In the description of tents here in the site you will see the terms like a catenary cut or perimeter cut, so what is this really, what is catenary cut tent floor? I give a short description here so that I can use it tents’ reviews as a reference.
Catenary cut or perimeter cut vs bathtub tent floor
In the catenary cut, you have the tent’s floor and the walls’ material as separate pieces that are connected and stitched to each other along the perimeter of the floor. So from this, you realize why the term perimeter cut is used. One example of such a design you can see in this Coleman 8 Person Instant Camping Tent. Though the two terms are not synonyms in the strict sense; the catenary is a natural shape of a fabric or rope when it is fixed at its ends, while the meaning of the perimeter should be obvious.
On the other hand, in a bathtub floor design, the floor material goes above the perimeter, and you have seams along a line which can be 10 – 20 cm above the ground. In most cases, you can notice it because of the difference in the colors of the floor and the walls, see it for example here in the Coleman Red Canyon 8 Tent.
It is believed that such a design is better in the sense that you have fewer seams on the ground so the chances for leaking are reduced. But even in such a case, the floor usually has seams somewhere in its area, so there is no guarantee for a fully waterproof floor.
So in the catenary cut the edges are straight and typically this implies a better-defined floor area, while in the bathtub case you have a rather loose profile around the perimeter, and this in particular when there are no many stake-out points around the perimeter.
In some tents, you can have them both. For example along the longer sides you have the perimeter cut, and along the shorter sides you have a bathtub shape.
In fact, the catenary cut itself raises the seams above the ground, so it may act as the bathtub design. This is because of the natural shape of the fabric when fixed at the two ends, as I mentioned above. You can see it in practice in this Sierra Design’s small tent, it is at 0:58 in the video:
So which is better?
I do not think that there is a definite answer. If the tent floor has no seams in its main body (this is more likely to have in smaller tents), then it is better to have peripheral seams above the ground. So this would imply the bathtub style design. But in large family camp tents, you have a huge floor area and it is unlikely that it would be without seams; and perimeter seams would not make much difference in any case.
A catenary cut floor is a better design regarding the wind flapping, which is not only annoying and it may keep you awake, but it also makes stresses on the fabric and stitches.
So in general, with perimeter seams raised above the ground, you have a better waterproofness, while taut side seams imply a better wind protection and less flapping.
I shall be happy to hear from you if you can add some thoughts on this issue, there is a comment box below.