially for long tubes) this proportion trick falls apart.


                • #9
                  I would like to narrow mine to 18"-24" inside the tubes.


                  • #10
                    Give me a shout

                    450 Hunter I will be back next week and in the shop on Friday. Give me a shout I think I have enouhg spare none schedule 40 and none anodized pipe, as well as used Lo Pro's laying around to play with for such a project for planning purposes.

                    After you tweek to yor comfort zone i.e. oar length etc you will have your plans for the real deal.

                    I will PM you some pictures of a couple of frames that have been modified for particular reasons so you will have a reference that is if you wish.

                    Blue Moose


                    • #11
                      Thanks BlueMoose
                      I'll try to get in touch with you.


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