Fish Cat Float tube

Hello, new member here, first post. This is my first "v" tube. Is that a correct term for the Fish cat?

So, I find a extreme deal on a used Fish Cat. It is in very good shape. Older model, no fabric fading or stains. In fact, very few rub marks on the pvc bottom!

When I bought the tube. The pontoon type bladders did not extend to the end in front or back, and the skin was wrinkled at the the Boston valves. Watched a video online from Aire. Worked the bladders into place, by filling with air and deflated several times, that is now fixed. Boat fills from stem to stern.

What is a issue is the foam seat. There are two foam seat blocks, measuring width 17 3/4" x 19 3/8" in length. The seat area the foam slides into measures 19" across, measured from where the seat material is stitched to the bladder pocket on each side (stitch seam to stitch seam of the seat box). With the fish cat deflated, and seat foam installed in the 17 3/4" width, the seat foam slides into the seat box with no effort, due to the 1 1/4" gap between seat box dimension and foam width. Even with the boat fully inflated (thumb pressure allows 1/2" of depression at the middle of each pontoon bladder, per the Aire website) neither foam block is wedged in tightly, still sloppy by 3/8" on each side of the seat foam. Will slop from side to side, and will slide out of the seat pocket if the seat back straps were not attached.

Remove the seat foam, turn the seat block and install the 19 3/8" width into the seat box. Now the foam must be hammer fist punched into place. Just like shown in the (Aire Youtube) Fish Cat seat foam installation video. But then, the seat foam seam is pointing the wrong direction. I don't understand why the 17 3/4" width fits very tightly when installed in the video. Yet, mine is so sloppy. I confirmed my seat foam was the correct size (with aire), and it is. Now I am curious about the seat box width.

What to use to widen the seat foam to fit tightly in the 17 3/4" width?

Also, I have searched all criteria on this site, regarding seat sag or the "taco" effect. I am looking for those that have made mods to the seat foam to eliminate the "taco" of the seat. And to install the foam in the correct orientation, but take up the 1 1/4" of width. As it is, the bladders want to suck in when sitting in the seat, until the 3/4" gap (3/8" each side x 2) is gone. Then the seat taco's to further complicate the inward compression of the pontoon air bladders.

What does your seat box width measure on the fish cat or fat cat compared to mine at 19"? Aire claims both the fish cat and fat cat seats use the same seat foam, and same air bladder. I can't imagine how the seat foam performs when the max rating of 300+ pounds is reached in the fat cat.

My thoughts are to find a boogie board (made of closed cell foam?) with a 1" width. Cut that to match the height and length of the foam seat (4 1/4 -3/8" x 19 3/8"). Slide one each 1" thick x 4 3/8" wide x 19 3/8" long piece along each side of the seat foam. There would be an extra 3/4" in overall width (19 3/4" seat foam, 19" seat box). Hopefully, the foam compression rate of the boogie board will allow for easy installation. But still be similar with the seat foam. With the tight fit, fully air filled bladders would do some compressing. That would solve the fit issue. But what to do about the seat sag? Built a frame out of pvc pipe, that grabs each pontoon and extends under the seat area? Use a piece of plywood, in a thickness that offers support. But not adding much weight?

Welcome to the board MotoBoat. Like you, many of us have FC4. Which model do you have? From the description of two foam blocks, it could either be the older model FC4 LS, or FC4 LCS, which I do have. The foam measurement for mine is 19" square, which I have modified with an air cushion, using Komori's suggestion. Of course, if there was any extended wear, or exposure to high temp (not necessarily directly, but indirectly such as the trunk of the car/attic space/outdoor storage bin), the material tends to stretch under tension.

The foam block as the seat should be tightly pushing against both bladder's walls, preventing that taco effect, which I do know what you're talking about for my older tubes. If you cannot find any supporting sized foam block, or your boogie board does not sufficiently provide sidewall supports to prevent the taco effect, you may have to use PVC frame structuring for the front and back of the existing foam block to keep the V-tube from concaving inwards. Using PVC is the only way to prevent increase of total weight, but with very low rigidity. Using plywood is great as sidewall shimmy, but the surface is rough unless you coat for smoothness, but also waterproofing. Even with a few small pieces of plywood, that shouldn't add more than 5lbs of total weight if that's required for.

U did say it's an older tube so maybe Asianguy is on to something. It's quite possible the tube stretched thus the sloppy free play. Time to mod.

Why use wood? Ever think about picking up a cheap plastic cutting board? I figure you're just looking to make it more rigid correct?

Asianguy, I do not now what model I have. The boat simply say's fish cat on the side. Is dark blue in color. Perhaps the most important information besides color, is this tube is a 03 model (based on serial number). If your seat foam is 19" square, that tells me that was the seat foam size at one point, before evolving to the standard size of 17 3/4" x 19 3/8". Which, matches my seat box measurement! And, your tube being an older one like mine, this makes sense. Is your seat foam 1 piece or two?

What is your seat box width measurement?

I did see your foam seat mod. Found that very interesting. I am hesitant to do that mod for two reasons. 1) Major issue: Access to the inflation/deflation valve, for seat comfort adjustment, or warm day expansion/contraction issues. 2) Minor issue: Rather than having a foam/air seat hybrid. My thought is to have the foam seat intact, and a air bladder seat for hiking with this tube.

I have an assortment of air seats from 2 man inflatable rafts. In various shapes and sizes. One fits perfectly into the seat back. Having the same top curve as the foam, fills the seat back in L, W, and H being slightly over size for the space. I could not believe how lucky that was.

Have you done a PVC mod to the seat? Or, that is what comes to mind if undertaking the mod? I have 1/2" of extra width, above or below the seat foam for placing wood, plastic, pvc pipe......ext.

Kin, I have entertained a plastic cutting board or thick piece of plexiglass. The cutting board idea was tossed when I gave that a bend test, not very rigid, and therefore no real advantage except for filling space.

The pvc inside the seat box is out due to space restrictions. This leaves outside the seat box, and from below.

This leaves the plywood. I did a bend test with a 1/2" x 19" x 20". I get 3/4" deflection with full body weight. That is really good! Aggressive surface and edge sanding would solve any roughness issues.

But am hoping for solutions others have used to successfully solve the taco. Be it wood or other material.

Is the taco effect based on occupant weight? Seams some have the issue, some do not. Or it does not bother some, others it does.

Thanks for your responses!

The taco effect is pretty much a combination of weight and tube design. The more rigid the frame, the less you'll have the taco affect (why some tubes have a cross bar in front while others do not).
I'm thinking that a cutting board should be able to give you a better cross bar effect (sandwich the foam inserts between two cutting boards to your desired specs?). The wood idea is great, but it's heavy and would suck to have it get waterlogged/splintered.

I have space on the sides and top of the seat foam. Are you suggesting cutting board material for sides to take up the 1 1/4". And, sandwich the top and bottom of the seat foam with the same material, for the crossbar effect?

Interesting............

I feel you don't need it along the sides, just space out the two foam pieces you have with the 1 1/4 difference between the two.
[foam]1 1/4" space [foam]
top and bottom cutting board or some other hard piece.

Are you putting weight on the tube sitting on the ground or are you putting weight on it with the tube in actual water? There's a difference between the two. Hope you factored that into your arrangements.

Yellowrock wrote:Are you putting weight on the tube sitting on the ground or are you putting weight on it with the tube in actual water? There's a difference between the two. Hope you factored that into your arrangements.

I am glad you asked. I have not had the tube in the water as of yet. Only weight tested the tube on the floor in the house. How does the seat sag differ in water vs on land? I had assumed the seat had some floatation properties. But not enough to offset 230lbs of occupant weight.

Before purchasing the tube I had read online where many had issues with the foam seat taco effect, seat sag with the Fish Cat, Fat cat, Togiak, Cumberland.